Planetary scientists at NASA's Goddard Flight Center claim to have identified hotspots of methane gas emission, extremely localized plumes whose concentration fades quickly in time. An atmosphere-wide distribution that's stable in time would indicate a balance between geological sources and destruction by sunlight. Localized sources, however, suggest much more active sources. What's the best source of methane most people know about? Cows. That's unlikely on Mars. But backing off a level, the important factor is LIFE. NASA team leader Michael Mumma puts forward the idea that subterranean bacteria could be producing the noxious fumes, which periodically percolate to the surface in short lived bursts. But it could also be a geological source deep below the surface. The CH4 was identified spectroscopically, analyzing the exact wavelengths of the light emitted from certain regions over time. It's exactly the same strategy the astronomers of old used, "just looking at what color things are", but since we worked out (some) quantum mechanics the same light can tell us so much more. Unfortunately, it can't make the crucial distinction between life or rock-based gas. But if we can just get a bit closer we can find out.

A bug discovered deep in a goldmine and nicknamed "the bold traveller" has got astrobiologists buzzing with excitement. Its unique ability to live in complete isolation of any other living species suggests it could be the key to life on other planets. A community of the bacteria Candidatus Desulforudis audaxviator has been discovered 2.8 kilometres beneath the surface of the Earth in fluid-filled cracks of the Mponeng goldmine in South Africa. Its 60°C home is completely isolated from the rest of the world, and devoid of light and oxygen.

If life on Mars exists, it may dwell in a violent home. The Red Planet is no stranger to fiery volcanic eruptions: It is home to the solar system's largest volcano, Olympus Mons. The planet is also well-endowed with ice, which has collected in large sheets near its north and south poles. Yet a key ingredient for life as we know it -- liquid water -- remains elusive. But what if fire met ice in the Martian north? On Earth, volcanoes sometimes erupt beneath glaciers, melting huge quantities of water and spawning massive floods. Lakes of meltwater are sometimes pinned at the bottoms of glaciers.

The unanticipated discovery of a mineral in Mars’ arctic soil doesn’t rule out the possibility that the red planet could support life, scientists with the Phoenix lander said today. While cautioning that the discovery of perchlorate, an oxidizing agent found in rocket fuel, still had to be confirmed by more experiments, scientists with the UA-led Phoenix Mars Mission rejected speculation that the mineral’s presence killed the possibility of life on the planet. “These compounds are quite stable and don’t destroy organic compounds,” said Peter Smith, the UA’s lead scientist for the mission. “This is an important piece in the puzzle and it is neither good nor bad for life.” While perchlorate can be hazardous to some life forms on Earth, others use the molecules for life, including in remote arid desert regions. “The interesting thing is perchlorate is a relatively inert oxidant,” said Richard Quinn, a mission scientist. “There are some microbes that use it as an energy source.”

NASA's Phoenix lander has discovered a toxic chemical in soil near Mars' north pole, dimming hopes for finding life on the Red Planet, the probe's operators said Monday. The chemical, perchlorate, is an oxidant widely used in solid rocket fuel. Researchers are still puzzling over the results and checking to make sure the perchlorate wasn't carried to Mars from Earth, the University of Arizona-based science team said. "While we have not completed our process on these soil samples, we have very interesting intermediate results," Peter Smith, the principal investigator for the project, said in a written statement. Early readings from a device aboard Phoenix called the Microscopy, Electrochemistry and Conductivity Analyzer, or MECA, "suggested Earth-like soil," Smith said. "Further analysis has revealed un-Earthlike aspects of the soil chemistry," he said. The Phoenix team has scheduled a teleconference for Tuesday to discuss the findings.

Could the Mars Phoenix lander have been contaminated by bacteria from Earth? The possibility was raised by rumor-multipliers feasting on an Aviation Week report that the White House had been briefed on "major new Phoenix lander discoveries concerning the 'potential for life' on Mars." The report has since been retracted, but it raised the prospect, if only wildly, that the Phoenix found Martian soil so habitable because transplanted microbes flourished there. But that, say researchers, is highly unlikely. Mars explorers have a profound self-interest in ensuring that bacterial hitchhikers don't confound their results: imagine asking for NASA funding after claiming a plucky strain of underarm bacteria as extraterrestrial life. And if Earthly bacteria survives a trip and then flourishes, it could upset an alien ecosystem -- the equivalent of finding something rare and priceless by stepping on it.

The White House has been alerted by NASA about plans to make an announcement soon on major new Phoenix lander discoveries concerning the "potential for life" on Mars, scientists tell Aviation Week & Space Technology. Sources say the new data do not indicate the discovery of existing or past life on Mars. Rather the data relate to habitability--the "potential" for Mars to support life--at the Phoenix arctic landing site, sources say. The data are much more complex than results related NASA's July 31 announcement that Phoenix has confirmed the presence of water ice at the site.

Research on methane at a Mexican salt flat could help reveal the source of methane that has been detected in the atmosphere of Mars. But first scientists have to decipher the unique – and seemingly contradictory - isotopic signature of the Mexican methane.

The Phoenix lander may have been coated with dozens of species of bacteria when it left Earth – and some may be hardy enough to scrape by on Mars, two new studies suggest. But researchers say the parts of the lander that will contact water ice on Mars – which might provide a toehold for life – have been carefully sterilised, minimising the chances that terrestrial life could colonise the planet. NASA has long realised that spacecraft could potentially seed other planets with terrestrial life. To cut the chances of transporting microbes to space, probes such as Phoenix, which landed on the northern plains of Mars on 25 May, are now assembled in clean rooms ventilated with filtered air. NASA also swabs the craft to measure the levels of particularly hardy spore-forming bacteria, which can lay dormant for decades and withstand extreme temperatures. But the agency doesn't routinely check for less resilient bacteria or microbes that can't be cultured, since harsh ultraviolet radiation on Mars is thought to quickly kill most such organisms.

A lake that might once have been habitable may have filled a crater for a long time on early Mars, new spacecraft images reveal. NASA's Mars Reconnaissance Orbiter (MRO) captured the images that suggest the debris-strewn Holden Crater once held a calm body of water that could have harbored life. There is so far no convincing evidence life does or ever did exist on Mars, however. The crater debris includes a mix of broken boulders and smaller particles called megabreccia.

Nasa says its Mars rover Spirit has discovered "the best evidence yet" of a past habitable environment on the planet's surface. Spirit has been exploring a plateau called Home Plate, where it discovered silica-rich soil in May. Researchers are now trying to determine what produced the patch of nearly pure silica - the main ingredient of window glass. They believe the deposits came from an ancient hot-spring environment or an environment called a fumarole, in which acidic steam rises through cracks. On Earth, both of these types of settings teem with microbial life, said rover chief scientist Steve Squyres.

A new experiment similar to a pregnancy test but designed to search for signs of life on Mars is now exposed to the vacuum of space above Earth. The European Space Agency's (ESA) postage-stamp-sized experiment, called the "Life Marker Chip" (LMC), was launched last week aboard a Russian rocket launched from Baikonur Cosmodrome, Kazakhstan. Strapped to the ESA's large Foton-M3 capsule, the tiny experiment harbors more than 2,000 life-detecting samples that glow if they encounter life-critical compounds, such as proteins or DNA. Scientists and engineers hope the life-sensing chip can remain viable in the harsh radiation, temperatures and vacuum of space during a trip to Mars.

A Mars-orbiting satellite recently spotted seven dark spots near the planet's equator that scientists think could be entrances to underground caves. The football-field sized holes were observed by Mars Odyssey's Thermal Emission Imaging System (THEMIS) and have been dubbed the seven sisters --Dena, Chloe, Wendy, Annie, Abbey, Nikki and Jeanne--after loved ones of the researchers who found them. The potential caves were spotted near a massive Martian volcano, Arisa Mons. Their openings range from about 330 to 820 feet (100 to 250 meters) wide, and one of them, Dena, is thought to extend nearly 430 feet (130 meters) beneath the planet's surface. The researchers hope the discovery will lead to more focused spelunking on Mars.

Two NASA space probes that visited Mars 30 years ago may have found alien microbes on the Red Planet and inadvertently killed them, a scientist is theorizing. The Viking space probes of 1976-77 were looking for the wrong kind of life, so they didn't recognize it, a geology professor at Washington State University said. Dirk Schulze-Makuch presented his theory in a paper delivered at a meeting of the American Astronomical Society in Seattle, Washington. The paper was released Sunday.

Lab experiments with primitive microbes taken from an Antarctic lake have shown that the hardy single-celled organisms can tolerate at least the warmest of the frigid temperatures found on Mars. And they found that these species of microorganisms "huddled" together in colder temperatures to form a chemically linked unit called a biofilm. The finding marks the first time this phenomenon has been detected in the Antarctic species of so-called extremophiles. The findings provide more evidence for the ideas that liquid found beneath Mars’ surface could harbor microbial life and that life could exist elsewhere in the solar system and galaxy, which is generally incredibly cold.