#Dust devils around stars may help planets grow A dusty tornado around a young star could help solve a lingering conundrum:
how do massive planets grow from tiny grains of debris? Planets abound across the galaxy
and astronomers have seen young stars ringed by dusty discs from which planets are assumed to form.
But the steps in between have been unclear. The standard picture is that inside a dust disc grains smaller than a few micrometres will clump together until they grow into rocky bodies up to 10 times the mass of Earth.
Some of these clumps begin gathering gas from the disc and become the cores of gas giants like Jupiter.
But there is a catch. According to models of this process as the clumps get larger they feel more drag as they move through the gas and dust.
The clumps slow down and start to drift towards the star. Eventually they either collide with each other
and break apart or spiral in to their doom. The farther you get from the star the smaller the clumps that can form before they start to drift inwards.
For a star like our sun a dusty clump in the same orbit as Earth can grow to about a metre wide.
At about the distance of the Kuiper belt the region past Neptune where comets are born the would-be planet cores can't get much bigger than a millimetre.
This is a very big problem. If you can grow large particles they will disappear very quickly says Nienke van der Marel of Leiden Observatory in The netherlands.
Theorists had suggested an escape route for the protoplanets. Their idea was that pressure differences in the disc could spontaneously create vortices trapping the larger dust grains
and allowing them to keep growing until they were massive enough to overcome the death spiral.
Now observations made with the Atacama Large Millimetre/submillimetre Array (ALMA) in Chile show that the star Oph IRS 48 probably has just such a vortex in the outer regions of its planet-forming disc.
Older observations had spotted a gap in the disc suggesting that the star has an orbiting body about 10 times the mass of Jupiter that is clearing a space.
and colleagues observed the star at three wavelengths: one sensitive to dust grains a millimetre across
But the millimetre-sized dust grains are concentrated in a large crescent-shaped structure on one side of the star a sign that a vortex may be holding the larger grains in place.
But is the strange structure really helping to build protoplanets? It is quite far from the star
so it might be more of a comet factory says van der Marel. We really hope that in the next coming years we're going to find similar dust traps around other stars where they are close enough to the star that they can form a planet she says.
The observation is dramatic and surprising and the interpretation of the dust clump as a vortex is plausible says Philip Armitage an astrophysicist at the University of Colorado in Boulder.
But there's a problem. In the Oph IRS 48 system the Jupiter-like object is creating the pressure instabilities that would spawn the observed vortex.
It's a direct chicken -and-egg thing he says. If the idea is sound there must be a way to make vortices without first making giant planets perhaps involving the star heating the gas until it creates a region of instability.
Whether discs generally have large-scale structures which might be vortices or other kinds of traps that's still an open question he says.
Journal reference: Science DOI: 10.1126/science. 1236770correction: When this article was published first on 6 june 2013 it mistook the temperature of the gas that Nienke van der Marel
#Antares rocket launch heats up private space race Watch out Spacex there's a new commercial rocket in town.
After a few delays due to weather and a technical glitch the Antares launch vehicle lifted off on its maiden flight on 21 april.
The launch sets the stage for a second company to begin resupply missions to the International space station.
Since the space shuttles retired in 2011 NASA has been contracting with private firms to deliver cargo and soon hopefully astronauts to the space station.
California-based Spacex became the first private firm to officially resupply the ISS last October.
Its Falcon 9 rocket lifted off from Cape canaveral in Florida carrying a Dragon capsule filled with cargo and science experiments.
Antares built by spaceflight company Orbital Sciences of Dulles Virginia lifted off from the Mid-atlantic Regional Spaceport on Wallops Island Virginia at 22.00 GMT.
Antares was designed to deliver the company's Cygnus cargo craft to the ISS. For the test flight the rocket climbed high into a clear blue sky carrying a mock cargo ship with the same mass
and dimensions as Cygnus to avoid putting the real thing at risk. About 10 minutes into the mission the Cygnus dummy successfully separated from the rocket
and went into a temporary orbit. It will fall back to Earth in about two weeks and disintegrate upon reentering the atmosphere.
The dummy contains instruments that will collect data about the launch to be transmitted back to mission managers before re-entry.
When the real Cygnus flies it will carry about 2 tonnes of cargo per trip.
The Dragon capsule can deliver a payload of 3 tonnes. The two craft have comparable capabilities claims Mark Pieczynski of Orbital Sciences.
But while Dragon can return from its missions loaded with cargo no Cygnus craft will ever make it back to Earth.
and will burn up in Earth's atmosphere. Orbital's agreement with NASA includes this trial launch and a full demonstration mission in
which the rocket will bring a real loaded Cygnus craft to dock with the ISS perhaps as early as June.
If all goes well the company is contracted to make a total of eight cargo missions to the station over the next three or four years y
#Curiosity's discoveries hint at life's cradle on Mars NASA's Curiosity rover has found what it was looking for in its very first taste of Martian rock much to everyone's surprise.
The scoop of grey powder contains definitive evidence that the Red planet was suited once to life.
All the signs are had that Mars plentiful slightly salty water that could have supported primitive microbes. The hope is that Mars can help us understand the origins of life
even if the planet's early transformation into a cold dry hostile world meant life never got started there.
Determining the habitability of Mars was Curiosity's chief goal when it landed in Gale crater in August 2012.
But the rover was expected to hit pay dirt months from now when it reached a 5-kilometre-high mound of layered sediments in the middle of the crater.
Instead it struck lucky with a sample of rock drilled on 9 february in an area called Yellowknife Bay near
and you had been on the planet you would have been able to drink it says rover project scientist John Grotzinger.
The thinking is that Mars would have had liquid water billions of years ago around the time Earth was playing host to early life.
But at some point Mars dried out and lost much of its atmosphere. The planet also only briefly had a magnetic field to protect its surface from cosmic radiation
which can damage DNA. These changes might have stopped any emergent life in its tracks or even prevented it from starting at all.
Records of the earliest life have been hard to find on warm wet Earth. Paradoxically water which is necessary for life is a mild oxidant
But if microbes did exist on Mars traces of them may still be preserved on the cold dry world.
If we could find evidence primitive life got a start on Mars that could fill in a lot of gaps in our understanding of conditions on early Earth says Jeffrey Bada of the University of California in San diego. What we find on Mars won't be a magic bullet to say'Ah!
And even if no hints of microbes can be found Mars's habitable regions could still serve as snapshots of a prebiotic world frozen in time says Michael Meyer lead scientist for NASA's Mars exploration programme.
Mars may have preserved that history of what was going on what you might call proto-biology before life even got started he says.
NASA is now considering how best to equip the next rover a Curiosity clone that will launch in 2020 says Meyer.
Teams are expected to choose the science instruments by early 2014 based on recommendations from Mars researchers.
and what NASA ultimately selects says Meyer. This article appeared in print under the headline Rover finds hint of life's cradle on Mar l
#Rover finds first life-friendly environment on Mars Microbes could have lived on Mars . Though we don't know yet
if they actually did NASA's Curiosity rover has found the first definitive evidence that the Red planet was suited once to life
and perhaps the first direct evidence of life-friendly conditions anywhere beyond Earth. This is probably the only definitively habitable environment that we've described
Determining if Mars could have supported ever life was the rover's chief goal when it landed in Gale crater in August 2012.
Curiosity was expected to hit pay dirt months from now when it reached a 5-kilometre-high mound of layered sediments in the middle of the crater.
Instead the discovery came from the rover's first sample of the insides of a Martian rock drilled on 9 february near an ancient stream bed in an area called Yellowknife Bay.
All these clues point to ancient Mars hosting neutral slightly salty liquid water that could have supported primitive life.
and you had been on the planet you would have been able to drink it. The rover's Sample Analysis at Mars instrument (SAM) also found carbon dioxide and hints of other carbon-based molecules in the drilled sample.
Part of Curiosity's mission is to find preserved organics compounds that include both carbon and hydrogen.
That would be a direct sign that something actually lived on the Red planet. These new hints of carbon are tantalising
Mars is going to pass behind the sun from Earth's perspective for the entire month of April blocking communications between the rover and mission control.
The next drill scoop will have to wait until the planet comes back into Range in the meantime the science team has plenty of data to fuel new discoveries and daydreams.
I have an image now of possibly a freshwater lake on a Mars with a thicker atmosphere maybe a snowcapped Mount Sharp said NASA science administrator John Grunsfeld.
#Curiosity's first drilling hints at Martian mining NASA's Curiosity rover bored into a Martian rock on 9 february and pulled out its first sample of the planet's insides to ingest
The achievement could lay the groundwork for future Mars explorers to build structures or even to mine the Red planet.
This is the only time anybody's drilled into Mars says Louise Jandura of NASA's Jet propulsion laboratory (JPL) in Pasadena California chief engineer for Curiosity's sampling system.
what Mars was like 3 or 4 billion years ago. However it is not the first space drilling to take place.
Astronauts drilled into rocks on the moon and Soviet landers drilled on the moon and on Venus. Curiosity's predecessors the rovers Spirit and Opportunity each had a tool that scraped away the top layers of rocks to see what was beneath
but they were equipped not to extract anything for analysis. That means Curiosity is the first Mars rover to make a deep hole and collect
what was inside to be analysed. Drilling anywhere is hard but drilling on a rover kicks it up a notch says Jandura.
The rover used the drill bit at the end of its robotic arm to make a hole 1. 6 centimetres wide and 6. 4 centimetres deep in a flat veined outcrop thought to have once been saturated with water.
Although Curiosity's digging into Mars has been extremely modest its achievement could lay the groundwork for construction and mining on the Red planet.
#8th-century tree rings hint at close-range space blast A blast of radiation that hit Earth circa AD 770 may have been caused not by a solar flare but by the energetic debris from the collision of two nearby neutron stars.
but Miyake found a 1. 2 per cent leap in those years that could only have been caused by extremely high-energy cosmic rays hitting the Earth.
and European trees from the same era while Antarctic ice cores from 775 also have increases in beryllium-10 another isotope caused by cosmic rays.
There is nothing similar anywhere else in around 3000 years of tree ring records leading Miyake to suggest a massive solar flare as the cause.
and there is no historical record of such an energetic solar flare. The aurora would have been seen up to tropical latitudes says Valeri Hambaryan of the University of Jena Germany.
Some researchers have suggested that an unknown supernova might be responsible for a red crucifix in the sky recorded in the Anglo-saxon Chronicle a history of Anglo-saxon life compiled by anonymous scribes.
If that were the case the stellar remnants would still be visible today. That is why Hambaryan and his colleague Ralph Neuhauser are now proposing a short gamma-ray burst (GRB) as the cause.
GRBS are known to occur in distant galaxies and thought to be caused by the collision of two neutron stars black holes or white dwarfs.
The pair suggest that the odd isotope levels in the trees and in the Antarctic ice are the first evidence for a burst much closer to home.
They suggest looking for a neutron star between 3000 and 12000 light years away left over from such a merger.
#Largest structure challenges Einstein's smooth cosmos A collection of galaxies that is a whopping four billion light years long is the biggest cosmic structure ever seen.
The group is roughly one-twentieth the diameter of the observable universe big enough to challenge a principle dating back to Einstein that on large scales the universe looks the same in every direction.
Roger Clowes of the University of Central Lancashire in Preston UK and colleagues discovered the structure using data from the Sloan Digital Sky Survey the most comprehensive 3d map of the universe.
They identified a cluster of 73 quasars the brightly glowing cores found at the centre of some galaxies far larger than any similar structure seen before.
Since 1982 astronomers have known that quasars tend to clump together in large quasar groups or LQGS.
We look for quasars that have a certain separation from the next nearest quasar says Clowes. The newly discovered and appropriately named Huge-LQG (see black circles in image) happens to be in the same region of the sky as one of the earliest known quasar clusters
which Clowes helped find in 1991. That group contains 34 quasars and measures roughly one billion light years across (red crosses) so it is dwarfed by Huge-LQG.
The discovery of Huge-LQG joins a collection of observations that seem to challenge the cosmological status quo.
When Albert Einstein first applied his theory of general relativity to the universe as a whole to make the calculations workable he was forced to assume that one large part looks much like any other large part.
This became known as the cosmological principle. Still a question remained: how large is a large part?
Previous calculations gave a value of one billion light years as the maximum possible size of a cluster.
But other evidence such as a controversial stream of galaxies that seem to be moving in the same direction dubbed dark flow is also poking holes in the uniformity of the universe.
The search for such large structures is key to furthering our understanding of the universe
which the universe is supposed to be boring he says. But the cosmological principle is ingrained so that it is hard for researchers to shake.
because it will make cosmology too bloody complicated says Sarkar. Journal reference: Monthly Notices of the Royal Astronomical Society DOI:
#Multibillion-dollar race to put internet into orbit The next-generation internet could come from above, with fleets of satellites delivering broadband to under-served areas of the world THE race is on to build a new kind of internet.
A host of companies and billions of dollars are in play, with the ultimate goal of ringing the planet with satellites that will allow anyone, anywhere,
to get online at broadband speeds. Presently, satellite internet relies on spacecraft that are travelling in geosynchronous orbit
at the same speed as Earth rotates. But while this ensures the satellites are always in the same spot above Earth
it means there is a large time lag in the service, as radio waves take a quarter of a second to make the round trip up to a geosynchronous satellite and back.
Added to the time for the other trips your data must take across the rest of the internet,
the lag becomes unworkable for real-time applications like video or voice chat (see diagram). To speed up the service firms are looking at using satellites closer to Earth.
This month, Virgin galactic and chip-maker Qualcomm announced their backing of a venture called Oneweb.
This plans to put 648 satellites in orbit about 1200 kilometres above Earth's surface, where the round trip time for radio waves is just a few thousands of a second, fine for any online application.
Spacex immediately announced its own plan to do the same, building and launching 4000 satellites to a similar altitude.
That would more than double the number of satellites in orbit. The race has attracted more than just newcomers.
Iridium Communications based In virginia, has provided satellite telephone services and low-bandwidth internet since the late 1990s.
Its existing network of 66 satellites is set to be replaced by a new one called Iridium NEXT.
Due to start launching this year, the new satellites will be capable of delivering high-speed internet on a par with
what Oneweb and Spacex envisage. And O3b, a sister company to Oneweb, already has 12 satellites at an altitude of 8000 kilometres.
The firm provides connectivity to Colombia, the Democratic republic of the congo, South Sudan and Papua new guinea. Even internet giant Google has got in on the rush to space
investing $1 billion in Spacex's venture. The move is motivated by net neutrality concerns, says Kerri Cahoy, an aerospace engineer at the Massachusetts institute of technology.
If the internet service providers that rule the physical infrastructure of the internet start charging web services to deliver content to users,
the thinking goes, an alternative route to customers via satellites will be invaluable. It's not the only reason."
"It's a very interesting combination of motivations, "says Cahoy.""Some of these guys are fuelled by ads.
The more eyes they reach and more products they convince people to buy, the more business.
"Will the space around Earth become crowded with all these satellites vying to route our data?"
"I'm not worried about the physical interaction of the satellites as much as what they're using for the transmission.
"Beaming down Radio transmission is the most common way to communicate between satellites and Earth.
lower powered satellites that can still talk to the ground easily.""Radio has been the de facto,
"Miniaturisation and large drops in the cost of satellite components are boosting the push to space,
These have combined to increase access to orbit as never before.""I've got students that will leave with a master's
or six spacecraft,"says Cutler.""That's never happened before.""Companies like O3b and Spacex are planning to launch internet satellites with masses of hundreds of kilograms,
but Cutler says those of the future could be closer to 5 or 10 kilograms.
Antenna weight can be brought down by using antennas that unfurl themselves in space, like those being developed by Sergio Pellegrino at the California Institute of technology.
This means antennas of similar size to today's can be made of lighter materials as they will only have to support their own weight in microgravity, rather than On earth's surface.
if companies make their equipment small enough to fit in Cubesats small, lightweight satellites that can piggyback on the launches of other vehicles."
"That way every rocket that goes up is kicking off Cubesats, "he says, with each small orbiter perhaps holding only a fraction of a functional communications rig."
"What you want to do is start to self-assemble, "he says. Instead of building large satellites On earth and then fighting gravity to get them in orbit,
the components themselves would be launched, then come together in space to form a light, powerful satellite.
A network of such orbiters should be able to provide coverage that is similar to the signals terrestrial cellular towers already pump out."
"It's a brand new space race in many ways, "says Cutler.""But instead of being fuelled from a defence perspective,
As an analogy Weitzner says imagine trying to shape environmental policy without any way of measuring carbon levels in the atmosphere
It s crazy that something as trivial as physical space as the size of the lunch table could affect productivity Waber says.
A large pink dot appears to follow the pedestrian a symbol of the robot perception of the pedestrian position in space.
says Ali-akbar Agha-mohammadi, a postdoc in MIT Aerospace Controls Lab. ormally, a robot may make some decision,
a professor of aeronautics and astronautics, will present details of the visualization system at the American Institute of Aeronautics and Astronauticsscitech conference in January.
and other packets of data between continents, all at the speed of light. A rip or tangle in any part of this network can significantly slow telecommunications around the world.
or propulsion systems for fist-sized nanosatellites. In the latest issue of the IEEE Journal of Microelectromechanical systems Velsquez-Garc a his graduate students Eric Heubel and Philip Ponce de Leon and Frances Hill a postdoc in his group describe a new prototype
Higher currents thus promise more-efficient manufacturing and more-nimble satellites. The same prototype also crams 1900 emitters onto a chip that s only a centimeter square quadrupling the array size and emitter density of even the best of its predecessors.
and not a beam of droplets says Herbert Shea an associate professor in the Microsystems for Space technologies Laboratory at the cole Polytechnique F d rale de Lausanne.
Shea believes that at least in the near term the technology s most promising application is in spacecraft propulsion.
whereas it would take very little effort to use it as propulsion for small spacecraft he says.
The reason you d like to be in ion mode is to have the most efficient conversion of the mass of the propellant into the momentum of the spacecraft t
It should absorb virtually all wavelengths of light that reach Earth s surface from the sun but not much of the rest of the spectrum since that would increase the energy that is reradiated by the material
and has the additional benefits of absorbing sunlight from a wide range of angles and withstanding extremely high temperatures.
The sunlight s energy is converted first to heat which then causes the material to glow emitting light that can in turn be converted to an electric current.
In order to take maximum advantage of systems that concentrate sunlight using mirrors the material must be capable of surviving unscathed under very high temperatures Chou says.
And since the new material can absorb sunlight efficiently from a wide range of angles Chou says we don t need really solar trackers
In this paper the authors demonstrated in a system designed to withstand high temperatures the engineering of the optical properties of a potential solar thermophotovoltaic absorber to match the sun s spectrum.
#Shrink-wrapping spacesuits For future astronauts the process of suiting up may go something like this:
Instead of climbing into a conventional bulky gas-pressurized suit an astronaut may don a lightweight stretchy garment lined with tiny musclelike coils.
She would then plug in to a spacecraft s power supply triggering the coils to contract and essentially shrinkwrap the garment around her body.
not only support the astronaut but would give her much more freedom to move during planetary exploration.
Now MIT researchers are one step closer to engineering such an active second-skin spacesuit: Dava Newman a professor of aeronautics and astronautics and engineering systems at MIT and her colleagues have engineered active compression garments that incorporate small springlike coils that contract in response to heat.
The coils are made from a shape-memory alloy (SMA) a type of material that remembers an engineered shape
In subsequent tests the group found that the pressure produced by the coils equaled that required to fully support an astronaut in space.
With conventional spacesuits you re essentially in a balloon of gas that s providing you with the necessary one-third of an atmosphere of pressure to keep you alive in the vacuum of space says Newman who has worked for the past decade to design a formfitting flexible spacesuit of the future.
While skintight spacesuits have been proposed in the past there s been one persistent design hurdle: how to squeeze in and out of a pressurized suit that s engineered to be extremely tight.
To find an active material that would be most suitable for use in space Holschuh considered 14 types of shape-changing materials ranging from dielectric elastomers to shape-memory polymers before settling on nickel-titanium shape
The first option would overheat an astronaut and require heavy battery packs a design that would significantly impede mobility
and is given likely infeasible the limited power resources available to astronauts in space. Holschuh and Newman are currently exploring the second option looking into potential mechanisms to lock
As for where the coils may be threaded within a spacesuit Holschuh is contemplating several designs. For instance an array of coils may be incorporated into the center of a suit with each coil attached to a thread that radiates to the suit s extremities.
Or smaller arrays of coils could be placed in strategic locations within a spacesuit to produce localized tension
While the researchers are concentrating mostly on applications in space Holschuh says the group s designs
We re trying to keep our astronauts alive safe and mobile but these designs are not just for use in space.
This research was funded by NASA and the MIT Portugal Program m
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