Australian Science

Category: Space

  • Giant Impact: making the moon

    Giant Impact: making the moon

    It began… where it always begins — out there — in the vastness of space. What would it look like, that void of empty nothingness? So early on in the sound of creation, indescribable things all around. Not yet planets, not yet moons. Not yet defined. A titanic mass of rock. Different. Ugly and melancholic. Mischievous and cumbersome. As immediately as it’s gone, another smaller rock — about a tenth the size of its predecessor — in the other direction. We will come to realise that they are almost on the same path. A perilous planetary orbit around our sun.

    One is a destroyer. The other is to be destroyed. The larger mass continues to grow as it gobbles up remnants from a cloud of dust. A hot, violent place with molten rock mantles wrapped around a dense hot core. On the other side of our sun swings the smaller mass. Both will have the same fate. On the far side, they collide. A cataclysm of apocalyptic proportions. In the vacuum/vacuous of space not a sound is heard. The smaller rock ploughs into its destroyer, like the little man in a fight with a lot to prove. It sinks deep into its molten core. Spiralling vast amounts of debris in long arcs into orbit. Debris, drawn together by nothing more simple than gravity, clump together, forging something close to a primitive moon. And with primitive moons come primitive planets. Finally, one defines the other.

    This has always been the theory… at least, more eloquently put in the form of maths, calculations, numbers and analysis. The origin of our Moon by giant impact has always been the leading theory. Leading because it is able to explain so many features of the Earth-Moon system. From it’s current spin and angular momentum to its composition. Both Earth and Moon are very similar in their oxygen, tungsten, chromium, and titanium isotopes — leading to the logical conclusion that one was formed from the other, since these isotopes vary differently in different planetary bodies and meteorites.

    However, simulations have shown this not to be the case. It is the Moon that should have a similar isotopic composition to the smaller impactor in this scenario, but instead it is made up mostly of material from Earth. Researchers had been tinkering around with the permutations and combinations to find such a scenario of impact that could satisfy all conditions. But to date, none had come close.

    In papers published in Science by researchers from Harvard and the Southwest Research Institute, a new model is proposed. One that adequately accounts for a similarity in composition while also coming out with an appropriate mass for Earth and Moon. One paper describes two bodies of similar mass colliding slowly, while the other describes a giant erosive impact (with a small impactor) happening really fast. Both have the same solution to the problem. That is to have the Earth-Moon system losing angular momentum over time, reaching its present state through the Sun’s gravitational influence. Thereby, in the end, both coming to a compromise in explaining the physics and the overall geo-chemistry of the Earth-Moon system.

  • The nearest solar system to ours has an Earth-sized planet…

    The nearest solar system to ours has an Earth-sized planet…

    Already there’s an artist’s impression of the
    newly discovered ‘Alpha Centauri B a’

    Yes—you read right. Alpha Centauri has a planet, and it is roughly the size of Earth. And at just 4.37 light years distance, it is theoretically reachable (with a whole lot of space travel development!) despite the frustrating limitations put on us by Mr Einstein.

    In a paper appearing in the journal Nature today, lead author Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal) explains how they use the 3.6-metre telescope at the European Space Observatory’s La Silla Observatory in Chile to detect the tiny back-and-forth wobbles to a sun’s position that are caused by the gravitational mass of a planet revolving around it.

    BUT don’t pack your bags yet. This planet is closer to its sun than Mercury is to our Sun. So close in fact that it orbits it in just 3.2 days. So close that its surface temperature is likely to be around 1200 degrees Celsius.

    So not exactly in the much-sought-after ‘Goldilocks zone’—that orbital distance from a sun that would allow liquid water to exist on a planet, making it theoretically hospitable to life—as we know it anyway…

    And besides, while 4.37 light years sounds pretty close—that’s some 56 trillion kilometres—56,000,000,000,000 kilometres. To put that into perspective, Voyager 1 is currently 18,353,400,000 kilometres from Earth, and it was launched in 1977! How’s that in light years? Just 16 hours, 59 minutes and 38 seconds of light-travel time. So we’d probably need something like Arthur C Clarke’s Rama spaceship to make the crossing, because we’d be in there for a very long time…

    Let’s just clarify some details. Alpha Centauri isn’t one star, it’s actually three:

    • Alpha Centauri A (α Cen A)—about 110% the size of our Sun and 152% the luminosity
    • Alpha Centauri B (α Cen B)—about 91% the size of the Sun and half its luminosity
    • Proxima Centauri (α Cen C)—a red dwarf about 1/7 the size of the Sun (just 1.5 times the size of Jupiter) and less than 2% its luminosity

    Alpha Centauri A and B form a binary 4.37 light years from us. The distance they are apart varies between the distance from the Sun to Saturn, and to Pluto. Proxima is gravitationally connected to the binary, but actually slightly closer—4.24 light years away, making it the closest star to our solar system. This system is so close to ours that most of the night sky viewed from any planet there would be recognisable to us, with most constellations virtually unchanged from how they look here.

    Comparative star sizes

    Alpha Centauri is very easy for us to find in the Southern Hemisphere. It’s the fourth-brightest star in our skies at magnitude -0.27, is in the constellation Centauri and is also one of the Pointers to the Southern Cross—the furthest one from Crux. It’s also the brightest of the two pointers and indeed the whole Centauri constellation—hence the alpha in the name. A reasonable amateur telescope or even good binoculars will resolve the binary system, with clear differences between the sizes of the two stars. You need a fair bit better telescope and very good seeing to find Proxima…

    The discovery was made using the HARPS instrument on the ESO telescope—the High Accuracy Radial Velocity Planet Searcher spectograph. Rather than detecting sideways wobbles, HARPS was able to discern variations in the star’s light due to red-shifts and blue-shifts of the forward and away aspects of the star’s wobbles! Considering that the relative velocity this movement is in the order of the speed a baby would crawl, it’s a truly remarkable achievement.

    No doubt others will be looking to verify the finding over coming months. There’s a small (10 to 25%) chance that the planet could be orbiting in an elliptical plane that has it passing in front of α Cen B from our perspective. If so, the other main way that planets are found could be used. This method detects periodic dips in the star’s brightness caused by the planet’s partial eclipse, and is the way the Kepler Space Telescope has been used to find hundreds of other exoplanets.

    Sources:

    http://www.eso.org/public/news/eso1241/

    http://www.nature.com/news/the-exoplanet-next-door-1.11605

    http://bigstory.ap.org/article/earth-sized-planet-found-just-outside-solar-system

    http://www.sciencenews.org/view/generic/id/345756/description/The_alien_next_door

    http://en.wikipedia.org/wiki/Alpha_centauri

  • Citizen Scientists Discover Four-Star Planet with NASA Kepler

    Citizen Scientists Discover Four-Star Planet with NASA Kepler

    The discovery of planets continues to expand beyond the domain of professional astronomers. A joint effort of amateur astronomers and scientists has led to the first reported case of a planet orbiting a double-star that, in turn, is orbited by a second distant pair of stars.

    Aided by volunteer citizen scientists using the Planethunters.org website, a Yale-led international team of astronomers identified and confirmed discovery of the phenomenon, called a circumbinary planet in a four-star system. Only six planets are known to orbit two stars but none of these are orbited by a distant binary.

    Image Credit: Haven Giguere/Yale

    Coined PH1, the planet was identified by the citizen scientists participating in Planets Hunters, a Yale-led program that enlists the public to review astronomical data from NASA’s Kepler spacecraft for signs of planets transits distant stars.

    “I celebrate this discovery as a milestone for the Planet Hunters team: discovering their first exoplanet lurking in the Kepler data. I celebrate this discovery for the wow-factor of a planet in a four-star system,” said Natalie Batalha, Kepler scientist at NASA Ames Research Center, Moffett Field, Calif. “Most importantly, I celebrate this discovery as the fruit of exemplary human cooperation– cooperation between scientists and citizens who give of themselves for the love of stars, knowledge, and exploration.”

    A bit larger than Neptune and thought to be a gas giant, PH1 orbits its host stars every 137 days. Beyond the planet’s orbit approximately 900 times the distance between the sun and Earth, a second pair of stars orbits the planetary system.

    The research paper submitted to the Astrophysical Journal is scheduled to be presented today at the annual meeting of the Division of Planetary Sciences of the American Astronomical Society in Reno.

    Ames Research Center in Moffett Field, Calif., manages Kepler’s ground system development, mission operations and science data analysis. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., managed the Kepler mission’s development.

    Ball Aerospace and Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

    The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA’s 10th Discovery Mission and is funded by NASA’s Science Mission Directorate at the agency’s headquarters in Washington.

    For information about the Kepler Mission, click here.

    Source.

  • What an Astronaut’s Camera Sees from ISS

    What an Astronaut’s Camera Sees from ISS

    When astronauts head to the International Space Station (ISS), Dr. Justin Wilkinson,  the chief geoscientist at NASA, asks them to snap pictures of various geographical locations. From this vantage point 250 miles above the planet’s surface, he learns many things — for example, he tells Slate, “there are a lot more examples of a geographical phenomenon called an inland delta or megafan—that is, deltas formed far from coastlines—than was once thought.

  • 2013 looks like being the year of the comet

    2013 looks like being the year of the comet

     

    Comet Lovejoy, taken by astronaut Dan Burbankfrom the ISS

    The astronomy world has been buzzing since it was announced on 24 September – C/2012 S1 is a new comet that could be lighting up our skies like none in living history by November 2013. It’s been named Comet ISON after the telescope research network used to discover it – the International Science Optical Network, using its 16″ telescope in Russia.

    It has since been confirmed, using one of the scopes from the public subscription-based telescope network iTelescope.

    With a trajectory taking it very close to the Sun, people are predicting that it could be bright enough to be visible in daylight, like Venus. Ernesto Guido, Giovanni Sostero & Nick Howes  advised on the blog for the Associazione Fruiulana di Astronomia e Meteorologia that it will pass within 0.012AU of the Sun – with one AU being the distance of Earth from the Sun – at the end of November and about 0.4AU from Earth in early January 2014. That’s about 1.8 million kilometres from the Sun.

    They predict it will become a naked-eye object from early November, and peak in negative magnitudes between 25 November and 3 December, with the brightest a whopping -10.6. Given the visual flop that was the last Haley’s Comet visit, they urge caution with these calculations. But calculations by others appear to confirm that it will likely be very bright.

    (more…)

  • A flawless launch for the world’s first commercial space mission

    A flawless launch for the world’s first commercial space mission

    Photo: Ben Cooper http://www.launchphotography.com/SpX-1.html

    Elon Musk’s commercial space travel venture SpaceX has ticked off another global first – the first commercial space flight. Watch a replay of the launch first stage:

     

    The SpaceX Falcon 9 rocket roared off the launch pad at 11:35am Canberra time, boosting the robotic Dragon capsule into a three-day chase of the International Space Station, carrying a NASA-commissioned resupply cargo. The media kit includes the full cargo manifest – 905 kilograms each way.

    What it doesn’t mention is that the cargo includes a freezer with vanilla and chocolate ice cream for the crew! Special treat.

    SpaceX are switched on with their broadcasts too – they had multiple onboard cameras giving some amazing perspectives, such as this one of the second stage rocket glowing white hot.

    This one shows the solar array deployment – unfolding surprisingly quickly.

    During the broadcast, SpaceX confirmed the stories behind the naming of their craft: the Falcon 9 is named after Han Solo’s Millenium Falcon on Star Wars, and the 9 is for the nine Merlin rocket engines that power it. This screengrab shows the Falcon breaking the sound barrier.

    The capsule itself is named Dragon, after the old show Puff the Magic Dragon, following criticism back in 2002 of SpaceX’s goals. This screengrab shows Dragon docked to the ISS.

     

    Recently, SpaceX also tested their “grasshopper” configuration – a set of legs on the base of the first stage. The goal here is to retain some fuel in the booster and return the whole thing back to a gentle landing for reuse.

    This shows the shock absorbers on the grasshopper legs. It was only a short hop a few metres off the ground, but it’s a start.

    And what about this as a workplace?

    Finally, here’s the launch control room in SpaceX HQ. NASA it is not!

    The Dragon capsule looks very cylindrical there – just a wide angle lens distortion.

  • For sale: One world class infrared telescope

    For sale: One world class infrared telescope

    Image © Tom Kerr/A Pacific View

    The world’s largest and most productive dedicated infrared observatory just went on the market in an unprecedented attempt to try and prevent it from being shut down and dismantled. In a bold move, the directors of the United Kingdom InfraRed Telescope (UKIRT), based on Mauna Kea in Hawaii, have just released a prospectus detailing the telescope’s impressive achievements and capabilities in the hopes that they can find sponsorship and save the observatory from certain doom. That may sound melodramatic, but doom genuinely is the most fitting description.

    The Anglo-Australian Telescope, also abandoned by the UK, but still safe in the care of the Australian government. (Image Credit: Ahilan Parameswaran/Wikimedia Commons)

    UKIRT’s death knell has, in fact, already been tolled. At the start of Summer, the UK’s Science and Technology Facilities Council announced that it would be terminating funding and that all telescope operations were to cease by September 2013. The UKIRT board released an official statement explaining their grim disappointment over the decision, and morale has been low for everyone involved with the telescope ever since.

    Unfortunately, since their formation in 2007, the STFC have seemingly been determined to rid the UK of its telescope access. Another casualty was the Anglo-Australian Telescope (AAT). Constructed at Siding Spring Observatory in New South Wales, the AAT was originally built and operated in partnership between Australia and the UK, but since it’s 36th birthday in 2010 it has been owned and funded solely by Australia. The AAT is still the largest optical telescope in Australia and it continues to the crown jewel of the Australian Astronomical Observatory. Sadly, the future for UKIRT looks rather more bleak.

    Should they fail to find funding to continue it’s operation, then in September 2013 UKIRT will have to be dismantled and erased from Mauna Kea. Under the agreement originally made with the Hawaiian government, any telescope no longer in operation must be removed, and the mountain must be returned to its natural state. This once proud telescope will simply be no more – a heartbreaking prospect in the eyes of a great many astronomers worldwide.

    The most tragic part is that UKIRT is actually at its most productive right now. After being the world’s largest dedicated infrared observatory for over three decades, UKIRT is currently boasting a record level of productivity. Being as it’s exceptionally cheap to run and maintain (compared to other world-leading telescopes, it costs little more than pocket change), it’s easily one of the most productive telescopes in the world. And the directors are quite literally offering it to anyone in the world who may have the money to finance it. A dramatic move – no world class telescope has ever been simply offered up for sale on the global market before. Now, all the astronomical community can do is to hope that someone is willing to buy it.

    Whether you happen to be a billionaire playboy philanthropist interested in owning a telescope, or just curious to know more about UKIRT, their prospectus is online for all to see.

    Image © Tom Kerr/A Pacific View
  • My mega grab-bag of astronomy resources for teachers, students, telescope beginners and space fans

    My mega grab-bag of astronomy resources for teachers, students, telescope beginners and space fans

    Whether you are a parent, teacher, student or simply an interested enthusiast, here are a number of interesting sites, podcasts, and social media people for you to draw on as you get going in amateur astronomy.

    Podcasts provide an amazing resource – all free. Most are available via iTunes, the original publishers’ websites, or a raft of other podcast aggregators. There are very good apps to allow you to download podcasts to your smartphone for listening when suitable – Podcruncher is my choice for the iOS platform – brilliant app and service. Just don’t bother trying to use the Apple Podcasts app – it’s a total lemon. Good podcast apps also allow you to increase the playback speed up to double normal (Podcruncher goes in quarter increments) and surprisingly you learn to follow it. In fact, it can get so listening at normal speed is far too slow!

    Many of these links also have Twitter accounts (where noted), so you can keep right up to the minute!

    Astronomy podcasts:

    In Australia there is the wonderful StarStuff, an independent project run by Stuart Gary but sponsored by the ABC, with the 30-minute podcasts at ABC. @abcstarstuff


    Canberra’s Steve Nerlich produces Cheap Astronomy, regular 10-minute shows of varying complexity. @cheapastro

    Overseas, despite a truly ugly website, the fantastic Naked Scientists from UK’s Cambridge University have a stack of brilliant podcasts on general, science, archaeology, earth sciences, oceans, Africa, great kitchen-friendly experiments, and the monthly 60-minute Naked Astronomy, steered by Ben Valsler.

    Tony Darnell works in the Space Telescope Science Institute and as a hobby runs Deep Astronomy, with videos and podcasts generally about 10-minutes.

    There are a stack of NASA video and audio podcasts. Of interest are the space telescope ones for Hubble, Spitzer, Chandra, plus This Week @ NASA, Universe, Earth…where to stop? You’ll be amazed at how much NASA is doing – for an agency that altogether too many people think has shut up shop!

    365 Days of Astronomy is a real mixed bag of 10-minute podcasts – one for every day of the year. And it’s well worth looking back over previous episodes. Following are some specific ones worth checking out.
    Teachers could start with four of the best called ‘Wonders From Class’ by Diane Turnshek from Carnegie Mellon Uni. Over four podcasts and with great passion, she describes how she engages and interests her students with the field of astronomy. Part 1, Part 2, Part 3, and Part 4. Some others for beginning viewing and then a bit more:
    Common Q&As about telescope use – from RapidEye Observatory
    8 Telescope Tips for Beginners – by Telescope Man
    Buying your first telescope – Telescope Man again
    Have a plan – by Ed Sunder of flinstonestargazing.com
    How to be an armchair astronaut – From Riding With Robots – now there’s a site to spend some time at!
    Armchair astronauts exploring the solar system – by Doug Ellison ofunmannedspaceflight.com @doug_ellison
    Exploring space with your computer – a guide to computer simulation tools by Bruce Irving of JPL
    Moving onto photographing what you see:
    Introduction to astrophotography – by Adam Pender
    Webcam astrophotography – by Alexander Hobson
    Amateur astrophotography for beginners – by Richard Drumm
    Astroimaging under light polluted skies – by Robert Vanderbei
    Expanding further – into spectroscopy:
    Basic spectroscopy for amateurs  and Part 2 – by Mark DeVito and Tom Field

    And if you’d like to go a bit further, you can subscribe to an entire university astronomy course via podcast – all the learning but no horrible assignments or exams! Here’s one in audio format from Ohio State Uni. There are others too, including video. Check iTunes, or iTunesU, the app for which includes study notes and the ability to record your own notes as you go along.

    Observing podcasts:

    The Sydney Observatory posts a monthly podcast summarising the night sky viewing for the month – great for Southern Hemisphere viewers and East Coast Australians in particular. They have the added benefit of a transcript so you can print and highlight the key bits as a night sky viewing plan. @sydneyobs

    NASA’s Jet Propulsion Lab has a short monthly video podcast, plus there’s a stack of related brain food on their site.

    Observing with Webb – another USA podcast by Rod Webb, but many of the sights will be visible here, just in different locations.

    Telescope Man – look for the monthly viewing summaries. No nonsense, best viewing tips, with catalogued numbers if you have a go-to scope, but based on Texas. Plenty of other good beginner podcasts too.

    Non-podcast observing resources:

    The Hayden Planetarium (part of the American Museum of Natural History and headed up by none other than Neil deGrasse Tyson @neiltyson) has a good monthly sky report. You can see a lot of what they discuss, but of course not all. You’ll also find their 3D atlas to the Universe.

    Slooh has several large telescopes around the world and you can view the feeds for free. They have guest speakers during regular events. @slooh

    Heavens Above allows you to register and enter your location, then get schedules of when key objects will pass over your patch of the sky – from GPS satellites to the International Space Station. Find out why the brightness scale goes backwards, planet and comet locations, and more.

    If you just want to focus on passes of manned vehicles like the ISS or Soyuz, then check the RSS subscription for your location at NASA Human Spaceflight.

    Stellarium – a free public domain computer planetarium. Free-standing once installed with no need of web access, so you can switch to red mode and take your notebook computer out with you.

    Celestia – another free planetarium. This one lets you explore off-planet, and even check out various space missions.

    Eyes on the Solar System – NASA’s mission tracking simulator. Go for a ride along with every NASA space mission past and present. A great way to piggy back onto the Mars Curiosity rover and relive her descent to Mars last August!

    Non-podcast astronomy resources:

    NASA’s Breaking News is a good resource, and has a useful RSS feed – check out Google Reader for how to collate key websites simply via RSS feeds, and Feedler Pro is a great app for viewing your Google Reader subscriptions on iThings. @NASA

    NASA also has a comprehensive education section, with specialist information for teachers at different levels, students and a kids club. Too much to list and it seems to grow every time you return. It’s not all about the US either – they have an international Scientist for the Day competition running right now for school students.

    It’s hard to go past Space.com for some of everything you want, and great RSS and Twitter feeds. They have a good shop too – from meteorites to kids’ spacesuits, genuine gone-to-space memorabilia to clothing. I mean, you’ve got to look the part for your classes right? @spacedotcom

    With broadband, giant televisions with network sockets, and a high definition feed from NASA TV, there’s never been a better time for live viewing rocket launches, spacewalks, and more. Keep an eye on the schedule for education shows too. Be warned though, spacewalks are REALLY long and slow-mo. Some younger viewers will have a short attention span for them. But launches…Phroar! Crank up the volume.

    The Square Kilometre Array is the project to build the world’s biggest radio telescope – right here in Australia. And in South Africa. It will be the biggest science project ever in our history. Good video clips explaining the project.

    Bad Astronomy blogger Phil Plait sorts the facts from the nonsense. @BadAstronomer

    Universe Today by Fraser Cain, who also does weekly virtual star parties with Dr Pamela Gay via Google+, YouTube and Cosmoquest. Also does the Astronomy Cast podcast.

    The Space Tweep Society has great articles, photos and videos from spacefans on Twitter who travel the world to attend Tweetups – key space events like launches – and hang out with other fans who use Twitter to share their experiences with their followers. The travels to Russia are brilliantly recounted.

    Registax allows you to stack multiple photos or frames from a video clip to produce a single sharp picture. Free!

    Galaxy Zoo is a citizen science website that allows anyone to help the scientists categorise galaxies as seen by Hubble. There have been a number of people credited on scientific journals for the new wonders they discovered on Galaxy Zoo! And now on a spin-off you might help find exoplanets…

    Tweeps you should follow:

    @NASAKepler – the search for exoplanets
    @SpaceflightNow – space news up to the moment, from Florida
    @Nightskyonline – Australian amateur astronomer, alerts to sights
    @SpaceX – the future of manned missions
    @elonmusk – the boss of SpaceX – a real-life Tony Stark
    @MarsRovers – updates from Opportunity on Mars
    @MarsCuriosity – updates from the Mars Science Laboratory herself
    @matt_heverley – lead Mars Curiosity rover driver
    @marsroverdriver – Scott Maxwell, formerly driving Opportunity, now Curiosity
    @spaceroboticist – Vandi Thomas – there are women driving Curiosity too
    @NASAWebbTelescp – the future of space telescopes, being built now
    @twisst – alerts of ISS passes over your location
    @Aussie_Starman – Mark Rigby, head of the Brisbane Planetarium
    @NASAJuno – Juno is heading to Jupiter
    @carolynporco – the wonderful head of the Cassini mission around Saturn
    @PULSEatParkes – high school students taking over The Dish at Parkes!
    And all the other ones named earlier.
    Apps:

    Lastly, iPhone and iPad apps are simply brilliant for finding out exactly what you are looking at in the sky.
    Star Walk – virtual planetarium, my favourite, $3 – worth every cent!
    Distant Suns – virtual planetarium, free
    SkyOrb – virtual planetarium, free
    Pocket Universe – first off the line with this whole virtual planetarium approach, $2
    3D Sun – know about and watch solar flares before anyone else, free
    Cassini – find out what this probe is doing around Saturn, free
    APOD – astronomy picture of the day – website and iPhone app, free
    Exoplanet – the latest on every exoplanet discovered, free
    NASA – their own app, and simple access to NASA TV – never miss another launch! Free
    Mars Images – what it says on the box, free
    ISS Spotter –  brilliant way to make sure you don’t miss passes of the Space Station – live maps and smart alarms, free
    Mission Clock – don’t miss your dose of roar, $5
    Meteor Counter – help scientists monitor meteor density, free, great activity for families.

    Anyway, that’s enough for now. But rest assured, it is only scratching the surface. There’s a whole world of astronomy resources out there online for you.

  • Hubble goes to the eXtreme to assemble the deepest ever view of the Universe

    Hubble goes to the eXtreme to assemble the deepest ever view of the Universe

    Like photographers assembling a portfolio of their best shots, astronomers have assembled a new, improved portrait of our deepest-ever view of the Universe. Called the eXtreme Deep Field, or XDF, the photo was assembled by combining ten years of NASA/ESA Hubble Space Telescope observations taken of a patch of sky within the original Hubble Ultra Deep Field. The XDF is a small fraction of the angular diameter of the full Moon.

     

    The Hubble eXtreme Deep Field (XDF)

    The Hubble Ultra Deep Field is an image of a small area of space in the constellation of Fornax (The Furnace), created using Hubble Space Telescope data from 2003 and 2004. By collecting faint light over one million seconds of observation, the resulting image revealed thousands of galaxies, both nearby and very distant, making it the deepest image of the Universe ever taken at that time.

    The new full-colour XDF image is even more sensitive than the original Hubble Ultra Deep Field image, thanks to the additional observations, and contains about 5500 galaxies, even within its smaller field of view. The faintest galaxies are one ten-billionth the brightness that the unaided human eye can see [1].

    Magnificent spiral galaxies similar in shape to the Milky Way and its neighbour the Andromeda galaxy appear in this image, as do large, fuzzy red galaxies in which the formation of new stars has ceased. These red galaxies are the remnants of dramatic collisions between galaxies and are in their declining years as the stars within them age.

    Peppered across the field are tiny, faint, and yet more distant galaxies that are like the seedlings from which today’s magnificent galaxies grew. The history of galaxies – from soon after the first galaxies were born to the great galaxies of today, like the Milky Way – is laid out in this one remarkable image.

    Hubble pointed at a tiny patch of southern sky in repeat visits made over the past decade with a total exposure time of two million seconds [2]. More than 2000 images of the same field were taken with Hubble’s two primary cameras: the Advanced Camera for Surveys and the Wide Field Camera 3, which extends Hubble’s vision into near-infrared light. These were then combined to form the XDF.

    “The XDF is the deepest image of the sky ever obtained and reveals the faintest and most distant galaxies ever seen. XDF allows us to explore further back in time than ever before,” said Garth Illingworth of the University of California at Santa Cruz, principal investigator of the Hubble Ultra Deep Field 2009 (HUDF09) programme.

    The Universe is 13.7 billion years old, and the XDF reveals galaxies that span back 13.2 billion years in time. Most of the galaxies in the XDF are seen when they were young, small, and growing, often violently as they collided and merged together. The early Universe was a time of dramatic birth for galaxies containing brilliant blue stars far brighter than our Sun. The light from those past events is just arriving at Earth now, and so the XDF is a time tunnel into the distant past when the Universe was just a fraction of its current age. The youngest galaxy found in the XDF existed just 450 million years after the Universe’s birth in the Big Bang.

    Before Hubble was launched in 1990, astronomers were able to see galaxies up to about seven billion light-years away, half way back to the Big Bang. Observations with telescopes on the ground were not able to establish how galaxies formed and evolved in the early Universe.

    Hubble gave astronomers their first view of the actual forms of galaxies when they were young. This provided compelling, direct visual evidence that the Universe is truly changing as it ages. Like watching individual frames of a motion picture, the Hubble deep surveys reveal the emergence of structure in the infant Universe and the subsequent dynamic stages of galaxy evolution.

    The planned NASA/ESA/CSA James Webb Space Telescope (Webb telescope) will be aimed at the XDF, and will study it with its infrared vision. The Webb telescope will find even fainter galaxies that existed when the Universe was just a few hundred million years old. Because of the expansion of the Universe, light from the distant past is stretched into longer, infrared wavelengths. The Webb telescope’s infrared vision is ideally suited to push the XDF even deeper, into a time when the first stars and galaxies formed and filled the early “dark ages” of the Universe with light.

    Notes

    The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

    The HUDF09 team members are G. Illingworth (University of California, Santa Cruz), R. Bouwens (Leiden University), M. Carollo (Swiss Federal Institute of Technology, Zurich (ETH)), M. Franx (Leiden University), I. Labbe (Leiden University), D. Magee and P. Oesch (University of California, Santa Cruz), M. Stiavelli (Space Telescope Science Institute), M. Trenti (University of Cambridge), P. van Dokkum (Yale University), and V. Gonzalez (University of California Observatories/Lick Observatory).

    [1] The faintest objects detected in the XDF are 31st magnitude.

    [2] The total exposure time is approximately two million seconds, or 23 days. Because Hubble can only observe for about 45 minutes of every 97-minute orbit, the observations that make up the XDF represent 50 days of telescope time.

    Image credit: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team
    Links

    Source: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50874

  • A long time ago in a galaxy far, far away

    A long time ago in a galaxy far, far away

    Feast your eyes on this image…

    Image credit: The CLASH team/Space Telescope Science Institute

    The tiny object in that inset may not look like much. A blurry smudge of red pixels. Not nearly as dramatic as the stunning bouquet of galaxies all around it. But in astronomy, not everything is quite so straightforward. That small red smudge is probably the most exciting thing in this whole image. You see, it too is a galaxy. An unimaginably ancient one.

    An ultraviolet image of the nearby Andromeda Galaxy – possibly similar to what we might see of MACS 1149-JD if we could get a more detailed view… Credit: NASA/Swift/Stefan Immler (GSFC) and Erin Grand (UMCP)

    The light that made this unassuming red dot left its source less than 500 million years after the Big Bang and the birth of the Universe. The photons that make up that light have been travelling for over 13.2 billion years. This galaxy was blazing brightly as the oldest known stars in our own galaxy, the Milky Way, were just starting to shine. Back when the gas which would one day become the Sun was still drifting silently amongst stars which are now long dead, and before planet Earth was even a whisper of interstellar dust. Before a massive star forged the iron atoms in your blood, and before a supernova scattered those atoms into space. Before anything we know from the world around us existed, even the stars we see as we look up to the night sky, this galaxy was shining in the dark.

    The Universe was a much smaller place back then. Over the billions of years these photons have been travelling, the Universe itself has expanded with them in the midst of it – stretching them out, redshifting them to longer and longer wavelengths. The light we see here as red was probably ultraviolet once, when it left the galaxy which created it.

    Ancient galaxies like these are difficult to see, purely because they’re so distant. So few photons make it this far that only the most sensitive telescopes can make them out, and even then they need a helping hand. The bloom of galaxies in this image is a massive galaxy cluster called MACS J1149+2223. A collection of galaxies bound together by gravity, clusters like these are some of the largest and most massive objects in the Universe. With that much mass gathered together, gravity starts to do some interesting things, and one of the most interesting is gravitational lensing. Because the gravity of all of those galaxies distorts spacetime, it actually causes the space around the galaxies to act like a titanic lens. A gravitational lens. The ancient red galaxy in this image is only visible because it’s magnified, not only by the Hubble Space Telescope, but by that gravitational lens too.

    It would be naive to assume that this galaxy, dubbed MACS 1149-JD, is special somehow. Instead, it’s most likely to be one of a huge number of primordial galaxies. Except that this one just happened to be in the right place at the right time. A whole population of these ancient galaxies were likely shining brightly at the time, full of hot stars which were driving the reionisation epoch – the time when the Universe went from being an opaque, dark fog, to a clear place where photons could travel long distances. The photons in this image may well have been some of the first photons to have travelled through that ancient and newly transparent Universe.

    The scientific paper is available from Nature – DOI: 10.1038/nature11446

  • Science or fringe science? Removing the ‘giggle factor’ from Near Earth Object impacts

    Science or fringe science? Removing the ‘giggle factor’ from Near Earth Object impacts

    On June 30, 7.17am in a remote, sparsely inhabited area in Siberia, Russia, near the Podkamennaya Tunguska River, occurred an event of enormous devastation. An asteroid or comet estimated to be 40-50 meters in diameter, exploded at low altitude with an energy almost 200 times that of the atom bomb dropped on Hiroshima. Trees where knocked down over an area of two thousand square kilometres, hundreds of reindeer where killed and the seismic shock from the airborne explosion was registered on barometers in England. Eyewitnesses 60km away, reported seeing the northern sky covered with fire, followed by an enormous bang, though thankfully no human deaths were recorded.

    Fallen trees at the Tunguska impact site

    Dan Yeoman from NASA’s Jet Propulsion Laboratory stated in an interview in 2008, “the Tunguska event is of great importance not only because of the devastation caused to a thankfully remote area, but also as it is the only modern era event of this type where we actually have first-hand accounts.

  • Alien encounters and the man from Grenada

    Alien encounters and the man from Grenada

    The month of August indeed belonged to the tiny rover that could — Curiosity. We were all hooked right from the landing and until those first images of the red planet were beamed back. Not even Will.i.am could spoil it for us. We revelled in everything in between, from the missed high-fives, peanuts, Neil deGrasse Tyson’s conversation with the rover, to — yes, unfortunately — Will.i.am’s new single being broadcast from the surface. Curiosity even spawned this generation’s cultural hallmark that is the fake twitter account. If there is any one milestone that denotes you’ve reached a certain level of cultural status… it’s the fake twitter account. From Mrs Rupert Murdoch to dead literary figures, the fake twiteratti are just as important as the real ones.

    In an odd roundabout way, all of this got me thinking about a bizarre event that happened in 1977.

    The United Nations debating such topics as aliens and extra-terrestrial encounters of any kind seems like something confined to the annals of science fiction. And yet, the most significant debate any international body has had on the prospect of alien encounter happened at the 32nd session of the United Nations General Assembly, for reasons unbeknown to me and probably many at the committee.

    Member nations and delegations convened at the 32nd session of the General Assembly to listen to the man from Grenada, Sir Eric M. Gairy, the Prime Minister and Minister for External Affairs of Grenada (evidently taking his title to its farthest logic conclusion — what could be more external than space?).

    He began with a reading from the Bible — Psalm 100, then launching into an engaging speech that touched on freedom and independence of nations, human rights, wars and conflicts. It quickly took on another flavour. The smallest nation in the UN (at the time) had centre stage and was determined to make the most of it. Mr. Gairy began to speak of unidentified flying objects (UFOs) with the same unabashed enthusiasm he was getting a reputation for.

    He concluded by recommending that not only the UN take it seriously but they should set up a department to study UFOs. The UN already had a space outfit — the Of

  • Kepler Astronomers Find First Planetary System Around a Binary Star

    Kepler Astronomers Find First Planetary System Around a Binary Star

    NASA’s Kepler mission has found the first multi-planet solar system orbiting a binary star, characterized in large part by University of Texas at Austin astronomers using two telescopes at the university’s McDonald Observatory in West Texas. The finding, which proves that whole planetary systems can form in a disk around a binary star, is published in the August 28 issue of the journal Science.

    “It’s Tatooine, right?” said McDonald Observatory astronomer Michael Endl. “But this was not shown in Star Wars,” he said, referring to the periodic changes in the amount of daylight falling on a planet with two suns. Measurements of the star’s orbits showed that daylight on the planets would vary by a large margin over the 7.4-Earth-day period as the two stars completed their mutual orbits, each moving closer to, then farther from, the planets (which are themselves moving).

    The binary star in question is called Kepler-47. The primary star is about the same mass as the Sun, and its companion is an M-dwarf star one-third its size. The inner planet is three times the size of Earth and orbits the binary star every 49.5 days, while the outer planet is 4.6 times the size of Earth with an orbit of 303.2 days.

    Artist's concept of the Kepler-47 system.

    The outer planet is the first planet found to orbit a binary star within the “habitable zone,” where liquid water could exist and thus create a home for life. However, the planet’s size (about the same as Uranus) means that it is an icy giant, and not an abode for life. It’s a tantalizing taste of discoveries waiting to be made.

    The combination of observations from the NASA mission and McDonald Observatory allowed astronomers to understand the characteristics of Kepler-47’s two stars and two planets.

    The Kepler mission looks for minute dips in the amount of light coming from a star that might indicate a planet is passing in front of it, an event called a “transit.” The space telescope is also adept at identifying eclipsing binary stars, in which two stars pass in front of each other as they orbit each other. In the case of Kepler-47, they found both stellar eclipses and planet transits in one system.

    So Kepler astronomers Jerome Orosz (lead author on the study) and William Welsh of San Diego State University flagged the Kepler-47 system as worthy of follow up from the ground. They asked the McDonald Observatory Kepler team to work with them.

    Endl studied the binary star with the 9.2-meter Hobby-Eberly Telescope (HET, one of the world’s largest telescopes), as well as the 2.7-meter Harlan J. Smith Telescope at McDonald.

    “The challenging thing is that this is a very faint star,” Endl said, “about 6,000 times dimmer than can be seen with the naked eye.”

    He was taking spectra of the system — looking for characteristics in its light to indicate the motions of the primary star. (The secondary star is too faint to measure.) The McDonald observations enabled astronomers to calculate the mass of the primary star.

    These values, along with the Kepler eclipse and transit timings, were plugged into a model that calculated the relative sizes of all the bodies involved, Endl said.

    The Kepler team at McDonald Observatory also includes Bill Cochran (a co-Investigator of the Kepler mission), research scientist Phillip MacQueen, graduate students Paul Robertson and Eric Brugamyer, and recent graduate Caroline Caldwell.

    “This is the type of research where McDonald Observatory really excels,” Cochran said. “We have excellent scientific instruments on our telescopes, and the queue-scheduled operation of the HET allows us to obtain spectra at the optimal times when they will give us the best information about the stars.”

    Source.

  • Neil Armstrong’s speech in Sydney 24 August 2011

    Neil Armstrong’s speech in Sydney 24 August 2011

    UPDATE: Regrettably, the CPA engaged lawyers to threaten me with everything they could think of if I didn’t pull the recording (below). So pull it I have. Please feel free to pass on any feelings about this to them. At least for the time it was available, about 500 people got to hear the great man’s words. All is not lost though. I have a contact in the US who is friends with one of the family. When the time is right, I hope she will be able to raise the issue with him. Too soon right now of course.

    On 20 July 1969, my entire school in the very young city of Canberra packed into the hall to watch Neil Armstrong step onto the Moon. The school’s only television set was tiny, and my only real memories of that historic day were black and white blobs on the television screen, and teachers constantly shushing all the children.

    But I did witness the event, and it is one of the earliest endures memories I have from my childhood – certainly the earliest world event I can recall. As an inspiration, the Moon landings – this first one, and all the others that followed – laid the foundation for an education in science.

    On 24 August 2011, Neil Armstrong delivered a very rare and unique speech in Sydney. And it was to rekindle in me an interest in science and space exploration that had laid essentially dormant for many years.

    Neil Armstrong delivering his speech in Sydney, 20 August 2011

    Somewhat curiously, the event was the 125th Anniversary of the Certified Practising Accountants Australia. The CPA’s CEO Alex Malley pulled off a real coup, based on the knowledge that Armstrong’s father Steven had been an auditor.

    Courtesy of my wife being a CPA, I was privileged to attend that incredible event with her. I recorded the entire speech, plus about one hour of questions and answers after that, but I was only using a cheap point-and-shoot camera, picking up the sound through the PA system. I haven’t published it beforehand though, not wanted to circumvent any speaking tours he might undertake.

    However, one year and one day following that event, the man who inspired so many of us has passed away, following complications stemming from heart surgery he had a couple of weeks ago. So I feel there’s now a responsibility to get his words out there for everyone.

    The speech is about 42 minutes. It doesn’t include the questions and answers – I’ll post that as soon as can get get the editing done.

     

    CPA Australia also published an extended interview with Armstrong. The introduction to that interview contained these prophetic words:

    “Rarely, if ever again, will Neil Armstrong conduct an interview such as this.”

    Nor a speech like this one…

    A sad sad day.