When Jupiter’s tides ripped Comet Shoemaker–Levy 9 to shreds, only for the icy chunks to succumb to the intense Jovian gravity, ultimately slamming into the gas giant’s atmosphere, mankind was treated to a rare cosmic spectacle (in human timescales at least). That was the first time in modern history that we saw a comet do battle with a planet… and lose. But next year, astronomers think there’s a chance — albeit a small one — of a neighboring planet getting punched by an icy interplanetary interloper. However, this planet doesn’t have a generously thick atmosphere to soften the blow. Rather than causing bruises in a dense, molecular hydrogen atmosphere, this comet will pass through the atmosphere like it wasn’t even there and hit the planetary surface like a cosmic pile-driver, ripping into the crust. What’s more, we’d have robotic eyes on the ground and in orbit should the worst happen.

An analysis of a rock sample collected by NASA's Curiosity rover shows ancient Mars could have supported living microbes. Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon -- some of the key chemical ingredients for life -- in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet last month. "A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington. "From what we know now, the answer is yes."

While attention has been focused on the Mars rover Curiosity, NASA’s other active Mars rover, Opportunity, has quietly been going about its business and may have stumbled across an intriguing new geologic puzzle. Opportunity has begun examining ancient clays on Mars that would have formed in the presence of water with neutral acidity, a condition favorable for life as we know it. “This is our first glimpse ever at an ancient Mars where conditions would be suitable for life,” said astronomer Steve Squyres of Cornell University, the lead scientist for Opportunity’s mission, here at the American Geophysical Union conference on December 4, 2012

Despite widespread speculation about a potentially significant discovery on Mars, the Curiosity rover's first detailed look at a Martian soil sample with an instrument capable of detecting organic compounds hasn't found any "definitive" signs of materials that play key roles in biological processes on Earth, scientists said Monday. While the rover's Sample Analysis at Mars, or SAM, instrument detected signs of an oxygen-chlorine compound -- perchlorate -- and trace amounts of chlorinated methane compounds, which contain carbon, researchers say more tests are needed to make sure the carbon originated with the sample and was not brought to Mars aboard Curiosity.

It could be decades before man steps foot on Mars, but scientists have warned that if he ever does, he'll bring with him trillions of tiny invaders that pose danger of contaminating the Red planet. Scientists say a swarming mass of 100 trillion microbes will travel with every astronaut who may land on Mars. While these microbes have evolved over thousands of years to help humans do everything from digesting their food to keeping bacteria from killing them, there's no telling how they might interact with the Martian environment, the Daily Mail reported.

Scientific maverick J. Craig Venter says he is confident there is life on Mars and this week announced plans to send a "biological teleporter" to the Red Planet to find Martian DNA and beam it back to Earth. “There will be life forms there,” Venter, who is best known for helping to sequence the human genome, said at a Wired Health conference held in New York this week. According to the Los Angeles Times, Venter said he plans to send a machine to Mars to seek out Martian life and sequence its DNA. The alien genome could then be beamed back to Earth, where it could be reassembled in a super-secure space lab. "People are worried about the Andromeda strain," Venter said. "We can rebuild the Martians in a P-4 spacesuit lab instead of having them land in the ocean."

New analysis of 36-year-old data, resuscitated from printouts, shows NASA found life on Mars, an international team of mathematicians and scientists conclude in a paper published this week. Further, NASA doesn't need a human expedition to Mars to nail down the claim, neuropharmacologist and biologist Joseph Miller, with the University of Southern California Keck School of Medicine, told Discovery News. "The ultimate proof is to take a video of a Martian bacteria. They should send a microscope -- watch the bacteria move," Miller said. "On the basis of what we've done so far, I'd say I'm 99 percent sure there's life there," he added.

ESA's Mars Express has returned strong evidence for an ocean once covering part of Mars. Using radar, it has detected sediments reminiscent of an ocean floor within the boundaries of previously identified, ancient shorelines on Mars. The MARSIS radar was deployed in 2005 and has been collecting data ever since. Jérémie Mouginot, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) and the University of California, Irvine, and colleagues have analysed more than two years of data and found that the northern plains are covered in low-density material. "We interpret these as sedimentary deposits, maybe ice-rich," says Dr Mouginot. "It is a strong new indication that there was once an ocean here."

Observations from NASA's Mars Reconnaissance Orbiter have revealed possible flowing water during the warmest months on Mars. "NASA's Mars Exploration Program keeps bringing us closer to determining whether the Red Planet could harbor life in some form,” NASA Administrator Charles Bolden said, “and it reaffirms Mars as an important future destination for human exploration." Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars' southern hemisphere. "The best explanation for these observations so far is the flow of briny water," said Alfred McEwen of the University of Arizona, Tucson. McEwen is the principal investigator for the orbiter's High Resolution Imaging Science Experiment (HiRISE) and lead author of a report about the recurring flows published in Thursday's edition of the journal Science.

Plants on distant hospitable planets could have developed black foliage and flowers to survive, according to a new study. Flora that would appear black or grey to human eyes could have evolved on planets orbiting dim "red dwarf" stars, according to unpublished research that is being presented at the National Astronomy Meeting in Llandudno, Wales.

More than 30 years after NASA's Viking landers found no evidence for organic materials on Mars, scientists say a new experiment on Mars-like soil shows Viking did, in fact, hit pay dirt. The new study was prompted by the August 2008 discovery of powerful oxygen-busting compounds known as perchlorates at the landing site of another Mars probe called Phoenix. Scientists repeated a key Viking experiment using perchlorate-enhanced soil from Chile's Atacama Desert, which is considered one of the driest and most Mars-like places on Earth, and found telltale fingerprints of combusted organics -- the same chemicals Viking scientists dismissed as contaminants from Earth. "Contrary to 30 years of perceived wisdom, Viking did detect organic materials on Mars," planetary scientist Christopher McKay, with NASA's Ames Research Center in California, told Discovery News. "It's like a 30-year-old cold case suddenly solved with new facts."

Samples of Mars dirt collected by NASA's Viking Mars landers back in the 1970s may have contained carbon-based chemical building blocks of life as we know it, a new study suggests. During their missions, the two Viking landers vaporized Martian dirt and scrutinized the samples for signs of organic - or carbon-based - molecules that could serve as the raw ingredients for life. At the time, all they found were chlorine compounds attributed to contamination, but the new research suggests the Viking probes' heat-treatment may have generated these chlorine compounds from naturally occurring Martian organics, destroying them in the process. "This doesn't say anything about the question of whether or not life has existed on Mars, but it could make a big difference in how we look for evidence to answer that question," study co-author Chris McKay, of NASA's Ames Research Center in Moffett Field, Calif., said in a statement.

A lake in Argentina's remote, inhospitable northwest may offer clues on how life got started on Earth and how it could survive on other planets, scientists say. Researchers have found millions of "super" bacteria thriving inside the oxygen-starved Lake Diamante, in the center of a giant volcanic crater located over 15,400 feet above sea level. The bacteria's habitat is similar to primitive earth, before living and breathing organisms began wrapping a protective atmosphere of oxygen around the planet. The conditions -- which include high arsenic and alkaline levels -- could also shed light on life beyond Earth.

A geological map, created using data from a plethora of orbiting spacecraft, presents new evidence that lakes persisted early in Mars' history. The map focuses on Hellas Planitia, an area located in the planet's southern hemisphere that is well known for its giant impact basin – the Hellas basin – which spans over 2,000 kilometres in diameter and plunges to a depth of eight kilometres.

A new discovery of bacterial life in a Martian-like environment on Earth suggests our neighboring red planet could also be hospitable to some form of microbial life. Researchers found methane-eating bacteria that appear to be thriving in a unique spring called Lost Hammer on Axel Heiberg Island in the extreme north of Canada. This spring is similar to possible past or present springs on Mars, the scientists say, so it hints that microbial life could potentially exist there, too. There is no firm evidence that Mars does or ever did host life, however.