Space and Astronomy News: February 2013

Thursday, February 28, 2013

Stargazer's Delight: Moon Gets Close to Bright Star Tonight

Pay close attention to the rising waxing gibbous moon tonight (Feb. 28), and if you live anywhere in the western hemisphere, you'll be able to watch an excellent demonstration of the movement of the moon in its orbit around the Earth.

Normally we see the moon rise in the east and then move across the sky, reaching its highest point in the south before descending down toward the western horizon. Of course, this movement is due to the west-to-east rotation of our Earth. But the moon too is also moving in a west-to-east direction in its orbit against the star background, circling Earth at roughly 2,200 miles an hour (3,500 kilometers per hour), the equivalent of its apparent diameter on the sky. Usually though, we're not aware of that movement during the course of a typical night.

But during an eclipse, when the moon interacts with Earth's shadow, that eastward motion becomes readily apparent. The moon's eastern (left) edge first touches the shadow, and then some minutes later (depending on how deeply the moon plunges into the shadow), it leaves the shadow behind, the last vestige of it disappearing on its western (right) edge.

While it appears that the shadow was creeping over the moon, it was actually the moon moving along in its orbit crossing through the shadow. [Top 10 Cool Moon Facts]

Another way to see the moon's motion through space is to watch when it closely passes a bright star or planet. Such will be the case this evening, when the moon has a close interaction with the bluish first magnitude star, Spica, in the constellation Virgo. Spica is the 16th brightest star in the sky, and soon after the moon comes above the east-southeast horizon at around 9:30 p.m. local time, you'll also see Spica near the moon. What you'll see depends on where you live.

For the eastern United States and Canada, the moon, 87-percent illuminated, will appear above and to the right of Spica as they move up above the horizon. But by 1 a.m. EST (Friday morning, March 1), the gap between them will have narrowed considerably and the moon will now appear just below and to Spica's right; their closest approach to each other.

If you live in the northeast United States, Spica will appear less than a moon's width from the moon's lower limb. If you live in the southeast United States, they'll appear even closer - less than half a moon's width from the lower limb.

You should still be able to see Spica with the naked eye, although the moon will be over 100,000 times brighter; you might want to use binoculars to see it better. The moon will then move slowly away from Spica. By 2:15 a.m. it will appear directly underneath the star as they stand almost due south, and as dawn is breaking at around 5 a.m., you'll see the moon will have shifted noticeably below and to Spica's left.

From the western United States, Spica and the moon will appear closest together right after they've risen at around 9:30 p.m. PST. Spica will appear very close to the moon's upper left rim, and then the moon will spend the rest of the night gradually moving away to the east. The moon will appear directly below Spica at the stroke of midnight, and at the break of dawn, the moon will have moved directly off to Spica's left.

The most dramatic view will be afforded to those living along the Pacific coast of Mexico and Central America as well as a large swath of South America, where the moon will actually pass directly in front of Spica. We could call this an eclipse of a star, though it's more popularly called an occultation.

This map of the moon-Spica occultation zone for 356 locations is available courtesy of IOTA, the International Occultation Timing Association.

Editor's Note: If you take a great photo of the moon and Spica, or any other night sky object that you'd like to share for a possible story or image gallery, send photos, comments and your name and location to managing editor Tariq Malik at spacephotos@space.com.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York. Follow SPACE.com onTwitter @Spacedotcom. We're also on Facebook & Google+.

NASA Discovers New Radiation Belt Around Earth

A ring of radiation previously unknown to science fleetingly surrounded Earth last year before being virtually annihilated by a powerful interplanetary shock wave, scientists say.

NASA's twin Van Allen space probes, which are studying the Earth's radiation belts, made the cosmic find. The surprising discovery - a new, albeit temporary, radiation belt around Earth - reveals how much remains unknown about outer space, even those regions closest to the planet, researchers added.

After humanity began exploring space, the first major find made there were the Van Allen radiation belts, zones of magnetically trapped, highly energetic charged particles first discovered in 1958.

'They were something we thought we mostly understood by now, the first discovery of the Space Age,' said lead study author Daniel Baker, a space scientist at the University of Colorado.

These belts were believed to consist of two rings: an inner zone made up of both high-energy electrons and very energetic positive ions that remains stable in intensity over the course of years to decades; and an outer zone comprised mostly of high-energy electrons whose intensity swings over the course of hours to days depending primarily on the influence from the solar wind, the flood of radiation streaming from the sun. [How NASA's Twin Radiation Probes Work (Infographic)]

The discovery of a temporary new radiation belt now has scientists reviewing the Van Allen radiation belt models to understand how it occurred.

Radiation rings around Earth

The giant amounts of radiation the Van Allen belts generate can pose serious risks for satellites. To learn more about them, NASA launched twin spacecraft, the Van Allen probes, in the summer of 2012.

The satellites were armed with a host of sensors to thoroughly analyze the plasma, energetic particles, magnetic fields and plasma waves in these belts with unprecedented sensitivity and resolution.

Unexpectedly, the probes revealed a new radiation belt surrounding Earth, a third one made of super-high-energy electrons embedded in the outer Van Allen belt about 11,900 to 13,900 miles (19,100 to 22,300 kilometers) above the planet's surface. This stable ring of space radiation apparently formed on Sept. 2 and lasted for more than four weeks.

'The feature was so surprising, I initially foolishly thought the instruments on the probes weren't working properly, but I soon realized the lab had built such wonderful instruments that there wasn't anything wrong with them, so what we saw must be true,' Baker said.

This newfound radiation belt then abruptly and almost completely disappeared on Oct. 1. It was apparently disrupted by an interplanetary shock wave caused by a spike in solar wind speeds.

'More than five decades after the original discovery of these radiation belts, you can still find new unexpected things there,' Baker said. 'It's a delight to be able to find new things in an old domain. We now need to re-evaluate them thoroughly both theoretically and observationally.'

A radiation mystery

It remains uncertain how this temporary radiation belt arose. Van Allen mission scientists suspect it was likely created by the solar wind tearing away the outer Van Allen belt.

'It looks like its existence may have been bookended by solar disturbances,' Baker said.

Future study of the Van Allen belts can reveal if such temporary rings of radiation are common or rare.

'Do these occur frequently, or did we get lucky and see a very rare circumstance that happens only once in a while?' Baker said. 'And what other unusual revelations might come now that we are really looking at these radiation belts with new, modern tools?'

The scientists detailed their findings online Feb. 28 in the journal Science.

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World's 1st Smartphone Satellite Dials Earth from Space

A tiny satellite powered by a Google Nexus One smartphone has become the world's first 'phonesat' to orbit Earth, its builders say.

The United Kingdom Space Agency's miniature STRaND-1 satellite launched into space on Monday (Feb. 25) is one of seven spacecraft riding into orbit aboard an Indian rocket. It will test several new space technologies, including its WARP DRiVE - a novel space propulsion technology that will test a water-alcohol based thruster system.

'We'd hate to pick up the bill on those roaming charges,' UK Space Agency officials wrote via Twitter after the successful launch of the rocket, India's Polar Satellite Launch Vehicle, from the Satish Dhawan Space Centre in Sriharikota, India.

The STRaND-1 nanosatellite is a small, box-shaped Cubesat. It weighs just 9.4 pounds (4.3 kilograms) and is about nearly 12 inches (30 centimeters) long and 4 inches (10 cm) wide. It was built by the British Surrey Space Center and Surrey Satellite Technology Ltd., to serve as a spaceflight training and technology demonstration mission, officials said.

'This is a great example of the innovative approach that you can take with cubesats to develop and prove low cost commercial technologies for space while at the same time proving an exciting way of training and developing engineering skills,' UK Space Agency's Chris Castelli, acting director of science, technology and exploration, said in a statement. 'We wish the STRaND-1 team every success and look forward to seeing how the mission performs.'

STRaND-1 combines its Google Nexus One Android-powered smartphone core with a Linux-based high-speed processor in order to control itself.

The nanosatellite is actually equipped with two new space propulsion systems. Its WARP DRiVE systems (short for Water Alcohol Resistojet Propulsion De-orbit Re-entry Velocity Experiment) will test a new way to intentionally destroy a satellite at the end of a mission by performing maneuvers that force the satellite to fall out of orbit. The second system is a set of eight electric 'pulsed plasma thrusters' that will be tested during the mission, Surrey officials explained in a statement.

There are apps for that

The STRaND-1 nanosatellite is also carrying several apps in its smartphone brain that serve crucial roles in the mission, Surrey officials added. They were selected during a Surrey-run Facebook contest in 2012 and include:

iTesla will recorded the strength of the magnetic field around STRaND-1 while in orbit.

STRaND Data App will display the smartphone's satellite telemetry on the phone itself so it can be photographed by an onboard camera.

360 App will use the built-in camera of STRaND-1's smartphone to take photos of Earth from space. The public can request images from the STRanD-1 satellite through the 360 app website.

Scream in Space App is designed to use the speakers in STRaND-1's smartphone to test the theory popularized by the tagline for the 1979 science fiction film 'Alien.' Surrey officials explained that 'the app will play videos of the best screams while in orbit and screams will be recorded using the smartphone's own microphone.'

In the United States, NASA is also developing its own version of the smartphone satellite. The U.S. space agency's aptly named PhoneSat project is expected to launch on a demonstration mission later this year.

Follow TechNewsDaily on Twitter @TechNewsDaily, or on Facebook.You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik.

Planet Mercury Once Covered in Magma, Study Suggests

The rocky, mostly dry surface of the planet Mercury may once have been roiling with hot magma, a new study based on observations by NASA's Messenger spacecraft suggests

NASA's Messenger, the first Mercury orbiter, has made its home around the closest planet to the sun since March 2011. From its close-up perch, the probe identified two distinct types of rocks that compose the planet's surface, which scientists were at a loss to explain.

Now, experiments in a lab at MIT suggest Mercury's puzzling surface makeup is most likely explained by a huge ocean of magma that existed shortly after the planet formed about 4.5 billion years ago.

'The thing that's really amazing on Mercury is, this didn't happen yesterday,' Timothy Grove, a professor of geology at MIT, said in a statement. 'The crust is probably more than 4 billion years old, so this magma ocean is a really ancient feature.'

Messenger identified the two rock types using its X-ray spectrometer, which was able to distinguish the chemical composition of materials on the planet's surface. [Latest Photos of Mercury from NASA's Messenger]

Scientists made synthetic rocks in the lab to simulate the two types of material, using finely powdered chemicals to piece together the closest possible matches to what was seen on the planet.

'We just mix these together in the right proportions and we've got a synthetic copy of what's on the surface of Mercury,' Grove said.

The researchers then subjected these samples to high temperatures and pressures to recreate the conditions they might have experienced throughout Mercury's evolution.

The analysis pointed to only one possible origin for the two rock types, the researchers said. An early ocean of magma created two layers of crystals, which eventually solidified and then re-melted into magma that was spread onto the surface of Mercury through volcanic eruptions.

The findings help piece together a more complete history for the solar system's tiniest planet.

'We're gradually filling in more blanks, and the story may well change, but this work sets up a framework for thinking about new data,' said Larry Nittler, a researcher at the Carnegie Institution of Washington. Nittler led the team that originally identified the two rock types on Mercury, but was not involved in the MIT laboratory study. 'It's a very important first step toward going from exciting data to real understanding.'

The scientists detailed their findings in the Feb. 1 issue of the journal Earth and Planetary Science Letters.

NASA's Messenger spacecraft (the name is short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging) launched in 2004 on a $446 million mission to study Mercury like never before. The spacecraft completed its primary mission in 2011 and is nearing the end of its first one-year mission extension.

Follow Clara Moskowitz on Twitter @ClaraMoskowitz or SPACE.com @Spacedotcom. We're also on Facebook & Google+.

Wednesday, February 27, 2013

NASA Deep-Space Missions Take Aim at Mars

CAPE CANAVERAL Fla. - The announcement today of an ambitious new project to launch the first private manned mission to Mars in 2018 may suggest to some that NASA has lost a step in the pursuit of deep-space exploration. But the U.S. space agency is forging ahead with plans for a flexible new spaceship and rocket to send astronauts deeper into space than ever before.

The nonprofit Inspiration Mars Foundation unveiled plans for a private Mars flyby mission today (Feb. 27) that calls for a January 2018 launch of a two-person crew - a man and woman, possibly a married couple - on a 501-day trip to the Red Planet and back. The mission would not land on Mars but bring a capsule and inflatable module within 100 miles (160 kilometers) of the Martian surface before zooming away back to Earth.

Just one hour after the Inspiration Mars Foundation announcement in Washington, D.C., NASA officials here at the Kennedy Space Center briefed reporters about the agency's own plans for deep-space missions, including an eventual Mars trek.

'We know we're eventually going to Mars, and there are multiple destinations between here and Mars,' Dan Dumbacher, NASA's deputy associate administrator for exploration systems, said in a briefing that did not address the private Mars project.

To do that, NASA is developing the new Orion deep-space capsule, the agency's first manned spacecraft since the space shuttle program ended in 2011. Orion is expected to launch on a new mega-rocket, the Space Launch System (SLS). [See Photos of NASA's Deep-Space Vehicles]

Project Orion

Orion and the SLS form the core of NASA's deep-space exploration program. In 2010, President Barack Obama set a lofty goal for NASA's future - send astronauts to an asteroid by 2025, then take aim at a manned Mars mission in the 2030s.

The aerospace company Lockheed Martin is building the four-person Orion capsule for NASA, with the European Space Agency providing the service module for the spacecraft. Orion's first test flight, called Exploration Flight Test 1, is slated to launch in 2014, and parts of the space capsule are being assembled at the Kennedy Space Center now.

Once the computers are in place sometime this summer, NASA scientists will power on the test capsule for the first time and check its systems on the ground, Orion project manager Mark Geyer said.

The NASA team plans to launch the capsule atop a Delta 4 rocket, sending it 3,000 miles (4,828 km) above Earth's surface. The main goal is to test the heat shields tasked with protecting crewmembers during Orion's manned missions, the first of which is slated to launch toward lunar space in 2021.

Giant rocket test

NASA's first SLS flight - the unmanned Exploration Mission 1 - is due to launch in 2017, officials said.

Currently, various components of the rocket are being built around the country. Starting in 2016, hardware is expected to begin arriving at the Kennedy Space Center for testing and assembly.

Orion and the Space Launch System won't launch together at first, but data from both flight tests will be used to help NASA scientists learn what improvements may be needed for each of the vehicles to boost safety and efficiency, project officials said.

'You want to make sure you've flown in that environment before you put anyone on board,' Geyer said.

Scientists will also test Orion's launch abort system during a separate test after the 2014 launch. Like NASA's Mercury, Gemini and Apollo capsules, the Orion spacecraft features an abort system designed to separate the capsule from its rocket during an emergency to carry its crew to safety. The agency's space shuttles had no such system.

During the launch abort test, NASA plans to stress the Orion capsule to its limits to replicate the conditions astronauts might experience in the case of a malfunction. The spacecraft will be ripped free of its booster and propelled 1 mile (1.6 km) away to safety through a series of intricate maneuvers performed by its abort system.

NASA is also preparing the ground facilities at Kennedy Space Center for the future missions. The Orion test flight will be run from a new firing room at the Launch Control Center, and NASA officials will be awarding a contract to a company that will reconfigure some of the structural models on the ground for the new rocket, explained Pepper Phillips, NASA's ground systems project manager.

Follow Miriam Kramer on Twitter @mirikramer or SPACE.com @Spacedotcom. We're also on Facebook & Google+.

Monster Black Hole's Spin Revealed for 1st Time

Astronomers have made the first reliable measurement of a supermassive black hole's spin, showcasing a technique that could help unravel the mysteries of these monsters' growth and evolution.

The enormous black hole at the center of the spiral galaxy NGC 1365 is spinning about 84 percent as fast as Einstein's general theory of relativity allows it to, researchers determined. The find demonstrates that at least some supermassive black holes are rotating rapidly - a claim previous studies had hinted at but failed to confirm.

'It's the first time that we can really say that black holes are spinning,' study co-author Fiona Harrison, of Caltech in Pasadena, told SPACE.com. 'The promise that this holds for being able to understand how black holes grow is, I think, the major implication.'

Staring at a black hole in X-ray light

Supermassive black holes are almost incomprehensibly huge, with some containing 10 billion or more times the mass of our sun. Scientists think one lurks at the heart of most, if not all, galaxies. [Gallery: Black Holes of the Universe]

NGC 1365, located about 56 million light-years from Earth in the constellation Fornax, does indeed harbor a gigantic black hole - one as massive as several million suns. And this behemoth is blasting out enormous quantities of energy as it gobbles up gas and other nearby matter, making it an intriguing target for astronomers.

In the new study, researchers analyzed observations two X-ray space telescopes - the European Space Agency's XMM-Newton observatory and NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) - made of NGC 1365 in July 2012.

By zeroing in on high-energy light emitted by iron atoms, the telescopes were able to trace the motion of the flat, rotating accretion disk that circles NGC 1365's black hole and funnels gas and dust into its greedy maw.

Astronomers found that the emissions are strongly distorted, suggesting that the inner edge of the accretion disk may be quite close to the black hole - close enough for gravitational effects to wreak havoc with the X-rays streaming from the disk. This in turn implies a rapidly rotating black hole, since general relativity states that the faster a black hole is spinning, the closer its disk can come to it, Harrison said.

But that's just one interpretation. Another holds that such distortion, which has been observed in accretion disk emissions before, could be caused by clouds of gas that hang between a supermassive black hole and the telescopes observing it. [The Strangest Black Holes in the Universe]

'This has been a big controversy - which of the two is going on?' Harrison said.

Pinning down a black hole's spin

The $165 million NuSTAR telescope, which just launched in June 2012, finally cracked the case.

Using NuSTAR's super-sensitive measurements of high-energy X-rays, the astronomers calculated that the purported gas clouds would have to be incredibly thick to produce the observed distortion levels - so thick as to make the whole idea untenable, at least in the case of NGC 1365's black hole.

'To shine through these thick clouds, the black hole would have to be so bright it would basically blow itself apart,' said Harrison, who's principal investigator for the NuSTAR mission. 'So what has to be happening is, what we're seeing is these relativistic distortions. And that means that the disk is coming close to the black hole, which means the black hole must be spinning rapidly.'

The research team, led by Guido Risaliti of the Harvard-Smithsonian Center for Astrophysics and the Italian National Institute for Astrophysics' Arcetri Observatory, calculated this rotation rate to be 84 percent of that allowed by general relativity.

It's tough to comprehend this figure, since it doesn't translate well into miles per hour. But it's safe to say that the black hole is spinning incredibly fast.

'The analogy of an actual velocity is not quite right,' Harrison said. 'But what you can say is that spinning black holes twist space-time around them. And if you were standing near the black hole, basically your space-time would be twisted, or dragged, around such that you would have to rotate once every four minutes just to be standing still.'

The new study was published online today (Feb. 27) in the journal Nature.

Learning about black hole growth

Astronomers think supermassive black holes acquire most of their spin as they grow, rather than being born with it. So studying their rotation rates can yield insights into how these monsters have evolved over time.

The superfast spin of NGC 1365's black hole, for example, implies that it did not grow via numerous small black-hole mergers, Harrison said, since the odds are very low that many such chaotic events would spin it up in the same direction.

Rather, it's more likely that NGC 1365's central black hole acquired its spin from one major merger, or simply by gobbling material from an accretion disk that has remained stable over the long haul.

The new study represents a first step toward a better understanding of the nature and evolution of supermassive black holes, Harrison said.

'We will make more measurements like this,' she said. 'Eventually what you'd like to do is have a bigger telescope that can actually measure more distant black holes so we can, using the statistics of the sample, understand how they grow over cosmic time.'

Follow SPACE.com senior writer Mike Wall on Twitter @michaeldwall or SPACE.com @Spacedotcom. We're also on Facebook and Google+.

Hubble Telescope Reveals Milky Way Galaxy's Cannibal Past

The Milky Way's far outer reaches may harbor a shell of stars left over from a long-ago act of galactic cannibalism, a new study suggests.

The finding supports the idea that our Milky Way has continued to grow over the eons by gobbling up smaller satellite galaxies, researchers said. And the results may help astronomers better understand how mass is distributed throughout the galaxy, which could shed light on the mysterious dark matter that's thought to make up more than 80 percent of all matter in the universe.

In the new study, scientists used NASA's Hubble Space Telescope to precisely measure the motion of 13 stars in the Milky Way's ancient outer halo, about 80,000 light-years from the galactic center. They picked the stars out of seven years' worth of archival Hubble observations, which were acquired when the telescope was staring at the neighboring Andromeda galaxy.

Identifying the handful of far-flung Milky Way residents was no picnic, as each Hubble image contained more than 100,000 stars. [Stunning Photos of Our Milky Way Galaxy]

'It was like finding needles in a haystack,' co-author Roeland van der Marel, of the Space Telescope Science Institute in Baltimore, said in a statement.

The team found that the outer halo stars had a surprisingly high level of sideways, or tangential, motion relative to their radial motion (which describes movement toward or away from the Milky Way's core).

The existence of a shell structure - which can be created by the accretion of a satellite galaxy - could explain the halo stars' unexpected motion, researchers said, noting that shell-like features have been observed around other galaxies.

'What may be happening is that the stars are moving quite slowly because they are at the apocenter, the farthest point in their orbit about the hub of our Milky Way,' lead author Alis Deason, of the University of California, Santa Cruz, said in a statement. 'The slowdown creates a pileup of stars as they loop around in their path and travel back towards the galaxy. So their in and out or radial motion decreases compared with their sideways or tangential motion.'

Deason and her colleagues plan to study more outer halo stars to determine if the shell at 80,000 light-years really does exist. Their overall goals are to gain a better understanding of the Milky Way's formation and evolution, and to calculate an accurate mass for the galaxy.

This latter aim has proven elusive to date.

'Until now, what we have been missing is the stars' tangential motion, which is a key component,' Deason said. 'The tangential motion will allow us to better measure the total mass distribution of the galaxy, which is dominated by dark matter. By studying the mass distribution, we can see whether it follows the same distribution as predicted in theories of structure formation.'

The new study has been accepted for publication in The Astrophysical Journal.

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Russian Meteor's Origin and Size Pinned Down

A meteor that exploded over Russia earlier this month likely hit Earth after a long trip from beyond the orbit of Mars, scientists say.

Astronomers and the public were caught off guard by the Russian fireball, which damaged thousands of buildings and wounded more than 1,000 people when it detonated over the city of Chelyabinsk on Feb. 15.

But some YouTube-aided detective work suggests that the meteor's parent body belonged to the Apollo family of Earth-crossing asteroids, whose elliptical orbits take them farther than one Earth-sun distance (about 93 million miles, or 150 million kilometers) from our star at some point, researchers said.

Jorge Zuluaga and Ignacio Ferrin of the University of Antioquia in Medellin, Colombia, reached this conclusion after analyzing several videos of the Russian meteor, especially one taken in Chelyabinsk's Revolutionary Square and another recorded in the nearby city of Korkino. [Russian Fireball: All You Need to Know (Video)]

They also took into account the location of a hole in the ice of Lake Chebarkul, about 43 miles (70 km) from Chelyabinsk. Scientists think the hole was caused by a piece of the space rock that hit Earth on Feb. 15.

Using trigonometry, Zuluaga and Ferrin calculated basic elements of the fireball's path through Earth's atmosphere.

'According to our estimations, the Chelyabinski meteor started to brighten up when it was between 32 and 47 km up in the atmosphere,' they write in their paper, which has been posted to the online astronomy preprint site ArXiv.org. 'The velocity of the body predicted by our analysis was between 13 and 19 km/s (relative to the Earth) which encloses the preferred figure of 18 km/s assumed by other researchers.'

The pair then entered these figures into a software program developed by the United States Naval Observatory called NOVAS (short for Naval Observatory Vector Astrometry), which calculated the likely orbit of the meteor's parent body.

Some other scientists agree that this orbit took the space rock relatively far from the sun at times - farther than Mars, in fact.

'It came from the asteroid belt, about 2.5 times farther from the sun than Earth,' Bill Cooke, of NASA's Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Ala., said in a statement. Cooke was not involved in Zuluaga and Ferrin's study.

Meanwhile, the size of the meteor's parent object has come into clearer focus, thanks to measurements made by a global network of infrasound sensors operated by the Comprehensive Test Ban Treaty Organization (CTBTO). These sensors monitor extremely low-frequency sound waves, which are a common product of nuclear explosions.

As the Russian meteor burned through Earth's atmosphere, it generated the most powerful infrasound signal ever detected by the CTBTO network, researchers said. And this signal revealed a great deal about the asteroid's size, speed and explosive power.

'The asteroid was about 17 meters in diameter and weighed approximately 10,000 metric tons,' Peter Brown, a physics professor at the University of Western Ontario in Canada, said in a statement. 'It struck Earth's atmosphere at 40,000 mph and broke apart about 12 to 15 miles above Earth's surface. The energy of the resulting explosion exceeded 470 kilotons of TNT.'

That's 30 to 40 times more powerful than the atomic bomb the United States dropped on the Japanese city of Hiroshima during World War II. The Russian fireball likely produced the most powerful such space rock blast since a 130-foot (40 m) object exploded over Siberia in 1908, flattening 825 square miles (2,137 square km) of forest.

Preliminary reports suggest that the Chelyabinsk fireball's parent asteroid was composed primarily of stone, with a smidge of iron thrown in.

'In other words, [it's] a typical asteroid from beyond the orbit of Mars,' Cooke said. 'There are millions more just like it.'

The Russian meteor struck just hours before the 130-foot asteroid 2012 DA14 gave Earth a close shave, missing our planet by just 17,200 miles (27,000 km). But the two space rocks are unrelated, researchers say, making Feb. 15 a day of remarkable cosmic coincidences.

You can see the Arxiv paper on the Russian meteor here.

Follow SPACE.com senior writer Mike Wall on Twitter @michaeldwall or SPACE.com @Spacedotcom. We're also on Facebook and Google+.

Tuesday, February 26, 2013

NASA Spacecraft Discovers Particle Accelerator at Saturn

NASA's Cassini spacecraft has spotted solar particles moving at incredible speeds near Saturn, giving scientists a rare up-close look at phenomena that occur during dramatic star explosions.

The particles flowed from the sun during a strong blast of solar wind, then plowed into Saturn's magnetic field shortly thereafter. This encounter, which Cassini observed in February 2007, created a shockwave that accelerated the particles to super-high energies, scientists said.

Similar shockwaves commonly form in the aftermath of massive star explosions called supernovas, ramping up nearby particles to nearly the speed of light. Researchers think supernova shockwaves are the primary source of cosmic rays, high-energy particles that pervade our Milky Way galaxy and slam into Earth's atmosphere continuously.

It can be tough to study distant supernovas and their shockwaves, so Cassini's observations provide a welcome proxy, scientists said.

'Cassini has essentially given us the capability of studying the nature of a supernova shock in situ in our own solar system, bridging the gap to distant high-energy astrophysical phenomena that are usually only studied remotely,' Adam Masters, of the Institute of Space and Astronautical Science, Sagamihara, Japan, said in a statement.

Masters is lead author of a study reporting the Cassini findings, which was published this week in the journal Nature Physics.

The Saturn shockwave may be the most powerful ever detected at the ringed planet and suggests that certain kinds of shocks can be surprisingly efficient particle accelerators, researchers said.

The $3.2 billion Cassini mission is a joint effort of NASA, the European Space Agency and the Italian Space Agency. Cassini launched in 1997 and arrived at the Saturn system in 2004, delivering a lander called Huygens to the planet's huge moon Titan in January 2005.

Cassini will continue studying the ringed planet and its many moons for several years to come; Cassini's mission has been extended through at least 2017.

Follow SPACE.com senior writer Mike Wall on Twitter @michaeldwall or SPACE.com @Spacedotcom. We're also on Facebook and Google+.

NASA's Curiosity Rover Eats 1st Mars Rock Sample

NASA's Mars rover Curiosity has consumed its first samples from inside a Martian rock in order to analyze the chemistry and mineralogy of the Red Planet.

The Curiosity rover deposited the powder-like samples, drilled from the interior of the Mars rock 'John Klein,' into two onboard laboratories so they could be studied in detail, rover mission scientists said in a statement Monday (Feb. 25).

Curiosity's first Mars rock samples were placed inside the Chemistry and Mineralogy (or CheMin) instrument, as well as the rover's Sample Analysis at Mars instrument during a two-day operation on Friday and Saturday (Feb. 22 and 23).

'Data from the instruments have confirmed the deliveries,' said Curiosity Mission Manager Jennifer Trosper of NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif.

The small Mars laboratories are built into the body of the car-size Curiosity rover. They are two of 10 instruments built to determine if Mars is now, or ever has been, capable of supporting microbial life.

Curiosity used a percussive drill mounted on its robotic arm to dig into the Mars rock John Klein on Feb. 8, revealing a surprisingly gray-colored interior of the rock. The discovery is intriguing to Mars scientists because it suggests that the rusty reddish-orange color of Mars is only skin deep.

The gray-colored rock powder 'may preserve some indication of what iron was doing in these samples without the effect of some later oxidative process that would've rusted the rocks into this orange color that is sort of typical of Mars,' Joel Hurowitz, sampling system scientist for Curiosity at JPL, told reporters on Wednesday (Feb. 20).

NASA's $2.5 billion Mars rover Curiosity landed on the Red Planet on Aug. 5 to begin a two-year primary mission to study its landing site, the vast Gale Crater. The rover is currently studying the John Klein rock target as a pit stop on the way to a destination called Glenelg, which is near the base of a mountain that rises up 3 miles (5 kilometers) from the center of Gale Crater.

You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik. Follow SPACE.com on Twitter @Spacedotcom. We're also on Facebook & Google+.