Mystery on Venus: 'Super-Hurricane' Force Winds Inexplicably Get Stronger

The howling, hurricane-force winds of Venus are blowing even faster lately, and scientists aren't sure why.

Average cloud-top wind speeds on Venus rose 33 percent between 2006 and 2012, jumping from 186 mph (300 km/h) to 249 mph (400 km/h), observations by Europe's Venus Express orbiter show.

"This is an enormous increase in the already high wind speeds known in the atmosphere," Igor Khatuntsev of the Space Research Institute in Moscow said in a statement. "Such a large variation has never before been observed on Venus, and we do not yet understand why this occurred." 

The strange winds of Earth's "sister planet" have long intrigued researchers. Venus has a super-rotating atmosphere that whips around the planet once every four Earth days; Venus itself takes 243 Earth days to complete one rotation. European Space Agency officials described the strong Venusian winds as "super-hurricane-force" phenomena.

Khatuntsev and his team determined wind speeds by studying images captured by Venus Express between 50 degrees north and south latitude. The researchers tracked the movements of tens of thousands of features in the cloud tops some 43 miles (70 kilometers) above the planet's surface.

Their work has been accepted for publication in the journal Icarus. A Japanese-led team also tracked cloud movements using Venus Express data in a separate but complementary study that will be published in the Journal of Geophysical Research.

"Our analysis of cloud motions at low latitudes in the southern hemisphere showed that over the six years of study the velocity of the winds changed by up 70 km/h over a time scale of 255 Earth days — slightly longer than a year on Venus," lead author Toru Kouyama, of the Information Technology Research Institute in Ibaraki, Japan, said in a statement.

Both new studies also detected regular variations in the atmosphere of Venus that appear to be linked to the rotational period of the planet, the local time of day and the height of the sun above the horizon, researchers said.

And both teams saw surprising and dramatic variations in wind speed, sometimes in as little as 24 hours. Sometimes clouds took 3.9 days to zip all the way around Venus, for example, while on other occasions the journey required 5.3 days.

The reasons for such shifts, as well as the long-term increase in wind speed, remain mysterious, scientists said.

"Although there is clear evidence that the average global wind speeds have increased, further investigations are needed in order to explain what drives the atmospheric circulation patterns that are responsible, and to explain the changes seen in localized areas on shorter timescales," Venus Express project scientist Håkan Svedhem said in a statement.

"The atmospheric super-rotation of Venus is one of the great unexplained mysteries of the solar system," Svedhem added. "These results add more mystery to it, as Venus Express continues to surprise us with its ongoing observations of this dynamic, changing planet."

Source of Article: Space.com

NASA's Grand Challenge: Stop Asteroids from Destroying Earth

There may be killer asteroids headed for Earth, and NASA has decided to do something about it. The space agency announced a new "Grand Challenge" today (June 18) to find all dangerous space rocks and figure out how to stop them from destroying Earth.

The new mission builds on projects already underway at NASA, including a plan to capture an asteroid, pull it in toward the moon and send astronauts to visit it. As part of the Grand Challenge, the agency issued a "request for information" today aiming to solicit ideas from industry, academia and the public on how to improve the asteroid mission plan.

"We're asking for you to think about concepts and different approaches for what we've described here," William Gerstenmaier, NASA's associate administrator for human explorations and operations, said today during a NASA event announcing the initiative. "We want you to think about other ways of enhancing this to get the most out of it."

Responses to the request for information, which also seeks ideas for detecting and mitigating asteroid threats, are due July 18.

The asteroid-retrieval mission, designed to provide the first deep-space mission for astronauts flying on NASA's Space Launch System rocket and Orion space capsule under development, has come under fire from lawmakers who would prefer that NASA return to the moon.

A draft NASA authorization bill from the House space subcommittee being debated right now would cancel the mission and steer the agency toward other projects. That bill will be discussed during a hearing Wednesday (June 19) at 10 a.m. EDT.

But NASA officials defended the asteroid mission today and said they were confident they'd win Congress' support once they explained its benefits further.

"I think that we really, truly are going to be able to show the value of the mission," NASA Associate Administrator Lori Garver said today. "To me, this is something that what we do in this country — we debate how we spend the public's money. This is the beginning of the debate."

Garver also maintained that sending astronauts to an asteroid would not diminish NASA's other science and exploration goals, including another lunar landing.

"This initiative takes nothing from the other valuable work," she said. "This is only a small piece of our overall strategy, but it is an integral piece. It takes nothing from the moon."

Part of NASA's plan to win support for the flight is to link it more closely with the larger goal of protecting Earth from asteroid threats.

If, some day, humanity discovers an asteroid headed for Earth and manages to alter its course, "it will be one of the most important accomplishments in human history," said Tom Kalil, deputy director for technology and innovation at the White House Office of Science and Technology Policy.

The topic of asteroid threats is more timely than ever, after a meteor exploded over the Russian city of Chelyabinsk on Feb. 15, the same day that the football-field-size asteroid 2012 DA14 passed within the moon's orbit of Earth.


Source of Article: Space.com

Distantly Orbiting Alien World May Challenge Planet-Formation Theories

Astronomers have found evidence of an alien planet forming surprisingly far from its host star, a discovery that could challenge the prevailing wisdom about how planets take shape.

Researchers using NASA's Hubble Space Telescope spotted a large gap in the planet-forming debris disk surrounding the red dwarf star TW Hydrae, which lies about 176 light-years from Earth in the constellation Hydra (The Sea Serpent).

This gap, which was likely carved out by an unseen newborn exoplanet six to 28 times as massive as Earth, sits 7.5 billion miles (12 billion kilometers) from TW Hydrae — about twice the distance from our own sun to Pluto. 

The gap's farflung location poses problems for the leading planet-formation theory, which holds that worlds grow slowly over tens of millions of years by sweeping up gas, dust and rocks from the protoplanetary disk.

Planet formation should proceed more slowly at relatively greater distances from the host star, according to this idea, because orbital speeds are reduced and there is less raw material in the outer reaches of the disk.

It should thus take the potential TW Hydrae planet more than 200 times longer to form than it took Jupiter, which lies just 500 million miles (800 million km) from the sun, researchers said. Jupiter is thought to have taken shape over the course of 10 million years or so.

But the numbers don't add up, because TW Hydrae, which is 55 percent as massive as the sun, is just 8 million years old.

An alternative idea posits that planets can form very rapidly — within a few thousand years — when pieces of the protoplanetary disk become gravitationally unstable and collapse on themselves. But even under this scenario, it's unclear how such a low-mass planet could form, researchers said.

"If the mass of this suspected planet is as low as it seems to be, this presents a real puzzle," astrophysicist Alan Boss of the Carnegie Institution for Science in Washington, D.C., who was not involved in the study, said in a statement. "Theory would say that it cannot exist!"

Further study of the TW Hydrae system may help astronomers figure out what's actually going on.

"If we can actually confirm that there's a planet there, we can connect its characteristics to measurements of the gap properties," study lead author John Debes, of the Space Telescope Science Institute in Baltimore, Md., said in a statement. "That might add to planet formation theories as to how you can actually form a planet very far out."

Complicating matters further is the observation, made by the Atacama Large Millimeter Array in Chile, that the TW Hydrae system lacks dust grains larger than a grain of sand beyond about 5.5 billion miles (8.9 billion km) from the star.

"Typically, you need pebbles before you can have a planet," Debes said. "So, if there is a planet and there is no dust larger than a grain of sand farther out, that would be a huge challenge to traditional planet formation models."

Debes and his team used Hubble's Near Infrared Camera and Multi-Object Spectrometer to study TW Hydrae in near-infrared light, then compared these observations to archival Hubble data and optical and spectroscopic observations from the observatory's Space Telescope Imaging Spectrograph.

The gap in the disk showed up in every case. Astronomers measured its width at about 1.9 billion miles (3 billion km), which helped them estimate the mass of the potential planet that carved it out. TW Hydrae's entire protoplanetary disk spans about 41 billion miles (66 billion km).

Source of Article: Space.com

Toxic Mars: Astronauts Must Deal with Perchlorate on the Red Planet

The pervading carpet of perchlorate chemicals found on Mars may boost the chances that microbial life exists on the Red Planet — but perchlorates are also perilous to the health of future crews destined to explore that way-off world.

Perchlorates are reactive chemicals first detected in arctic Martian soil by NASA's Phoenix lander that plopped down on Mars over five years ago in May 2008.

It is likely both of NASA's Viking Mars landers in 1976 measured signatures of perchlorates, in the form of chlorinated hydrocarbons. Other U.S. Mars robots — the Sojourner, Spirit and Opportunity — detected elemental chlorine. Moreover, orbital measurements taken by the Mars Odyssey spacecraft show that chlorine is globally distributed.

And more recently, NASA's Curiosity rover found perchlorates within Gale Crater, where it landed in August 2012.  

Unexpected results

Finding calcium perchlorate "was one of our most unexpected results," said Peter Smith, the Phoenix principal investigator at the University of Arizona in Tucson.

"Perchlorate is not a common word in the English language; all of us had to go and look it up," Smith said during Spacefest V, a conference held May 24-27 in Tucson, Ariz. "Perchlorate has become an important component of the soil … and half a percent is a fair amount," he said.

Smith said microbes on Earth use perchlorate for an energy source. They actually live off highly oxidized chlorine, and in reducing the chlorine down to chloride, they use the energy in that transaction to power themselves. In fact, when there's too much perchlorate in drinking water, microbes are used to clean it up, he said.

Furthermore, seasonal flow features seen on Mars may be caused by high concentrations of the brines of perchlorate, which has a strong attraction to water and can drastically lower its freezing point, Smith told SPACE.com.

Devilishly dangerous

The high levels of perchlorate found on Mars would be toxic to humans, Smith said.

"Anybody who is saying they want to go live on the surface of Mars better think about the interaction of perchlorate with the human body," he warned. "At one-half percent, that's a huge amount. Very small amounts are considered toxic. So you'd better have a plan to deal with the poisons on the surface."

Any humans exploring Mars, Smith said, will find it hard to avoid the finest of dust particles. "It'll get into everything…certainly into your habitat."

Undeniably, Martian dust devils laden with perchlorates are sure to be devilishly dangerous.

But Smith also noted that perchlorate is used within the pyrotechnics industry, and ammonium perchlorate is also a component of solid rocket fuel. "So maybe you can mine it as an on-the-spot resource," he said.

Good news, bad news

Perchlorate has made, and continues to make, the search for organics on Mars all but impossible, said astrobiologist Chris McKay of NASA's Ames Research Center in Moffett Field, Calif.

"Its presence is good news for the possibility of life on Mars…but very, very bad news for humans, McKay told SPACE.com. "Once again, Mars is full of surprises."

"It's bad for astronauts because it is toxic for humans, as it interferes with the thyroid," he said.

McKay is one of the co-authors of a new research paper delving into perchlorates on Mars; the work was led by Alfonso Davila of the SETI Institute in Mountain View, Calif. That review is slated to appear in the International Journal of Astrobiology and focuses on perchlorate as both a chemical hazard as well as a resource for humans.

Dual implications

The research emphasizes that perchlorate is widespread in Martian soils at concentrations of between 0.5 to 1 percent. There are dual implications of calcium perchlorate on Mars. On one hand, at such concentrations, perchlorate could be an important source of oxygen. But it could also become a critical chemical hazard to astronauts.

In the forthcoming paper, the researchers propose a biochemical approach for the removal of perchlorate from Martian soil that would not only be energetically cheap and environmentally friendly, but could also be used to obtain oxygen both for human consumption and to fuel surface operations.

Managing exposure

In many ways, managing calcium perchlorate exposure on Mars is viewed as no different than managing for example, uranium, lead or general heavy-metal-contaminated areas in modern mines, where dust suppression, dust extraction and regular blood monitoring are employed. Other ideas suggested by the study team include a wash-down spray that can clean suits and equipment of dust deposits.

More proposals are on the table, too. For instance, Mars suits could be kept on the outside of extravehicular activity rovers or habitation modules. The astronauts would climb into their suits through a bulkhead opening, and then the suits would be sealed from within. Thus, Mars crews avoid coming into contact with outside materials.

This approach was originally proposed as a way for astronauts to avoid back contamination when coming in contact with rock and regolith materials. But it might also help in dealing with perchlorates.

Knowledge gaps

There is growing interest in appraising perchlorate as a long-term exposure risk to humans on Mars before the first human sets foot on the Red Planet.

NASA has identified key strategic knowledge gaps that need to be addressed before humans can be sent to Mars. Two key areas are the potential hazards to humans, and the existence of resources that can support human and robotic operations.

"I'd put it in the category of, this is exactly why we do robotic exploration before sending humans," Doug Archer, a scientist with the Astromaterials Research and Exploration Science Directorate of NASA's Johnson Space Center in Houston, said of the perchlorate research.

Archer said perchlorate's existence on Mars would have posed an even larger problem had it not been discovered. 

"But now that we know it's there, I am confident we will be able to design around it," he said. "I have a lot of co-workers here at Johnson Space Center who work in the human exploration side of things, and none of them seem to think perchlorate is a showstopper. So sending robotic explorers as precursors to human exploration is shown to be a very useful strategy."

Source of Article: Space.com

Obese Black-Hole Galaxies Could Reveal Quasar Secrets

Gluttonous black holes in the center of some galaxies could be precursors to the brightest objects in the known universe.

A recently proposed type of galaxy with an overwhelmingly large black hole in its center could give astronomers a better understanding of the formation of quasars — bright objects in galaxies with supermassive black holes. The centers of these obese black-hole galaxies (OBGs) could harbor black holes so massive that radiation from where the black hole accretes would overwhelm that of the stars within its galaxy.

New research indicates that some of the most luminous quasars seen from Earth were likely OBGs first before something "lit up" the black hole and had it pump out energy visible from Earth.

The simulations indicate there could be a million OBGs in the observable universe, making the team behind the work ask, why don't we see them?

Tanking up

The team, led by scientists from the Max Planck Institute for Extraterrestrial Physics in Germany, was trying to figure out why astronomers can see quasars from a very far away, at the beginning of the universe. (More distant objects are older and have less metal in them.)

"People have hypothesized there could be these black holes forming from this metal-free gas reservoir ... which is completely free of stars," said Bhaskar Agarwal, a doctoral research fellow at Max Planck who led the research.

This means the black holes in OBGs could have formed separately from the stars surrounding them, contradicting recent observations by the Herschel Space Observatory. In that earlier finding, astronomers suggested that galaxies that have black holes in their center — including the Milky Way — see the stars and black holes evolve together.

Other research, including observational research, also shows OBG-like objects with a very massive black hole at the center of the galaxy, Agarwal told SPACE.com.

But if the black holes in OBGs formed solo from a reservoir of gas, the stars must have come from somewhere. The simulations suggested the black hole would have remained on its own until a merger between galaxies brought stars within its vicinity.

Halting star formation

The astronomers' simulations showed there could be a million of those OBGs within the observable universe. Many of them, however, would be invisible with conventional searches; most black holes are seen through the X-rays they produce when they gobble up matter. If there were no matter to feed on, the black hole would remain silent.

OBGs also could have an environment where stars evolved slower than usual. OBGs form in the presence of radiation from a nearby galaxy — sometimes, the one that merges to bring stars near the black hole, or sometimes, a nearby galaxy.

That same radiation also delays star formation in other metal-free galaxies. How this affects OBG evolution is not exactly known, however. The team is working on a more advanced simulation that takes into account the metallicity of stars within an OBG.

"The only thing we did not treat in this model was propagation of metals in a galaxy to black-hole collapse in the first place," Agarwal said.

If an OBG's black hole is active, the spectral energy distribution could be visible with instruments aboard the James Webb Space Telescope

 that can peer into the near- and mid-infrared spectra of light — with a resolution able to see to the edge of the universe.

Observations, though, would have to wait until at least 2018, when James Webb is supposed to make it into orbit.

Source of Article: Space.com

Ailing NASA Telescope Spots 503 New Alien Planet Candidates

NASA's Kepler spacecraft has spotted 503 new potential alien worlds, some of which may be capable of supporting life as we know it.

"Some of these new planet candidates are small and some reside in the habitable zone of their stars, but much work remains to be done to verify these results," Kepler mission manager Roger Hunter, of NASA's Ames Research Center in Moffett Field, Calif., wrote in an update last Friday (June 7).

The latest haul brings Kepler's tally of exoplanet candidates to 3,216. Just 132 of them have been confirmed by follow-up observations to date, but mission scientists expect at least 90 percent will end up being the real deal.

The new finds were pulled from observations Kepler made during its first three years of operation, from May 2009 to March 2012, researchers said. The telescope hasn't done any planet hunting since being hobbled by a failure in its orientation-maintaining system last month.

Uncertain future

The $600 million Kepler spacecraft launched in March 2009, kicking off a 3.5-year mission to determine how common Earth-like planets are throughout the Milky Way galaxy.

Kepler spots exoplanets by detecting the tiny brightness dips caused when they pass in front of their stars' faces from the instrument's perspective. The observatory does this precision work by staying locked onto 150,000-plus target stars using three gyroscope-like devices called reaction wheels.

Kepler launched with four functioning reaction wheels — three for immediate use and one spare. But one wheel, known as number two, failed in July 2012. And a second (number four) gave up the ghost last month, robbing the spacecraft of its precision pointing ability.

If at least one of the failed wheels cannot be recovered, Kepler's planet-hunting days are almost certainly over and a new mission will have to be drawn up for the spacecraft.

Engineers have identified a number of tests that could help gauge the likelihood of bringing back the balky wheels, Hunter said. They're currently developing these commands on the Kepler testbed at Ball Aerospace in Boulder, Colo., where the spacecraft was built.

"It will likely be several weeks before they are ready to implement the commands on the reaction wheels aboard the spacecraft," Hunter wrote in the June 7 update. "We will continue to provide updates on significant changes as these plans develop and mature."

More finds to come

Whether or not Kepler can get healthy again, the mission's exoplanet finds will keep rolling in for years to come, researchers say.

Kepler has collected huge amounts of data, and team members have had time to go through just about half of it so far.

"We have excellent data for an additional two years," Kepler principal investigator Bill Borucki, also of NASA Ames, told reporters last month. "So I think the most interesting, exciting discoveries are coming in the next two years."

Source of Article: Space.com

Milky Way Neighbor Galaxies Get Amazing Portraits in UV

Stitching together thousands of images, astronomers have created the most detailed ultraviolet light portraits of the Milky Way's two closest neighbors: the Large and Small Magellanic Clouds.

The stunning wide-field results give scientists a peek at the hot young stars of these satellite galaxies, which hover around the Milky Way less than 200,000 light years away.

The mosaics were assembled by astronomers at NASA and Pennsylvania State University using the space agency's Swift satellite. The images were unveiled last week at the American Astronomical Society meeting in Indianapolis.

"Prior to these images, there were relatively few UV observations of these galaxies, and none at high resolution across such wide areas, so this project fills in a major missing piece of the scientific puzzle," Michael Siegel, lead scientist for Swift's Ultraviolet/Optical Telescope (UVOT), said in a statement.

The Large Magellanic Cloud (LMC) is one-tenth the size of the Milky Way, and the Small Magellanic Cloud (SMC) is just half that size. But since both are relatively close to our own galaxy, they appear quite large — too large to fit in UVOT's field of view. That's why researchers needed thousands of images to cover both galaxies.

The portrait of LMC, cobbled together from 2,200 snapshots, has a resolution of 160 megapixels and reveals about 1 million ultraviolet sources, according to a statement from NASA. The 57-megapixel mosaic image of the SMC, meanwhile, is made of 656 individual images and shows about 250,000 ultraviolet sources.

Ultraviolet images allow astronomers to look at the hottest young stars and star-formation regions while blocking out older stars, mostly those more than 500 years old, which don't emit as much light at such higher energies. One particularly dazzling piece of the LMC portrait shows the Tarantula nebula, where powerful stellar winds from newborn stars create a spider-like shape.

The images of the LMC and SMC include light ranging from 1,600 to 3,300 Angstroms. (One Angstrom equals one ten-billionth of a meter.)  

The images give a panoramic window into the evolution of stars in the SMC and LMC, which is impossible for astronomers to do for our own Milky Way since we are inside it, Stefan Immler, who led NASA's contribution to the project from the Goddard Space Flight Center in Greenbelt, Md., explained in a video from the space agency.

Source of Article: Space.com