Simultaneous warming on Earth and Mars suggests that our planet's recent climate changes have a natural—and not a human- induced—cause, according to one scientist's controversial theory. Earth is currently experiencing rapid warming, which the vast majority of climate scientists says is due to humans pumping huge amounts of greenhouse gases into the atmosphere. In 2005 data from NASA's Mars Global Surveyor and Odyssey missions revealed that the carbon dioxide "ice caps" near Mars's south pole had been diminishing for three summers in a row. Habibullo Abdussamatov, head of the St. Petersburg's Pulkovo Astronomical Observatory in Russia, says the Mars data is evidence that the current global warming on Earth is being caused by changes in the sun. "The long-term increase in solar irradiance is heating both Earth and Mars," he said.

Nighttime clouds detected for the first time on Mars help to keep the planet’s surface warm after sunset when temperatures drop, a new study suggests. The nocturnal clouds are five times thicker than their daytime counterparts and hover close to the ground, almost like a fog. The study, conducted by researchers at NASA and the National Oceanic and Atmospheric Administration (NOAA), is detailed in the Feb. 1 issue of Geophysical Research Letters.

Rather than having had its air knocked out into space, Mars might just be holding its breath. New findings suggests the missing atmosphere of Mars might be locked up in hidden reservoirs on the planet, rather than having been chafed away by billions of years' worth of solar winds as previously thought. Combining two years of observations by the European Space Agency’s Mars Express spacecraft, researchers determined that Mars is currently losing only about 20 grams of air per second into space. Extrapolating this measurement back over 3.5 billion years, they estimate that only a small fraction, 0.2 to 4 millibars, of carbon dioxide and a few centimeters of water could have been lost to solar winds during that timeframe.

The changing appearance of gullies on Mars over the last seven years suggests that liquid water flowed recently on the red planet and may still seep out in brief bursts, researchers said Wednesday. In what is billed as "the squirting gun," new images of known gullies on Mars show evidence of new flows and deposits, pointing to explosive events in which some form of water burst from crater walls and ran down their slopes. "We've had this story of ancient water on Mars," said researcher Kenneth Edgett, who participated in the Mars gully study, during a press briefing at NASA's Washington, D.C. headquarters. "Today we're talking about liquid water that is present on Mars right now."

Evidence of Mars gushers and craters sometime in the past five years! Dr. Michael Malin of Malin Space Science Systems in San Diego stated, "We think that the water is coming from deep in the ground. It's warmed as it gets closer to the center of Mars. The outer parts of Mars are really, really quite cold, but the inner part is probably still warm, just as the Earth's interior is warm. As the water came up, it reached the surface and initially froze at the surface. But as more and more water came up, it would build pressure behind the frozen water in front of it and eventually it would break out of behind that barrier and flow down the surface. So we think there's an ice dam that is holding back water for some period of time, and then that dam breaks, and water comes out, and as it comes out, and as the dam breaks, it consists of rock debris from the rock around that water, it includes ice fragments from the dam and it includes liquid water. And it flows down these very steep slopes, 20, 30 degree slopes and picks up rock debris and spreads out and forms the deposit that we see. So what we think is that there's a trickle of water initially just sort of building up pressure behind the ice dam, and then eventually there's a rapid release of many thousands of cubic meters of water that comes out, like swimming pools amounts of waters come rushing out of the ground in a very short, brief event and then the surface refreezes, and then more water builds up time and pressure and then eventually breaks again."

An ocean of water once wrapped around Mars, suggests the discovery of soil chemicals by NASA’s rovers. But the same chemicals also indicate that life was not widespread on the planet at the time the ocean was present. Sulphates, which form most readily in liquid water, had already been detected by the Spirit and Opportunity rovers. The minerals have been interpreted as evidence for past bodies of water on the surface. But it has not been clear how large these bodies of water might have been. Now, a new analysis of rover data suggests that the sulphates were once dissolved in a planet-wide ocean. The study was carried out by James Greenwood of Wesleyan University and Ruth Blake of Yale University, both in Connecticut, US.

Mars is home to the highest clouds ever discovered above the surface of a planet, astronomers said today. The European Space Agency's orbiting Mars Express spacecraft found clouds that are between 50 and 62 miles (80 to 100 kilometers) above the red planet. The highest clouds on Earth top out at about 52 miles (84 kilometers). The surprising clouds are most likely made of carbon dioxide, researchers said. There were detected with a camera that senses ultraviolet and infrared light, so there is no conventional picture of them. The clouds were spotted by observing distant stars just before they disappeared behind Mars. The stars would dim as they went behind clouds.

Peculiar spots, fan-like markings, and spider-shaped features on Mars' southern ice cap are seasonal formations, researchers announced today. The shapes are formed by thin layers of dark dusty material that are sprayed by roaring jets of carbon dioxide that erupt through the ice cap. This dusty material may also be the reason that the southern ice cap doesn't reflect much light. The mystery markings, generally 50 to 150 feet wide, appear every southern spring as the Sun rises over the red planet's ice cap. They last about three to four months.

If Mars ever supported life, it was likely early on in its history when it was wet, say scientists who've made a timeline of the planet's geological evolution. The planet had three geological eras, the team of French, American, Italian, Russian and German scientists report in Friday's issue of the journal Science.

Warm, wet conditions that made Mars possibly suitable for life were wiped away by a sweeping climate shift marked by fierce volcano activity and other upheavals, an international science team reported Thursday — billions of years after the fact.

First there was Google Earth, then Google Moon. On Monday, Google Inc. expanded its galactic reach by launching Google Mars, a Web browser-based mapping tool that gives users an up-close, interactive view of the Red Planet with the click of a mouse. The Martian maps were made from images taken by NASA's orbiting Mars Odyssey and Mars Global Surveyor.

Large areas of the Red Planet were once turned white by heavy snowfalls that were common on Mars several million years ago, scientists say. A new model of the ancient Martian climate has revealed that the glacial deposits of the planet’s tropics were laid down by snow carried to equatorial regions by monsoon winds. The findings, published today in Science, resolve the mystery about the source of the rocks and debris at the foot of Mars’s tropical mountains and volcanoes spotted by Nasa’s Viking mission in 1976.

On Earth we have the Northern and Southern Lights, and there's a similar phenomenon on Mars too. But instead of sticking to the planet's poles, these faint auroras can show up anywhere on the planet; wherever there are patches of strong magnetic fields. Over the past six years, NASA's Mars Global Surveyor has turned up 13,000 aurora events on the Red Planet, and mapped their locations. These mini magnetic fields can potentially protect the planet's surface from the Sun's solar wind.

From the shoreline of an ancient salty sea to the bottoms of deep, flood-carved channels, Mars is scarred with geological signs that indicate liquid water once flowed on the its surface. These findings, combined with the discovery of tiny, spherical "blueberries" and the detection of water ice in the planet's polar ice caps, have lead scientists to scour the planet for liquid water in recent years. The elusive quarry has remained hidden, possibly because it may not exist for more than a fleeting second. Due to Mars' low temperatures and extremely low atmospheric pressure – less than a hundredth that of the Earth– pure water evaporates from ice to gas so quickly that it skips the liquid phase. But now, new research by a team of scientists at the University of Arkansas suggests that liquid water could persist for some time on Mars, so long as it is salty.

Scientists have found evidence that large amounts of water-ice hide within massive sand dunes on Mars. One of the dunes, called Kaiser Dune, which spans 6.5km and rises 475m above the Martian surface, is among the largest in the Solar System. The icy dunes could be a valuable resource for any future manned missions to the planet, said Dr Mary Bourke.

NASA’s Mars rover Spirit has caught a bevy of dust devils racing across the surface of Mars, which researchers compiled into a stunning new movie. While scaling Husband Hill at its Gusev Crater landing site, cameras aboard Spirit recorded several dust devils blowing across the Martian surface. Researchers condensed the windy devils’ 12-minute, 17-second passing into a short black and white movie clip. “Wind processes are the only active processes that we know are happening on Mars,” said rover science team member Patrick Whelley, who has been studying the dust devil images, in a telephone interview. “They’re short term geologically and occur…[but] they have shaped the landscape.”

Mars is a rocky planet with an ancient volcanic past, but new findings show the planet is more complex and active than previously believed – at least in certain places. Finding those places, however, turns out to be trickier than just looking at landforms like river valleys or lakebeds or searching for specific minerals. "Context is everything," said Philip Christensen, Principal Investigator for the Thermal Emission Spectrometer (TES) on Mars Global Surveyor and for the Thermal Emission Imaging System (THEMIS) on Mars Odyssey, as well as lead scientist for the Mini-TES instruments on the Mars Exploration Rovers. "There has been a lot of excitement about finding specific features or minerals, but THEMIS, together with the TES infrared spectrometer, is giving us an overview by finding all the minerals. It gives us context – the underlying geology of the place."

On the whole, Mars can seem rather boring. It is covered with basalt, the most basic type of rock, and generally appears to lack geologic diversity. It does not shake or rumble much. And then there's that red dust everywhere. But a closer look reveals pockets of rocks that rival the complexity of our own planet. The finding means Mars is more active beneath the surface than scientists realized.

For more than 150 years, astronomers and skywatchers have noticed that Mars' south pole is off center, and Mariner 4 confirmed it in the mid-1960s with the first close-range images of the Red Planet. But why the cap is offset from its geographical pole has remained an enigma all these years -- until two summers ago when a group of planetary observers and theoreticians decided to take on the challenge at the first annual Mars Polar Atmospheric Interactions Workshop, held in Santa Fe, New Mexico. Now, with publication of their research earlier this month* the mystery is officially solved -- and not so surprisingly Mars' dynamic topography is at the heart of it.

A study co-authored by a University of Hawai'i professor has concluded that an area of Mars has much larger than believed deposits of the mineral olivine, offering clues about water — or the lack of water — on the Red Planet. While Mars today is a dry and cold world, river channels and other water-carved features suggest it may have had a more hospitable past.

Mars is now a cold, dry desert, but robotic satellites and rovers have returned new evidence of a warmer and wetter climate more than 3.5 billion years ago, when conditions may have been more favorable for life. Geologists at the Smithsonian National Air and Space Museum's Center for Earth and Planetary Studies, working with colleagues at the University of Virginia, have discovered 21 river channels in the dry Martian valleys, which provide new clues to this ancient climate. The researchers have determined that Martian rivers were about the same size as their counterparts on Earth, suggesting similar amounts of runoff from thunderstorms or rapid snowmelt. The findings will appear in the June issue of the journal Geology.

Scientists have long wondered why Mars' southern polar cap is offset from its geographical south pole. Now they've solved the mystery. Two different localized climates are to blame, and they can in turn be blamed on two impact craters. Weather generated by the two regional climates creates conditions that cause the southern polar ice to freeze out into a cap whose center lies about 93 miles (150 kilometers) from the actual south pole. "Mars' permanent south polar cap is offset from its geographic south pole, which was a mystery going back to the first telescopic observations of Mars," says Anthony Colaprete, a space scientist from NASA Ames Research Center. "We found that the offset is a result of two martian regional climates, which are on either side of the south pole."

A new study of old rocks on Earth could force a revision of theories about Mars. The results suggest ancient Mars might have been more magnetic than thought, challenging basic assumptions about the evolution of the red planet. Unlike modern Earth, Mars has almost no magnetic field today. Evidence has suggested Mars didn't have a very strong magnetic field early on, either.

A new look at ancient craters on Mars finds five that are arrayed along an arc that's part of a giant circle around the planet. The circle may have been Mars' equator long ago. The craters might all have been formed when one giant asteroid broke apart, its fragments slamming into the planet at different times and locations around the then-equator, says Jafar Arkani-Hamed of McGill University in Montreal. If the analysis is right, it has implication for where water might lurk beneath the Martian surface today.

The method used by planetary scientists to estimate the ages of various regions of Mars is flawed. "This really changes things," says Nadine Barlow of Northern Arizona University in Flagstaff. For instance, the findings will significantly change our understanding of when Mars may have been volcanically active. To estimate the age of any region on Mars, geologists count the number of meteor craters they can see in images of the area. The idea is that the older a surface, the more craters should have accumulated over time. Crater counts give an indication of the relative age of different Martian regions.

Even though Mars' atmosphere is only about 1 percent as dense as Earth's, there's still enough air to whip up whirlwinds known as dust devils. NASA's Mars Global Surveyor has tracked the mini-tornadoes from orbit, but they've never been spotted from ground level. Until now. Last week, after more than a year of watching, the Spirit rover captured a couple of wisps making their way across the desolation of Gusev Crater, said a member of the rover science team, Geoffrey Landis of NASA's Glenn Research Center. "In some of the navigation camera images, we actually spotted two dust devils, and one of those dust devils was visible in the rear hazcam," Landis said.

Befitting the powerful Roman god of war for which Mars was named, the red planet's 'dust devils' can be as lofty as five miles (eight kilometers) tall. A dust devil is a wind-generated vortex, or whirlpool in the atmosphere. Nearly every child has seen small whirlwinds that spin dust or leaves in spirals on Earth. Besides large 'dust devils,' the martian environment, from time to time, spawns huge dust storms that may cover nearly the entire planet. Both martian winds and dust devils, big and little, are constantly changing the planet's environment. To expand knowledge of dust devils and the red planet's feisty winds, NASA is simulating both of them in a laboratory at NASA Ames Research Center, located in California's Silicon Valley.

A huge, frozen sea lies just below the surface of Mars, a team of European scientists has announced. Their assessment is based on pictures of the planet's near-equatorial Elysium region that show plated and rutted features across an area 800 by 900km.

A frozen sea, surviving as blocks of pack ice, may lie just beneath the surface of Mars, suggest observations from Europe's Mars Express spacecraft. The sea is just 5° north of the Martian equator and would be the first discovery of a large body of water beyond the planet's polar ice caps. Images from the High Resolution Stereo Camera on Mars Express show raft-like ground structures - dubbed "plates" - that look similar to ice formations near Earth's poles, according to an international team of scientists.

Water was common across a vast region of ancient Mars, creating habitable conditions for long stretches of time billions of years ago, scientists said Thursday. New data reveal water in the Meridiani Planum region of Mars extended across hundreds of thousands of square miles, at least as groundwater and possibly as shallow lakes or seas. The work significantly expands the amount of surface area on Mars known to have once been water-laden, and it extends the period of time that the water was present.

Like Earth and Venus, the night side of Mars emits a subtle glow, scientists reported last week in the journal Science. The night-side air glow at the red planet, elusive until now, was detected by the European Space Agency's Mars Express orbiter. In an interview with Astrobiology Magazine, Jean-Loup Bertaux, principal investigator for the Mars Express SPICAM instrument, explains what lights up the martian evening sky, and why our understanding of that process could aid future missions to Mars.

The case for the presence of methane in Mars' atmosphere expanded, but the theories about its abundance and source floated in different directions as Vladimir A. Krasnopolsky, of Catholic University of America, and Michael J. Mumma, of NASA, updated their previous findings at the American Astronomical Society's Division for Planetary Sciences (DPS) annual meeting held in Louisville, Kentucky last week. Using Earth as the analogue, Krasnopolsky maintained that the methane is uniformly distributed in the atmosphere of Mars, and took the hypothetical leap that living bacteria under the surface are "a plausible source" of the odorless and colorless gas. Mumma, on the other hand, reported the methane to be significantly "enhanced" in some areas, and veered out of the (Earth) box, suggesting that distinctly Martian processes may be in play.

The revelation in 2000 that gully features have been spotted on Mars sparked numerous ideas as to how the geological features were formed. A study team is analyzing images of gullies captured by the Mars Global Surveyor’s (MGS) Mars Orbiter Camera, adding in laser altimeter and spectrometer data taken by the same spacecraft. They believe the gullies are the products of shallow and deep aquifers in Mars' subsurface. Aquifers are defined as an underground geological formation or group of formations that contain water -- a source of ground water for wells and springs.

Since the arrival of Mars Global Surveyor and more recently Mars Odyssey spacecrafts, a range of facts has revealed the existence of frozen water ice in the top meters of high latitudes near-surface (~60°-90°) of both martian hemispheres. However, its origin was still unexplained. Climatic simulations directed by astronomers from Paris Observatory and researchers from IPSL Planetology Departement (Paris VI) and published in the journal "Nature", show that this ice may come from an ancient reservoir of equatorial ice created during high obliquity episodes on Mars but which became unstable during the more recent episodes of low obliquity. This study has permitted to illustrate the existence of glacial cycles on Mars even more severe than on Earth.

here is mounting evidence of the role of water in Mars’ evolution. That fact appears to have been favorable to the development of life -- and the leftover calling card of past biology may be preserved in that world’s geologic record. Even more compelling is the thought that life may well have taken a beating and kept on ticking over time. And if so, where on the planet is it today? Scientists are admittedly awash in new data.

It was the best of times, it was the worst of times, as the storyline begins. Shifted to a planetary context, the classic Dickens phrase also can be applied to Earth and Mars. The two worlds, created at about the same time in the history of the solar system and similar in size and composition, both started along the path to a livable environment. The findings by NASA's twin Mars exploration rovers this year have made that assumption clear.

A Ph.D. student at Virginia Tech has research published this week in Nature that shows Mars probably had liquid water at some point, but likely for only a short time, geologically speaking. NASA's Mars Rover Opportunity recently found the mineral jarosite and possibly gypsum on Mars' surface, further adding to the speculation that water existed there in the past because those minerals "generally form in a wet environment," according to a Nature news release.

If water ever flowed over Mars' surface, it was a one-night stand, say geochemists studying the properties of an unusual mineral allegedly found by the Opportunity rover at Meridiani Planum. The possible detection of a normally short-lived mineral called jarosite seems to indicate that there was liquid water on at least Meridiani Planum. But the moisture didn't last long and hasn't been back since.

A lumpy boulder named after Canadian bush pilot Wop May could help solve a Martian mystery. The Wopmay rock has the members of NASA's Mars Exploration Rover Project excited. They believe it may contain clues indicating that parts of the planet were once submerged in water.

Mars used to be a mover and a shaker. Scientists don't know if it still entertains seismic activity, however. No mission has ever been equipped to properly measure any rattling that might still occur. Now a study comparing images of intriguing pits on Mars to similar features on Earth suggests the red planet indeed still rumbles. "It's likely that there may be marsquakes today, but seismic monitoring will be required to know for sure," said study leader David Ferrill of the Southwest Research Institute in San Antonio, Texas. "Until then, it's just scientific speculation."

Epsom-like salts believed to be common on Mars may be a major source of water there, say geologists at Indiana University Bloomington and Los Alamos National Laboratory. In their report in this week's Nature, the scientists also speculate that the salts will provide a chemical record of water on the Red Planet. "The Mars Odyssey orbiter recently showed that there may be as much as 10 percent water hidden in the Martian near-surface," said David Bish, Haydn Murray Chair of Applied Clay Mineralogy at IU and a co-author of the report. "We were able to show that under Mars-like conditions, magnesium sulfate salts can contain a great deal of water. Our findings also suggest that the kinds of sulfates we find on Mars could give us a lot of insight into the history of water and mineral formation there."

Like a comet, Mars has a tail, a stream of particles pushed away from the planet by the Sun's energy. New measurements of the Martian tail reveal how much air the planet loses to space every day and allow scientists to estimate the tremendous loss that may have occurred billions of years ago, making the red planet the dry and cold world it is.

The solar wind has a much bigger impact on Mars than previously thought according to the first results from the ASPERA-3 instrument on Mars Express. Rickard Lundin of the Swedish Institute of Space Research and an international team of co-workers have found that the solar wind -- a supersonic plasma of charged particles that flows from the Sun -- can penetrate deep into the atmosphere of Mars. One consequence of this is that water and other volatile molecules could escape from the planet (R Lundin et al. 2004 Science 305 1933).

A new test that produced methane under conditions mimicking the deep interiors of Earth and Mars lends support to an idea that the gas could theoretically support unseen colonies of microbes on both worlds. And the study hints at the possibility of a potential vast supply of petroleum products. While the lab work doesn't reveal what's really down there, it has nudged a controversial theory about what's under our feet one step closer to the mainstream. The research was led by Henry Scott of Indiana University at South Bend and was published online last week by the National Academy of Sciences.

A new theory about ancient Mars puts some fizz back in the idea that the red planet was once warm, wet and potentially habitable. Many studies have suggested that early Mars was covered by large oceans and blanketed by a thick atmosphere rich in carbon dioxide -- the stuff that puts the bubbly zing in soda. But if that's all true, then when the oceans evaporated a lot of the carbon dioxide should have turned into what scientists call carbonates, which should be strewn all over the place. Problem is, the carbonates aren't there. One recent study found trace amounts in Martian dust, just enough to conclude that Mars probably didn't have vast oceans. The new model provides a way around this problem. It suggests the chemistry of Martian seas was different than has been assumed, so the clues have been missed.

Methane could be forming in Earth's mantle, US scientists have shown. The result suggests that untapped and unexpected reserves of natural gas and oil may exist deep beneath the planet's surface. Fossil fuels such as oil and natural gas are organic materials made up of carbon and hydrogen. The consensus view is that all commercially viable petroleum and natural gas is made by biological processes - although methane can also be made in small amounts within volcanoes. In fact, the recent detection of methane in Mars's atmosphere has been interpreted as evidence either of ongoing volcanic activity or of life.

Mars' river valleys are anything but, say researchers who have made the first numerical study of some of the Red Planet's allegedly water-formed landscapes. On Earth, "whenever there is a river, there is a valley," said researcher Thomas Stepinski of the Lunar and Planetary Institute. "However, you don't see that on Mars."

Life is hard. For some, it's almost impossible. Specialized microorganisms called extremophiles thrive in nuclear waste, volcanic vents, boiling geothermal geysers and even deep inside rocks. Their unique biology allows them to feast on chemicals and radiation that would kill most organisms. But there is a place on Earth so hostile to life that even extremophiles perish: Chile's Atacama Desert.

Mars appears to have been volcanically active more recently than previously supposed, according to growing evidence from Europe's Mars Express orbiter. New estimates suggest volcanoes could have been active between one million years ago and 20 million years ago, but more work is needed to refine the dates. Previous spacecraft data suggested that volcanism on Mars ceased some time around 600-500 million years ago. Some researchers even speculate Mars could be volcanically active today.

Far from being a one-time event, it now appears that surface water flowed on Mars for eons. Nasa has announced that, after descending down further into the Endurance crater, the Opportunity rover has found a 'razorback'. It is believed that this was formed by 'fracture fill' from the minerals in percolating water. Since this feature extends through several geologic layers, it argues for a long period of wetness near the surface. This would seem to substantially increase the chance that life once existed on the red planet.

The forested mountains of northeastern Utah can be as green and inviting as any in the world, but just over the ridge, you can find an alien landscape as well: rolling hills of red dirt and rock, much like the vistas visible from the Spirit rover on Mars. The similarity isn't just coincidental. Like at least part of the Red Planet, Utah's red hills were once covered with water. In fact, as you drive through Logan Canyon, the fossilized traces of marine worms from 400 million years ago are visible literally on the side of the road. Today, that bounty of water is gone, leaving Martian-style dirt and stone that is reddened by iron oxide.

Mars was not only awash with water, it also once had rainfall, according to a new French study. The evidence comes from infra-red imaging, which probed under dust deposited over the millions of years and found dense networks of dry valleys, whose branching bear the hallmarks of having been carved out by rain. The research, published in the US journal Science on Friday, could prompt a rewrite of the Martian history books, for it suggests the planet had a longer "summer" than anyone thought.

Geologist Steve Ridell took us where few have gone before... Mars on Earth. We're on the Hanford Reach National Monument in Eastern Washington - making our way up Rattlesnake Mountain. "This is essentially an earth analog for a lot of what planetary scientists have been looking at on Mars, in particular."

Even before marble-shaped pebbles nicknamed “blueberries” were discovered on Mars by the Opportunity rover, University of Utah geologists studied similar rocks in Utah’s national parks and predicted such stones would be found on the Red Planet.

Mars has an average global temperature of about minus sixty degrees Celsius (or minus 166 F). Watching seasonal changes on the red planet has been fascinating from the vantage point of a unique constellation of orbiting satellites. How will Mars change as its northern hemisphere now enters a winter cycle?

NASA’s Spirit rover has found concentrated salt below the surface of Mars, offering more evidence of past water activity, mission scientists said Tuesday. The six-wheeled robot found the salt while analyzing the composition of a trench it had dug in a large crater. Scientists believe the salt may have been deposited after water drained through the soil, dissolving materials in rocks.

Gullies on Mars that appear to have been carved by flowing water could instead have been created by landslides of dry powdery material, scientists have found. Troy Shinbrot and colleagues of Rutgers University in New Jersey say that Mars's smaller gravity, which is 38% weaker than Earth's, would allow rockfalls to last longer than they do on Earth. This means landslides could cause the kind of geological features usually only associated with running water.

Why is Mars so much rustier than the Earth? The red planet has more than twice as much iron oxide in its outer layers as our own, yet most planet scientists reckon the two bodies were formed from the same materials. David Rubie and colleagues from the University of Bayreuth, Germany, say they have an answer.

Scientific understanding is often a matter of making the right comparisons. In terms of studying the Earth, one of the best comparative laboratories exists one planet over -- on Mars. In many ways, the study of Mars provides Earth-bound scientists with a control set as they look at the processes of climate change, geophysics, and the potential for life beyond our own planet.

Scientists have found clues that dust devils on Mars might have high-voltage electric fields, based on observations of their terrestrial counterpart. This research supports NASA's Vision for Space Exploration by helping to understand what challenges the Martian environment presents to explorers, both robotic and eventually human.

For the next three years, Wei Luo will have Mars in his sights. The assistant professor of geography at Northern Illinois University in DeKalb is leading an academic team that will study the networks of valleys stretching across the red planet. Luo, along with researchers at Washington University in St. Louis and the University of Virginia, won a $187,000 NASA grant to study satellite images of Mars to determine what forces formed its landscape - groundwater, surface water, wind, volcanoes, gravity or impacts from asteroids.

When a rover confirmed that rocks on Mars had once been steeped in water, it was easy to imagine a warmer, gentler past for the planet -- one in which primitive organisms might have formed and frolicked in balmy pools of primordial soup. But that picture is misleading.

Mars is a wanted world -- dead or alive. Scientists find themselves awash in a range of intriguing findings regarding the distinctive landscapes of the red planet. The onslaught of sensor data from trailblazing Mars orbiters -- along with the ongoing Spirit and Opportunity rover missions -- are setting the stage for more refined inquiries into the planet's past and its present status.

The water-linked gray iron mineral that was the main reason the Opportunity Mars rover was sent to Meridiani Planum may have been a mirage, say researchers. The rare large-grained, shiny-gray form of rust called gray hematite — associated on Earth with watery, high-pressure and high-temperature rocks — was thought to have been detected years ago from orbiting spacecraft only at Meridiani. But although Opportunity has found other evidence that the plain was likely a shallow sea, it has yet to find a single flake of the gray hematite.

Scientist offers a few theories for presence of gas exuded by life forms. Mars scientists in Europe and the United States have detected tantalizing signs of methane gas in the Martian atmosphere, and cannot yet explain why it's there.