Skymania News and Guide

‘Seven planets’ in new solar system

2010-08-24T18:03:22Z

Astronomers have discovered a new solar system that appears to have almost as many planets as our own. They found up to seven planets orbiting a star that is of a similar type to the Sun, including one that is likely to be rocky and less than 1.5 times the size of the Earth.

Artist's impression of new solar system (ESO)

The star, labelled HD 10180, lies 127 light-years away from us in the constellation of Hydra, the water snake. Its collection of worlds was detected using a giant telescope operated by the European Southern Observatory at La Silla on a mountaintop in Chile.

A highly sensitive and world-beating “planet hunter” called HARPS was used to analyse light collected by the telescope’s 3.6-meter wide mirror, or “eye on the sky” over six years.

It found clear evidence for five giant planets similar in size to Uranus or Neptune in our own solar system. But there were also tantalising signs that two other planets are also present, one of which would be the smallest, or least-massive, yet found orbiting another star.

The positions of the planets in the new solar system also follow a similar pattern to that generally followed by our own Sun’s family of eight worlds, with each planet in order from the star being roughly twice as far as its sibling.

Using 190 measurements taken by the HARPS spectrograph, the team of astronomers followed tiny wobbles in the star’s position produced by the gravitational pull of its individual planets. The five strongest-pulling objects were diagnosed to be between 13 and 25 times the mass, or size, of Earth, and orbiting the star over timescales of six to 600 days.

The two other suspected planets include one about the size of Saturn which orbits in 2,200 days, or just over six years. The other would be the least massive planet ever found around another star, having a mass of only 1.4 times that of Earth.

There the resemblance must end because it appears to lie only a 50th as far from its parent star as Earth does from the Sun and it zips round it in a “year” lasting just 1.18 days. The five confirmed giant planets would all lie within the orbit of Mars in our own solar system.

Alien hunters will be encouraged by the growing evidence that planets are commonplace in the galaxy, providing more potential locations for life to have developed. Some have been found to be like planets in our own solar system. And scientists can even look for ET’s fingerprints in the planets’ atmospheres.

Reporting his team’s discovery in France today, astronomer Christophe Lovis said: “We have found what is most likely the system with the most planets yet discovered. This remarkable discovery also highlights the fact that we are now entering a new era in exoplanet research – the study of complex planetary systems and not just of individual planets.”

As well as HARPS, major planet discoveries are being made by Europe’s Corot space probe, a network of ground cameras called SuperWASP, and NASA’s Kepler space telescope.

• Discover space for yourself and do fun science with a telescope. Here is Skymania’s advice on how to choose a telescope. We also have a guide to the different types of telescope available. Check out our monthly sky guide too!

©PAUL SUTHERLAND, Skymania.com

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Yet another impact seen on Jupiter

2010-08-23T06:37:40Z

Yet another asteroid impact has been recorded on Jupiter by amateur astronomers, raising the possibility that these are occurring more frequently than was imagined.

Mr Tachikawa's image of new flash

Japanese observer Masayuki Tachikawa, of Kumamoto city, recorded a bright flash on the planet on August 20 with a Philips Toucam Pro2 webcam attached to his telescope, a 150mm refractor.

It was confirmed by a video from another Japanese observer, Aoki Kazuo, as having happened at 18h 31m 56s UT.

The event appears to resemble another bright flash that was independently observed by two different amateur astronomers on June 3, just two and a half months ago.

And that came after one of those observers, Anthony Wesley, of Broken Hill, Australia, recorded a dark spot that seemed to have been left by another impact a year earlier in July 2009.

There are suggestions that the latest flash, which happened on the edge of the dark North Equatorial Belt, might have been caused by an asteroid up to 1km wide hitting Jupiter, but that would appear to be purely guesswork at this stage. See more images of the new Jupiter impact here.

As the biggest planet in the solar system, lying on one edge of the main asteroid belt, Jupiter is bound to be something of a magnet for smaller objects. This year’s impacts are little more than fleabites to Jupiter and comparable to a large pebble producing a brilliant fireball in our own atmosphere.

Image of June's crash by Anthony Wesley

Last year’s dark spot, which was about the size of the Earth, suddenly appeared near the planet’s south pole and resembled markings left when a disintegrating comet hit Jupiter 15 years earlier.

That string of impacts was predicted in advance as astronomers watched the comet, Shoemaker-Levy 9, break up to resemble a string of pearls. Hubble took images of the scars left by both impact events.

However, nothing was seen following the flash that occurred in June, suggesting the impactor was swallowed up by the gas giant’s clouds without an ill effects.

©PAUL SUTHERLAND, Skymania.com

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Jupiter’s red spots in double act

2010-08-19T17:29:26Z

Amateur astronomers could be forgiven for seeing double on Jupiter as the famous Great Red Spot closes in on a colourful rival. A second oval feature is running up against its bigger brother, giving stargazers two red spots to view at once through their backyard telescopes.

Jupiter pictured by Simon Kidd showing its two red spots and moon Io

The spectacle comes just weeks after astronomers reported that one of the giant gaseous planet’s prominent dark belts had disappeared.

The smaller feature – dubbed Red Jr and big enough to swallow the Earth – used to be white. It formed from three oval storms in Jupiter’s atmosphere. Two merged in 1998 and the third was absorbed in 2000 to form a spot labelled Oval BA.

Alert observers noticed that its centre starting to turn red back in 2005 and it became more prominent the following year as it had a previous close encounter with the Great Red Spot. For most of the time, because different bands in Jupiter’s atmosphere rotate at different speeds, the two spots are widely separated. However, they come close together every two years or so, and this has created the present spectacle.

The pair of spots are clearly shown in the accompanying photograph by planetary observer Simon Kidd, of Welwyn, England, taken through his Celestron C14 at his home observatory.

Simon told Skymania: “The two spots are coming quite close to each other so it will be fascinating to watch and see what will happen. Perhaps the smaller spot will fade and lose colour or be deflected by the larger spot. One of the appealing things about astronomy is that one can observe such incredible phenomena from one’s own back garden!”

Robin Scagell, vice-president of the UK’s Society for Popular Astronomy, commented: “This shows that amateur observers can still play a part in monitoring the planets, even from the UK’s cloudy skies. Amateurs around the world can give virtually 24-hour coverage of Jupiter, but the Hubble Space Telescope only observes it occasionally.”

Jupiter is perfectly placed for observing the double act at the moment, rising late in the evening when it appears the brightest object in the sky apart from the Moon. Because Jupiter rotates in a little under ten hours, the spots are visible to us for around five hours at a time. You can find the optimum times, when the Great Red Spot lies on the planet’s central meridian, at this Sky & Telescope page.

Both red spots are swirling superstorms within which winds blow at around 350mph. The Great Red Spot, which is twice the Earth’s size, has been raging since at least 1831 and an earlier form of it was recorded by Cassini in 1665. Infrared images taken with NASA/ESA’s Hubble Space Telescope indicate that Jupiter’s storms are driven by heat from within the planet.

In May, astronomers were surprised when Jupiter’s South Equatorial Belt, which borders the Great Red Spot and is normally one of two main dark belts on the planet, had completely faded away. Amateur astronomers have also been first to detect impact scars on Jupiter.

©PAUL SUTHERLAND, Skymania.com

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NASA probe snaps fragile Earth

2010-08-18T19:09:44Z

You are here! A new NASA photo from the depths of space shows a fragile Earth as never seen before. Our planet and its companion Moon hang against a starry background in a dramatic shot from the Messenger probe between us and the Sun.

The Earth and Moon from Messenger (NASA). Click on image to enlarge

The unmanned spacecraft looked back as it heads on a journey that will eventually put it in orbit around Mercury, the closest world to the Sun. It was looking for a type of asteroid called vulcanoids that it is thought may lie between us and the Sun but be invisible from Earth because of the Sun’s glare.

During one of its sweeps, it picked out the Earth and Moon from a distance of 114 million miles (183 million km). No detail is visible on their bright surfaces which “burned out” as the search tried to pick out the fainter, smaller chunks of rock. If we could zoom in, they would appear full phase rather than crescents because of Messenger’s viewpoint.

No vulcanoids have yet been found but if they do exist, they will provide vital clues about the formation of the inner solar system, say experts.

Messenger’s principal investigator Sean Solomon, of the Carnegie Institution of Washington, said: “Our searches for vulcanoids may not turn up any objects. But a discovery of even one vulcanoid would change our thinking about the evolution of Mercury. The solar system still has many surprises in store for us, so it makes sense for us to be ready for the unexpected.”

Messenger, which was launched in 2004, has two more orbits of the Sun to make before it settles around rocky Mercury next year. So far it has made three flights past Mercury on its convoluted journey, photographing parts of the planet never seen before including a spectacular spider formation in 2008 plus a giant crater last year.

Its discoveries include evidence of volcanic activity and details of its magnetic field and tenuous atmosphere. The new image of Earth and Moon, released by NASA yesterday, was taken on May 6. See the full-size image here.

Observations from Earth of Mercury’s rotation suggest that it has a liquid core. The planet may have formed in a huge cosmic collision.

©PAUL SUTHERLAND, Skymania.com

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Ideal conditions for Perseid fireworks

2010-08-20T16:44:08Z

Sky watchers will enjoy a spectacular natural firework show this week thanks to perfect conditions for the year’s finest meteor shower. The Earth has begun to plough through a river of debris dumped by an ancient comet which is producing a display of shooting stars called the Perseids.

A bright Perseid meteor

The shower is one of the most reliable for astronomers in the northern hemisphere but 2010 is especially good because New Moon this week means there will be no overpowering moonlight to spoil the show.

Watchers with clear skies can look forward to viewing many of the bright meteor streaks as they burn up in the upper atmosphere. They are called the Perseids because they appear to stream in from the direction of the constellation of Perseus. However, they can appear in any part of the sky.

The meteor shower peaks between Wednesday and Saturday (August 11-14) and a single observer in perfect conditions might see up to 100 meteors an hour on Thursday night. There is no danger as the meteors are only the size of grains of sand and are completely vaporized.

The Earth has already entered the outer regions of the stream of meteoroids, left by a comet called Swift-Tuttle, and observers are already reporting sightings on Twitter with current rates at around 20 an hour. We have produced a special two-part Skymania guide to observing meteors to help you see them.

The radiant from which the meteors appear to stream is low in the sky when darkness falls but climbs steadily in the sky through the night and highest rates of all are likely to be seen in the early hours of Friday morning. (Because Perseus is a far northern constellation, fewer meteors are seen in the southern hemisphere).

Robin Scagell, vice-president of the UK’s Society for Popular Astronomy, said yesterday: “Warm summer nights make the Perseids great fun to watch out for. Make yourself comfortable in a deckchair under a clear sky, away from the streetlights, and you should soon see a few streaking across the sky.”

One British fan, Adrian West, is so keen to encourage people to observe the meteors’ beautiful trails that he has produced an entertaining Hollywood-style trailer, now on YouTube, for the Perseids as part of a Twitter #meteorwatch campaign. There is a Meteorwatch website too. (Note: This got so busy on the night of maximum that it crashed under the demand!) Go to our Skymania meteor watching guide.

By the way, don’t be surprised if you occasionally see a starlike point moving more slowly against the heavens while you are carrying out your vigil. It is likely to be one of the many satellites that now orbit the Earth. They can be distinguished from aircraft because they are silent and tend to show a single steady white glow whereas planes have coloured flashing lights. You may also notice a very bright object low in the east in the late evening and rising higher as the night progresses – that is the giant planet Jupiter.

©PAUL SUTHERLAND, Skymania.com

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Mountain UFOs mystery ‘is solved’

2010-08-20T16:36:08Z

The latest batch of “X-files” released by the UK’s Ministry of Defence appears to solve one of Britain’s most notorious UFO legends. On January 23, 1974, just before 10pm, villagers ran from their homes in the Llandrillo area of North Wales after hearing a loud explosion and seeing mysterious lights in the sky.

A satellite burns up - in this case Hayabusa (NASA)

Police sent a search team of ten officers to scour the Welsh mountains, later joined by an RAF mountain rescue team from Anglesey. They found no trace of an air crash.

It became known as the Berwyn Mountain Incident with similarities to the United States’ famous Roswell Incident. Conspiracy theorists claimed that a flying saucer had crashed in the hills and that alien remains had been discovered in the wreckage.

They claimed the area was cordoned off after the “crash” and local villages visited by mysterious investigators, who they described as the “Men in Black”. But evidence collected by the military now shows that lights seen in the sky at the time of the incident were the fragments of a disintegrating Soviet rocket as it burned up in the Earth’s atmosphere.

During the investigation, it was discovered that, by chance, there had been an earthquake around the time of the reported UFO crash. Experts ruled out an impact as the tremor’s cause, saying there would have been a crater clearly visible. Instead they put it down to a landslide which they suggested coincided with a shower of meteors and lights from poachers’ torches.

Skymania has previously included Berwyn Mountain among Britain’s top five UFO mysteries. Now the MoD has revealed papers about the events in a document released by the National Archives and labelled DEFE 24/2045.

It quotes from the logbook of a merchant ship, the SS Tokyo Bay, which had been sailing of the West African coast at the time. The log, passed on to the UK Met Office, reported that Mr R A Gill, the ship’s Second Officer, observed five objects, “spectacularly incandescent”, traversing the sky in very close formation and in a northerly direction.

The report gives the time of the sighting as 2150 GMT – around the same time as the lights witnessed from Wales. The Met Office gives the date, however, as January 24 though this would have been the date when the night being logged January (23/24) ended.

The MoD concluded that the Welsh UFOs were “probably the decay of the Soviet comunications relay satellite Molniya 2-8′s rocket body which decayed at about this time”.

The UK government has been declassifying and releasing all 160 documents relating to “flying saucers” over the country since 2008. It came after sustained pressure from several investigators who were using the Freedom of Information Act to seek details of individual incidents.

©PAUL SUTHERLAND, Skymania.com

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Double blast on Sun aimed at Earth

2010-08-22T15:12:04Z

UPDATE, August 4: Auroral displays have been seen overnight across Europe and the northern USA as predicted. Watch out for more!

A blast of violent space weather could hit the Earth tomorrow following two massive explosions on the Sun. NASA astronomers witnessed a huge flare above a giant sunspot the size of our planet and linked to an even larger eruption across the surface of Sun.

The Sun viewed on August 1 from SoHo (ESA/NASA)

By chance, the explosions were aligned towards Earth, sending a solar tsunami racing millions of miles across space.

Experts estimate a wave of supercharged gas called plasma will reach us this Tuesday when it will buffet the natural magnetic shield protecting Earth. It could trigger spectacular displays of the aurora or northern and southern lights.

The solar outbursts on Sunday August 1 were recorded by several satellites including NASA’s new Solar Dynamics Observatory which watched its shockwave rippling outwards. The flare over the sunspot was swiftly followed by an eruption 250,000 miles (400,000 km) away in a feature called a filament

UK solar expert Dr Lucie Green, of the Mullard Space Science Laboratory, in Surrey, followed the flare-ups using Japan’s orbiting Hinode telescope.

She said last night: “What wonderful fireworks the Sun has been producing! This was a very rare event – not one, but two almost simultaneous eruptions from different locations on the sun were launched toward the Earth.

“These eruptions occur when immense magnetic structures in the solar atmosphere lose their stability and can no longer be held down by the sun’s huge gravitational pull. Just like a coiled spring suddenly being released, they erupt into space.

“It looks like the first eruption was so large that it changed the magnetic fields throughout half the Sun’s visible atmosphere and provided the right conditions for the second eruption. Both eruptions could be Earth-directed but may be travelling at different speeds. This means we have a very good chance of seeing major and prolonged effects, such as the northern lights at low latitudes.” (Update, August 4: Dr Green’s subsequent analysis of satellite data reveals that there were four eruptions!)

Dr Green pointed out that if the eruptions do collide with the Earth’s magnetic field the conditions need to be right for there to be an effect like the northern lights. Specifically, the magnetic field at the front of the eruption needs to be pointing north. For latest news on the eruptions, check out Spaceweather.com.

Scientists have warned that a really big solar eruption, like the Carrington Event witnessed from Surrey in 1859, could destroy satellites and wreck power and communications grids around the globe if it happened today.

Such an event would be the biggest disaster ever to hit mankind, preventing the production of essential supplies including food, water and medicines. Other eruptions have been observed directed towards us but thankfully less severe.

©PAUL SUTHERLAND, Skymania.com

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Asteroid threat – but not until 2182

2010-07-30T19:06:16Z

A rather large asteroid is on a possible collision course with the Earth, space scientists have revealed. But there is no need to panic – even if an impact date is confirmed, it is not likely to be for 172 years.

Impression of an asteroid impact

An international team, including NASA experts, say in new research that the space rock has a one-in-a-thousand chance of an impact.

They may sound like high odds, but they are enough to mean the threat from the 560-meter (612-yard) wide asteroid will have to be taken seriously.

If such a cosmic missile hit land, it would blast a crater several miles wide – enough to devastate a city and wreak destruction for hundreds of miles around.

The good news is the evidence suggests that if there is an impact then it is most likely to happen in 2182. That is clearly a long way of and provides time to work out strategies to deal with the threat.

The asteroid was discovered in 1999 and is dubbed 1999 RQ36. The scientists had labelled it a “potentially hazardous asteroid” of the Apollo group because its orbit brings it close to Earth. But it was then considered a much lower risk.

Now scientists from Spain, Italy and NASA’s Jet Propulsion Laboratory in California have used computer models to produce a more accurate forecast of its path. Their results are published in the science journal Icarus.

The asteroid’s orbit has been fairly well known thanks to 290 visual observations and 13 measurements using radar, say the scientists. It takes around 14 months to go round the Sun. However, a disturbance called the Yarkovsky effect, caused by the force of sunlight on smaller bodies, introduces a significant “orbital uncertainty”.

Maria Eugenia Sansaturio, of Valladolid University, Spain, said: “The total impact probability of asteroid 1999 RQ36 can be estimated at 0.00092 – approximately one-in-a-thousand chance – but what is most surprising is that over half of this chance (0.00054) corresponds to 2182.”

Scientists had previously suggested sending a space mission called OSIRIS-REx to collect samples of the cosmic missile. Bill Cutlip of NASA’s Goddard Space Flight Centre in Greenbelt, Maryland, said: “This asteroid is a time capsule from before the birth of our solar system. You can’t underestimate the value of a pristine sample.”

Scientists have reduced the threat from another 300-meter wide space rock called Apophis which is due to make two close approaches to Earth within the next 30 years.

The first, on Friday the 13th of April, 2029, is virtually certain to miss us though it will come closer than TV and other geostationary satellites, at a distance of only 18,300 miles. But uncertainty over the effect of that close encounter meant that astronomers could not rule out the chance of an impact seven years later in 2036.

Now, however, the chance of a catastrophic collision on 13 April of that year have dropped from one-in-45,000 to an even more reassuring one-in-250,000.

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Water surprise – Moon is not so dry

2010-07-30T19:08:56Z

When Man first recorded features he saw on the Moon before the first telescopes, he assumed the large, smooth dark regions were seas just like on Earth.

The dark lunar "seas" (Paul Sutherland)

He gave them Latin names like Mare Tranquillitatis (the Sea of Tranquility) and Oceanus Procellarum (the Ocean of Storms).

But many years later scientists put our natural satellite under proper scrutiny and found that the “seas” were really vast plains of lava that had flowed from within and solidified billions of years ago. Far from being Earth-like, the Moon was a dry, dusty world, drier than the most arrid desert on our own planet.

Now in an astonishing reversal of ideas, new research shows that those Moon rocks are not as dry as was long assumed. There are certainly no rivers, lakes or any other liquid water. But a special form of it – hydroxyls – appears to be locked away in the lava. Experts say it could be converted easily into normal water just by heating it.

The implications are hugely significant for space exploration as well as astronomy. It means that setting up lunar colonies and observatories where astronauts and scientists could develop a permanent presence becomes a real possibility (given a change in political will, of course). There will be no need for the hugely expensive transportation of water supplies from Earth to keep our explorers alive.

Surprisingly perhaps, the new finding comes following a reaxamination of lunar basalt brought back to Earth by Apollo 14 astronauts nearly 40 years ago in 1971. Geologists at the California Institute of Technology (Caltech) and the University of Tennessee found structurally bound hydroxyl groups in the rock – in other words water.

Jeremy Boyce, main author of a paper about the discovery in the science joural Nature this week, said: “The fact that we were able to quantitatively measure significant amounts of water in a lunar mineral is truly surprising.”

His team took a detailed look at a mineral within the basalt called apatite using an ion microprobe that can analyze grains much smaller than the width of a human hair. Results showed that levels of hydrogen, sulphur, and chlorine in the sample sample were indistinguishable from apatites found in terrestrial volcanic rocks.

The story of water on the Moon has unfolded in a surprising way in less than a year. Last October a US probe fired a missile into a crater near the Moon’s south pole and confirmed that there is water ice in the shadows, dumped by comets over billions of years.

Later a scan from another probe found tons more water around the lunar north pole. Also last year it was found that a form of dew has spread across the Moon, presumably from this ice, penetrating into its topsoil.

And now comes the amazing finding that those supposedly dry lunar seas really do contain water after all.

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Star kicked out by giant black hole

2010-07-22T17:25:46Z

A runaway star found racing through space at an incredible 2.5 million km an hour (1.6 million mph), suffered a brush with a monster black hole at the heart of our galaxy, astronomers believe.

High-speed star's route (NASA/ESA)

Data collected using the Hubble space telescope suggests the speeding sun was part of a triple-star system that was drifting through the Milky Way a hundred million years ago.

But the threesome passed dangerously close to the centre of our galaxy where the supermassive black hole lurks.

The space scientists say it swallowed up one of the stars and booted the other two out of the Milky Way. As they flew, the two stars merged to form one super-hot blue star.

Labelled HE 0437-5439, it is now speeding about 200,000 light-years from galactic central point and high above the whirling disk of the Milky Way, according to a Hubble news release.

Around 16 hypervelocity stars are known, all of which have been discovered in the past five years. They are all suspected to have been flung from our galaxy’s centre but this is the first time the theory has been successfully tested.

As we reported two years ago, another team of astronomers previously suggested the star had been fired on its path by another yet-undiscovered black hole in a satellite galaxy of our own called the Large Magellanic Cloud.

But US Astronomer Warren Brown, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, a member of the Hubble team that observed the star, said: “Using Hubble, we can for the first time trace back to where the star comes from. Its motion points directly from the Milky Way center,”

“The star is travelling at an absurd velocity, twice as much as the star needs to escape the galaxy’s gravitational field. There is no star that travels that quickly under normal circumstances – something exotic has to happen.”

Watching hypervelocity stars is not simply a curiosity for astronomers. They believe that studying their trajectories could help them to learn how invisible dark matter is distributed around the galaxy. Astronomers claim to have proved the supermassive black hole exists by studying the motions of stars around it at the centre of the Milky Way.

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