Urban Astronomer News

Carnival of Space #236

2012-02-24T07:53:35.071Z

Better late than never: The 236th Carnival of Space has been up for some time, and you can get to it here: http://www.universetoday.com/93653/this-weeks-carnival-of-space-237-right-here/. The carnival plays on home ground this week, as it is hosted by Nancy Atkinson, editor of Universe Today. Give it a read to catch up on the past week's most interesting news on astronomy and space science!

Public Lecture: Space weather may invade your space

2012-02-19T21:26:30.083Z

Finally, something for people who don't live in Cape Town! This interesting talk will be held at the Sci-Bono Discovery Centre in Newtown, Johannesburg this Thursday. Note that, unlike the SAAO talks, you do need to contact the organises if you're planning to attend - details below:

TOPIC: Space weather may invade your space! Solar flares and Radio Communications

SCIENTIST: An Electric Engineer, Dr. Pierre Cilliers is a research physicist in the Space Science Directorate of the South African National Space Agency (SANSA). Based in Hermanus, SANSA is home of the Regional Space Weather warning for Africa. Between biking, running and enjoying nature Dr. Cilliers studies the impact of space weather on the upper atmosphere, the electrical power network and on communication systems.
DATE: Thursday 23rd February 2012
TIME: 6:30 for 7:00 pm

VENUE: Auditorium, Education Centre, Sci-Bono Discovery Centre, Miriam Makeba Street between Jeppe and President, Newtown, Johannesburg

RSVP: Refilwe Pico at 011 639 8448 or speaktoascientist@sci-bono.com

Secure lit Parking available directly in front of the building. Callum’s coffee shop will be open for light snacks and drinks before the event.

Public Lecture: From Stars to Surface

2012-02-16T09:56:13.160Z

SA Astronomical Observatory will host a free public lecture presented by Dr. Christian Hettlage on Saturday, February 25 at 20h00. The title of his talk is "From Stars to Surface: Surveying South Africa". After the talk, there will be tours of the site and stargazing.

Summary of the talk
Throughout centuries, navigation at sea was based more on experience than proper maps or measurements. It was only through technological advances such as the sextant and reliable clocks that this situation was drastically improved, these developments turned astronomers into official time-keepers. On land, nineteenth century astronomers were tasked with conducting accurate survey work. Twentieth century discoveries in physics, astronomy and space sciences enabled us not only to be guided in our cars by a friendly mechanical voice, or plough fields in straight lines by means of satellites, but also to survey our planets in unprecedented detail and even to estimate the size of planets around other stars.

The talk will outline this history of finding your way on land, sea and beyond, focusing on South Africa in particular.

Carnival of Space #236

2012-02-11T16:15:17.804Z

Welcome to the 236th Carnival of Space! Your host this week is Peter Lake of AstroSwanny, and features (once again!) a selection of the past week's most interesting news on space science and astronomy. Come visit, and be amazed!

Public Lecture: Evolution of Galaxies: What the MeerKAT can tell us

2012-02-06T09:48:15.242Z

Dr. Sarah Blyth, a lecturer in the Department of Astronomy at UCT, will give a free public lecture at S.A. Astronomical Observatory in Cape Town on Saturday, February 11 at 20h00. The title of her talk is "Evolution of Galaxies: What the MeerKAT can tell us". After the talk, there will be stargazing and tours of the site. Meerkat is currently being built in the arid Karoo region of South Africa and will be the largest and most sensitive radio telescope in the Southern Hemisphere until the completion of the Square Kilometer Array (SKA) in 2024. In addition to the valuable science MeerKAT will be doing, it also serves as a stepping stone for the development and testing of the technologies that SKA will require.

Evolution of Galaxies: What the MeerKAT can tell us
Some big unanswered questions in extragalactic astronomy are "How do galaxies form?" and "How did they get to look the way we see them today?". Astronomers hope to answer some of these questions of galaxy formation and evolution by studying the neutral hydrogen gas which is a significant component of galaxy structure. The next generation of radio telescopes such as the MeerKAT, which is currently being built in the Northern Cape, and the Square Kilometre Array (SKA) will enable us to study the neutral hydrogen in far away galaxies, allowing us to trace its evolution over cosmic time.

The end of Sumbandilasat

2012-02-09T09:43:22.449Z

Cape Town, viewed in red and infrared light.
Image by: Sumbandilasat

As South Africans, many of us don't even know that we have a space program, so we're especially proud of our locally built satellites. The most recent was Sumbandilasat, an Earth Observation micro-satellite operated jointly by the CSIR, the University of Stellenbosch and SunSat (A local company which designs and builds satellites). Sumbandilasat was launched in September 2009, on a Soyuz-2 launch vehicle from the Baikonur Cosmodrome, and was built to a budget using off-the-shelf components wherever possible. Although this approach allowed costs to be kept extremely low (for a satellite of its class...), it left the satellite with insufficient radiation hardening, with the consequences becoming apparent shortly after launch. A solar flare damaged the power distribution network, crippling two of the attitude control wheels and leaving the satellite in an uncorrectable tumble. Despite this, operators were able to synchronise the ground-facing cameras to succesfully return high-resolution images of the Earth. Even considering the fragility of the satellite, SunSat declared the mission a success since, after all, it was only ever designed as a technology demonstrator. According to SunSpace engineer Niki Steenkamp, the satellite has been an enormous success and has survived far longer than anticipated. Priceless information and experience has been gained through the satellite, experience that can only comes from actually building and launching a satellite.

But over time, radiation from continued solar events have damaged more and more systems until the recent announcement that Sumbandilasat was no longer able to perform its functions, and would be abandoned. No mention has been made regarding parking the satellite in a graveyard orbit (to avoid contributing to the growing problem of orbital debris), so presumably the uncontrolled tumbling has made such maneuvres impossible. Nevertheless, certain non-critical functions (including an repeater built for ham radio use) are still working, and might likely continue to operate for the foreseeable future.

Hayabusa: The Sequel

2012-02-07T13:17:30.295Z

Artist's conception of Hayabusa 2 approaching the asteroid 1999 JU3.
Credit: Akihiro Ikeshita/JAXA

If you've been reading Urban Astronomer from the beginning, you'll know that I was a big fan of the Japanese Space Agency's (JAXA) Hayabusa mission. Naturally, I'm thrilled to hear that JAXA have recently announced Hayabusa 2, which will hopefully perform a little better than the first attempt.

Hayabusa (meaning 'Falcon') was a robotic spacecraft equipped with an explosive harpoon and cutting-edge ion propulsion engines, sent out to collect samples from the asteroid Itokawa and bring them home. Unfortunately, the mission suffered an unbelievable number of malfunctions, with numerous systems (everything from the engines to the power supply to the sampling harpoon itself) failing one after the other. Still, with a great deal of ingenuity and persistence, mission controllers managed to not only limp the stricken craft home (only three years late!) but actually found useable samples in the cannisters which were parachuted back to Earth!

Hayabusa 2 will be slightly different from its parent. It will be visiting asteroid 1999 JU3 (a roughly spherical asteroid, a bit under a kilometer in diameter) using the same ion engines, but the guidance and navigation systems, the steering and the antennae have all be redesigned to be more reliable. The sampler will also use a much more gentle operation than its predecessor - instead of being blasted into the target like a harpoon, it will approach gently and then detonate an explosive charge to dislodge surface material, which should scoop a much larger sample into the cannisters.

I have high hopes for this mission. Here's to Hayabusa 2, may she complete her mission with the minimum of fuss, and bring home the maximum amount of space dirt!

Carnival of Space #235

2012-02-04T13:10:37.087Z

Carnival time! The carnival of space is a painstakingly selected summary of the best and most interesting of the past week's online writing about astronomy and space science. This week's host is Matthew Young of The Constant Amateur and can be found here. Click on through for a particularly readable carnival!

Could your school discover an asteroid?

2012-02-03T20:26:42.397Z

To mark Global Astronomy Month this April, a special asteroid search program will be launched by astronomy outreach group International Astronomical Search Collaboration (IASC), in conjunction with Astronomers Without Borders. Fifteen school will be selected from around the world to receive telescope images only hours after they have been taken by the Astronomical Research Institute on a regular basis so that students can scan them to search for new Asteroids. The program runs from 23 March to 27 April, and interested schools must submit their applications here by 16 February 2012. They will also obviously need access to PC's and a high speed internet connection. If you are a teacher and would like to give your class the opportunity to do some real science, while working with a global team, I'd strongly suggest you get your application in as soon as possible!

For more information, visit the official website here: http://www.astronomerswithoutborders.org/gam2012-programs/all-programs/1009.html

Carnival of Space #234

2012-01-31T08:25:32.609Z

And so it comes to this: the 234th Carnival of Space has just been launched, and is hosted by Ray Sanders of Dear Astronomer. Ray has trawled the internet for the best and most interesting news on space science and astronomy and presented them all in one Carnival for your enjoyment. Visit the carnival here to appreciate all his hard work!

Public Lecture: Cultural Astronomy of Aboriginal Australians

2012-01-26T14:02:21.621Z

Our continuing thanks to Thembela Mantungwa for these updates

S.A. Astronomical Observatory in Cape Town will host a "Cultural Astronomy of Aboriginal Australians" public talk on Friday, February 3 at 17h00. The talk will be presented by Duane W. Hamacher of the Macquarie University in Sydney, Australia.

Bio:

Duane W. Hamacher is currently managing the Macquarie University Planetarium and Observatory. Also, he is a member of the Aboriginal Astronomy Project, that is linked to the Research Centre of Astronomy, Astrophysics and Astrophotonics. Accordingly, he holds a joint position between the Department of Indigenous Studies (research) and the Department of Physics & Astronomy (Outreach).
His research areas are in Australian Cultural Astronomy, Indigenous Knowledge, History of Science, Observational Astronomy, Meteorite Impacts, Science Education and Communication. His first degree is a Bachelor of Science in Physics from the University of Missouri. Followed by an M.S. in Astrophysics from the University of New South Wales. He has recently submitted a PhD in Indigenous Studies at Macquarie University.

Abstract:

The Cultural Astronomy of Aboriginal Australians
Aboriginal Australians are among the oldest continuous cultures on earth, having arrived in Australia over 50,000 years ago. Threaded among the hundreds of different groups, each with a distinct language and culture with a deep knowledge of the night sky. This knowledge extends beyond simply naming stars or having stories about them. It includes a deep intellectual component that involved noting the complex motions of the sun, moon, and stars. The relationship between meteors, meteorites, and impact craters, the mechanics of eclipses, and the relative positions of stars in the sky and their connection to terrestrial events, such as the changing of seasons, the availability of food sources, and the passage of time. Evidence of this is recorded with community elders and in various artistic forms, such as stone arrangements and petroglyphs. In this talk, Duane will explore the role and development of scientific astronomy in Aboriginal cultures and discuss some of the amazing research being conducted by members of the Aboriginal Astronomy Project.

Citizen Science - Moon Mappers

2012-01-25T20:02:58.619Z

For the past week, whenever I've had a few spare minutes to kill, I've logged into my Moon Mappers account and done my bit for lunar science. A Cosmoquest project, the goal is to map out every single crater on the moon from imagery returned by the Lunar Reconnaissance Orbiter (LRO) and find unusual structures that require study. There are an enormous number of craters, however, so volunteers can choose between one of two sub-projects. In the first, where I'm putting my effort, you simply mark craters and other features of interest. In the second, you verify existing computer-generated maps -- the best algorithms are still only 80% accurate, so any work put in here goes straight to refining and improving the algorithms used to detect and identify craters.

The project is still in Beta, with under a hundred users (which I suppose makes me special in some way - I will be able to say I was doing it before it became popular and went all commercial!), but is still open to new volunteers. New users are required to complete a tutorial session before their work will be counted, but this shouldn't take more than two minutes, and doesn't insult your intelligence.

Carnival of Space #233

2012-01-21T06:02:39.449Z

Another week, another Carnival of Space. This week's host is Bill Dunford from Riding with Robots, and he gives us an interesting selection of news from the world of space science and astronomy. Click through here and read about the physics behind Death Stars, the building of stars, and the cleaning up of space debris.

2011 among hottest years on record

2012-01-20T11:29:41.351Z

NASA's Goddard Institute for Space Studies have just released their annual Surface Temperature Analysis report, in which they release their findings on average global temperatures for the previous year. You can read the report here, but the gist of it is that 2011 was the ninth warmest year since accurate global measurements began in 1880. That puts nine of the ten hottest years in recorded history in the 21st century, and all ten in the past 13 years. The warmest year was a tie between 2005 and 2010, with 2011 only 0.12°C cooler than that.

According to GISS director James E. Hansen, "We know the planet is absorbing more energy than it is emitting, so we are continuing to see a trend toward higher temperatures. Even with the cooling effects of a strong La Niña influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record."

GISTEMP 2011

The video clip to the left shows how temperatures in various locations around the planet have changed over the past 131 years, with red colours indicating that temperature increases, and blue indicating cooling. To provide the baseline, global temperatures over 30 years (from 1950 to 1980) were averaged for each measuring point. The changing colours on the map show changes relative to that average temperature. Such a long period was used for the base to ensure a real average, and to iron out any temporary highs and lows. The resulting video is quite striking.

Public Lecture: Decoding the Distance Scales of Astronomy

2012-01-19T20:32:34.474Z

Thanks yet again to Thembela Mantungwa at SAAO for the heads-up:

Deatrick Foster, a PhD student at Vanderbilt University in the USA will give a free public lecture at SA Astronomical Observatory in Cape Town on Saturday, January 28 at 20h00. The title of his lecture is "Decoding the Distance Scales of Astronomy: The cosmic distance ladder" After the talk, there will be stargazing and tours of the site.

Abstract:
Astronomers use a variety of techniques to measure distances to the stars. These methods are areas of active research in astronomy with significant implications for our understanding of the Universe. No single technique can measure distance for all the different size scales encountered in astronomy. With few exceptions, distances based on direct measurements can probe only a small fraction of our own Galaxy. For distances beyond that, getting reasonable distance estimates require us to make assumptions based on our best understanding of the underlying physical conditions involved. For example, we may recognise a particular distant object as a member of a class whose properties are consistent enough to use for accurate estimation of distances. This presentation is an overview of the methods used for determining the vast distances in astronomy.

Increased Solar activity helps clear away Space Junk

2012-01-19T14:21:07.674Z

Some good news after the ISS was recently forced to dodge a piece of orbital debris: As the sun moves into its active phase, the upper layers of the Earth's atmosphere heat up and expand, causing a tiny amount of drag on orbiting satellites, to the eternal frustration of their operators. But space junk, which tends to be small, slows down and begins spiraling downwards till it eventually re-enters the atmosphere and burns up. A report from NASA's Orbital Debris Program Office shows that the effect is strong enough that, over the course of 2011, the number of debris in Low Earth Orbit (LEO) actually decreased, despite increasing launch activity. As a specific example, they refer to the Fengyun-1C anti-satellite test of January 2007, when the People's Republic of China demonstrated an anti-satellite rocket by blasting one of their defunct weather satellites into shrapnel. The result of the test was to scatter thousands of scraps of metal across the orbit. As radar tracking stations monitored the debris (in order to be able to alert the ISS and satellite operators of impending collisions), they noted that by the beginning of 2011 only 6% of the debris had re-entered the Earth's atmosphere, yet less than a year later fully half had since fallen to Earth.

As the world's space-faring governments gradually wake up to the problem of debris in Earth orbit, it's good to know that natural phenomena will provide some assistance in dealing with the problem.

ISS dodges crash debris

2012-01-14T21:13:31.848Z

Back in 2009, a defunct Russian satellite (Cosmos 2251) collided with another satellite (Iridium 33) belonging to a satellite phone network, spraying a field of debris across their two orbits and bringing the problem of space junk to public attention. Then on 13 January 2012, the International Space Station (ISS) was forced to fire the engines on its Svezda Service Module to manoeuvre the 450 tonne structure out of harm's way, when ground tracking stations sounded the alarm that it was on a collision course with a piece of debris from the earlier smash.

The piece of debris in question was only about 10 cm across, so one might wonder what damage it could possibly do to something as big and solid as the ISS. But remember that the ISS orbits Earth at about 27,500 km/h, which gives us a rough idea of what the impact speed could have been. Compare this to a .50 calibre rifle bullet (the sort originally designed to let snipers disable parked vehicles and aircraft from a safe distance with a single shot) which is only 1.25cm's across and leaves the barrel at a measly 3000km/h, and you'll get an idea of the utter devastation that was avoided!

Luckily, the avoidance manoeuvre occured shortly before the ISS was scheduled to perform an orbital boost, so the two procedures were simply combined into one single operation.

Updated to include the names of the satellites involved in the earlier collision

Rings around exoplanets

2012-01-17T11:49:58.477Z

Artist's illustration of a ringed exoplanet.
Illustration Credit: Michael Osadciw / University of Rochester

Astronomers studying an exoplanet over 400 light years away have found that it has a system of rings similar to those around Saturn. The planet was discovered when two separate survey projects noticed the light from a star in the Scorpius-Centaurus association (the nearest region of recent massive star formation to the Sun) dimming slightly at regular intervals. After eliminating other possible explanations, they concluded that the star must have a planet, and that it's orbit was aligned with the Earth, causing it to block out some of the star's light once per orbit.

When Eric Mamajek (Assistant Professor of Physics and Astronomy at Rochester University) and graduate student Mark Pecaut studied the recorded light curve more carefully, they found that it did not dip in the usual smooth manner. Instead, it dimmed irregularly -- whatever was eclipsing the star could not be spherical in shape.

“When I first saw the light curve, I knew we had found a very weird and unique object,” said Mamajek. “After we ruled out the eclipse being due to a spherical star or a circumstellar disk passing in front of the star, I realized that the only plausible explanation was some sort of dust ring system orbiting a smaller companion -- basically a ‘Saturn on steroids.’”

Of course, we should not be surprised to find ring systems outside the Solar System. Although Saturn's rings are unique for their incredible brightness and beauty, rings can be found around most planets in our own Solar System, provided you look with sensitive enough instruments. Perhaps they will turn out to be almost as common as planets throughout the universe.

Carnival of Space #232

2012-01-16T07:29:25.876Z

Hot on the heels of last weeks edition, Amy Teitel of Vintage Space brings us the 232nd Carnival of Space. You know it's going to be a good one because it features Urban Astronomer! The carnival of space is a weekly round-up of the previous weeks best astronomy and space science writing on the web, and is a convenient way to stay on top of what's been going on.

Join the worldwide citizen-science star-hunt, GLOBE at Night, happening now!

2012-01-15T07:40:53.601Z

Press release from Constance E. Walker, Ph.D, director of the GLOBE at Night campaign:

More stars. Less light. Participate in GLOBE at Night!
Calling all Earthlings! Take a few minutes to get involved in the GLOBE at Night campaign to preserve dark skies! GLOBE at Night is a citizen-science campaign open to people all over the world to raise awareness of the impact of light pollution by inviting citizen-scientists to measure their night sky brightness and report their observations to a website from a computer or smart phone. Light pollution threatens not only our “right to starlight”, but can affect energy consumption, wildlife and health. Through 2011, people in 115 countries contributed 66,000 measurements, making GLOBE at Night one of the most successful light pollution awareness campaigns to date. Please join us to participate in the 2012 campaign an hour after sunset til about 10pm January 14 through 23, February 12 through 21, March 13 through 22, and April 11 through 20. For information and resources, visit us at www.globeatnight.org

Carnival of Space #231

2012-01-13T10:39:36.594Z

A little late this week is the 231st Carnival of Space, hosted by Chris Dann of Weird Warp. As usual we have a heady brew fermented from the best writings on space science and astronomy that were presented on the web over the past week. Click through and enjoy!

Public Lecture: Our strangely repulsive Universe

2012-01-12T12:31:53.922Z

With thanks to Thembela Mantungwa for letting us know:

Dr. Chris Clarkson, a postdoctoral research fellow in the Department of Mathematics and Applied Mathematics at UCT will give a free public lecture at S.A. Astronomical Observatory in Cape Town on Saturday, January 14 at 20h00. The title of his lecture is "Our strangely repulsive Universe: the dark energy mystery in cosmology" After the talk, there will be stargazing and tours of the site.

Summary of the lecture:

Our strangely repulsive Universe: the dark energy mystery in cosmology

Late last year, the Nobel prize in physics went to three cosmologists for “the discovery of the accelerating expansion of the Universe through observations of distant supernovae”. But what does their discovery mean? And what are the implications? In this talk he will explore our universe on the very largest scales in space and time, and investigate how everything we observe fits neatly together into a single 'Big Bang' picture of the universe. Then we'll see that the 'dark energy' that seems to be accelerating the cosmic expansion rate may be telling us something far deeper: that our universe is not alone...

GRAIL's orbit the Moon

2012-01-10T21:25:50.129Z

Using a precision formation-flying technique, the twin GRAIL
spacecraft will map the moon's gravity field, as depicted in this
artist's rendering.
Image credit: NASA/JPL-Caltech

The two spacecraft of the Gravity Recovery And Internal Laboratory (GRAIL) mission recently settled into orbit around the Moon after their launch in September last year. They will spend the next few months gently maneuvering into formation on a circular orbit passing over the Moon's poles, at an altitude of only 55km above the lunar surface, in preparation for some clever sciencing. The two spacecraft, GRAIL-A and GRAIL-B, are equipped with a GPS-like system of precisely timed radio signals to measure their separation with an accuracy of only several microns. Such precise measurements are the key to the mission's science objective: mapping the Moon's gravity field.

Since the Moon is not a perfectly smooth uniform sphere, its gravity field is slightly irregular. The field in an open plain, for example, is different to the field next to a massive mountain (which has its own gravity which combines with that of the rest of the Moon). The theory is that, as the individual GRAIL spacecraft pass through the stronger and weaker areas of the Moon's gravity field, their orbits will be affected by a very tiny amount. Over time, enough of these peturbations will be recorded for mission scientists to be able to map not only the mountains and hills of the Moon, but geological features hidden beneath the surface. There is a similar mission mapping the Earth, (GRACE) which has been running since 2002.

Carnivals of Space #229 and #230

2012-01-08T21:03:06.878Z

I've been away from my keyboard for long enough to miss two Carnivals of Space. You can catch up with them both right here. The 229th carnival is hosted by Next Big Future, and the 230th is hosted by Cheap Astronomy. Both continue the grand old tradition of the Carnival of Space by collecting a week's worth of astronomy and space science news into one easily digestible package for your entertainment.

2012 to be Huge!

2012-01-08T20:56:11.794Z

It's a little late for new-year messages, but since I've just returned from a long deserved break with my wife, I'll be making no apologies. 2012 will be Urban Astronomer's third year, and this is when we're going to start stepping things up a little bit. I will start small, with a bit of rebranding, but we're planning to start expanding into new realms, such as print and video. These are new to me, but I have some expert help on standby and hope to start making big waves!

Far more ambitious, though, is the goal of moving to a new hosting service. Currently we run on Google Sites, which has to be about the easiest way to post content on the web. I've been more than satisfied with their product over the years, but they do have certain limitations, not least of which is the maximum storage space of 100MB. Before using Google Sites, I was always used to manipulating a site's source code by hand at the operating system level, and want to retain that level of control. But this will be hard - Urban Astronomer is approaching 700 individual pages. I might not even fully understand the problem I'm trying to solve for a while, so this particular change might not even happen this year.

But enough of vague hopes and ill-defined goals. We've grown consistently over the years, and begun to show measurable advertising revenue, and for this I'm grateful to all of you, my readers. Keep reading, keep mailing, and keep pushing me to higher and higher standards!

VLT Timelapse Video

2011-12-27T21:35:54.471Z

I seldom post anything for purely aesthetic reasons, but this timelapse video of the southern skies, recorded at the ESO's VLT (Very Large Telescope - four individual 8.2 meter telescopes capable of working together as a single instrument), just blew my mind. I highly recommend setting it to full screen and enjoying the show. The sequence is composed of images taken by Stephane Guisard and Jose Francisco Salgado.