Outer space

Lunar Eclipses: What Are They; When is the Next One?

2014-11-04T07:59:00.001-08:00

Skywatcher and photographer David Paleino snapped this view of the total lunar eclipse of June 15, 2011 from Italy using a Fujifilm FinePix S2000HD camera.
Credit: David Paleino

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Lunar eclipses occur when Earth's shadow blocks the sun’s light, which otherwise reflects off the moon. There are three types — total, partial and penumbral — with the most dramatic being a total lunar eclipse, in which Earth’s shadow completely covers the moon.

The last lunar eclipse was on Oct. 8, 2014. [Related: Blood Moon Photos: Total Lunar Eclipse Thrills Skywatchers]

The next lunar eclipse is on April 4, 2015. It will be a total eclipse, best seen from the Pacific Ocean and bordering regions in the Americas, Asia and Australia.

Throughout history, eclipses have inspired awe and even fear, especially when total lunar eclipses turned the moon blood-red, an effect that terrified people who had no understanding of what causes an eclipse and therefore blamed the events on this god or that. Below, you’ll find the science and history of lunar eclipses, learn how they work, and see a list of the next ones on tap. [See also our guide to Solar Eclipses.]

This montage of images taken by skywatcher Kieth Burns shows the Dec. 20, 2010 total lunar eclipse. The photos won a NASA contest to become an official NASA/JPL wallpaper for the public.
Credit: NASA/JPL-via Kieth Burns

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What is a lunar eclipse?

A lunar eclipse can occur only at full moon. A total lunar eclipse can happen only when the sun, Earth and moon are perfectly lined up — anything less than perfection creates a partial lunar eclipse or no eclipse at all. Some understanding of simple celestial mechanics explains how lunar eclipses work. [Infographic: Total Eclipse of the Moon]

Because the moon’s orbit around Earth lies in a slightly different plane than Earth’s orbit around the sun, perfect alignment for an eclipse doesn’t occur at every full moon. A total lunar eclipse develops over time, typically a couple hours for the whole event. Here’s how it works: Earth casts two shadows that fall on the moon during a lunar eclipse: The umbra is a full, dark shadow. The penumbra is a partial outer shadow. The moon passes through these shadows in stages. The initial and final stages — when the moon is in the penumbral shadow — are not so noticeable, so the best part of an eclipse is during the middle of the event, when the moon is in the umbral shadow.

Total eclipses are a freak of cosmic happenstance. Ever since the moon formed, about 4.5 billion years ago, it has been inching away from our planet (by about 1.6 inches, or 4 centimeters per year). The setup right now is perfect: the moon is at the perfect distance for Earth’s shadow to cover the moon totally, but just barely. Billions of years from now, that won’t be the case.

Types of lunar eclipses

Total lunar eclipse: Earth’s full (umbral) shadow falls on the moon. The moon won’t completely disappear, but it will be cast in an eerie darkness that makes it easy to miss if you were not looking for the eclipse. Some sunlight passing through Earth’s atmosphere is scattered and refracted, or bent, and refocused on the moon, giving it a dim glow even during totality. If you were standing on the moon, looking back at the sun, you’d see the black disk of Earth blocking the entire sun, but you’d also see a ring of reflected light glowing around the edges of Earth — that’s the light that falls on the moon during a total lunar eclipse.

Partial lunar eclipse: Some eclipses are only partial. But even a total lunar eclipse goes through a partial phase on either side of totality. During the partial phase, the sun, Earth and moon are not quite perfectly aligned, and Earth’s shadow appears to take a bite out of the moon.

Penumbral lunar eclipse: This is the least interesting type of eclipse, because the moon is in Earth’s faint outer (penumbral) shadow. Unless you’re a seasoned skywatcher, you likely won’t notice the effect.

The blood-red moon

The moon may turn red or coppery colored during the total portion of an eclipse. The red moon is possible because while the moon is in total shadow, some light from the sun passes through Earth's atmosphere and is bent toward the moon. While other colors in the spectrum are blocked and scattered by Earth’s atmosphere, red light tends to make it through easier. The effect is to cast all the planet's sunrises and sunsets on the moon.

The moon turned a blood red over the Sossusvlei Desert Lodge on NamibRand Nature Reserve in Namibia in this stunning photo taken by skywatcher George Tucker on June 15, 2011.
Credit: George Tucker

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"The exact color that the moon appears depends on the amount of dust and clouds in the atmosphere," according to NASA scientists. "If there are extra particles in the atmosphere, from say a recent volcanic eruption, the moon will appear a darker shade of red."

Christopher Columbus leveraged a blood-red eclipse in 1504 to frighten natives on Jamaica into feeding him and his crew. It was on Columbus’ fourth and final voyage to the New World. An epidemic of shipworms ate holes in the ships of his fleet; Columbus' was forced to abandon two ships. He then beached his last two on Jamaica on June 25, 1503. The natives welcomed the castaways and fed them. But after six months, Columbus’ crew mutinied, and robbed and murdered some of the Jamaicans, who had grown weary of feeding the crew.

Columbus had an almanac that foretold a lunar eclipse on Feb. 29, 1504. He met the local chief, and told him the Christian god was angry with his people for no longer supplying food. Columbus said to expect a sign of God’s displeasure three nights later, when He would make the full moon appear "inflamed with wrath." When the blood-red moon came to pass, the natives were terrified and “with great howling and lamentation came running from every direction to the ships laden with provisions,” according to an account from Columbus’ son.

Just before the total phase of the eclipse was about to end, Columbus said God had pardoned the natives and would bring the moon back. The crew was well fed until help arrived in November and Columbus and his men sailed back to Spain.

When is the next lunar eclipse?

Here is a schedule of upcoming lunar eclipses:

April 4, 2015: Total eclipse. Visible from the Pacific Ocean and bordering regions in the Americas, Asia and Australia.

Sept. 28, 2015: Total eclipse. Visible from eastern Pacific Ocean, Americas, Europe, Africa, western Asia.

March 23, 2016: Penumbral eclipse. Visible from Asia, Australia, Pacific Ocean, western Americas.

Sept. 16, 2016: Penumbral eclipse. Visible from Europe, Africa, Asia, Australia, western Pacific Ocean.

This photo of the total lunar eclipse of Dec. 20, 2010 by Jimmy Westlake shows the blue edge to Earth's shadow set against the reddened moon.
Credit: Jimmy Westlake

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Dwarf Planet Pluto: Facts About the Icy Former Planet

2014-11-04T07:58:00.002-08:00

Some craters and other surface features spotted on Pluto by NASA's New Horizons probe in 2015 may end up bearing the name of "Star Trek" characters, as this screenshot from a Google+ Hangout demonstrates.
Credit: SETI Institute (via Google+/YouTube)

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Pluto is the only dwarf planet to once have been considered a major planet. Once thought of as the ninth planet and the one most distant from the sun, Pluto is now seen as one of the largest known members of the Kuiper Belt, a shadowy disk-like zone beyond the orbit of Neptune populated by a trillion or more comets.

Pluto was reclassified as a dwarf planet in 2006, a change widely thought of as a demotion that has attracted controversy and debate that has continued in scientific communities for the last eight years.

American astronomer Percival Lowell first caught hints of Pluto's existence in 1905 from odd deviations he observed in the orbits of Neptune and Uranus, suggesting that another world's gravity was tugging at them from beyond. He predicted its location in 1915, but died without finding it. Its discovery came in 1930 from Clyde Tombaugh at the Lowell Observatory, based on predictions from Lowell and other astronomers.

Pluto is the only world named by an 11-year-old girl, Venetia Burney of Oxford, England, who suggested to her grandfather that it get its name from the Roman god of the underworld. Her grandfather then passed the name on to Lowell Observatory. The name also honors Percival Lowell, whose initials are the first two letters of Pluto.

Physical characteristics

Since Pluto is so far from Earth, little is known about the planet’s size or surface conditions. Pluto has an estimated diameter less than one-fifth that of Earth or only about two-thirds as wide as Earth's moon. The planets’ surface conditions probably consist of a rocky core surrounded by a mantle of water ice, with more exotic ices such as methane and nitrogen frost coating its surface. NASA’s Hubble Space Telescope also revealed evidence that Pluto’s crust could contain complex organic molecules. Chemicals such as nitrogen and methane may lay frozen beneath the icy crust.

Pluto's orbit is highly eccentric, or far from circular, which means its distance from the sun can vary considerably and at times, Pluto’s orbit will take it within the orbit of the planet Neptune. When Pluto is closer to the sun, its surface ices thaw and temporarily form a thin atmosphere, mostly of nitrogen, with some methane. Pluto's low gravity, which is a little more than one-twentieth that of Earth's, causes this atmosphere to extend much higher in altitude than Earth's. When traveling farther away from the sun, most of Pluto's atmosphere is thought to freeze and all but disappear. Still, in the time that it does have an atmosphere, Pluto can apparently experience strong winds.

Pluto's surface is one of the coldest places in the solar system at roughly minus 375 degrees F (minus 225 degrees C). For a long time, astronomers knew little about its surface because of its distance from Earth, but more is coming, bit by bit, with the Hubble Space Telescope returning images of a planet that appears reddish, yellowish and grayish in places, with a curious bright spot near the equator that might be rich in carbon monoxide frost. When compared with past images, the Hubble pictures revealed that Pluto had apparently grown redder over time, apparently due to seasonal changes.

This is the most detailed view to date of the entire surface of the dwarf planet Pluto, as constructed from multiple NASA Hubble Space Telescope photographs taken from 2002 to 2003.
Credit: NASA, ESA, and M. Buie (Southwest Research Institute)

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Orbital characteristics

Pluto's highly elliptical orbit can take it more than 49 times as far out from the sun as Earth. It actually gets closer to the sun than Neptune for 20 years out of Pluto's 248-Earth-years-long orbit, providing astronomers a rare chance to study this small, cold, distant world. So after 20 years as the eighth planet (in order going out from the sun), in 1999, Pluto crossed Neptune's orbit to become the farthest planet from the sun (until it was demoted to the status of dwarf planet).

Composition & structure

Atmospheric composition: Methane, nitrogen

Magnetic field: It remains unknown whether Pluto has a magnetic field, but its small size and slow rotation suggest it has little to none.

Chemical composition: Probably a mixture of 70 percent rock and 30 percent water ice.

Internal structure: Probably a rocky core surrounded by a mantle of water ice, with more exotic ices such as methane and nitrogen frost coating its surface.

Credit: Karl Tate, SPACE.com

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Orbit & rotation

Average distance from the sun: 3,670,050,000 miles (5,906,380,000 km) — 39.482 times that of Earth

Perihelion (closest approach to the sun): 2,756,902,000 miles (4,436,820,000 km) — 30.171 times that of Earth

Aphelion (farthest distance from the sun): 4,583,190,000 miles (7,375,930,000 km) — 48.481 times that of Earth

Pluto's moons

In 1978, astronomers discovered Pluto had a very large moon nearly half its size, dubbed Charon, named for the mythological demon who ferried souls to the underworld in Greek mythology. The huge size of Charon sometimes leads scientists to refer to Pluto and Charon as a double dwarf planet or binary system.

Pluto and Charon are just 12,200 miles (19,640 km) apart, less than the distance by flight between London and Sydney. Charon's orbit around Pluto takes 6.4 Earth days, and one Pluto rotation — a Pluto day — also takes 6.4 Earth days. This is because Charon hovers over the same spot on Pluto's surface, and the same side of Charon always faces Pluto, a phenomenon known as tidal locking.

While Pluto appears reddish, Charon seems grayish. Scientists suggest Pluto is covered with nitrogen and methane while Charon is covered with ordinary water ice. In its early days, the moon may have contained a subsurface ocean, though it probably can’t support one today.

Compared with most of solar system's planets and moons, the Pluto-Charon system is tipped on its side in relation to the sun. Also, Pluto's rotation is retrograde compared to the other worlds — it spins backward, from east to west.

In 2005, as scientists photographed Pluto with the Hubble Space Telescope in preparation for the New Horizons mission — the first spacecraft to visit Pluto and the Kuiper Belt — they discovered two other tiny moons of Pluto, now dubbed Nix and Hydra. These are two to three times farther away from Pluto than Charon, and they are thought to be just 31 to 62 miles (50 to 100 km) wide.

Scientists using Hubble discovered a fourth moon, Kerberos, in 2011. This moon is estimated to be 8 to 21 miles (13 to 34 km) in diameter. P4's orbit is between the orbits of Nix and Hydra. On July 11, 2012, a fifth moon Styx, was discovered, fueling the debate about Pluto’s status as a planet.

The four newly spotted moons may have formed from the collision that created Charon, hurled away from Pluto by the gravity of the massive moon.

Research & exploration

Pluto's distance from Earth has made it hard to see with telescopes and a daunting challenge to explore with spacecraft — NASA's New Horizonsmission will be the first probe to study Pluto, its moons, and other worlds within the Kuiper Belt. It was launched on January 2006, making its closest approach to Pluto on July 2015, and carries some of the ashes of Pluto's discoverer, Clyde Tombaugh.

The limited knowledge of Pluto creates unprecedented dangers for the exploration. Prior to the mission’s launch, scientists only knew about the existence of three moons. The discovery of Keberos and Styx during the spacecraft’s journey fueled the idea that more satellites could orbit the dwarf planet, unseen from Earth. Not only the moons, but the debris fields they may have created, could prove hazardous to New Horizons.

'Interstellar' Sneak Peek: We Have Seen It, and It's Awesome

2014-11-04T07:58:00.000-08:00

A theatrical poster for the space epic "Interstellar," which is directed by Christopher Nolan and stars Matthew McConaughey (shown here). The film will be released throughout the United States on Nov. 7, 2014.
Credit: Paramount Pictures

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LOS ANGELES — All the buzz around the upcoming space epic "Interstellar" is understandable. The film is a great ride — big, bold, loud, dramatic and visually stunning.

The crowd at the TCL Chinese Theater here in Hollywood for a sneak-peak viewing on Thursday (Oct. 23) — a collection of journalists and actors who got an invite and fans who waited in line for ages to get in — soaked up "Interstellar" throughout its nearly three-hour running time, even erupting in cheers at several key points during the film.

In short, the feeling inside the theater seemed to be that "Interstellar," which will hit theaters nationwide in the United States on Nov. 7, doesn't disappoint despite its considerable hype. ['Interstellar': A Space Epic in Pictures]

That hype stems partly from the film's star power. "Interstellar" was directed by Christopher Nolan, who has helmed a number of commercially and critically successful films, including "Memento," "Inception" and the "Batman" Dark Knight trilogy. And it features big-name actors such as Matthew McConaughey, Anne Hathaway, Jessica Chastain and Michael Caine.

The subject matter of "Interstellar" is also responsible for some of the excitement, especially among space fans. As the film's trailers have shown, a series of crises on Earth are driving humanity toward extinction. So McConaughey's character, Cooper, leads a small band of explorers in a search for an exoplanet that could serve as a new home for our species.

This intergalactic search is aided by a journey through a wormhole — a sort of tunnel through the fabric of space-time that allows relatively rapid travel between two widely separated points. "Interstellar" also features stunning depictions of spaceflight, alien worlds and what its creators say is the most accurate visualization of a black hole ever accomplished in a mainstream movie.

In fact, the film's black hole is so visually realistic that scientists could learn a thing or two from it, said renowned theoretical physicist Kip Thorne, one of the executive producers of "Interstellar."

"We're going to write several technical papers about this — one aimed at the astrophysics community and then something for the computer-graphics community — saying, Here are some things we've discovered about gravitational lensing by rapidly spinning black holes that we never knew before," Thorne said in a video produced by Wired magazine that was released last week.

Keep checking back in with Space.com for more news about "Interstellar," including a full review and an analysis of the science in the film.

Interestingly, "Interstellar" comes out on the same day (Nov. 7) as another movie of interest to space-science fans — "Theory of Everything," a biopic about famous astrophysicist Stephen Hawking.

See Elusive Planet Mercury Before Dawn Saturday

2014-11-04T07:57:00.003-08:00

Mercury will be best placed for Northern Hemisphere observers on Nov. 1, 2014 just before sunrise. It will be visible for a few days before then, and for a week after.
Credit: Starry Night software

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Although Mercury is one of the brightest objects in the sky, even the most dedicated stargazers rarely see the innermost planet because it is usually so close to the sun.

This week is one of the rare opportunities when Mercury is relatively easy to spot. It will mean getting up before the sun, but once spotted, you will be able to follow Mercury until it is drowned out by daylight.

All apparitions of Mercury are not created equal. Because of the tilt of the ecliptic — the path that the planets follow across the sky — the inner planets, Mercury and Venus, are much higher in the sky at some times than others. The best times to see Mercury, if you live in the Northern Hemisphere, are March or April evenings and October or November mornings.

This year, Mercury reaches greatest western elongation from the sun on Saturday (Nov. 1). This means that Mercury is as far as it can get in a westward direction from the sun as it rises over the eastern horizon. I’ve found the best time to spot Mercury is about half an hour before sunrise.

The easiest way to find Mercury is to sweep just above the horizon with binoculars. The brightest star on the eastern horizon will be Arcturus. Mercury will be below Arcturus and well to its right. Once spotted in binoculars, you should have no trouble locating it with your unaided eyes.

If you point a tracking telescope on Mercury, you will be able to continue to observe it as it climbs in the sky, followed by the sun. This is the best opportunity to detect the faint markings on Mercury’s surface, which are usually lost because of Mercury’s brilliance and low altitude. Seen higher against a bright sky, these low contrast markings become more evident.

Even so, they will challenge even experienced observers because of Mercury’s small angular size. The best most of us can hope to see in a telescope is Mercury’s phase: like Venus and the moon, Mercury goes through a series of phases. On Saturday, it will look like a miniature "last-quarter moon."

Ebola Outbreak May Hold Lessons for Handling Samples from Mars

2014-11-04T07:57:00.001-08:00

Centers for Disease Control microbiologists are shown in this 2007 photo in the process of suiting up to access the interior of the organization's Biosafety Level-4 (BSL-4) laboratory.
Credit: CDC

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Measures taken in the current Ebola outbreak may hold some clues for how to handle samples brought back to Earth from Mars, a place that could potentially host extraterrestrial microbes.

The 1971 sci-fi film "The Andromeda Strain" dramatized the idea of alien organisms infecting the Earth. Based on a novel by Michael Crichton, the film depicts the spread of an alien germ brought back to Earth by a satellite. An elite team of specialists responds, relying on protective hazmat suits, decontamination and disinfection safety levels, and a secret, high-tech underground facility named Wildfire to study and deal with the deadly extraterrestrial organism.

NASA officials have wanted to build and launch a robotic lander that scoops up some Martian samples and returns them to Earth. Similarly, a human expedition to Mars would surely hunt for past or present evidence of life on the Red Planet. Hauling back Martian samples means potentially dealing with biological "hot property," as well as public concern about creepy crawlers from Mars eating away at Earth's biosphere. [The Search for Life on Mars (A Photo Timelinractice

"While the Ebola situation bears no resemblance to a sample-return mission to Mars, there is a concern that the public could link the two if not properly informed," said John Rummel, a professor of biology at East Carolina University in Greenville, North Carolina.

NASA has long studied the idea of robotically rocketing samples of Mars back to Earth.
Credit: NASA/JPL

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Rummel is a former chair of the Panel on Planetary Protection of the International Council for Science's Committee on Space Research (COSPAR), and is a member of the NASA Advisory Council's Planetary Protection Subcommittee.

Rummel told Space.com that a Mars sample would be contained from the time it leaves Mars until it is proven not to pose a biohazard threat.

"Even more important than the containment facility in which the testing will be done is the fact that scientists will 'practice, practice, practice' to ensure that the sample is contained until shown to be safe for release," Rummel said.

False negatives

The "very tragic set of events" of the current Ebola outbreak may indeed raise public fears about handling potentially infected samples, said Catharine Conley, Planetary Protection Officer at NASA Headquarters in Washington DC.

"In that context," Conley said, "it is true that the greater public awareness of issues related to hazardous materials not being contained properly, and particularly the unfortunate examples of false negatives — like the person not appearing to be sick when he got off the plane in Dallas — do make it easier to communicate similar concerns in the area of planetary protection."

Future Mars expeditions will surely search for evidence of past life on the Red Planet, even potentially identifying organisms that are alive and well on that distant world.
Credit: NASA/JSC

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The current outbreak also highlights "the need to have good protocols in place prior to bringing potentially hazardous materials back to Earth, and having a very careful and well-tested plan for how to determine that they are 'safe,'" Conley told Space.com.

"This is something planetary protection has been working on for quite a while now … but recent events demonstrate how important it is for Earth safety to avoid false negatives, as well as avoiding false positives to protect human activities at Mars," Conley said.

Mass reaction

"I see many issues that we know are a problem being illustrated by the mass reaction, kerfuffle, and misinformation and misunderstanding surrounding Ebola," said Penelope Boston, an astrobiologist and director of the Cave and Karst Studies Program at the New Mexico Institute of Mining and Technology in Socorro.

Boston is a geomicrobiologist and astrobiologist with more than 35 years experience.

"If I were personally going to deal with an agent like Ebola I would go train for six months at a Biosafety Level 4 (BSL-4) containment facility before I trusted myself to work with the virus," Boston said. "I would always have a safety officer bird-dogging my every movement — the buddy system — that is employed in so many hazardous military and civilian contexts," she said.

Safety procedures

When going into dangerous and potentially deadly environments, like the sulfuric acid cave in Tabasco, situated in southern Mexico, Boston said, a dedicated safety monitor is part of the exploration team.

Genesis solar wind sample curators at NASA's Johnson Space Center handle collectors in the ultraclean Genesis cleanroom. Curators wore suits to keep the collectors clean. The wearer's body is totally enclosed, and exhaled air is filtered through a HEPA filter, seen on the rear side belt. Genesis samples are the first extraterrestrial materials returned to Earth by NASA since the Apollo program, which ended in the early 1970s.
Credit: NASA/JSC

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"That's because no person can both keep their mind on the intensive scientific work they are doing and be absolutely assured of their own adherence to very fussy safety procedures," Boston told Space.com.

"And of course, with spacecraft, we also have the issue of organic chemical cleanliness to deal with, because that could seriously affect the results of highly sensitive life-detection experiments," Boston said. "So the space exploration case is a double-whammy that we are developing protocols to deal with."

Quarantine and containment

Bringing organisms back to Earth from space was spotlighted in the 1971 sci-fi movie, "The Andromeda Strain." The film depicts the spread of an alien germ transported back to Earth by a "Project Scoop" satellite.
Credit: Universal Pictures

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The Center for Disease Control (CDC) has guidelines for all types of biological pathogens, and NASA has worked with the health agency in planning for Mars, said Margaret Race, a senior research scientist at the SETI Institute in Mountain View, California.

Race focuses on the scientific, technical, legal and societal issues of ensuring that missions to the Red Planet and other solar system bodies do not either inadvertently bring Earth microbes to Mars, which would complicate the search for indigenous extraterrestrial life, or return any microbes to Earth. [Mars Myths and Misconceptions: A Quiz]

The CDC has designated different levels of containment. The most virulent agents are kept in Biosafety Level 4 (BSL-4) and have "special" protocols.

"The CDC generally works with known pathogens, but also oversees all types," Race said. "If in doubt, keep it contained and continue to study it," she told Space.com. "Quarantine and containment requirements are updated as needed, for example in response to things like Ebola."

NASA developed its draft Mars sample handling and testing protocols in coordination with experts from CDC and other regulatory agencies, Race said.

Red Planet protocols

NASA's protocols for Mars samples will take into account both safety and scientific accuracy, Race said.

"Clearly, science considerations also apply," she said. "According to studies by the U.S. National Research Council, the risks of Mars sample returnmaterials are deemed very low, but not zero."

Ebola virus
Credit: Frederick A. Murphy/CDC

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NASA will take a deliberately conservative view in handling pristine returned Martian materials, Race aid. This is both for planetary protection considerations, as noted in Outer Space Treaty requirements that are promulgated by COSPAR, and to protect the scientific integrity of the samples.

"Protocols will be updated well in advance of any sample return mission from Mars. There's already a comprehensive process of review and integration of planetary protection requirements that has been endorsed for implementation well in advance of any sample return mission," Race emphasized.

"Obviously, any Mars sample return plans will comply with the most up-to-date CDC and other requirements," Race concluded.

Orbital Sciences Forms Investigation Team for Antares Rocket Explosion

2014-11-04T07:56:00.001-08:00

This image shows the aftermath of the Antares rocket explosion, which took place on Oct. 28, 2014. The photo was taken from the air on Oct. 29.
Credit: NASA/Terry Zaperach

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Orbital Sciences Corp. has assembled an investigation team to examine exactly what went wrong when the private spaceflight company's Antares rocket exploded shortly after liftoff on Oct. 28.

Officials with NASA, the Federal Aviation Administration and Orbital Sciences have been working toward understanding what caused themassive failure of the rocket, but they have not found the root cause of the accident yet. The rocket mishap took place on a launch pad at NASA's Wallops Flight Facility on Wallops Island, Virginia. The Antares was carrying an unmanned Cygnus spacecraft loaded down with supplies for the International Space Station at the time of the explosion. Orbital Sciences holds a contract with NASA to fly these robotic resupply missions to the orbiting outpost.

The Accident Investigation Board (IAB) will first work on putting together the proper timeline of events during the launch, according to Orbital. "Due to the large amount of data available, the AIB is able to work with a rich source of information about the launch," Orbital officials said in an update Wednesday (Nov. 3). "One of the initial tasks for the AIB is to reconcile the data from multiple sources, a process that is now underway, to help create the launch sequence timeline." [Read more news about the Antares explosion]

David Steffy, the Chief Engineer of Orbital’s Advanced Programs Group, has been chosen as the chairman of the Accident Investigation Board. Other members of the board are:

David Swanson, Senior Director of Safety and Mission Assurance for Orbital’s Technical Operations organization
Wayne Hale, Director of Human Spaceflight, Special Aerospace Services
David Cooper, member of Orbital’s Independent Readiness Review Team for the company’s Launch Systems Group
Eric Wood, Director of Propulsion Engineering for Orbital’s Launch Systems Group
Tom Costello, Launch Vehicle Assessment Manager in the International Space Station Program at NASA’s Johnson Space Center
Matt Lacey, Senior Vehicle Systems Engineer for NASA’s Launch Services Program

The Federal Aviation Administration's oversight team for the investigation includes Michael Kelly, Chief Engineer for the FAA Office of Commercial Space Transportation and Marcus Ward, Mishap Response Coordinator for the same office.

Asteroid-Mining Tech Among Casualties of Antares Rocket Explosion

2014-11-04T07:55:00.003-08:00

Planetary Resources' Arkyd 3 technology-demonstration spacecraft, which was destroyed when Orbital Sciences' Antares rocket exploded on Oct. 28, 2014.
Credit: Planetary Resources

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The rocket explosion that destroyed a cargo vessel bound for the International Space Station Tuesday (Oct. 28) also took out an asteroid-mining company's first spacecraft.

Orbital Sciences Corp.'s Antares rocket exploded in a huge fireball just seconds after launching from NASA's Wallops Flight Facility in Virginia Tuesday evening. The crash caused no injuries but destroyed Orbital's unmanned Cygnus capsule, which was toting 5,000 lbs. (2,268 kilograms) of food, supplies and other gear to the International Space Station for NASA.

Among Cygnus' cargo was the Arkyd 3 satellite, a tiny technology demonstrator built by asteroid-mining firm Planetary Resources. [Orbital Sciences' Antares Rocket Explosion in Pictures]

The plan was to deploy Arkyd 3 (also known as A3), which measured just 12 by 4 by 4 inches (30 by 10 by 10 centimeters), from the space station into free-flying low-Earth orbit, where it would test out avionics, control and other systems for future asteroid-prospecting spacecraft.

Planetary Resources is taking the loss of A3 in stride.

"While we are saddened about the unfortunate consequences of this launch failure, our own development schedule, budget and plan are practically unaffected," Planetary Resources President Chris Lewicki wrote in a blog post today (Oct. 29).

"In fact, we are already hard at work developing our next test vehicle, the Arkyd 6, which is planned for launch in Q3 2015," he added. "It will build on the learnings from our development of the A3 and iterate to our next level of design. Multiple spacecraft and safety in numbers is part of our strategy, and we will continue with it for just these occasions."

Representatives of the Washington state-based firm, which counts Google execs Larry Page and Eric Schmidt among its investors, have said they hope to launch asteroid-hunting "Arkyd 100" scouts to low-Earth orbit in the next few years. Further down the road, Planetary Resources plans to launch other robotic probes to investigate potential mining targets up close, in deep space.

Eventually, the company aims to extract and sell asteroid resources, starting with water. Asteroid water can be split into oxygen and hydrogen — chief components of rocket fuel — allowing voyaging spaceships to top up their tanks without returning to Earth, mining advocates say.

Editor's Note: NASA officials are urging residents of the area around Wallops Flight Facility to stay away from any pieces of rocket debris that might wash up on shore or be found on land. If you think you may have found pieces of the rocket, please call the incident response team at (757) 824-1295.

Meanwhile, back on Earth

2012-08-29T13:02:00.001-07:00

Astronomy’s lessons about the home planet.

(Photo: Getty Images)

Most people think of astronomy as the science of the night sky. When you go back to astronomy’s roots, however, what’s striking is how much the earliest skywatchers learned about the Earth.

Here’s an example to try at home: a way you can easily observe the Earth’s rotation. Extend the Southern Cross’s main axis four times towards the south and you’ll locate a point in the sky we call the south celestial pole. Our planet turns around this point once every 23 hours 56 minutes 4 seconds and, if you watch the stars for long enough, it’s quite easy to sense that apparent motion. The rotation period is slightly shorter than a solar day (which is the interval between two successive noons) so the sky looks slightly different at the same time on consecutive nights.

Modern astronomy also encompasses far more than stargazing. Information is gleaned from every nook and cranny of the universe by all means at our disposal, and the picture created of things ‘out there’ is remarkably cogent and complete. It encompasses the entire spread of space and time, and it’s been building for millennia – a gradual evolution of an ever-more-complete portrait.

Until about the sixth century BC, the ancient Greeks were completely taken in by the flat-Earth illusion. Then, a certain Anaximander came up with the surprising idea that the Earth is roughly cylindrical in form, boundless towards the east and west, but curved north and south. He based this picture on the simple observation that as one travels to the north or south, the height of the constellations above the horizon changes.

Early in the fifth century BC, Parmenides seems to have refined the picture to that of a spherical Earth. Then, towards the early 200s BC, the observant Eratosthenes spotted sunlight pouring directly down a vertical well at Syene (now Aswan), on the Nile, when he knew with certainty that it was casting oblique shadows back home, 850 km north in Alexandria. That enabled him to estimate the diameter of the Earth. His value was amazingly close to the 12,756 km found by today’s measurements.

One earthly phenomenon that would certainly have baffled some ancient peoples is the aurora. The spectacular northern and southern lights tend to be seen at latitudes well away from the Equator, but southern Australia is occasionally treated to an appearance. Often, it is just a faint red glow on the southern horizon, but the characteristic arcs and streamers of a great auroral display can sometimes be seen.

An aurora is caused by energetic sub-atomic particles from the Sun interacting with the Earth’s magnetic field. They are more common at times of high solar activity, when ‘space weather’ is at its worst. And one thing ancient people certainly didn’t have to put up with is the disruption to power and communications systems that such weather can cause...

Six of the best Australian astronomical observatories

2012-08-29T13:01:00.004-07:00

Star trek your way around the country at these heavenly observatories.

Anglo-Australian Telescope (Photo: Frances Mocnik)

1. Perth, WA

Australia’s oldest continuously operating professional observatory has been looking up for more than 100 years, and in 2005 was listed on the State’s heritage register. Visitors can gaze through the observatory’s 76 cm telescope, the largest in regular public use in the Southern Hemisphere.

2. Arkaroola, SA

Perched in the Flinders Ranges, these three observatories – two full-sized astronomical domes and star chairs with a roll-off roof – claim some of Australia’s best viewing conditions.

3. Canopus Hill, Hobart, TAS

Situated at a latitude of 43° south and operated by the University of Tasmania, the 1 m telescope provides opportunities for year-round study of the Magellanic Clouds.

4. Siding Spring, Coonabarabran, NSW

Owned by the Australian National University, this observatory has some of Australia’s largest optical telescopes, including the 3.9 m Anglo-Australian Telescope. Equipped with a robotic wide-field spectrograph, it’s able to simultaneously observe hundreds of galaxies and stars.

5. Paul Wild, Narrabri, NSW

View one of the world’s most advanced radio telescopes, the Australia Telescope Compact Array. Belonging to the CSIRO, the six 22 m antennae observe star formation, the late stages of stars’ lives, supernovae and magnetic fields.

6. Mt Kent, QLD

Located 30 km south-west of Toowoomba, this 1.6 ha University of Southern Queensland site includes three telescopes which specialise in studying the influence of the Sun on climate change on Earth, including drought.

Digital side of the Moon landing

2012-08-29T13:01:00.002-07:00

The landing's recent anniversary has brought the Moon to us, thanks to the digital age 40 years on.

(Image: Moon in Google Earth)

Imagine if you could have built an exact replica model of the Moon from your space-themed Lego set – and rotated it to have a look – and you’ll have some idea of the visual you’ll get with Google Earth’s new moon tool.

To celebrate the 40-year anniversary of the moon landing, Google added a ‘land on the Moon’ tool to their highly celebrated Google Earth programming.

The Moon side of things was revealed at a launch in the US, where astronauts Buzz Aldrin, Andrew Chaiken and Anousheh Ansari were among speakers promoting the commemorative tool. The room was reportedly decked out with lunar rocks and satellite images, in what could be described as a congratulatory reminder of America’s continuing advancements in technology, from space exploration through to the digital age.

Google's 'land on the moon' tool

The point is a virtual 3D rendition of the moon’s environment, based on real stills taken during the lunar landing (and following expeditions). So you can see the original photographs, and then pan out to the Lego-esque simulation for a 360 degree view.

The virtual space contains cool lunar video footage, some previously unreleased by NASA, that effectively offers a tour of the Moon’s surface and environment, just as easily as we employ street view to check out unfamiliar neighbourhoods, or stare idly at our own houses.

There’s an amazing collection of information in this program, and space nuts will be thrilled that it’s all collated in an interactive, dynamic application that happily eats away work hours.

It certainly seems apt that 40 years after the first Moon landing, the digital age allows us to retrace that “small step for man” – and it’s all powered by the largest web-based organisation on our little planet.

Download the Moon from Google HERE and tell us what you think!

Through the Hubble

2012-08-29T13:01:00.000-07:00

Some of the best footage and photos from the Hubble Space Telescope.

(Photo: NASA)

Open Gallery

Since the Hubble Space Telescope began its indefinite orbit in 1990, it has surfaced countless observations of previously unseen corners of the universe, and its natural processes.

Two renowned images, known as the Deep Field and Ultra Deep Field, are referred to by some as the most important images in our understanding and observation of the greater universe and its contents.

The Ultra Deep Field image captures thousands of galaxies, and looks back billions of light years. Thanks to digital rendering, we can watch a 3D navigation that simulates movement through the galaxies in the deepest of images taken by Hubble, providing a sense of space and the universe's rate of expansion. The video begins with some Hubble history, that leads up to a digital fly-through of the Ultra Deep Field.

Look at the GALLERY: Photography from the Hubble

For information on the Hubble Telescope, visit their website.

News: Texting with the stars

2012-08-29T13:00:00.003-07:00

Thousands of people are sending text messages to the potential inhabitants of a star across the universe.

Artist's impression of Gliese 581d

Half way through National Science Week 2009, and already 18,000 human beings have taken the time to compose a text message to prospective aliens on an earth-like star 20 light years away.

Some of the messages are now live on the website HelloFromEarth.net – where people can register their greetings to life forms that may exist in another neighbourhood of our vast universe.

The collected messages, to be transmitted from the Canberra Deep Space Communication Complex, are estimated to reach their destination – a star called Gliese 581d – around December 2029.

Gliese 581d, discovered in April 2007, is believed to be within the ‘habitable zone’ of its star – an astronomical concept that theorises that the possibility of liquid water forming could allow for the existence of life forms, on planets such as ours.

NASA will aid the venture by encoding the text file at their Jet Propulsion Laboratory in California, USA, prior to final transmission from the Australian capital.

The website’s ongoing feed of the amounting messages provides a worldwide cross-section of those who are enthused to send an intangible greeting to the unknown. Many are genuine:

“Hope you receive this message as it could mean the start of something magnificent - With awe and respect from Earth.” – Theresa, Canberra

Some are quite moving:

“Hi.I am Gilbert From Australia I hope we can be friends. You might seen a lot of wars here on Earth but that is Fine, we ll be friends Eventually.” – Gilbert, Sydney

And of course, the absurd:

“Is there good fishing on Gliese 581D? If yes, please send GPS waypoints & tide times. Reciprical waypoints will be provided for Australian coastal waters.” – Kim, Sydney

And Australia is generally well represented:

"You are cordially invited to an Interplanetary BBQ. 6.00pm, 4th October, 2452 at my place BYO Meat and Beer. RSVP: Year 2100 Cheers." – Daniel Edmonds, Melbourne

With creative possibilities as far-reaching as our apparent space communication ability, the program is online fun for all ages, and a great illustration of this national festival’s value in getting Aussie kids enthusiastic about science.

Why is the sky blue?

2012-08-29T13:00:00.001-07:00

Astronomer, award-winning science communicator and AG columnist Fred Watson tackles the big questions about the Earth, Moon and other heavenly objects.

Great Sandy National Park, Queensland (Photo: Getty Images)

Why is the sky blue?

Poor old Leonardo da Vinci. As an artist who dealt in light, colour and movement, he wanted to understand how nature produces all these phenomena. And he had a jolly good shot at it, from analysing the tumbling of water over stones in a brook to reasoning why the faintly illuminated lunar disc can sometimes be seen between the horns of the crescent Moon – “the old Moon in the arms of the new”. Thus Leonardo might be described as the first real scientist; certainly he was one of the most accomplished figures of the Renaissance.

One thing eluded him, however. Why is the sky blue? He got close to the answer in a manuscript he penned in 1509 (which is owned today by Bill and Melinda Gates, of Microsoft fame). Here, Leonardo explains that he thinks the blue of the sky is caused by the mixture of white light – from sunlight illuminating the air – and the blackness of space beyond. A good idea, but wait a minute – shouldn’t that produce grey? And a fairly dirty grey, at that?

While he was on the right track, Leonardo wasn’t equipped to understand the essential ingredient, which is a subtle optical phenomenon called scattering. Indeed, it was not until 1871 that the noble English scientist, Lord Rayleigh, got to the bottom of it all. Scattering is something that happens whenever light rays strike microscopic particles – including molecules of air. Thus, the flood of sunlight hitting the atmosphere is simply scattered in all directions, which is why the sky is luminous in daytime.

The reason it is blue, though, is that Rayleigh’s theory predicts that blue light is about 3.2 times more likely to be scattered than red light in any interaction with a particle. And that is exactly what we see. While the light of the sky still contains red light, it is overwhelmed by the blue.

Why do stars twinkle?

Once again, scientists have a fancy name for a common phenomenon that everyone is familiar with. It’s scintillation and, in this context, it refers to the effect that our continuously moving atmosphere has on light.

If the atmosphere was at exactly the same temperature throughout, the stars wouldn’t twinkle and the night sky would lose much of its charm. In reality, however, the atmosphere is made up of countless bubbles of warmer and cooler air, jostling together as they are carried along by the wind. This turbulent motion takes place at all heights above the ground, and is often very rapid in the high-altitude jet stream.

Because the temperature of air governs its density – and that, in turn, dictates the extent to which it will bend light – these moving atmospheric cells act like invisible lenses. Admittedly they are very weak lenses, because the refractive (light-bending) power of air is feeble, but they are enough to cause the twinkling of stars – and to compromise observations made with giant telescopes.

Twinkling arises because the moving blobs of air act to alternately focus and defocus the starlight arriving at our eyes. The effect is that the star gets rapidly brighter and dimmer – that is, it twinkles, or scintillates. Looking through a telescope, you can detect this focusing and defocusing as the star image seems to contract and expand. It is also in frenzied random motion, like a moth fluttering around a lamp, as the light rays are bent this way and that in the moving air.

For 300 years, astronomers have referred to the degree of turbulence in the atmosphere as “seeing”. When the seeing is good, the star images in their telescopes are stable points of light. When it’s not, they become inflated, trembling blobs, and the exquisite detail that the telescope is capable of revealing is lost altogether in the shaking of the air.

Generally, the seeing gets better as you look higher in the sky – and thus the twinkling seen with the unaided eye is reduced. That is because the path of starlight through the atmosphere is shortest for stars that are overhead. For the same reason, high-altitude sites like mountain tops have better image quality for astronomers than sea-level locations – there is less turbulent air above them. The seeing is also strongly dependent on local weather conditions. It is often depressingly poor after the passage of a cold front, for example. But the twinkling on such occasions is, well…charming.

Why does the Moon look so big when it's low in the sky?

Of all the phenomena relating to the Moon, this one is undoubtedly the most frequently remarked upon. It is especially obvious around the time of full Moon, when the disc of our satellite looks positively huge as it rises at dusk in the eastern half of the sky. And the full Moon appears similarly enormous when it sets towards the west as dawn breaks. The effect is extremely convincing – psychologists tell us that the Moon seems to be two to three times larger near the horizon than when it is high in the sky. You’ll have noticed I said “psychologists” here, and not “physicists”. That is because this effect is not real, but takes place entirely inside our own heads.

It is the human brain that causes the apparent increase in size, not the physics of the atmosphere or the geometry of the Earth-Moon system. The effect is known famously as the ‘Moon illusion’.

There are many simple ways of proving that it is, indeed, a psychological illusion. A thin pencil held at arm’s length, for example, will just about cover the Moon whether it’s high in the sky or low on the horizon. And photographs of the Moon taken in the two situations prove the same thing.

So why do our eyes tell us it looks so big? This conundrum of perception has long been a subject of debate among cognitive psychologists. There is at least one hefty volume of learned text on the topic, written by some of the world’s foremost experts during the late 1980s. Browsing through this tome gives the distinct impression that psychologists were (and perhaps still are) groping to understand why our minds tell us so convincingly that the Moon is bigger than usual when it’s simply not true.

It used to be thought that the Moon illusion arises because a low Moon is surrounded by familiar objects like hills, trees and buildings, while a high one is seen in isolation. Thus the horizontal Moon is seen at its “real” size, but the lonely Moon high in the sky appears diminished. There is nothing familiar to compare it with, so it shrinks. More recent thinking suggests there’s more to it than this, however, and the most popular of today’s theories relates our impression of the size of the Moon to the perceived shape of the sky itself.

It has been known for many years that we think of the sky not as a hemispheric dome over our heads, but as a flattened dish. In other words, our perception of the sky is that it is much further away near the horizon than over our heads. It’s no mystery why this should be so – those fluffy clouds we often see scattered uniformly over a fair-weather sky, for example, appear to become smaller as our gaze moves down from the point overhead (the zenith) towards the horizon. Of course, in reality, they’re all similarly sized, but the effect of perspective makes them seem to shrink. On a very clear day in flat country, where the view is uncluttered by trees and buildings, clouds near the horizon appear perhaps 50 times smaller than their local counterparts because they are so much further away. No wonder our brains tell us that the sky is more like an upside-down dinner-plate than an upside-down fruit bowl.

Now, into this trick of perception steps the Moon.

We most often see it high up, so we have a built-in impression of how big it should look. As it rises over the horizon it is, as we have seen, essentially the same size as it always is. But hang on a minute – the human mind says that anything near the horizon is a long way off, and therefore must look small. The Moon, however, is the same size, challenging the brain to compute what is going on. How does the brain respond? There are no prizes for guessing that it tells us the Moon is bigger than it should be, because it doesn’t look as small as the brain expects. Hence the Moon illusion.

Finally, many commentators have noted that the Moon illusion can be made to disappear by standing with your feet astride and bending down to look at the Moon between your legs. Personally, I have always thought this was a cunning ploy on the part of astronomers to make the rest of us look stupid, but there is probably something to be said for radically changing the way you observe the scene to dispel the deception. A bit more speculatively (since there’s clearly no need to adjust your nether garments to observe the Moon), I wonder if this could be where the expression “mooning” comes from?

Source: Australian Geographic Oct - Dec 2007

Buzz Aldrin's vision of future space exploration

2012-08-29T12:59:00.003-07:00

In an exclusive interview with AG, astronaut Buzz Aldrin discusses what's to come in the space race, and looks back on that giant leap.

Photos courtesy of NASA

THE ASTRONAUT BORN Edwin E. Aldrin Jr but best known as Buzz – his legal name since 1982 – was the first spaceman without test-pilot experience hired by NASA, which wanted his brain for physics and astronautics and made him one of the first men to walk on the Moon. He remains one of only a dozen people ever to have taken lunar steps. This July marks the 40th anniversary of Apollo 11’s precision journey to the Moon and that historic walk.

Buzz has lost none of his drive or curiosity in his 79 years and is a sought-after speaker for his views on the future of space exploration. His opinions are wide-ranging, detailed and bold: no less than one would expect from one of three men (Neil Armstrong and Michael Collins were his Apollo 11 crewmates – Mike orbited the Moon but didn’t walk on it) who completed arguably the 20th century’s greatest feat of adventure exploration.

“I think the field of astronomy has just burgeoned tremendously in the last 10 years,” Buzz says. “I don’t think we ever thought that we’d see the kind of returns that we’ve been able to get from the Hubble Space Telescope. And I think we’re going to be just that much more ‘gee whiz’ impressed by the new telescopes coming. And to think that we could send satellites, spacecraft, on the grand tour by using gravity assist instead of fuel; the fact that we can run spacecraft around Saturn and multiple passes of the moons… my goodness, nobody would have expected that.”

No-one knows better than Buzz that rocketing people into space is in a different league from sending automated probes, but he sees a renewed push for manned space exploration building momentum. “Some things that require building rockets and obtaining money and convincing politicians; they can take a little longer. But we also have [renowned physicist] Stephen Hawking saying that we need another commitment to have another giant leap in space. That’s why I’m motivated to look quite a bit beyond the current thinking. Because I want to see Stephen Hawking’s ‘giant leap’.”

Buzz’s vision includes the Moon – the place where Neil Armstrong gave the term “giant leap” its most famous airing – as a stepping stone, but his horizon lies further out in space, and he sees it reached through a combination of experience, innovation, long-term planning and greater international cooperation.

He advocates using the Space Shuttle and possibly Orion spacecraft, now under development in the USA, to continue building the International Space Station (ISS), and says that China, India, South Korea and Brazil should be brought into the ISS agreement (currently the United States, Russia, Japan, Canada and the 10 nations of the European Space Agency are signatories). “The cost of entry, for the Chinese at least, is free transport of some of the other partners in as many Shenzhou spacecraft as they can build,” Buzz says. He thinks one of the Shuttle’s last services (it’s due to be decommissioned next year) should be to take a test module to the ISS to research life support for long-duration missions. “We need to do that; we need to find out how to protect against cosmic radiation, cosmic rays and solar flares. We need to learn how to protect the human for muscle tone and bone loss. We need artificial gravity. We need to be doing those things and we need to plan missions that go beyond the Moon.”

That’s where it gets interesting. The Moon will almost certainly figure in further investigation and planning for manned deep-space missions, and may even witness human habitation at some stage, but humans need to look further, according to Buzz. “It’s just not a good place with 13–14 days of daylight and darkness and no atmosphere, and no radiation protection. So we send our people somewhere else. We’ll send them to fly by an asteroid in 2018, to rendezvous for 30 days with a near-Earth object in 2020, and to rendezvous with [asteroid] Apophis in its close path to the Earth in 2021. And then in 2025 we can land people on [Mars’ moon] Phobos, do it again in 2027, and again in 2029, then we land people permanently on the surface of Mars.”

Buzz’s “permanently” means precisely that: “One-way trips; they don’t come back. They are the first settlers, just like the Polynesians that headed for Hawaii – they didn’t turn around and then go back. Neither did the Pilgrims on the Mayflower wait around for the return trip. They came to settle. And any of the Earth’s national leaders who chart a course to do that for humans – to emigrate, to be the first immigrants to another place, to set up a station – may save humankind in case the Earth is ever wiped out. That’s what we need to do and I think the timing is right to do it now.”

BUZZ’S EARLY YEARS were all about flight. His dad, an aviator, took Buzz aloft for the first time as a two-year- old, in 1932: “My father flew me from Newark Airport [in New Jersey] down to Miami [Florida] in the same plane that he had flown over the Alps in 1929.”

His childhood was wingtip-to-wingtip with stories about early aviation pioneers such as Amelia Earhart and Charles Lindbergh. Soon after, as a bright and inquiring boy, he delighted in the rapid development of aircraft during World War II, and not surprisingly focused on wanting to learn to fly as a military pilot. He went into the US Air Force and qualified as a fighter-jet pilot, flew combat missions during the last six months of the Korean War (1950–53), and was later deployed in a fighter squadron in Germany. “I realised in Germany that a few [pilots] had outstanding coordination, outstanding eyes, could see things that other people couldn’t see and maybe were at home, easier, quicker than I was in a new and different airplane: these are the guys that make great test pilots,” Buzz says. Rather than going through test-pilot training, Buzz opted to improve his academic credentials, and went to study at Massachusetts Institute of Technology (MIT), his father’s alma mater.

“While I was there [first Soviet cosmonaut] Yuri Gargarin went up, then [American] Alan Shepard [see “Race to the Moon”, page 64], and I knew what I could do, so I wrote my thesis on manned orbital rendezvous in space,” he says. “What a lucky choice that was, because in 1961 we decided to go to the Moon, and the way to get to the Moon was going to be lunar orbit rendezvous. I applied for the second group of astronauts, in 1962, but NASA couldn’t pick me because I hadn’t had test-pilot training. But mysteriously they changed the rules the next year to put more emphasis on academic experience, so I came in as an egghead from MIT.

“I was given the opportunity to fly in the last Gemini mission [in November 1966], and what we were having trouble with was not rendezvous, but space walking. I happen to be a good scuba diver and I welcomed the opportunity to train under water, and that…enabled us to do space walking very nicely on the last mission. All of that stuff put me in a good position to be on a backup crew for a mission in Apollo.”

Buzz and Neil were assigned as backup crew for Apollo 8, the first manned orbit of the Moon, in December 1968, and the Apollo 9 and Apollo 10 missions further tested the spacecraft and systems needed for a Moon landing. By then the whole world knew that Neil, Buzz and Mike – the Apollo 11 crew – would be given the opportunity to land on the Moon. “What could a young kid growing up when I grew up, what more could he possibly ask for, than to be in the right place, at the right time for all these events?” Buzz says.

The right place was the Moon’s Sea of Tranquility on 21 July 1969 (20 July in the USA), where Buzz and Neil landed their craft Eagle and took humankind’s first steps on another heavenly body. Does he have a single strong memory of that extraordinary day?

“I think it was the unrecorded couple of seconds after we shut the engine down and were stable. And we looked at each other, and my recollection is that I patted Neil on the shoulder; his recollection is we shook hands, I’m not sure which. But that was a moment more significant than any others. It was not beautiful out there; but [there was] magnificence in human beings achieving what we achieved. Not we, but the world. And when we came back people said: ‘We did it, we did it!’ Yes we did. Human beings did it. But what a desolate spot was chosen. What we looked at had no life, no colour, black sky, no stars, not very attractive.”

FOUR DECADES LATER space travel is, if not exactly commonplace, accepted without the awe that was attached to it in the 1960s. And as has happened throughout history, adventure and exploration have broken ground for their mass-market pursuer, tourism. British entrepreneur Sir Richard Branson’s company Virgin Galactic – among others – is developing craft for suborbital spaceflight and accepting reservations for as-yet unscheduled flights. Prospective private ‘astronauts’ need at least US$200,000 to get aboard.

Private enterprise has always played a role in spacecraft construction and Buzz sees Richard’s efforts as a force for good because they will reinvigorate the idea of human space flight. He notes, however, that Virgin Galactic’s hybrid craft are strictly for suborbital flight and won’t be useful for true space applications, which require much greater launch velocities to reach Earth orbit. Richard has adopted the Fédération Aéronautique Internationale’s standard of 100 km altitude as the boundary of space and his suborbital craft will go only a little further, but accelerating a spacecraft to orbital speed requires more than 60 times the energy needed to lift it to 100 km.

With so much energy needed to boost big payloads into Earth’s orbit and beyond, some of the world’s most innovative thinkers have pondered alternatives to rockets. Science-fiction author and inventor Arthur C. Clarke is among those who’ve advocated the “space elevator” as a means to reach orbit. The fine points of different space elevator proposals vary, but the basic idea is the same: it’s a fixed structure that extends from the surface of the Earth at the Equator, to a point approximately 36,000 km directly above, that remains in synch with the Earth’s orbit – a geostationary orbit (GSO). Clarke was among the first to give GSOs wider coverage when he published his paper “Extra-Terrestrial Relays – Can Rocket Stations Give World-wide Radio Coverage?” in Wireless World magazine in 1945.

Buzz – who’s co-written two science-fiction novels, The Return and Encounter with Tiber, among other books – has a lively and practical view of the space elevator and its place in contemporary space thinking and planning. “I think we, science fiction [writers] and others [such as UFO enthusiasts], have excited people with fantasies that lead to expectations that just don’t work,” he says. “Let’s say a space elevator goes from the Equator all the way up to [GSO] and it’s got something stationary up there. Whatever mass crawls up there is going to pull that stationary something down unless a mass goes up the other way, okay? That’s a little bit of a problem, but the biggest problem is the following: it goes from the Equator up to GSO and beyond, and it moves at 24 hours a revolution, okay? However, all the other satellites below that are moving faster. And each satellite – pay attention here – each satellite that’s lower crosses the Equator twice, or it’s on the Equator all the time.

“So it’s only a question of time before there’s a collision between the elevator and [one of] those thousands and thousands of satellites already there. You can’t move it out of the way, it’s a fantasy idea. It won’t work! But you know [Clarke] was a pretty smart person to point it out, and I hit the palm of my hand against my forehead and I said, ‘Why didn’t I think of that?’”

BUZZ DESCRIBES AUSTRALIA'S role in the Apollo program as “immense”, and lauds its continued exploration efforts through astronomy and the Deep Space Network (DSN), which tracks deep-space probes. The Canberra Deep Space Communication Complex (CDSCC) – better known as Tidbinbilla Deep Space Tracking Station – is one of just three DSN complexes in the world and the only one in the Southern Hemisphere. “Everything that goes out beyond the Earth, [automated probes] and telescopes depend upon that deep-space tracking network,” Buzz says. “It doesn’t get enough credit.”

Buzz likes to see credit given where it’s due and there’s one idea he’s happy to push. “I think on July 20 of this year the [US] President ought to nominate and confirm, living or dead, the 24 people who reached the Moon, as such a great distinction from the almost 500 who have been in Earth’s orbit, and to make them official lunar ambassadors at large, carrying the title, ‘The Honorable’,” he says. “That makes a statement to all other world nations, that we make a big thing about what we did then, and we encourage you to be able to do the same thing. It was a peaceful program, and we came in peace for all mankind. We knew it was potentially a big thing, and I think it needs to be remembered as a big thing. But it’s not as big a thing as sending humans permanently to the surface of Mars.”

Where are all the stars?

2012-08-29T12:59:00.001-07:00

As Earth Hour approaches, urban light pollution interrupts the visibility of stars.

CSIRO telescope, Parkes (Photo: Getty Images)

HOPEFULLY, AS A CONSCIENTIOUS AG reader, you intend to celebrate Earth Hour. On 27 March at 8.30 p.m. local time, as many as 1 billion people in a thousand cities around the world will turn off their lights for an hour, continuing an annual event that had its origins in 2007 in Sydney.

Astronomers welcome the initiative of Earth Hour, because it draws attention to something that most of them feel passionate about. While they, too, worry about the carbon footprint of wasted light, and agonise over the plight of nocturnal animals confused by city lights, they also have a serious professional concern.

Our view of the Universe through optical (visible-light) telescopes depends on being able to detect faint images against a natural background luminosity of the sky itself. Even in the absence of artificial lighting, this sky-glow threatens to swamp the feeble celestial objects that astronomers are trying to investigate. Any kind of light pollution adds to this background, which is why the world’s largest telescopes are placed in remote locations.

You might be surprised to know, however, that city lights are effectively scattered by the Earth’s atmosphere across hundreds of kilometres. For example, astronomers using Australia’s largest optical telescope, the 3.9 m Anglo-Australian Telescope near Coonabarabran, NSW, are used to seeing the glow of Sydney, 350 km away, from the walkway around the dome.

This effect has been mapped on a worldwide scale by Pierantonio Cinzano, based at the University of Padua, Italy. Pier-antonio’s studies show that two-thirds of the world’s population live in light-polluted conditions, and about one-fifth can no longer see the Milky Way.

It’s also clear that light pollution is encroaching on many of the world’s major observatory sites. Remoteness is no longer enough. What’s ultimately needed is a reduction in urban waste-light, which can be achieved through better lighting design. As well as satisfying astronomers and reducing urban energy bills, this will have the far more important effect of reducing greenhouse-gas emissions on a scale vastly greater than Earth Hour.

Dwarf planets accumulate in outer Solar System

2012-08-29T12:58:00.004-07:00

Pluto may be demoted again, as researchers work to properly define dwarf planets.

Illustration: NASA/JPL-Caltech/R. Hurt (SSC-Caltech)

PLUTO’S STATUS MAY TAKE a further hit, say Australian astronomers, if around 50 neighbouring space objects join the ranks of the dwarf planets.

Pluto was demoted to ‘dwarf planet’ in a decision by the International Astronomical Union (IAU) in 2006. This decision – which was unpopular with the general public – was based on the discovery of many objects which were a similar size or larger than Pluto in a zone of the Solar System known as the Kuiper Belt.

Other dwarf planets include Ceres, the largest asteroid in the rock-strewn belt between Mars and Jupiter, and four Kuiper Belt objects: Eris, Makemake, Haumea and Quaoar.

Now, astronomers Charley Lineweaver and Marc Norman, from the Australian National University in Canberra, say the definition of what it means to be a dwarf planet should be revised to include many smaller objects too.

“Small Solar System objects are irregularly shaped, like potatoes,” Charley says. “If an object is large enough that its self-gravity has made it round, then it should be classified as a dwarf planet.”

Defining dwarf planets

The IAU’s definition decrees that a dwarf planet must orbit the Sun, must not be a satellite of another planet, must not have cleared its orbit of debris (like larger planets do) and it must be of sufficient mass to assume a nearly round shape. They also state that dwarf planets should be of a certain brightness, which is only possible with objects with a radius of more than 420 km.

Charley and Marc now argue that the radius which defines a dwarf planet should instead be from 200–300 km, depending on whether the object is made of ice or rock.

They base their smaller radius on the limit at which objects naturally form a spherical rather than potato-like shape because of "self-gravity". Icy objects less than 200 km (or rocky objects less than 300 km) across are likely to be potato shapes, while objects larger than this are spherical.

This is because as an object in space becomes larger, the effects of its own gravity become more important in dictating the final shape. They call this limit the ‘potato radius’, and the results were published recently in theProceedings of the 9th Australian Space Science Conference.

Arbitrary boundary

“The boundary between dwarf planets and small Solar System bodies is somewhat arbitrary, but is based on…how round an object is,” Charley told Australian Geographic. “In science it’s our job to figure out [the truth],” and we shouldn’t ignore the fact that many smaller objects in the vicinity of Pluto also resemble dwarf planets, just because we don’t want to upset the status quo, he says.

Astronomer Simon O’Toole at the Anglo-Australian Observatory in Sydney says the recommendations are a “natural progression and a nice, simple model”.

“It’s nice to have a physical approach as to what is a dwarf planet and what is not," says Simon, who agrees that the IAU’s definition is arbitrary. “I have no problem with there being hundreds of dwarf planets eventually,” he says.

See the full paper here.

Sailing the Endeavour: Day three

2012-08-29T12:58:00.001-07:00

The swell takes its toll on crewmates on board the Endeavour replica (Photo: Aaron Cook)

AG writer Aaron Cook steps aboard the Endeavour replica to relive the beginnings of Australia's colonial era, and learn a bit about sailing an 18th century ship. Tune in for his daily blog, thanks to Australian National Maritime Museum.

WHILE EXPLORING THE AUSTRALIAN coast, Cook recorded in his journal his first sighting of people on 22 April 1770 — but high seas stopped him from approaching land. “We had a large hollow Sea from the South-East rowling in upon the land, which beat every where very high upon the Shore,” Cook wrote.

Aboard his ship's replica, I wonder if the present 2.5 m swell is similar to the experience Cook recorded. As the ship rocks endlessly from side to side, many of my crewmates enter the world of seasickness.

We cycle through watch duties: bow and stern lookouts, rounds to check the safety of the ship, and helming. Two at a time, we get to take the wheel of Endeavour. A compass charts our path and whenever we stray more than a few degrees off course, we swing the wheel a couple of spokes. The wheel action turns the tiller, which turns the rudder that steers the ship. I can’t quite believe I’m steering the Endeavour.

Take a visual tour of the Endeavour

View Large Map

NOW THAT WE'RE OFFSHORE, our watery path is lit only by the Milky Way, ablaze against the pitch black night. To the west, a giant dome of lifeless light springs from Sydney. It’s an interesting contrast to see the Milky Way in all its glory, alongside the light pollution that normally prevents city-dwellers from seeing more than a few stars.

The constellation Orion descends, chased by Scorpio through the sky. At this stage, two people require the assistance of a “happy buckets”, PVC buckets with smiley faces drawn in the bottom. On bow lookout I start to feel a bit dodgy. To take my mind off the constant rise and fall I watch the bioluminescence that is sparked off by the wave pushed ahead of Endeavour.

Every time the bow descends, constellations of light appear in the water to match those that hang in the sky above. The cause of this diamond dust is a group of single-celled marine plankton calleddinoflagellates, which give off flashes of blue light when disturbed.

BY NEXT MORNING, ABOUT a quarter of the crew have a bucket on hand. Even one of the professional crew is struck down by the dreaded mal de mer — an affliction caused by a disturbance to the body’s balance system in the inner ear. I’m not sure if Cook ever got sea-sick, but there are rumours that Lord Nelson, that other great British sailor, was a chronic sufferer (there's even a shanty about it).

Luckily, there isn’t much to do today. The officers are happy with the sails that are set and we’re making good ground. After tracking southeast during the night, we have to turn the ship northwest in a technique called “wearing”, similar to a modern day “jibe”.

The rest of the day is plain sailing, but even those that don’t get sick feel at least a little queasy. Tomorrow, we will reach Broken Bay.

Vast asteroid crater found in Timor Sea

2012-08-29T12:57:00.003-07:00

The crater's discovery may answer questions about a period of significant global cooling 35 million years ago.

Artist's impression of an asteroid in front of Earth (Image: Getty Images)

EVIDENCE OF A MASSIVE crater, at least 50 km across, has been discovered under the Timor Sea and may help scientists explain a rapid cooling of the planet 35 million years ago.

The new findings, announced today and published in the Australian Journal of Earth Sciences, suggest that the impact could have contributed towards the formation of the Antarctic ice sheet.

When Dariuz Jablonski, an oil exploration geologist with Finder Exploration, was conducting seismic surveys in the Timor Sea north of Broome in Western Australia, he found what he suspected to be the remains of large crater site. Dariuz asked Dr Andrew Glikson of the Australian National University in Canberra to help investigate.

Crater diameter 100 km

Andrew, a specialist in extraterrestrial impacts, conducted tests on rock specimens from the sea floor. He found structural features which suggested great heats and pressures and he concluded that the area was the raised “dome” of a crater produced by an asteroid collision 35 million years ago.

"The identification of microstructural and chemical features in drill fragments taken from the... drill hole revealed evidence of a significant impact," he says.

The minimum size of the dome, which "represents elastic rebound doming of the Earth crust triggered by the impact" is 50 km across, but the full size of the crater could be significantly larger, he told Australian Geographic. "It would be possibly 100 km.”

From the probable diameter of the crater, Andrew estimates that the asteroid which struck the Timor Sea was between 5 and 10 km in size.

Correlation with global cooling

This impact coincided with a time of heavy asteroid bombardment globally. Several other craters have been documented from a similar time, including one off the Western Australian coast measuring 120 km in diameter. Another asteroid impact structure in Siberia is 100 km in size.

Andrew believes that collisions such as this may have played a role in the rapid decline in global temperatures. He says that the onslaught of numerous asteroids shifted the Earth's plates to create a rift between South America and Antarctica known as the Drake Passage, which still exists today.

“It allowed the circum-Antarctic ocean current, a cold current, to be established — this allowed the Antarctic ice sheets to form,” he says. These ice sheets, along with the newly established circular current around Antarctica, forced cooler water into the world’s ocean and may have resulted in a well documented cooling of the planet.

Aboriginal astronomers: world's oldest?

2012-08-29T12:57:00.001-07:00

Indigenous perspectives are adding insight to western astronomical understanding of the southern night sky.

Star-trail in the Australian outback (Photo: Steve Wilson)

THERE’S GROWING EVIDENCE THAT Australia’s indigenous people could be the world’s oldest astronomers, according to astrophysicist Ray Norris, who is based at CSIRO's Australia Telescope National Facility in Sydney.

He has researched Aboriginal stories about the night sky for five years and says one of the earliest European records of indigenous astronomy was made by William Stanbridge, an Englishman who emigrated to Australia in 1841 and ran sheep at Lake Tyrrell, in northern Victoria. Stanbridge befriended members of the local Boorong people. They showed him how they viewed the constellations and Stanbridge published their stories in his 1857 essay On the Astronomy and Mythology of the Aborigines of Victoria.

Stanbridge’s writings recorded the Boorong’s holistic use of astronomy and explained how they integrated their understanding of the stars with knowledge of the land and seasons, Ray says. For example, the constellation western astronomers know as Lyra forms the base of what the Boorong called Neilloan – a malleefowl, whose outline in the night sky heralded the bird’s egg-laying period, as it appears in the southern hemisphere between March and October, coinciding with its mound-building season.

He believes astronomy can, like music and the arts, build a strong bridge of understanding between indigenous and non-indigenous Australians. Ray explains that different Aboriginal groups have varying interpretations of southern sky constellations. But there are broad similarities between many, such as the Coalsack Nebula (the emu in the sky).

DEPENDING ON THE CONTEXT, many Aboriginal groups also have different stories for the same constellations. Bill Yidumduma Harney, an elder of the Wardaman south-west of Katherine, in the Northern Territory, says his people, for example, use many different constellations for a variety of purposes. The Wardaman also use traditional cosmology to tell them about the land, the seasons – even time. “When you’re travelling it will tell you where to go. You can tell by the stars what time it is without a watch,” says Bill, who co-authored Dark Sparklers, a book on the subject.

Stephen Gilchrist, indigenous art curator at Melbourne’s National Gallery of Victoria, is spreading the message. He recently mounted an exhibition called Shared Sky featuring works by artists depicting Australia’s night sky. “Aboriginal ancestral narratives aren’t just about the land – they’re also about the Sun, the Moon and the stars,” Stephen, from Western Australia’s Inggarda language group, explains. “Indigenous people have a very holistic understanding of the universe. It doesn’t just stop at the horizon.”

Arnhem Land’s Yolngu people have ancestral narratives about tides, eclipses, the rising and setting of the Sun, Moon and planets. Stephen says there is a new fascination with the way Australia’s first people apply knowledge about the sky and land. Indigenous cosmic understanding can go hand in hand with established European interpretations, he says.

Perspectives of the southern cross

This distinctive constellation is widely viewed as a significant symbol by indigenous groups.

> To Victoria’s Kulin Nation people, based around Melbourne, the Southern Cross represents Bundjil, a sky god in the form of an eagle.

> For the Anindilyakwa of Groote Eylandt, in the Gulf of Carpentaria, the Southern Cross is two fishermen and their cooking fires.

> Coastal SA’s Ngarrindjeri people see the Southern Cross as a stingray chased by two sharks – the two pointers adjacent the cross. The shark is a sacred Ngarrindjeri totem.

> The Boorong people – a group that no longer exists but has descendents in Victoria – saw the Southern Cross as ringtail possum Bunya hiding in a tree from the wicked emu Tchingal whose silhouette could be seen in the Coalsack Nebula.

> The Arrernte people of Central Australia see the Southern Cross as the wedge-tailed eagle Waluwara. The four brightest stars make up his talons; the Coalsack Nebula his nest.

Source: Australian Geographic Issue 97 (Jan - Mar 2010)

Space has lost one of its shining stars, says Fred Watson.

2012-08-29T12:55:00.000-07:00

Space has lost one of its shining stars, says Fred Watson.

Neil Armstrong in 1969. (Credit: NASA)

FOLLOWING THE PASSING of Neil Armstrong on Saturday at the age of 82, the world of astronomy and space science has been paying tribute to one of its greatest icons. Across the globe, scientists and non-scientists alike have been inspired throughout their lives by Armstrong's great achievement in 1969.

By becoming the first human to set foot on another celestial body, he touched the lives of everyone who had ever given a thought to our environment in space, and will be greatly missed. His death truly marks the end of an era.

Neil Armstrong will be remembered as a modest, thoughtful individual, who was the consummate pilot in both aviation and spaceflight, and who had an unwavering trust in the technology he worked with.

Moon landing

He displayed great courage in carrying out his duties in the flights of Apollo 11 and Gemini 8, and, earlier, in the X-15 rocket plane. He was the perfect choice of commander for Apollo 11 - absolutely the right man for the job at the right time. Though reclusive in later years, his wisdom was frequently called upon (for example, in the aftermath of the Challenger disaster of 1986), and he never lost his enthusiasm for space exploration.

Landing humans on the Moon was not just the first great milestone in human space travel, but a pivotal event in human history. It is almost impossible to overestimate the importance of the Apollo 11 success, even though the motivation to carry it out was largely political, set against the backdrop of the burgeoning Cold War. It ranks as one of the greatest technical achievements of all time.

Since that event, science has been overwhelmed with dazzling scientific results from the space programme, and our understanding of ourselves, our planet, and the Universe at large have been transformed as a result.

And, while the budgets of space agencies like NASA may be regarded by some as generous, they are trivial compared with big-ticket items like defence spending. NASA's total funding over the past 50 years would be consumed in a matter of months by the Pentagon.

Future of human spaceflight

Despite the popular misconception that NASA has pulled out of human space exploration, the future looks bright as the agency turns to new and more viable technologies than the former space shuttle programme.

With commercial US operators already ferrying supplies to the International Space Station, and scheduled to begin ferrying astronauts up and down within a few years, NASA can concentrate on the big ticket items - visits to Mars and the asteroid belt, and, once again, the Moon.

Its flagship project is the four-person Orion module, which will begin test flights in 2014. When that advanced craft first conveys humans into space in the early 2020s, it will owe much to the extraordinary legacy of Neil Armstrong.

Fred Watson is Astronomer-in-Charge of the Australian Astronomical Observatory at Coonabarabran in north-western NSW, and well-known to ABC radio listeners. He has written a regular column in the Australian Geographic journal for many years.

Binoculars - The Sky's The Limit (Part Two)

2012-08-28T11:42:00.005-07:00

Binoculars - The Sky's The Limit (Part Two)

Coated lenses are important. Multi-coated is good, and fully multi-coated, meaning all lenses are coated on both sides, is best. Ruby-coated is not desirable, and gives objects a green cast.

For the prisms, or blocks of glass that reflect the light inside the binoculars, BK-7 are fine and BAK4 are the best.

Choose from reliable brand names of astro binoculars such as:

Celestron – many styles with wide fields that produce a sharp, bright image
Giant – offers large binoculars for extra wide sky viewing
Stabilized - popular for viewing from a moving vehicle or boat because they reduce or eliminate the effects of vibration:
- gyro-stabilized use a motor to drive a gyroscope that controls the prism platform
- vary-angle prismatic use a microprocessor to control the prisms
- cardanic suspension uses a mechanically suspended prism system

Don't Forget Accessories for Your Astronomy Binoculars

Use a camera tripod with a binocular adapter or purchase a binocular mount to keep your binoculars steady. An ordinary camera tripod by itself won't do because the angle won't be quite right for sky viewing.
Don't clean your binoculars unless you must, and keep your fingers off the lenses. When necessary, use a microfibre cloth and liquid cleaner designed for binoculars.
A portable chair is great for those special nights when you are waiting for a satellite to pass.
Star maps and guides will help you find your way around the sky.
Buy a red light flashlight for map viewing, or shield the glow with red cellophane.

Invest in a good pair of astronomy binoculars and a sky map and begin your exploration of the universe. You should visit our astronomy forums and other binocular review websites to see what astronomy enthusiasts are using these days.

About the Author

Scott Gray is a freelance writer and outdoor enthusiast who loves to provide useful information about the different types of binoculars including zoom binoculars.

Binoculars - The Sky's The Limit (Part One)

2012-08-28T11:42:00.004-07:00

Binoculars - The Sky's The Limit (Part One)

Forget buying a telescope and equip yourself with a good pair of astronomy binoculars for your study of the night sky. Binoculars are not only cheaper than scopes, they allow you to see more of the sky at once, are more portable, and are easier to use. There is a wide range of prices and styles, and you should decide what features are most important to you before you begin shopping.

Consult consumer reviews and customer recommendations before you buy, although the general rule is that you get what you pay for in binoculars. Comparison shopping and ordering online makes the process easy.

Basic Tips for Choosing Astronomy Binoculars

There are two lenses in binoculars, and the ocular lens is the one closest to the eye and the objective lens is at the far end. When considering binocular sizes (e.g., 10 x 50), the former number describes the magnification of the ocular lens, which, in this case, means that objects will appear 10 times larger than seen just using the naked eye, and the latter number describes the size of the objective lenses. The larger the objective size, the more sky can be seen and consequently the binoculars themselves will be heavier and bigger.

If you are buying a pair of binoculars for multi-purposes (e.g., astronomy, bird watching, and viewing sporting events), you will probably be happy with zoom binoculars because you can easily and quickly adjust them for various distances. If your binoculars are going to be used primarily for astronomy, don't buy zoom lenses because they won't give you the sharp image that other styles will.

Lightweight binocs are less cumbersome than heavy, but even light, hand-held binoculars will start to shake and the image will blur when your arms become tired. Using binocular mounts or tripods prevents this problem and enables you to buy good binoculars without worrying about their weight.

Small binoculars have a narrow field of vision and since it is nice to be able to see a good stretch of the sky at once, don't buy too small a size. For example, 7 x 50 is good and 7 x 40 is acceptable, but don't go down to 7 x 30 or less if you are a beginner star gazer, or you will have a lot of trouble locating objects in the sky by moving from one object to another.

Avoid quick focus lenses or insta-focus because they go in and out of focus too easily, and avoid a fixed focus because you can't adjust them enough.

Go to part two of this article

Stargazing with Binoculars (Part Two)

2012-08-28T11:41:00.002-07:00

Stargazing with Binoculars (Part Two)

Terms You Need to Know

Ocular Lens – is the lens closest to the eye and the number indicates the magnification (i.e., 10 x 50 means that objects will appear 10 times larger than seen with the naked eye). Choose a magnification of at least 7.
Objective lens – is the lens farthest from the eye and the number indicates the size of lens at the far end. Choose 40 or better for a wide-angled viewing range (i.e., 10 x 40).
Zoom lens – can be adjusted for various distances and will be indicated by more than one number before the "x" ( i.e., 20/40 x 50).
Prisms – are blocks of glass that reflect the light within the binoculars. BAK4 prisms are the finest quality and BK-7 are good.
Anti-reflection coating – is described as multi-coated (good) or fully-coated (best). Avoid ruby-coated which gives the view a green cast and does nothing to increase night vision.
Diopters – is the optical scale for spherical power.

Viewing Tips

Adjust the binoculars by covering one objective lens, and then look through the binoculars with both eyes at a distant object and turn the center focus dial until the image is sharp and clear. Covering the other lens, and with both eyes open, focus on the same object and use the adjustable eye piece to make it sharp and clear. Future viewing at various distances will now require only an adjustment to the central focusing dial.
Heavy binoculars require a tripod or they will start to shake when your arms become tired.
For stargazing, choose a night when the moon is not visible or not very bright. The darker your surroundings, the better the view of the night sky. Wear warm clothing, and select a safe location.
Wait in the dark until your eyes are accustomed to the darkness (15 to 20 minutes). If you are using a star map to identify stars, planets, and constellations, make sure your flashlight has a red-glow setting or shield it with red cellophane.
Locate a bright star with your naked eye, and then use the binoculars to get a clearer look. "Star hop" by starting with a point you can identify, like the north star. Locate it by eye, find it with the binoculars, and then, by using it as a reference point, move on to the next object. After a little experience, you will be able to find and identify stars with your binoculars that can't be seen with the naked eye, and you will be on your way.

Astronomy is an ancient and beautiful science. Begin your exploration of the universe today!

About the Author

Scott Gray is a freelance writer and outdoor enthusiast who loves to provide useful information about the different types of binoculars including zoom binoculars.

All about telescopes: refractors, reflectors and more

2012-08-28T11:40:00.005-07:00

All about telescopes: refractors, reflectors and more

A telescope is an optical instrument used to magnify and enhance the view of faraway objects, be they astronomical or terrestrial. Most telescopes fall into one of two main categories: refractor or reflector. Also available are Schmidt-Cassegrain telescopes - a combination of reflector and refractor.

If you are considering buying a telescope you would be well advised to read our Telescope Buyers' FAQ.

Refractor

A refractor telescope uses convex (bending outwards) lenses to collect, focus and magnify light. Rays of light travel through the objective (main) lens where they are focused at the focal length of the eyepiece.

Reflector

A reflector telescope, on the other hand, uses concave (bending inwards - like a cave) mirrors. As the diagram illustrates, light travels down the tube where it is reflected (hence the name reflector) up to a secondary mirror near the top of the tube, which directs the light into the eyepiece. This exact system is known as a Newtonian Reflector. There are quite a few variations on this including the Georgian and Cassegrain reflectors.

Schmidt Cassegrain

A third type of telescope, which has gained immense popularity over the last 30 years, is the Schmidt Cassegrain telescope (SCT). This type of telescope uses both lenses and mirrors in a compound system as can be seen in the third diagram.

Advantages and Disadvantages

Each telescope has its own advantage, for instance the refractor is better for observing the planets and the moon and the reflector for deep-sky objects (e.g. galaxies). However, the refractor suffers from what is known as chromatic aberration. This is when the different wavelengths of light are brought to focus at different points due to the glass in the objective lens refracting (bending) the different wavelengths to different degrees. This, however, is only noticeable in refractors with an aperture (diameter of objective lens) of 10cm (4") or more. It can be corrected using achromatic and apochromatic (modified) lenses.

This can be very expensive, so very large apertures reflectors are more popular. The third type that I mentioned was the Schmidt Cassegrain telescope. It has grown in popularity because it combines the best of a reflector and refractor. They are very portable as the tube does not have to be as long as that of a reflector - this is because of the light being 'folded over'. They have an ease of use not available with the other telescopes and there are plenty of readily available accessories, e.g. computer controllability. They are most popular in their 20cm (8") guise - I own a 20cm SCT myself. SCTs, with their stable and sturdy tripods, are very useful for astrophotography.

Radio Astronomy

2012-08-28T11:40:00.002-07:00

Radio Astronomy

This article is the first in a series on Radio Astronomy. To view the second article: second radio astronomy article.

It is surprising to many people that radio astronomy does not entail listening for ET to phone home. SETI, (the search for extraterrestrial intelligence), represents a relatively tiny portion of radio astronomy. It would seem that the public perception of radio astronomy conjures up images of astronomers in tight jeans wearing headphones to detect some weak signal buried in the galactic noise. If we apply a brief reality check, we find that radio astronomy is much like optical astronomy, in that telescopes (instruments that detect, image and magnify) are used to observe the cosmos.

The difference is that while optical telescopes present images that are familiar in composition (i.e. they present images at frequencies which we can directly see), radio telescopes observe the cosmos at much lower frequencies. Most of us have seen the stunning images acquired by the Hubble Space Telescope. To be sure these images not only give us a glimpse of the wonders of the universe, but move us in spirit by generating a sense of awe. Unfortunately, the primary sensory input device for us humans (our eyes) is very limited in "bandwidth" (the span of electromagnetic frequencies, or 'colours', to which it is sensitive) and while the images move us, they do not give up their secrets easily. As a consequence, much of what is happening in the universe is hidden from our view.

To put it simply, each colour is a different frequency, and most of the colour pallet with which the cosmos is painted is invisible to our eyes. It only makes sense to expand our sensitivity, through instrumentation, to the other frequencies in the electromagnetic spectrum. The radio telescope is one of these instruments. It allows us to observe and image the universe at frequencies below our visual abilities which in turn reveals much of what is going on in the universe. Because certain radio frequencies pass effortlessly through pesky dust and gas clouds, we can now study objects heretofore blocked from our view. Also, since certain gases, molecules, and materials in the universe either absorb or emit 'light' at radio frequencies, these structures can be directly viewed by the radio telescope. This ability not only allows the observer to image these objects but also allows the observer to gather much more information such as composition, velocity, temperature and mass.

The span of frequencies that makes up the radio spectrum is immense, thus the variety and types of instruments that make up radio telescopes is varied in design, size, and configuration. Lower frequency (10 MHz - 100 MHz - wavelengths of 30 metres to 3 metres) instruments are generally arrays of antennas similar to "TV antennas" or are stationary reflectors of gigantic proportions with moveable focal points; some are over 30 meters high by 500 metres wide. At higher frequencies (100 MHz to 1GHz - wavelengths of 3 meters to 30 cm), very large parabolic or spherical reflectors are used, such as the large spherical "Dish" at Arecibo, Puerto Rico. At frequencies of 1 GHz to 10 GHz (wavelengths of 30 cm to 30 mm), medium to large parabolic reflectors are used 5 to 90 metres in diameter.

These reflectors are fully articulated and can observe any object simply by pointing the reflector. For frequencies above 10 GHz (wavelengths of 30 mm to .3 mm), high-precision parabolic reflectors are necessary, typically 3 to 20 metres in diameter. The reflectors are more like mirrors and are thermally stable as well as supported by complex structures since the surface curvature is held to demanding standards. The surface tolerances of these reflectors are held to plus or minus one hundredth of a millimetre for radio telescopes operating in the millimetre to sub-millimetre wavelength region. Each type of instrument opens a new set of "colours" with which for the astronomer may view the universe.

Optical telescopes give such clear images since the wavelength of visible light is so small in relation to the diameter of the focusing device (mirror or lens). Radio waves having enormous wavelengths by comparison do not focus into neat "pictures", rather they tend to interfere with one another since the focusing device (reflector) is tiny in relation to the wavelength. To construct a 10 mm wavelength radio telescope with the imaging capabilities of a small 4-inch optical telescope, one would need a reflector about 2 km (over 6000 feet!) in diameter; clearly this enormous size is impractical. It might seem at first glance that radio astronomy would be doomed to low-detail observations and rather dull data gathering tasks. The fact that light and radio waves tend to interfere with one another gives rise to a technique known as interferometry. Simply put, it allows two or more dish antennas to be placed widely apart or in arrays (such as the VLA "Very Large Array" in New Mexico) to function as if they were one large antenna (Aperture Synthesis). The interference between the signals of each of the receiving antennas, when timing corrections are introduced, allows for image reconstruction using Fourier Transforms. We can now get the resolution of a 2 km antenna by placing several antennas 2 km apart and correlating the data. Using this technique, it is possible to obtain milliarcsecond resolution. A milliarcsecond is roughly the equivalent of seeing a quarter in New York from Los Angeles!

With the advent of DSP (Digital Signal Processing), faster and smaller computers, and the introduction of super conducting amplifiers, radio astronomy has progressed at a breakneck pace. New arrays of antennas are being designed and built. Some contain over a thousand individual antennas all operating in harmony, giving resolutions that rival optical telescopes. Other arrays cover a hectare, and one in process covers a square kilometer as a "phased array", giving imaging capabilities not experienced before. The future for radio astronomy looks brighter than ever.

Jim Fredsti is a Research Engineer at

Owens Valley Radio Observatory,

California Institute of Technology,

Big Pine, California, USA.

To read the second article in this series: second radio astronomy article.