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Weekly Science Picks

Markus — Sun, 21 Jul 2013 07:56:55 +0000

I hope everyone’s enjoying a nice weekend! It’s my turn again for the weekly science picks, and this week is the 44th anniversary of the Apollo 11 moon landing. On July 20th 44 years ago, human beings took their first small steps onto the surface of an object in the solar system other than the Earth. While we may not have returned to the Moon since NASA’s Apollo program, it’s important to realise the leaps and bounds which human technology and scientific knowledge have made since then.

And speaking of those leaps and bounds…

Astronomers have managed to determine the colour an exoplanet would appear if were able to see it with our own eyes. Planet HD 189733b, one of the most well studied worlds out there in our galaxy, is a beautiful azure blue planet. But don’t let the similarity to our own planet’s colour fool you. The blue colour of HD 189733b is because it’s a hot jupiter, orbiting scorchingly close to its parent star, and that colour is because the rain on this world is made of glass!

Exoplanet HD 189733b Appears to be Azure Blue

“This planet has been studied well in the past, both by ourselves and other teams,

Cite this article:
Hammonds M (2013-07-21 07:56:55). Weekly Science Picks. Australian Science. Retrieved: Apr 29, 2024, from http://australianscience.com.au/news/weekly-science-picks-38/
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Weekly Science Picks

Markus — Sun, 19 May 2013 07:45:28 +0000

Greetings one and all, and a very happy science Sunday to you! This week’s generally been quite interesting. We’ve had good news, bad news, a little heated discussion… All the kind of things which keep the science community vibrant and interesting. As for specifically what that news was, well. Please do read on…

First up this week, sad news. After exemplary service ever since its launch in 2009 and a mission extension last year, the Kepler telescope has finally broken down. Kepler spots transiting exoplanets by staring unblinkingly at the same patch of sky, and in order to do that it needs to keep very still. Sadly, two of its four gyroscopes are out of action, meaning that Kepler may be shutting down for good.

Kepler’s Planet-Hunting Mission May Be Over

“Frankly, I’m absolutely delighted that we’ve got all this data, that we have been so successful, that we have found so many thousands of planetary candidates,

Cite this article:
Hammonds M (2013-05-19 07:45:28). Weekly Science Picks. Australian Science. Retrieved: Apr 29, 2024, from http://australianscience.com.au/news/weekly-science-picks-31/
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Weekly Science Picks

Markus — Mon, 22 Apr 2013 09:58:30 +0000

It’s been rather a turbulent week, all told. There’s been a lot going on in the news, both good and bad. Hopefully, this little handful of science news items will help you finish the last week and begin this next one on a lighthearted note!

NASA’s Kepler mission has found a star system which has not one, but two possibly terrestrial planets in its habitable zone.

Kepler-62: A Star System With Two Earths?

Whether either or both of Kepler-62’s optimally positioned planets actually has water is beyond the technical capabilities of the Kepler and other telescopes. Kepler works by detecting the very slight dips in light coming from a star caused by a planet passing by, relative to the telescope’s line of sight.

Sometimes the best way to learn more about nature is to try and recreate it. That happens to be exactly what happened when a group of roboticists were looking at insects…

Roboticists discover the secret of insect flight, and it’s not wings

They found that the moth moved its abdomen in direct response to its shifting visual environment. “If the pattern is rotating up (clockwise), the moth would raise its abdomen up (counterclockwise),” says study co-author Jonathan Dyhr, a University of Washington biologist. “The moth was raising or lowering its abdomen to counteract the movement.”

To celebrate the 23rd anniversary of the Hubble Space Telescope’s launch into orbit, NASA have released a brand new and frankly beautiful image of the iconic Horsehead Nebula. Phil Plait explains more…

Hubble’s Knight to Remember

The Horsehead itself is the site of ongoing star formation. The dense gas and dust inside the nebula is collapsing to form stars, and, at the same time, the edges are being eroded away by the fierce ultraviolet light of Sigma Orionis. The top of the Horsehead is acting a bit like a shield, protecting the material beneath it, which is why it’s taken on that umbrella-like shape. You can see more sculpted pillars of material around the sides, too, like sandbars in a stream.

Ants are fascinating little creatures, and a team of Swiss researchers have been studying the goings on inside a colony of them – by tracking them with barcodes!

Barcodes let scientists track every ant in a colony

Analyzing the color codes, they found that younger ants were more likely to work nursing the young, and older ants were more likely to be foragers. In general, they watched ants transition from nursing to cleaning to foraging as they age, but there’s a lot of individual variation in how quickly these transitions took place.

Finally, everyone’s favourite astronaut, Commander Chris Hadfield aboard the ISS answers an interesting question. What happens if you wring out a wet cloth in zero gravity? Click the link to watch the video!

What happens when you wring out a washcloth in space?

Two Nova Scotia high school students, Kendra Lemke and Meredith Faulkner, submitted this experiment to Canadian Space Agency and got to see astronaut Chris Hadfield actually test it out on the ISS. The results are seriously extraordinary and you need to see them.

Cite this article:
Hammonds M (2013-04-22 09:58:30). Weekly Science Picks. Australian Science. Retrieved: Apr 29, 2024, from http://australianscience.com.au/news/weekly-science-picks-27/
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It’s a small world after all

Markus — Mon, 11 Mar 2013 00:20:42 +0000

What we know of exoplanets has developed at the same time as the technology which we use to discover them. This is, in my opinion, the most exciting thing about the entire field of study. For instance, when we first started spotting planets around alien suns, we found huge gas giants. Hot jupiters, extremely massive and close to their parent stars. For a while, some conjectured that this type of planet may be quite common in the Universe. But since then, we’ve developed more powerful methods of searching the sky and, as it turns out, smaller planets are much more common than huge superjovian worlds. The latest piece in the puzzle comes courtesy of NASA’s Kepler space teescope. Near the end of last month, NASA announced the discovery of the smallest exoplanet ever found around a sun-like star!

Kepler-37b really is tiny. In fact, the whole Kepler-37 system is tiny – the entire system discovered so far can fit inside the orbit of Mercury! The innermost little world is under 100th the mass of Earth, it’s expected to have a radius of around 3867 km (assuming the same average density as the planets in our own solar system) making it smaller than Earth’s moon. One can only apprehensively wonder if this will spark yet another debate over how large an object has to be before it’s considered a planet. With such a tiny orbit, it also has a year lasting just 13 Earth days. Even though the star Kepler-37 is slightly smaller and cooler than the Sun, it’s still enough to heat the surface of tiny 37b to a roasting 700 Kelvin (nearly 430°C). Needless to say, while we all like stories which talk about potential alien life, this is unlikely to be a home for any lifeforms we might recognise.

Kepler-37b is very definitely the runt of the litter. Its sibling worlds, denoted by the letters c and d, are respectively slightly smaller than Earth and about twice the size of Earth. Of course, these planets are also very close to their parent star. The interesting thing is that we’re discovering more and more small worlds around other stars. More and more exoplanet astronomers are warming to the idea that small rocky planets are likely to be the most common in our galaxy. Our current technology might have trouble spotting them further than a certain distance from their parent stars, but they’re likely to be out there waiting to be found.

Even detecting Kepler-37b was quite a notable feat. It was only possible, in fact, because of a set of rather special circumstances. The star Kepler-37 is particularly quiet, lacking the noisy sunspots and features which cause brightness variation in most stars, making it a particularly clear target. It’s also relatively bright in Kepler’s field of view.

To learn more about this star, and hence get greater accuracy on the measurement of the planets it carries in tow, NASA astronomers used a technique known as asteroseismology. Not dissimilar to the way geologists measure earthquakes, asteroseismology is the study of vibrations within a star, measured by accurately observing pulsations in the star’s surface. All stars are constantly bubbling and boiling, and this causes the whole star to vibrate at a number of resonant frequencies – soundwaves – in exactly the same way a bell vibrates when it rings. By measuring the precise frequencies of those soundwaves, a lot can be determined about the interior of a star. Incidentally, this same technique can be used to effectively “listen” to the Sun.

Interestingly, because Kepler-37 has such an eerily peaceful surface for a star, it was very easy to measure those vibrations, making Kepler-37 the smallest star ever to be studied this way. Normally, only large stars are observed using asteroseismology because the measurements need to be very precise. Conveniently though, the Kepler telescope was built for breathtaking precision.

A tiny planet discovered orbiting a singing star 215 light years away. How poetic!

Image credits:
Top – NASA/Ames/JPL-Caltech
Middle – Karl Tate/ © space.com
Bottom – NASA/Ames/JPL-Caltech

Cite this article:
Hammonds M (2013-03-11 00:20:42). It's a small world after all. Australian Science. Retrieved: Apr 29, 2024, from http://australianscience.com.au/space/its-a-small-world-after-all/
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The Search for Exoplanets

Sharon — Wed, 23 Jan 2013 00:11:43 +0000

It seems like another day goes by and there’s another discovery of more exoplanets! On January 7, just one week into 2013, astronomers from the Kepler Mission Space Observatory announced the discovery of the latest exoplanet, the creatively named KOI-172.02. At this stage it appears that KOI-172.02 is an Earth-like planet candidate orbiting a star similar to our own sun. It almost seems like old news when scientists announce the discovery of a planet orbiting another star in our galaxy!

As at January 15, 2013 a total of 859 such planets have been identified (details can be found here). These are certainly exciting times for astronomers, but just how do astronomers search for exoplanets?

There are a number of methods used to detect exoplanets including astrometry, the transit method, radial velocity, gravitational microlensing, pulsar timing, eclipsing binaries, circumstellar disks and coronagraphy. Each method of observation has its pros and cons, is used in different circumstances, and produces different results. I will give an overview of each technique:

Astrometry is a technique that requires astronomers to precisely measure a star’s position in the sky, and then make more observations of the stars movement over time. If the star has an orbiting planet or planets, then the gravitational influence of the objects will cause the star to move in a tiny circular or elliptical orbit around the common centre of mass. Finding Earth-mass planets by astrometry requires extreme (sub-microarcsecond or 1 millionth of an arcsecond!!) precision. As the motion of the star is so small, this method has not yet been very productive in detecting exoplanets. However it’s expected that astrometric accuracy from ground-based telescopes will improve and become more useful.

Doppler Shift (Image courtesy of NASA)

One method that is very productive is the Radial Velocity method. This method requires the measurement of the velocity of a star’s centre of mass. Variations in the star’s radial velocity can be deduced from displacements in the star’s spectral lines due to the Doppler effect. If the motion of the star is towards the observer, then the received wavelengths are shorter than those emitted by the source, and longer if the motion is away from the observer. This is similar to the Doppler effect we observe in sound waves when a fire-engine passes us and the pitch of its siren changes! The Anglo-Australian Planet Search was a long-term program that searched for giant planets around more than 240 nearby solar type stars and as of 2010, discovered more than 30 exoplanets using the Doppler method. This method has been by far the most productive method of discovering exoplanets.

Another popular and effecitve method of detecting exoplanets is the Transit Method which measures the faint dip in brightness of a star when a planet transits the star (passes in front of it as observed from earth). As an exoplanet transits in front of its parent star, the observed brightness of the star drops by a very small amount. This method has emerged as one of the prevailing techniques to search for exoplanets. The amount by which the star dims depends on its size and on the size of the planet. A local example of this phenomenon was the transit of Venus across the face of the Sun in June 2004 and July 2012. The transit method is the second most productive method of detection, though confirmation from another method is usually considered necessary as dips in apparent brightness can arise from events other than a planetary transit. The Kepler Observatory uses the transit method and as of January 2013 it has discovered 2740 candidate exoplanets.

Transit Method (Image courtesy of NASA)

One of the more exciting, yet complex methods is Gravitational Microlensing. This method is used when the gravitational field of a star (close to us) acts like a lens and magnifies the light of a distant background star. When the alignment is exact you might think that the background star would be hidden from view, however the gravitational field of the foreground star bends the light of the background star towards us. This method has the advantage of being very sensitive to planets at large angular separations/distances from the parent stars. This makes gravitational microlensing one method well suited to finding low-mass planets. One major disadvantage is that the event can’t be repeated, as the alignment is unlikely to occur again. Also the planets tend to be very distant, so the other methods are unable to confirm the observations.

A pulsar is a fast-spinning neutron star that emits radio waves at very regular intervals as it rotates. We can use the Pulsar Timing method to discover exoplanets. Slight changes in the timing of its observed radio pulses can be used to track changes in the pulsar’s motion caused by the presence of planets. The presence of a planet orbiting a star affects the timing of the regular signals emitted by the star itself. This phenomenon can be used to detect planets around a pulsar. This method is very sensitive and is capable of detecting planets of a very small mass. In 1992, Wolszczan and Frail used this method to discover the first exoplanet around the pulsar PSR 1257+12. Unfortunately pulsars are pretty rare, so this method is not going to produce a large number of exoplanet discoveries. Also, it’s unlikely that life could survive on planets orbiting pulsars since high-energy radiation there is intense.

When a double star (binary) system is aligned such that the stars pass in front of each other in their orbit, the system is called an eclipsing binary star system. Astronomers can use the Eclipsing Binaries method to discover exoplanets. If a planet has a large orbit that carries it around both members of an eclipsing double star system, then the planet can be detected through small variations in the timing of the stars’ eclipses of each other.

Disks of dust surround many stars, and this dust can be detected because it absorbs ordinary starlight and re-emits it as infrared radiation. The Circumstellar Dust Disks method detects features in dust disks that may suggest the presence of planets. Dust is generated by collisions of small objects, including comets and/or asteroids, and radiation pressure from stars will push the dust particles out into stellar space. Therefore any detection of dust around a star indicates the possibility of recent collisions and other objects.

Lastly, a Coronagraph is an object when attached to a telescope, blocks out the direct light from a star so that nearby objects, which otherwise would be hidden in the star’s bright glare, can be observed. In the past coronagraphs have been developed to view the corona of the Sun, but new versions of similar instruments are being used to find extrasolar planets around nearby stars. Coronagraphs can be attached to either ground or space based telescopes. While stellar and solar coronagraphs are similar in concept, they are quite different in design. This is so that observations can be made of exoplanets which are much more distant than our own sun. A stellar coronagraph concept is currently being studied to fly on the Terrestrial Planet Finder mission. On ground-based telescopes, a stellar coronagraph can be combined with adaptive optics to search for planets around nearby stars.

Coronographic Mask showing Dust Disk (Image Courtesy of NASA)

Astronomers at the Harvard Smithsonian Centre for Astrophysics have recently estimated that as many as 17 billion earth sized planets exist in the Milky Way Galaxy alone! Yes, Billion! So I think that we’ll continue to hear about exciting new exoplanet discoveries all the way through 2013 and well beyond. By the way – if you’re really into exoplanets and consider yourself a ‘citizen scientist’ you can help discover new exoplanets! Planet Hunters is an organisation that encourages ordinary folks with no scientific training at all to help find planets from data provided by the Kepler Observatory! If you’re the first person to identify an exoplanet using their data, you’ll be included paper describing the discovery.

Cite this article:
Harnett S (2013-01-23 00:11:43). The Search for Exoplanets. Australian Science. Retrieved: Apr 29, 2024, from http://australianscience.com.au/science-2/discovery-of-exoplanets-tbc/
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Weekly Science Picks

Markus — Sun, 23 Dec 2012 00:28:12 +0000

By now, I think it’s safe to say that if you’re reading this, it means the world didn’t end on Friday. Which is rather a good thing, because a lot of interesting things have been happening recently! Even though I’ve been busy as can be, writing papers and trying to finish off a thesis there have still been a few fascinating little gems to catch my eye in the news this week…

Firstly, NASA have announced a new prototype space suit, with new and improved technology. Intended to be easier to put on, amongst other things, the most exciting part of the news is that these new suits are intended for deep space missions, focussing on safety “during spacewalks and potential surface activities”! Oh, but there’s just one thing which everyone’s noticed…

Nasa’s New Space Suit Looks Exactly Like Buzz Lightyear

Nasa said one of the key differences was that the new suit has a one-piece design, into which the wearer crawls in through a hole in the back, as opposed to the trousers-top-helmet version currently in use on the International Space Station.

Meanwhile, in Switzerland, physicists have been puzzled by the results they’ve seen from the LHC. While there’s now little doubt that they’ve detected a signature which matches what they’d expect from “a Higgs-like boson”, it seems like there’s more going on than they realised…

Two Higgs Bosons? CERN Scientists Revisit Large Hadron Collider Particle Data

Yesterday researchers at the Atlas experiment finally updated the two-photon results. What they seem to have found is bizarre—so bizarre, in fact, that physicists assume something must be wrong with it. Instead of one clean peak in the data, they have found two.

The Sun, is slightly larger and more active than Tau Ceti. Credit: R.J. Hall/Wikimedia Commons

Finally, one star near to Earth which has always garnered much attention from science fiction writers is Tau Ceti – right in our neighbourhood at a mere 12 light years away. For a long time, many have speculated on the potential for life-sustaining worlds around the Sun’s slightly more orange neighbour, and now it looks like there may well be. While we’re still waiting for confirmation, there may be 5 planets around Tau Ceti, and two of those might be candidates for sustaining life!

Nearby Tau Ceti may host two planets suited to life

The highlight of this alien solar system is Tau Ceti e, which has a mass of over four Earths and a year just under half as long as ours. It orbits in the star’s habitable zone, the region where liquid water is thought to exist. “It is in the right place to be interesting,” says [Hugh] Jones.

Short but sweet, that’s all for this week. I hope everyone has a lovely Christmas (or whichever of this season’s holidays and festivals you choose to celebrate). See you next time!

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Weekly Science Picks

Markus — Sun, 23 Sep 2012 00:48:37 +0000

It’s been an interesting week for science news, and I’ve been lucky enough to be asked to give this week’s science picks! This made me spend a little while sipping contemplatively on a cup of vanilla iced coffee and wondering where to even start…

The articles I’ve selected are, of course, slanted towards my own (rather geeky) interests, but all the same I hope you find them all as fascinating as I did!

First up, the news that Star Trek style warp drives may actually be possible, at least in theory, made me exclaim “Oh wow!” out loud. Fortunately, people who spend any time with me are generally used to me talking to myself while staring at a computer screen…

Warp Drive May be More Feasible than Thought

“Everything within space is restricted by the speed of light. But the really cool thing is space-time, the fabric of space, is not limited by the speed of light.”
– Richard Obousy, president of Icarus Interstellar

Artists impression of Mimivirus, the first giant virus to be discovered. Image Credit: InvaderXan/Wikimedia Commons

From the vastness of space to life under the microscope, biologists have been debating for years whether or not viruses qualify as a form of life. The latest evidence is that they may indeed be a life form in their own right, and an old one at that!

Giant Viruses are Ancient Living Organisms

They found that many of the most ancient protein folds in living organisms were present in the giant viruses, which “offers more evidence that viruses are embedded in the fabric of life,” Caetano-Anollés said.

Heritage Daily had a fascinating article about the archaeology of the future, and what precisely our distant descendents may one day think of us and the way we lived…

The Archaeology of the Future

The point is that most of what survives will not be determined by conscious decisions on our part. This may not be for want of trying, as shown by the current popularity of time capsules. The most impressive of these must be the KEO satellite, due to be launched in 2014 and to return to Earth 50,000 years later.

And speaking of what we know of the past, it’s been shown again and again that our primitive relatives, the neanderthals, were likely not the brainless savages they’re often depicted to be. Evidence suggests that neanderthals liked to collect bird feathers as ornaments.

Neanderthals Used Feathers as ‘Personal Ornaments’

“I think this is the tip of the iceberg,” said Prof Finlayson: “It is showing that Neanderthals simply expressed themselves in media other than cave walls. The last bastion of defence in favour of our superiority was cognition.” Neanderthals, he said, may have been “different”, but “their processes of thinking were obviously very similar”.

Curiosity self-portrait. Image Credit: NASA/JPL-Caltech/Malin Space Science Systems

As the Curiosity rover settles into its new home in Gale Crater on our neighbouring planet, one small worry is growing in the backs of the minds of certain NASA scientists. Could a blunder on the part of some engineers lead to Curiosity contaminating the surface of Mars with Earth life?

Drill Bits on Rover Could Contaminate Mars

John D. Rummel, a professor of biology at East Carolina University, said, partly in jest: “It will be a sad day for NASA if they do detect ice or water. That’s because the Curiosity project will most likely be told, ‘Gee, that’s nice. Now turn around.’ “

And finally, planet hunters are scouring the sky for exoplanets. Astrobiologists are hoping to soon be able to look into the atmospheres of those planets in search of life signs, in the form of certain molecules created by living organisms. But could they be fooled by those molecules coming from somewhere else?

Meteors Might Add Methane to Exoplanet Atmospheres

One key gas astrobiologists looking for extraterrestrial life would concentrate on would be oxygen […] Another possibility would be methane, a colorless, odorless, flammable organic gas that microbes on Earth produce. Seeing both together in an exoplanet’s atmosphere might be an especially significant sign of life, since they would both ordinarily remove each other from the atmosphere without something like life to constantly replenish them.

Have a good weekend!

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