RSSArchive for December, 2011

Road to Mars – Six minutes of terror!

Artist's impression of Mar Science Laboratory about to enter Mars' atmosphere.

Artist's impression of Mar Science Laboratory about to enter Mars' atmosphere.

THE MARS SCIENCE LABORATORY (MSL) team is calling it the “six minutes of terror”—the time between entering the Red Planet’s atmosphere and landing on its surface.

The NASA probe, carrying the Curiosity rover, will be using a totally new landing technique called the “sky crane”, whereby the six-wheeled vehicle will be lowered by cable down to the surface from an altitude of about 20 metres…courtesy of a rocket powered descent stage.

This graphic shows us the different parts of MSL: the cruise stage (which looks after the whole ensemble on the way to Mars); the backshell (which protects the rover during the cruise to Mars and initial atmosphere entry); the parachute (contained within the backshell); the descent stage (which will handle the final part of the descent); the rover itself; and the heatshield.

Breakout graphic showing the parts of MSL

The Curiosity rover is kept safe by several layers of protection on the cruise to Mars, and during atmospheric entry and landing.

Doing most of the work during the atmospheric entry will be the huge heatshield. At 14 metres wide, it is the largest heatshield ever sent to another planet, and about half a metre wider than that used by the Apollo spacecraft in the 1960s and 1970s. It will need to withstand temperatures up to 2,100 degrees Celsius. These couple of photos will give you an idea of the size:

MSL heatshield

The space shuttle aside, Mars Science Laboratory's heatshield is the largest ever to be flown in space.

View of the MSL heatshield

Here's another view, showing the craft upside down in a cradle.

Packed inside the backshell is the parachute, the largest ever sent to another planet. It’s also the largest “disc-cap-band” of any kind ever made. It is 16 metres wide and has 80 suspension lines that are 20 metres long. When deployed during the descent through Mars’ thin air, it will need to withstand a wind speed of Mach 2.2.

Here’s a photo of it, with some people standing nearby to give a sense of scale:

MSL parachute

The huge parachute that Mars Science Laboratory will use to slow its descent through the Martian atmosphere.

And here’s a video of it being tested at AEDC’s National Full-Scale Aerodynamics Complex 40-metre wind tunnel—the largest in the world—at NASA’s Ames Research Laboratory in California. The action starts about 53 seconds in:

Quite impressive isn’t it? The parachute will deploy just over four minutes after atmospheric entry, and about two-and-a-half minutes before landing. At this stage the craft will be travelling at about 1,450 kilometres per hour! Twenty-four seconds after the parachute unfurls, with the speed down to about 500 kilometres per hour, the heatshield will drop away.

Another 70 seconds (approximately) and the parachute and backshell will detach, and the descent stage rockets will fire up for the final, powered descent stage.

The following video animation takes us through the interplanetary cruise phase, and the whole entry, descent and landing. Let’s keep our fingers crossed that everyone works as planned on August 6 next year!

Story by Jonathan Nally. Images and videos courtesy NASA.

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Our Sun can expect inner turmoil in old age

Artist's impression of a red giant star

Our Sun will one day become a red giant star (artist's impression), swelling up to be much bigger than it is now. Astronomers have learned that the inside and outsides of such stars are very different.

SCIENTISTS HAVE MADE a new discovery about how old stars called ‘red giants’ rotate, giving an insight into what our Sun will look like in five billion years.

The international team of scientists, including University of Sydney astronomers Professor Tim Bedding and Dr Dennis Stello, has discovered that red giants have slowed down on the outside, while their cores spin at least 10 times faster than their outer layers.

The finding, just published in the prestigious journal Nature, tells us what the Sun will look like in five billion years when it develops into a red giant.

“The heart of a star determines how it evolves, and understanding how a star rotates deep inside helps us to understand how stars like our Sun will grow old,” said Professor Tim Bedding from the University of Sydney’s School of Physics.

Using NASA’s Kepler space telescope, the team “peered” deep inside ageing red giants to make their discovery of the difference in rotation rate between the core and outer layers of the stars.

Stars and the ice skater effect

The team, led by Paul Beck from Leuven University in Belgium, analysed waves inside the stars, which appear as rhythmic variations in the surface brightness of the stars.

The effect of rotation on the frequencies of the waves is so small it took the team nearly two years of almost continuous data gathering from the Kepler satellite to make their discovery.

Cutaway diagram of a red giant star

The cores of red giant stars have been found to spin at least 10 times faster than the outer layers.

“Red giants were once stars like our Sun, but as they age their outer layers expand to more than five times their original size and cool down significantly, so they look red,” explained Dr Dennis Stello, from the University of Sydney’s School of Physics.

“The opposite actually happens to the cores of red giants, as the core contracts and becomes extremely hot and dense,” said Dr Stello.

“We’ve just discovered that the core spins much faster than the outer layers in these old stars, which makes sense when you consider what happens to other spinning things like, say, an ice skater performing pirouettes.”

“A spinning ice skater will slow down if their arms are stretched far out, like the expanded outer layers of the red giants. The ice skater will spin faster if their arms are pulled tightly to the body, like the fast spinning contracted core of red giants.”

Star quakes reveal stellar inner secrets

The Kepler space telescope—one of NASA’s most successful space missions—is searching in the constellation Cygnus for potentially habitable planets by focussing on those similar in size to Earth. It does this by carefully and individually measuring the light coming from over 100,000 stars.

“Kepler is able to detect variations in a star’s brightnessof only a few parts in a million, so its measurements are ideally suited to detect the tiny brightness fluctuations of stars,” explained Dr Stello.

Artist's impression of the Kepler spacecraft

Artist's impression of the Kepler spacecraft

“We study these variations in brightness to work out what’s going on deep inside stars. It’s called asteroseismology—just as geologists use earthquakes to explore Earth’s interior, we use star quakes to explore the interiors of stars,” said Dr Stello.

Different waves reveal information on different parts of the star, and by a detailed comparison of the depth to which these waves travel inside the star the team found the rotation rate dramatically increased towards the stellar core.

In addition to helping us understand how stars age, asteroseismology will help Kepler’s mission of discovering Earth-sized planets outside our Solar System by characterising the host stars around which these planets orbit.

Adapted from information issued by the University of Sydney / ESO / L. Calcada.

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Australia’s newest telescopes – bird’s eye view

Artist's impression of ASKAP dishes

The Australian Square Kilometre Array Pathfinder (artist's impression) is under construction in a remote part of Western Australia.

A NEW WEB FEATURE makes it possible to take a ‘bird’s eye view’ over the Murchison Radio-astronomy Observatory (MRO) and see the construction progress of CSIRO’s ASKAP radio telescope.

ASKAP Live is an interactive map of the 36 antennae that will make up the Australian Square Kilometre Array Pathfinder (ASKAP). In addition to showing the location of each antenna, ASKAP Live gives pictures and status reports on the construction of each antenna.

Colour coding provides, at a glance, the construction status of each antenna: antennae indicated by green icons have already been completed, those currently being constructed are in blue, and the six antennae that will make up the Boolardy Engineering Test Array, or BETA, are marked with yellow or purple icons.

A screenshot from the ASKAP Live web site.

A screenshot from the ASKAP Live web site.

All 36 ASKAP antennae are being constructed at the MRO by their manufacturer, the 54th Research Institute of China Electronics Technology Group Corporation (known as CETC54), with the assistance of CSIRO’s ASKAP team and local contractors.

The antennae are first built and tested in China by CETC54, with the antenna sections then disassembled and shipped to Australia. The antennae are then reassembled on site at the MRO, approximately 315 kilometres north east of Geraldton in the Mid West region of Western Australia.

Once built, ASKAP will operate as part of CSIRO’s radio astronomy facility for use by Australian and international scientists.

As well as being a world-leading telescope in its own right, ASKAP will be an important test-bed for the Square Kilometre Array (SKA), a future international radio telescope that will be the world’s largest and most sensitive.

Take a look at ASKAP Live.

You can also view the ASKAP Webcam.

Adapted from information issued by CSIRO.

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Aussie tech helps telescopes “see in the dark”

NGC 300

Australian technology will soon enable astronomers to get a clearer view of distant galaxies, by reducing the effect of the natural airglow of the sky.

AUSTRALIAN SCIENTISTS have made a major breakthrough in the drive to improve their view of the night sky and greatly increase the efficiency of ground-based telescopes.

While the night sky looks dark to the naked eye, to an astronomer working at infrared wavelengths the air actually glows brightly, drowning out the view of distant astronomical bodies.

This happens because molecules in our atmosphere emit their own infrared radiation, swamping the faint infrared light coming in from deep space.

What astronomers have needed is a way to filter out the atmospheric emission while letting through the infrared waves from stars and galaxies.

Traditional filters can only remove selected wavelengths at a time. What if a system could be devised that removes many at once?

Enter the “photonic lantern” and high-tech, wavelength-suppressing optical fibres, both the brainchild of Professor Joss Bland-Hawthorn (University of Sydney) and the team he leads.

The complex system, under development since 2004, recently underwent its first real test under the night sky—at Siding Spring Observatory in New South Wales—and passed with flying colours.

The system removed the unwanted air emissionwavelengths just as planned, while letting through the infrared from deep space. In effect, it made the sky look darker and clearer.

Joss Bland-Hawthorn

Professor Joss Bland-Hawthorn leads the team that has developed the photonic lantern and wavelength-suppressing optical fibres. Photo courtesy University of Sydney.

The results of the field test were published this week in the scientific journal, Nature Communications.

Looking deeper into space

The optical fibres are specially made with internal patterns that act to filter out the unwanted wavelengths, while the photonic lantern combines the output from multiple fibres. That output can then be fed into a spectrograph, a device that splits light into separate wavelengths and enables analysis to be made of the chemical nature of the stuff (stars, galaxies, nebulae) that emitted the original infrared light.

Infrared wavelengths are very important because visible wavelength light emitted from astronomical bodies when the universe was young, has by now been redshifted into the infrared by the expansion of the universe. So in order to study the universe’s past, astronomers need to see at infrared wavelengths.

The first operational device to use the new photonics was commissioned earlier this year on the Anglo-Australian Telescope. This prototype instrument, called GNOSIS, paves the way to a more powerful instrument now under development by the AAO and the University of Sydney. Called SUNESIS, it will be operational by the end of 2012.

“This will mean we’ve gone from project inception to completion within 12 months, a remarkable effort,” says Bland-Hawthorn.

And they’re also aiming to have the technology ready soon for use on other major telescopes throughout the world.

“In particular, we’re aiming at the current 8- to 10-metre class of telescopes—the largest in the world—and then the new generation of 30-metre telescopes that are currently in the design phase,” says Bland-Hawthorn.

When installed on such large telescopes, the system will enable astronomers to see five times deeper into space in the infrared part of the spectrum, which corresponds to a 100-fold increase in the volume of space covered. And that means thousands more targets for their telescopes.

And that’s not the end of it. Space-based applications also beckon, and the University of Sydney team aims to test out other uses of the photonics technology aboard a micro-satellite to be launched in 2012, as well as with high-altitude balloon flights in collaboration with NASA.

Story by Jonathan Nally. Galaxy image courtesy ESO.

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Australia from Space: Part 4

MORE WONDERFUL IMAGES of Australia’s coastline, courtesy of the European Envisat Earth-monitoring satellite. Envisat was launched in March 2002 and at 8.5-tonnes is one of the largest satellites ever put into orbit. It circles the Earth every 101 minutes from north to south.

Satellite image of the Great Barrier Reef

An Envisat MERIS image of the Great Barrier Reef centred on Cape York Peninsula. Taken on 19 August 2004, this MERIS Full Resolution mode images has a spatial resolution of 300 metres.

Satellite image of the Southern Great Barrier Reef

This Envisat image features the southern part of the Great Barrier Reef off Australia’s Queensland coast. It is the world’s most protected marine area, one of its natural wonders and a World Heritage site. Spanning more than 2,000 km and covering an area of some 350,000 sq km, it is the largest living structure on Earth and the only one visible from space. This image was acquired by Envisat’s Medium Resolution Imaging Spectrometer (MERIS) on 8 November 2010 at a resolution of 300 metres

Satellite image of the Northern Great Barrier Reef

Another view of the Great Barrier Reef. Australian researchers have discovered that Envisat's Medium Resolution Imaging Spectrometer (MERIS) sensor can detect coral bleaching down to 10 metres depth. This means Envisat could potentially map coral bleaching on a global scale. MERIS acquired this image on 18 May 2008, working in Full Resolution mode to yield a spatial resolution of 300 metres.

Close up of the sea off northwestern WA

Sea and coral atolls off the West Australian coast, as seen by Envisat's MERIS ocean colour sensor.

Earlier Australia from Space pictorials:

Australia from Space: Part 1

Australia from Space: Part 2

Australia from Space: Part 3

Adapted from information issued by ESA.

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Kepler finds planet in the habitable zone

Artist's conception illustrates Kepler-22b

This artist's conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a Sun-like star. It is the first planet that NASA's Kepler mission has confirmed to orbit in a star's habitable zone—the region around a star where liquid water, a requirement for life on Earth, could persist. The planet is 2.4 times the size of Earth.

  • “Super Earth” found in its star’s “habitable zone”
  • Located 600 light-years away from our planet
  • Scientists studying 2,326 planet candidates

NASA’S KEPLER MISSION has confirmed its first planet in the “habitable zone,” the region around a star where liquid water could exist on a planet’s surface.

Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count.

Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets.

The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our Sun. The planet is about 2.4 times the radius of Earth.

Scientists don’t yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.

Clear confirmation

Previous research hinted at the existence of near-Earth-size planets in habitable zones, but clear confirmation proved elusive.

Two other small planets orbiting stars smaller and cooler than our Sun recently were confirmed on the very edges of the habitable zone, with orbits more closely resembling those of Venus and Mars.

“This is a major milestone on the road to finding Earth’s twin,” said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington.

Artist's impression of the Kepler space telescope

Artist's impression of the Kepler space telescope

“Kepler’s results continue to demonstrate the importance of NASA’s science missions, which aim to answer some of the biggest questions about our place in the universe.”

Kepler discovers planets and planet candidates by measuring dips in the brightness of more than 150,000 stars to search for planets that cross in front, or “transit,” the stars. Kepler requires at least three transits to verify a signal as a planet.

Follow-up with ground-based telescopes

“Fortune smiled upon us with the detection of this planet,” said William Borucki, Kepler principal investigator at NASA Ames Research Centre, who led the team that discovered Kepler-22b.

“The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season.”

The Kepler science team uses ground-based telescopes and NASA’s Spitzer Space Telescope to review observations on planet candidates the spacecraft finds.

The star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in the Northern Hemisphere’s spring through early autumn.

The data from these other observations help determine which candidates can be validated as planets.

Over 1,000 new planet candidates

Kepler-22b is located 600 light-years away. While the planet is larger than Earth, its orbit of 290 days around a Sun-like star resembles that of our world. The planet’s host star belongs to the same class as our Sun, called G-type, although it is slightly smaller and cooler.

Of the 54 habitable zone planet candidates reported in February 2011, Kepler-22b is the first to be confirmed.

The Kepler team is hosting its inaugural science conference at Ames this week, announcing 1,094 new planet candidate discoveries.

Diagram comparing our Solar System to Kepler-22

This diagram compares our own Solar System to Kepler-22, a star system containing the first "habitable zone" planet discovered by NASA's Kepler mission. The habitable zone is the sweet spot around a star where temperatures are right for water to exist in its liquid form. Liquid water is essential for life on Earth.

Since the last catalogue was released in February, the number of planet candidates identified by Kepler has increased by 89 percent and now totals 2,326.

Of these, 207 are approximately Earth-size, 680 are super Earth-size, 1,181 are Neptune-size, 203 are Jupiter-size and 55 are larger than Jupiter.

The findings, based on observations conducted May 2009 to September 2010, show a dramatic increase in the numbers of smaller-size planet candidates.

Abundant Earths out there?

Kepler observed many large planets in small orbits early in its mission, which were reflected in the February data release.

Having had more time to observe three transits of planets with longer orbital periods, the new data suggest that planets one to four times the size of Earth may be abundant in the galaxy.

The number of Earth-size, and super Earth-size candidates, has increased by more than 200 and 140 percent since February, respectively.

There are 48 planet candidates in their star’s habitable zone.

While this is a decrease from the 54 reported in February, the Kepler team has applied a stricter definition of what constitutes a habitable zone in the new catalogue, to account for the warming effect of atmospheres, which would move the zone away from the star, out to longer orbital periods.

“The tremendous growth in the number of Earth-size candidates tells us that we’re honing in on the planets Kepler was designed to detect: those that are not only Earth-size, but also are potentially habitable,” said Natalie Batalha, Kepler deputy science team lead at San Jose State University.

“The more data we collect, the keener our eye for finding the smallest planets out at longer orbital periods.”

Adapted from information issued by NASA/Ames/JPL-Caltech.

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Video – The Sun unleashes its fury

TO US DOWN HERE ON THE GROUND, the Sun seems unchanging and ever-reliable on a day-to-day basis. But satellites reveal the reality to be very different. Our nearest star is actually a boiling, roiling cauldron of hot gases, unseen magnetic fields and titanic explosions.

Those explosions are called coronal mass ejections, or CMEs, and they shoot enormous clouds of particles far out into the Solar System. Sometimes they hit Earth…but fortunately we’re protected by our planet’s strong magnetic field and thick atmosphere.

The Sun produced about a dozen CMEs between November 22 and 28, 2011. The SOHO spacecraft—which monitors the Sun 24/7—spotted them blasting out in different directions. The following video clip comprises over 1,300 frames, and gives us a sped-up view of those eight eventful days on the Sun:

In order to see the CMEs, SOHO had to block out the glare of the Sun using a coronagraph (black circle). A separate instrument took images of the Sun at the same time (superimposed in the middle) so that we could get the best of both worlds.

The next video was produced from images taken with a different Sun-monitoring spacecraft, the Solar Dynamics Observatory. It shows a portion of an extremely long filament (over 1,000,000 km) that was stretched across much of the face of the Sun and gracefully erupted into space (November 14, 2011).

Filaments are cooler gas structures that are tethered to the Sun by magnetic forces. About the upper third of this filament rose up and broke away, but the other two-thirds still remains in sight. The images were taken in extreme ultraviolet light. The clip covers about 12 hours of activity.

Finally, here’s an amazing video that gives us a complete time-lapse of the Sun spanning the entire months of September, October and November 2011 as seen through the SWAP ultraviolet instrument aboard yet another Sun-monitoring satellite, the European Space Agency’s Proba-2 (PRoject for OnBoard Autonomy).

Adapted from information issued by NASA / SDO / ESA.

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18 new giant planets found

Keck Observatory

The 18 new planets were detected using the Keck Observatory in Hawaii.

  • 18 new planets found orbiting “retired” stars
  • 50 per cent increase in this class of planets
  • Competing ideas for how giant planets form

DISCOVERIES OF NEW PLANETS just keep coming and coming. Take, for instance, the 18 recently found by a team of astronomers led by scientists at the California Institute of Technology (Caltech).

“It’s the largest single announcement of planets in orbit around stars more massive than the Sun, aside from the discoveries made by the Kepler [space telescope] mission,” says John Johnson, assistant professor of astronomy at Caltech.

Using the Keck Observatory in Hawaii—with follow-up observations using the McDonald and Fairborn Observatories in Texas and Arizona, respectively—the researchers surveyed about 300 stars.

They focused on “retired” A-type stars that are more than 1.5 times more massive than the Sun. These stars are just past the main stage of their life—hence, “retired”—and are now puffing up into what’s called sub-giant stars.

The astronomers searched for stars of this type that wobble, which could be caused by the gravitational tug of an orbiting planet.

By searching the stars’ spectra for Doppler shifts—the lengthening and contracting of wavelengths due to motion away from and toward the observer—the team detected 18 planets with masses similar to Jupiter’s.

This marks a 50 percent increase in the number of known planets orbiting massive stars.

Artist's impression of an exoplanet

There are competing ideas about how giant planets form.

Competing planet formation concepts

The researchers say the findings also lend further support to the idea that planets grow from seed particles that accumulate gas and dust in a cloud surrounding a newborn star.

In this concept, tiny particles start to clump together, eventually snowballing into a planet. If this is correct, the characteristics of the resulting planetary system—such as the number and size of the planets, or their orbital shapes—will depend on the mass of the star.

In another theory, planets form when large amounts of gas and dust in the cloud spontaneously collapse into big, dense clumps that then become planets. But in this picture, it turns out that the mass of the host star doesn’t affect the kinds of planets that are produced.

So far, as the number of discovered planets has grown, astronomers are finding that stellar mass does seem to be important in determining the prevalence of giant planets. The newly discovered planets further support this pattern—and are therefore consistent with the first theory, the one stating that planets are born from seed particles.

Nature vs nurture?

There’s another interesting twist, Johnson adds: “Not only do we find Jupiter-like planets more frequently around massive stars, but we find them in wider orbits.” If you took a sample of 18 planets around Sun-like stars, he explains, half of them would orbit close to their stars. But in the cases of the new planets, all are farther away.

Artist's impression of an exoplanet

Something stops giant planets from spiralling into their host stars.

In systems with Sun-like stars, gas giants like Jupiter acquire close orbits when they migrate toward their stars. According to theories of planet formation, gas giants could only have formed far from their stars, where it’s cold enough for their constituent gases and ices to exist.

So for gas giants to orbit nearer to their stars, gravitational interactions have to have taken place to pull the planets in. Then, some other mechanism—perhaps the star’s magnetic field—has to kick in to stop them from spiralling into a fiery death.

The question, Johnson says, is why this doesn’t seem to happen with so-called “hot Jupiters” orbiting massive stars, and whether that dearth is due to nature or nurture.

In the nature explanation, Jupiter-like planets that orbit massive stars just wouldn’t ever migrate inward. In the nurture interpretation, the planets would move in, but there would be nothing to prevent them from plunging into their stars. Or perhaps the stars evolve and swell up, consuming their planets.

Adapted from information issued by Caltech. Images courtesy Rick Peterson / W.M. Keck Observatory / Gbacon / STScI / AVL.

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Australian dish charts where stars are born

The Large Magellanic Cloud

The Large Magellanic Cloud (LMC) is the nearest sizeable galaxy to our Milky Way, and is therefore a popular target for astronomers studying the evolution of stars.

ASTRONOMERS HAVE MAPPED in detail the star-forming regions of the nearest star-forming galaxy to our own, a step toward understanding the conditions surrounding star creation.

The researchers, led by University of Illinois astronomy professor Tony Wong—and including Associate Professor Sarah Maddison and PhD student Annie Hughes, both of the Swinburne University of Technology in Melbourne, Australia—have published their findings in the December issue of the Astrophysical Journal Supplement Series.

The Large Magellanic Cloud (LMC) is a popular galaxy among astronomers both for its nearness to our Milky Way and for the spectacular view it provides, a big-picture vista impossible to capture of our own galaxy.

“If you imagine a galaxy being a disc, the LMC is tilted almost face-on so we can look down on it, which gives us a very clear view of what’s going on inside,” Wong said.

Mopra dish

CSIRO's 22-metre-diameter Mopra radio telescope, located near Coonabarabran in NSW.

As the LMC is in the far southern sky, it is an ideal target for Australian telescopes. And indeed, the team used the CSIRO’s 22-metre-diameter radio telescope at Mopra, near Coonabarabran in north-central New South Wales.

Where are stars born?

Although astronomers have a working theory of how individual stars form, they know very little about what triggers the process or the conditions in space that are optimal for star birth.

Wong’s team focused on areas called molecular clouds, which are dense patches of gas—primarily molecular hydrogen—where stars are born. By studying these clouds and their relationship to new stars in the galaxy, the team hoped to learn more about how gas clouds turn into stars.

Using the Mopra dish, the astronomers mapped more than 100 molecular clouds in the LMC and estimated their sizes and masses, identifying regions with ample material for making stars. This seemingly simple task engendered a surprising find.

Conventional wisdom states that most of the molecular gas in a galaxy is apportioned to a few large clouds. However, Wong’s team found many more low-mass clouds than they expected—so many, in fact, that a majority of the dense gas may be sprinkled across the galaxy in these small molecular clouds, rather than clumped together in a few large blobs.

MAGMA image of the LMC

False-colour image of the Large Magellanic Cloud galaxy combining maps of neutral atomic hydrogen gas (red), hydrogen energised by nearby young stars (blue), and new data from Wong’s team which roughly show the locations of dense clouds of molecular hydrogen (green). It's thought that stars form within molecular hydrogen clouds.

Star formation widespread in the LMC galaxy

The large numbers of these relatively low-mass clouds means that star-forming conditions in the LMC may be relatively widespread and easy to achieve.

To better understand the connection between molecular clouds and star formation, the team compared their molecular cloud maps to maps of infrared radiation, which reveal where young stars are heating cosmic dust.

“It turns out that there’s actually very nice correspondence between these young massive stars and molecular clouds,” Wong said.

“We can say with great confidence that these clouds are where the stars form, but we are still trying to figure out why they have the properties they do,” he added.

Adapted from information issued by University of Illinois at Urbana-Champaign. Mopra photo courtesy CSIRO. MAGMA image of LMC courtesy Tony Wong, University of Illinois.

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Gallery — Moon through the murk

ISS view of Earth's limb with the Moon in the background

Photo from the International Space Station shows the layers of Earth's atmosphere, with the Moon in the far background.

THIS STUNNING PHOTOGRAPH taken from the vantage point of the International Space Station, shows us what the layers of Earth’s atmosphere look like when seen edge on.

The darkest patch at the bottom of the image is likely to be cloud cover, showing a characteristic unevenness to its upper limits.

Just above that is an orange-red glow that marks the extent of the troposphere, the thick, lowest layer of the atmosphere that reaches up from the surface. The troposphere is where pretty much all of our weather occurs.

Just above the troposphere is a thinner, brown layer. This is the tropopause, which separates the troposphere from the next layer up, the stratosphere.

Indeed, the next layer we see in the image—a whitish-grey colour—is probably part of the stratosphere.

Above that are the topmost layers of the atmosphere—the mesosphere, thermosphere, and exosphere—which gradually fade from a pale blue into the black of space.

The gases and aerosols (tiny particles) in each atmospheric layer are good at filtering out particular colours in the light spectrum, and that’s why they appear to contrast each other so well.

Finally, in background we can see the Moon, 384,400 kilometres away, but seeming to be a lot closer.

See the full-size image here.

Story by Jonathan Nally. Astronaut photograph provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Centre.

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