Nasa’s veteran Curiosity rover has found complex organic matter buried and preserved in ancient sediments that formed a vast lake bed on Mars more than 3bn years ago.

The discovery is the most compelling evidence yet that long before the planet became the parched world it is today, Martian lakes were a rich soup of carbon-based compounds that are necessary for life, at least as we know it.

Researchers cannot tell how the organic material formed and so leave open the crucial question: are the compounds remnants of past organisms; the product of chemical reactions with rocks; or were they brought to Mars in comets or other falling debris that slammed into the surface? All look the same in the tests performed.

But whatever the ultimate source of the material, if microbial life did find a foothold on Mars, the presence of organics meant it would not have gone hungry. “We know that on Earth microorganisms eat all sorts of organics. It’s a valuable food source for them,” said Jennifer Eigenbrode, a biogeochemist at Nasa’s Goddard Space Flight Center in Maryland.

“While we don’t know the source of the material, the amazing consistency of the results makes me think we have a slam-dunk signal for organics on Mars,” Eigenbrode added. “It is not telling us that life was there, but it is saying that everything organisms really needed to live in that kind of environment, all of that was there.”

The car-sized rover, which has trundled a careful 12 miles (19.3km) since it landed in the planet’s Gale crater nearly six years ago, detected a slew of organic molecules in pieces of Martian mudstone it drilled from the ancient lake bed and heated in its onboard oven. When the samples reached 500 to 820C, the rover’s instruments detected a range of so-called aromatic, aliphatic and thiophenic vapours. The science team believes these are breakdown products of even larger organic molecules, similar to those found in coal, which were trapped in the Martian rocks in the distant past.

“To me it is amazing that we can show we have organic matter preserved for more than 3bn years in these rocks,” said Kirsten Siebach, a planetary geologist who was not involved in the work at Rice University in Houston, Texas. “This is very promising for the preservation of potential ancient life on the planet.”

“These molecules could have been part of life, but they could also have been food for life,” Siebach added. “To know that the water really was full of organic molecules really opens up the different ways that life could have existed on Mars.”

The Nasa rover has found hints of organics on the planet before. In 2015, mission scientists reported that Curiosity had detected whiffs of chlorine-containing organics in the planet’s rocks, but concerns over potential contamination and instrument glitches meant that the results did not convince everyone.

The latest findings, reported in the journal Science, are far more compelling. According to Inge Loes ten Kate, a geologist at Utrecht University in the Netherlands, “the results convincingly show the long-awaited detection of organic compounds on Mars.”

Facebook Twitter Pinterest An image from 23 May 2018 shows how Nasa’s Mars Curiosity rover successfully drilled a hole in a target called “Duluth”. Photograph: NASA

The discovery of organics in rocks mere centimetres beneath the Martian surface has raised hopes of finding richer deposits of the compounds deeper down. In those may lurk tell-tale signs of life itself, scientists say. “If we can find things like fatty acids, that would be the first potential hints of life,” said Eigenbrode.

In a separate paper published in Science, another Nasa-led team describes Curiosity’s latest measurements of the Martian atmosphere. Before the rover touched down in August 2012, missions to the red planet had already spotted methane in the atmosphere which spiked from time to time as plumes of the gas apparently rose from the planet. The discovery fuelled speculation that the gas might be the expulsions of Martian microbes eking out an existence deep underground. More mundane explanations included chemical reactions between water and Martian rocks.

The new measurements do not settle the question, but the team led by Christopher Webster at Nasa’s Jet Propulsion lab in California reveals the first regular pattern in Mars’s fluctuating methane. Tests on the Martian air show that background levels of methane rise and fall with the changing seasons. As winter gives way to summer in the northern hemisphere, the methane triples from 0.24 to 0.65 parts per billion.

Webster suspects that reservoirs of methane lie deep under the surface of Mars, perhaps in water crystals called clathrates, and leak the gas continuously. When the methane reaches the surface, it sticks to Martian dust but is released in ever-increasing quantities when the ground warms up in the summer.

“These subsurface reservoirs could be from ancient methane that was trapped underground, or from methane that is forming today. Either way it could be produced by chemistry or by microbial activity. We certainly cannot rule out a biological source at this stage,” said Webster.

Taking the measurements was no easy task. A year on Mars lasts two Earth years, so to spot a seasonal pattern in the methane levels, the scientists had to take readings for four Earth years. “That’s why it has taken us so long,” said Webster. “Talk about having patience.”</s>Organic matter has been found on Mars in soil samples taken from 3 billion-year-old mudstone in the Gale crater by the Curiosity rover, NASA announced Thursday. The rover has also detected methane in the Martian atmosphere.

The search for life outside Earth focuses on the building blocks of life as we know it, which includes organic compounds and molecules — although these can exist without life. Organic matter can be one of several things: a record detailing ancient life, a food source for life or something that exists in the place of life.

No matter its purpose, these work as “chemical clues” for researchers about Mars.

Methane is considered the simplest organic molecule. It’s present in other places in our solar system that could host life, like Saturn and Jupiter’s moons Enceladus, Europa and Titan. And if life does exist elsewhere, it may be very different or even form differently from how we understand life on Earth.

The new findings are also detailed in two studies published Thursday in the journal Science. Together, the researchers believe these findings to be “breakthroughs in astrobiology.”

“We have greatly expanded our search for organic compounds, which is fundamental in the search for life,” said Paul Mahaffy, study author and director of the Solar System Exploration Division at NASA’s Goddard Space Flight Center.

The two studies build on and advance smaller detections of atmospheric methane and ancient organic compounds on Mars. Those detections either caused debate or lacked the context for understanding, the researchers said.

But Curiosity’s data are providing a clearer and more conclusive picture of the conditions and processes on Mars — and what it may have been like on the Red Planet billions of years ago, when conditions were more suitable for life.

“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters. “I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”

We’ve been exploring the surface of Mars in hopes of understanding the Red Planet since NASA’s Viking mission in the 1970s. The Viking Project was the first US mission to safely land spacecraft on the Martian surface, as well as send back images.

And although hopes were high that the two landers and their instruments would detect signs of life or organic compounds in samples taken from the surface, that didn’t happen.

Decades later, Viking helped inspire the instruments on today’s Martian rovers. And Curiosity dug a little deeper beneath the surface, which is blasted with radiation, to see what stories the soil had to tell.

Curiosity sampled sites by drilling five centimeters below the surface in the Gale crater, which is where the rover landed in 2012. The 96-mile crater, named for Australian astronomer Walter F. Gale, was most likely formed by meteor impact between 3.5 to 3.8 billion years ago. It likely held a lake, and now includes a mountain.

The rover was able to heat the samples to between 932 and 1508 degrees Fahrenheit and study the organic molecules released through gas analysis. The organic molecules and volatiles, comparable to samples of sedimentary rock rich in organics on Earth, included thiopene, methylthiophenes methanethiol and dimethylsulfide.

They don’t exactly roll off the tongue, but researchers believe that these are fragments of larger molecules that were present on Mars billions of years ago. And the high amount of sulfur in the samples is most likely how they’ve lasted so long, the researchers said. Drilling beneath the surface, rather than sampling what was on top like Viking did, also helped.

Potential contaminants were analyzed and accounted for, so the results are the most conclusive yet.

“The Martian surface is exposed to radiation from space,” said Jen Eigenbrode, a study author and research scientist at the Goddard Space Flight Center. “Both radiation and harsh chemicals break down organic matter. Finding ancient organic molecules in the top 5 centimeters of rock that was deposited when Mars may have been habitable bodes well for us to learn the story of organic molecules on Mars with future missions that will drill deeper.”

Over five years, Curiosity has used its Tunable Laser Spectrometer to measure methane in the atmosphere at the Gale crater. Before, researchers couldn’t understand why the little bit of methane detected in the Martian atmosphere varied. With five years of data from a single location, they now have answers.

There is a seasonal variation to the methane that repeats, which means the methane is being released from the Martian surface or from reservoirs beneath the surface. The methane could even be trapped in water-based crystals beneath the surface.

Methane is a strong greenhouse gas, and it could have supported a climate that sustained lakes on Mars. That could even be happening beneath the surface now, the researchers said. The release of methane is an active process on Mars, which could suggest new things about what’s unfolding on the Red Planet.

Detecting this organic molecule in the atmosphere, combined with the finding of organic compounds in the soil, has strong implications about potential life on Mars in its past.

The Gale Crater was probably habitable 3.5 billion years ago, based on what Curiosity has shown us. Then, the conditions would have been comparable to Earth. This is also when life was evolving on our own planet.

Knowing that these molecules and compounds were present, then, gives new strength to the idea that life originated or existed on Mars and that more work by the Martian rovers can uncover the past.

NASA’s InSight Lander, launched on May 5, will land on Mars on November 26. Its two-year mission will explore Mars to see if it’s “geologically alive,” or active below the surface. For example, scientists want to know if it has “Mars quakes.” And the Mars 2020 rover, which is expected to launch July 2020, may be able to assist with one day retrieving soil samples from Mars.

“Are there signs of life on Mars?” asked Michael Meyer, lead scientist for the Mars Exploration Program at NASA Headquarters. “We don’t know, but these results tell us we are on the right track.”</s>November 26, 2011: "Curiosity" is a robotic rover exploring Gale Crater on Mars. This file photo released on June 23, 2014 by NASA, shows NASA's Curiosity Mars rover self-portrait. NASA announced Thursday, Sept. 11, 2014, that the rover has reached the base of Mount Sharp, its long-term science destination since landing two years ago.

The "building blocks" for life have been discovered in 3-billion-year-old organic matter on Mars, NASA scientists announced Thursday.

Researchers cannot yet say whether their discovery stems from life or a more mundane geological process. However, “we’re in a really good position to move forward looking for signs of life," said Jennifer Eigenbrode, a NASA biogeochemist and lead author of a study published Thursday in the journal Science.

The findings also were remarkable in that they showed organic material can be preserved for billions of years on the harsh Martian surface.

The material was discovered by the Mars Curiosity rover, which has been collecting data on the Red Planet since August 2012. The organic molecules were found in Gale Crater, believed to once contain a shallow lake the size of Florida's Lake Okeechobee.

For the past six years, "Curiosity has sifted samples of soil and ground-up rock for signs of organic molecules — the complex carbon chains that on Earth form the building blocks of life," according to Science. "Past detections have been so faint that they could be just contamination."

Now, samples taken from two different drill sites on an ancient lake bed have yielded complex organic molecules that look strikingly similar to the goopy fossilized building

 blocks of oil and gas on Earth.

The rover also discovered traces of methane in the Martian atmosphere, which was reported in a second paper in Science. That's significant because most methane on Earth, for instance, comes from biological sources.

"The detection of organic molecules and methane on Mars has far-ranging implications in light of potential past life on Mars," said Inge Loes ten Kate, a Utrecht University scientist in an accompanying article in Science. "Curiosity has shown that Gale Crater was habitable around 3.5 billion years ago, with conditions comparable to those on the early Earth, where life evolved around that time.

"The question of whether life might have originated or existed on Mars is a lot more opportune now that we know that organic molecules were present on its surface at that time," Kate said.

NASA's Thomas Zurbuchen said that "with these new findings, Mars is telling us to stay the course and keep searching for evidence of life. I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”

The nuclear-battery-powered Curiosity, a $2.5 billion mobile chemistry lab, was launched in 2011. NASA calls Curiosity the "largest and most capable" rover ever to make contact with Mars.

It's about the size of a car, has a 7-foot-long arm and carries 10 science instruments, 17 cameras and a laser to "vaporize" rocks.</s>(NASA) - The Curiosity rover found organic material and mysterious methane on Mars that suggest evidence that the planet could have supported ancient life, NASA announced Thursday.

The organic molecules, discovered in three-billion-year-old sedimentary rocks near the surface, contain carbon and hydrogen, and might also include oxygen and nitrogen.

"With these new findings, Mars is telling us to stay the course and keep searching for evidence of life," Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters, said. "I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet."

"Curiosity has not determined the source of the organic molecules," Jen Eigenbrode of NASA's Goddard Space Flight Center in Greenbelt, Maryland, said. "Whether it holds a record of ancient life, was food for life, or has existed in the absence of life, organic matter in Martian materials holds chemical clues to planetary conditions and processes."

According to NASA, billions of years ago a water lake inside Gale Crater held ingredients necessary for life, data from the rover reveals.

"The Martian surface is exposed to radiation from space. Both radiation and harsh chemicals break down organic matter," said Eigenbrode. "Finding ancient organic molecules in the top five centimeters of rock that was deposited when Mars may have been habitable, bodes well for us to learn the story of organic molecules on Mars with future missions that will drill deeper."

As far as the methane, NASA said it shows the possibility of biological origins, but could also have been generated by water-rock chemistry.

"This is the first time we've seen something repeatable in the methane story, so it offers us a handle in understanding it," Chris Webster of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, said. "This is all possible because of Curiosity's longevity. The long duration has allowed us to see the patterns in this seasonal 'breathing.'"

Click here to read much more about the Mars Curiosity rover findings.</s>NASA announced Thursday its Curiosity rover has found organic matter preserved on Mars, suggesting the red planet may have once been home to life.

“The chances of being able to find signs of ancient life with future missions, if life ever was present, just went up,” said Curiosity’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Pasadena, California.

Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington, said that with the new findings, “Mars is telling us to stay the course and keep searching for evidence of life.”

“I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the red planet,” he said.

The organic molecules are preserved in the bedrock in Gale Crater, which is believed to have once contain a shallow lake the size of Florida’s Lake Okeechobee.

Space.com previously reported Curiosity is climbing the three-mile high Mt. Sharp in the center of Gale Crater, where it has begun drilling on the Martian surface for the first time in 18 months.

NASA describes the Mars Curiosity rover, launched Nov. 6, 2011, as the most technologically advanced rover ever built. It landed on Gale Crater on Aug. 6, 2012, with the aim of determining whether Mars ever had the capacity to support microbial life.

The rover already has analyzed a rock sample collected by the vehicle in 2013 showing ancient Mars could have supported living microbes. It also detected other organic molecules in a rock-powder sample collected by its drill.

Last month, NASA launched its InSight Mars lander, which is expected to reach the planet at the end of the year.

NASA has set a goal of sending astronauts to Mars in the 2030s. Earlier this year, NASA announced a project to build robotic bees capable of flying on Mars.

The private space company SpaceX is planning test flights of its Mars spacecraft next year.

The National Space Council met for the first time in 25 years last October in an effort to return the United States to the forefront of space exploration.

Vice President Mike Pence, who chaired the council, said at the time that the U.S. will refocus its space program toward “human exploration and discovery,” beginning with a renewed American presence on the moon.

“American leadership in space will be assured,” Pence said at the National Air and Space Museum’s Udvar-Hazy Center in Chantilly, Virginia. “We will return Americans to the moon … and build the foundation we need to send Americans to Mars and beyond.”

Pence explained last October that America “seems to have lost our edge in space.”

“Rather than lead in space, too often we’ve chosen to drift and, as we learned 60 years ago, when we drift we fall behind,” he said.

“America must lead in space once again.”

Under President Obama, NASA’s administrator at the time, Charles Bolden, said in a 2010 interview with al-Jazeera that Obama had given him three charges, with perhaps the foremost being helping the Muslim world “feel good” about itself.

“One, he wanted me to help reinspire children to want to get into science and math; he wanted me to expand our international relationships; and third, and perhaps foremost, he wanted me to find a way to reach out to the Muslim world and engage much more with dominantly Muslim nations to help them feel good about their historic contribution to science, math, and engineering,” Bolden said.

The then-NASA chief added: “It is a matter of trying to reach out and get the best of all worlds, if you will, and there is much to be gained by drawing in the contributions that are possible from the Muslim [nations].”

Earlier in 2010, Obama canceled the Constellation program for manned space flight, the successor to the Space Shuttle.

His administration announced the moon program would be scrapped in favor of a plan to reach Mars. But the cancellation of the manned program meant NASA would need international assistance to go to Mars, angering former astronauts, who issued a statement denouncing the “devastating” plan that “destines our nation to become one of second- or even third-rate stature.”

Among the signatories of the statement were Neil Armstrong and Eugene Cernan, the first and last men to walk on the moon, and Apollo 13 commander Jim Lovell.

At the October council meeting, Pence pointed to space vessels on display at the museum that represent “a pinnacle in the history of man’s quest for knowledge and adventure.”

“Today, in the shadow of this history, we pledge to do what America has always done: We will push the boundaries of human knowledge,” he said.

“We will blaze new trails into that great frontier. And we will once again astonish the world as we boldly go to meet our future in the skies and in the stars.”</s>NASA’s Curiosity rover has uncovered signatures of an environment on the red plant that may once have been habitable.

In two separate studies on data collected by the Mars rover over the last few years, scientists have identified an abundant source of organic matter in the ancient soil, and traced some of the planet’s atmospheric methane to its roots.

The findings could help to guide the search for ancient microbial life and improve our understanding of seasonal processes on Mars.

NASA revealed details on the latest findings in a press conference Thursday afternoon.

While the announcement may not be the detection of life itself, the finding address factors that are ‘fundamental to our search for life,’ explained Paul Mahaffy, director of the Solar System Exploration Division at NASA’s Goddard Space Flight Center, during the conference.

The organic molecules identified in the Curiosity samples were found in rocks from an ancient lakebed, explained lead author and astrobiologist Dr Jennifer L. Eigenbrode.

The rover extracted and heated samples from Mojave and Confidence Hills in the Gale Crater – both of which are known to contain mudstones dating back roughly three billion years.

This revealed the presence molecules that resembled organic-rich sedimentary rock found on Earth, according to the team, including: thiophene, 2- and 3-methylthiophenes, methanethiol, and dimethylsulfide.

‘Those organic molecules could have come from life,’ Eigenbrode said, ‘but we don’t know that there was ever life on Mars. So those specific molecules are not evidence of life.’

Instead, the researcher explained, these molecules could be traced to non-life sources, such as meteorites.

'What were looking at here are a lot of layers that were put down in an ancient lake,' Eigenbrode said during the press conference, addressing the yet-unknown origins of the newly detected organic matter.

'That lake had been there for a long periods of time - hundreds of thousands, maybe millions of years.

'Organic materials can come into that lake through rivers, they can be windblown in, or they can be formed in the lake itself through biology,' Eigenbrode continued.

'One source could be meteorites infalling, or rock forming processes that form organics on their own.

'We don’t have enough information from the observations we've made to know what the source is, and how it got in there.'

According to the researcher, these molecules detected on Mars differ by a single carbon sidechain from those seen on Earth, suggesting they may be fragments of larger organic molecules.

While the discovery may not mean Curiosity has found evidence of ancient life on Mars just yet, it is a promising step forward ahead of missions that plan to dig even deeper into the Martian soil and a 'good sign' of the planet's ancient habitability, the researchers say.

‘The new findings reinforce our conclusions that there is Marian organic matter in the ancient sediments and they tell us about how the organic molecules are preserved in the rocks,’ Eigenbrode, lead author of one of the studies, told MailOnline in an email.

‘The detection of organic matter in rocks from an ancient habitable environment on Mars bode well for the future search for life on Mars.’

‘Organic matter could come from life, but the presence of organics is not evidence for life since organics can also come from non-life processes,’ Eigenbrode told MailOnline.

‘We found organic matter in rocks exposed at the surface where the environment is very harsh and tends to break down organic matter.

‘Finding it in this harsh place means we might find better preserved organic matter in other places, particularly where it has not been exposed to lots of radiation.

‘To do this, we might drill deep, which is what ESA’s ExoMars rover plans to do.

‘Alternatively, we could look for outcrops that have been recently excavated by erosion or meteorite impacts.

'Perhaps NASA’s Mars2020 mission will have this opportunity and will cache samples for return to Earth.’

In addition to the discovery of organic materials, the Curiosity data also reveal new clues on the origins of Mars' mysterious methane.

While methane is known to exist in the scant Martian atmosphere, just how it got there has remained a mystery.

On Earth, this compound is linked to biological sources – meaning it’s closely tied to the presence of life.

But on Mars, scientists have proposed numerous other abiotic processes that could have given rise to the methane in question.

In the second of the two new studies, researchers used measurements of atmospheric methane captured by the Curiosity rover to better understand its origins.

The team looked at data from three Martian years (55 Earth months), revealing strong fluctuations that appear to follow a seasonal cycle.

Mars’ methane, the researchers found, ranges from about 0.24 to 0.65 parts per billion, peaking near the end of summer in the Northern hemisphere.

After ruling out several possible sources, the authors say the data suggest large amounts of Martian methane is likely coming from beneath the surface, trapped in water-based crystals called clathrates.

This gas is then released in varying amounts as the temperature changes across the seasons, rising through the cracks and fissures in the ground to escape to the atmosphere.

'This is the first time we've seen something repeatable in the methane story, so it offers us a handle in understanding it,' said Chris Webster of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, lead author of the second paper.

'This is all possible because of Curiosity's longevity. The long duration has allowed us to see the patterns in this seasonal 'breathing.'

Each new piece of the puzzle is a crucial step forward in the search for Martian life.

'Are there signs of life on Mars?' said Michael Meyer, lead scientist for NASA's Mars Exploration Program, at NASA Headquarters.

'We don’t know, but these results tell us we are on the right track.'</s>NASA made history when it landed rovers on Mars for the first time in 1976, but not in all the ways scientists had hoped. The rovers, Viking 1 and 2, had an ambitious mission: to discover life. But the pair of rovers turned up almost nothing, and the few positive results were controversial. This prompted scientists to shift their approach, instead investigating whether the Martian environment could support life, now or in the past. Today, four decades later, NASA scientists announced that Curiosity has found what Viking didn’t: organic molecules. This is not a certain detection of life. Organic molecules make up all known life, but they can also form in abiotic chemical reactions. Still, the discovery of any organics on Mars is an astrobiological breakthrough. Together with the other habitability clues scientists have amassed over the years, this opens up a new phase in astrobiology on Mars. “The next step,” says Jennifer Eigenbrode, a NASA astrobiologist on the Curiosity mission, “is to search for signs of life” again.

The Curiosity rover landed on Mars in 2012 with a detective’s mission: to find clues about whether or not life could exist on the Red Planet. On the top of scientists’ wish list was evidence of organic matter, which emerged in 2013. But the organic molecules identified by the car-sized rover then were too few and ambiguous. So mission scientists sent Curiosity on a four-mile journey to the base of Mount Sharp in hopes of finding more conclusive evidence buried in old lake sediments.

And that did the trick. Mission scientists announced today in a paper published in the journal Science that Curiosity discovered a whole catalogue of preserved organic matter in the first rock layers that the rover checked there.

“We have just satisfied a mission objective for Curiosity,” says Jennifer Eigenbrode, study lead author and a member of the Mars Science Laboratory mission team.

Is this the discovery of Martians? It could be. Organic molecules are the building blocks of all known forms of life. But chemical reactions that don’t involve life can also produce them. In this case, the scientists couldn’t tell how these organics were formed.

But finding a trove of organic molecules on Mars is a big breakthrough for astrobiology, as organic molecules could be food for microbes, even if it doesn’t represent life itself. And this discovery ushers in a new phase in the search for life on Mars.

“All sorts of big questions could be answered by finding life on Mars or by not finding life on Mars,” says David Weintraub, a professor of astronomy at Vanderbilt University in Nashville and author of the book “Life on Mars: What to Know Before We Go.” “We now have really good reasons to look a whole lot harder,” he says.

NASA actually isn’t looking for life on Mars right now. Sure, if a Martian strolled by a rover’s cameras scientists would see it, but the rover is not equipped to make an unambiguous detection of life.

That was the goal when NASA deployed Viking 1 and 2 in 1976, which were the first mechanical envoys to set foot on Mars. The rovers performed experiments designed to detect Martian life, but they largely found none. The one experimental result that wasn’t an outright “no” was controversial. Despite its aspirations, the Viking program never even found signs life on Mars. And NASA didn’t launch another mission to Mars for over a decade.

“It made us much more cautious,” says Alexandra Pontefract, an astrobiologist at the Massachusetts Institute of Technology in Cambridge. “We didn’t want to fund an incredibly expensive mission and come up short again.”

What went wrong? There were too many uncertainties, Dr. Eigenbrode says. NASA was only just setting foot on the Martian surface, so scientists didn’t know enough about the environment to be able to get a clear yes or no answer.

“Viking was this sort of shot in the dark,” says David Grinspoon, an astrobiologist with the Planetary Science Institute. “And then we went, ‘oops, not only did we not find it, but we don’t really know what we’re looking for if it’s not exactly like Earth.’ And maybe that was not the best way to go about it.”

Scientists realized that they had to take a step back and try a more cautious, methodical approach. Much as a detective figures out whodunnit by filling in all the details of a crime first, astrobiologists set about piecing together a picture of the Martian environment to figure out if the planet could even support life, now or in the past.

Over the years, scientists have amassed a number of clues that can help answer the question of Mars’ habitability, including evidence of liquid water. And now they’ve added a catalogue of organic molecules to that list.

“If there are no organics, we can pretty much forget about there being life or ever having been life on Mars,” says Dr. Weintraub. Finding organics is critical.

The term “organic” means something different to a chemist than it does to a produce manager at a grocery store. In chemistry, nearly all molecules containing both carbon and hydrogen are organic compounds.

On Mars, organic molecules could have been produced by some form of either present or past lifeforms. But they could also be the result of abiotic chemical reactions on the surface of the planet. They could even have been transported from elsewhere in the solar system. Regardless of how these molecules originated, they are a key sign of habitability.

The case for past habitability on the Red Planet is bolstered by the discovery of preserved organic compounds revealed today, as they are as old as the around 3.5 billion year old sedimentary rocks in which they were found. But scientists revealed tantalizing hints about present-day Mars today, too. In another paper published simultaneously in the journal Science, they describe background levels of methane, also an organic, in Mars’s atmosphere that varies seasonally.

Methane gas can be a byproduct of life on Earth, but there are geological processes that can produce it, too. So like the organic molecules, it's not an unambiguous biosignature.

With future missions, scientists may be able to figure out whether or not the organic compounds are indeed biosignatures. “This gives us a lot of hope going forward in terms of organic detection on Mars,” Dr. Pontefract says.

Key details about the organics may have been obscured in Curiosity’s sample because the rover can only drill two inches into rock. The Martian surface is bombarded with radiation that can degrade organic compounds, explains Eigenbrode. But the planned ExoMars 2020 rover, part of a joint mission of the European Space Agency and the Russian space agency Roscosmos, will have a drill that can reach a depth of about 6.5 feet.

Furthermore, Pontefract says, ExoMars and NASA’s Mars 2020 mission will use tools that take a different approach to analyze organics. To look for organics, Curiosity drills about two inches into a rock, collects the dust created, then lights it on fire to break the samples down to their chemical components (which is a similar process to Viking’s). From those components, scientists work backward to figure out what molecules the rock was originally made of. The planned missions will use tools that can look for organic compounds directly in the rock.

This latest discovery of organics does more than open the door for more study of organic matter on Mars. It also signals the next step in our astrobiological investigation of Mars. That next step is to try to figure out if life is involved.

If Viking was phase one of our search for life on Mars, and the methodical quest for clues of habitability that followed was phase two, says Grinspoon, “this is the successful culmination of phase two.”

Previously, it was an open question whether signs of life might be preserved on the now-harsh Martian surface. This new discovery of old organics strengthens that possibility and offers new insights into how things preserve in Mars rock, Grinspoon says. “Maybe phase three would be to say, ‘okay, now we know there are preserved organics, let’s go for it and find the fossils.’ “

The next stage might not be just about past life, Pontefract says. “I think we’re moving toward extant [the opposite of extinct] life detection again.”

“I think part of the Mars community is frustrated with these incremental advances,” she says, so there’s a push to go look for life directly again.

The methodical approach since Viking has set scientists up to look directly for signs of life, Eigenbrode says. And, she says, it gives us an idea where to look. For present life, some scientists say we should look below the surface, in soils or in caves, where there might be liquid water still flowing and organic compounds around. For extinct life, scientists have an idea where lakes and rivers used to flow and sedimentary rocks might have built up, preserving life that may have flourished around those Martian waters.

“The next chapter of Mars exploration is just getting going,” Eigenbrode says. “And Mars always surprises us.”</s>The "building blocks" for life have been discovered in 3-billion-year-old organic matter on Mars, NASA scientists announced Thursday.

Researchers cannot yet say whether their discovery stems from life or a more mundane geological process. However, “we’re in a really good position to move forward looking for signs of life," said Jennifer Eigenbrode, a NASA biogeochemist and lead author of a study published Thursday in the peer-reviewed journal Science.

The findings were also remarkable, in that it showed that organic material can be preserved for billions of years on the harsh Martian surface.

The material was discovered by the Mars Curiosity rover, which has been collecting data on the Red Planet since August 2012. The organic molecules were found in Gale Crater — believed to once contain a shallow lake the size of Florida's Lake Okeechobee.

For the past six years, "the Curiosity has sifted samples of soil and ground-up rock for signs of organic molecules — the complex carbon chains that on Earth form the building blocks of life, according to Science. "Past detections have been so faint that they could be just contamination," the journal said.

Now, samples taken from two different drill sites on an ancient lakebed have yielded complex organic molecules that look strikingly similar to the goopy fossilized building

blocks of oil and gas on Earth.

The rover also discovered traces of methane on Mars.

"The detection of organic molecules and methane on Mars has far-ranging implications

in light of potential past life on Mars," said Inge Loes ten Kate, a Utrecht University scientist in an accompanying article in Science. "Curiosity has shown that Gale crater (where the material was discovered) was habitable around 3.5 billion years ago, with conditions comparable to those on the early Earth, where life evolved around that time.

"The question of whether life might have originated or existed on Mars is a lot more opportune now that we know that organic molecules were present on its surface at that time," Kate said.

The nuclear-battery-powered Curiosity rover, a $2.5 billion mobile chemistry lab, launched in 2011. NASA calls the Curiosity the "largest and most capable" rover ever to make contact with Mars.

It's about the size of a car, has a seven-foot-long arm, carries 10 science instruments, 17 cameras and a laser to "vaporize" rocks.</s>An illustration of Mars against the blackness of space. NASA scientists are gathering more clues about the potential for life on Mars. NASA/JPL-Caltech; Dave Mosher/Business Insider

NASA's 9-foot-long roving Martian science lab, the Curiosity Rover, may have just inched closer to discovering life on Mars.

New data collected and beamed back from the rover has given two teams of scientists from NASA new hints about how Mars might harbor key ingredients for microbial, carbon-based life.

The teams, which are studying methane and ancient rocks on Mars, released their findings in two separate papers today. The journal Science published the studies online Thursday afternoon, and the Curiosity Rover's Twitter account quickly posted about them, too.

"Methane swells each summer and ancient carbon-compounds locked in rocks. I haven't found life on Mars, but signs say…we're on the right track," the Rover tweeted.

Methane on Mars follows the seasons

The first study, led by NASA planetary scientist Chris Webster, represents a kind of sniff test of the red planet.

Scientists used Curiosity to record methane levels in the atmosphere around the rover over the course of four and a half Earth years, or more than two Martian years.

Their data show that methane concentrations change seasonally by a factor of three: Levels in Mars' northern hemisphere ranged from a low of around 0.24 parts per billion in the spring, then nearly tripled to a high of 0.65 parts per billion by the end of summer.

The Mars Curiosity Rover's path from August 6, 2012, through December 12, 2017. NASA/JPL-Caltech via Science

Temperatures on Mars fluctuate between around 67 degrees Fahrenheit at their highest to −243 degrees at their lowest (near the poles), so the researchers think seasonal changes are behind the shifts in methane levels. In the paper, they suggest methane may be locked up underground in water-based crystals called "clathrates." That methane could be slowly seeping out of the clathrates, rising through faults, fractures, and breaches in the rocks — then getting heated up once it reaches Mars' surface.

Methane is important in scientists' search for alien life because it may suggest the presence of life — 95% of the methane on Earth is produced by biological processes.

"It's produced from termites, or rice paddies, or cows, or sheep," Webster said during NASA's livestreamed announcement of the findings.

Certain microbes release methane as a gassy waste or byproduct, so it could serve as an indirect clue of life. However, geologic processes can also make methane.

Webster explained that discovering methane is also exciting because the compound doesn't last more than 300 years.

"If we see methane in the Martian atmosphere, that means something is happening today — it's being released or it's being created," he said.

Webster and his 43-person team also point out in their study that methane may have helped create past climates on Mars that facilitated the formation of water, since it's a greenhouse gas. This may have been at play in the formation of lakes that are known to have existed on Mars in the past — which can create breeding grounds for microbes.

Another team of scientists, led by NASA's Jen Eigenbrode, used the Curiosity Rover to drill 5 centimeters into soil in Mars's Gale Crater.

The mudstones inside that crater are ancient — more than 3 billion years old. Ashwin Vasavada, a project scientist at NASA's Jet Propulsion Laboratory, explained in the Thursday announcement that Curiosity helped scientists learn that "lakes existed for a long time — for hundreds of thousands if not millions of years" in the crater.

That makes it a promising spot for signs of life to be preserved.

Curiosity extracted some rocks, dumped them into a microwave-sized on-deck sample analysis machine (SAM), and heated them up to analyze any gases that came out of the samples.

The rover found several organic and chemical molecules similar to those you might find on Earth, like stinky dimethyl sulfide that wafts from cooking cabbage, and equally vile methanethiol, which is one of the key compounds in bad breath.

They think these tiny stink-bombs might be fragments of larger organic molecules, suggesting that maybe — just maybe — there was once life on Mars, or even still is.

"Organic matter can directly or indirectly fuel both energy and carbon metabolisms, and in doing so can support carbon cycling at the microbial community level," the authors wrote in their paper.

Other scientists aren't so sure that these results imply anything certain about life on the red planet.

Seth Shostak, a senior astronomer at the Search for Extraterrestrial Intelligence (SETI) institute, believes we'll find life in space in the next couple of decades, but he cautions that finding indirect evidence of life on Mars doesn't mean Martians exist.

"Chemical evidence, we've been through that before. Even the Viking landers got fooled by some chemical reactions in the dirt," Shostak told Business Insider, referencing the NASA Mars mission from the 1970s.

But he added that it's always gratifying for scientists to learn more about Mars.

"It takes us, maybe, a little bit farther down the yellow brick road in the direction of finding out whether Mars has biology, or ever did have biology," he said. "Knowing more doesn't hurt you, ever."</s>CAPE CANAVERAL, Fla. (AP) – New Mars discoveries are advancing the case for possible life on the red planet, past or even present.

NASA scientists reported Thursday the Mars rover Curiosity has found potential building blocks of life in an ancient lakebed.

The organic molecules preserved in 3 billion-year-old bedrock suggest conditions at Mars may have once been conducive to life. That leaves open the possibility that microorganisms once populated the red planet – and still might.

Curiosity also has confirmed seasonal increases of methane in the Martian atmosphere. Researchers say they can’t rule out a biological source.

Curiosity has been drilling since 2013. It previously found hints of methane and organic compounds, but these findings are the best evidence yet. More powerful spacecraft are needed to prove whether life ever existed on Mars.
NASA announces the discovery of preserved organic matter in an ancient lake bed on Mars by its Curiosity rover. It has not been determined if the matter was potentially related to past life on Mars or not.