December 9, 2013
Shortly after NASA’s Curiosity rover landed on Mars in August 2012, the scientists guiding the device decided to make a temporary detour before heading to the mission’s ultimate destination, Mount Sharp. Last spring, they guided the six-wheeled machine towards Yellowknife Bay, a slight depression with intriguingly lighter-toned sedimentary rocks, and drilled its first two holes in Martian rock in order to collect samples.
Afterward, as Curiosity drove away from Yellowknife Bay, onboard equipment ground the rock samples to a fine dust and chemically analyzed their content in extreme detail to learn as much as possible about the site. Today, the results of that analysis were finally published in a series of articles in Science, and it’s safe to say that the scientists probably don’t regret making that brief detour. Yellowknife Bay, they discovered, was likely once home to a calm freshwater lake that lasted for tens of thousands of years, and theoretically had all the right ingredients to sustain microbial life.
“This is a huge positive step for the exploration of Mars,” said Sanjeev Gupta, an Earth scientist at Imperial College London and a member of the Curiosity team, in a press statement on the discovery. “It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake’s calm waters, converting a rich array of elements into energy.”
Previously, Curiosity found ancient evidence of flowing water and an unusual type of rock that likely formed near water, but this is the strongest evidence so far that Mars may have once sustained life. The chemical analysis of the two rocks (named “John Klein” and “Cumberland”) showed that they were mudstones, a type of fine-grained sedimentary rock that generally forms at the bottom of a calm body of water, as small sediment particles gradually settle on one another and are eventually cemented together.
Isotope analysis indicated that these rocks formed sometime between 4.5 and 3.6 billion years ago, either during Mars’ Noachian period (in which the planet was likely much warmer, had a thicker atmosphere and may have had abundant surface water) or early on in its Hesperian period (in which it shifted to the dry, colder planet we see currently).
Additionally, a number of key elements for the establishment of life on Earth—including carbon, hydrogen, oxygen, sulfur, nitrogen and phosphorous—were found in detectable quantities in the rocks, and chemical analysis indicated that the water was likely of a relatively neutral pH and low in salt content. All of these discoveries increase the chance that the ancient lake could have served as a habitat for living organisms.
The scientists hypothesize that the microorganisms most likely to live in this environment would have been chemolithoautotrophs, a type of microbe that derives energy by breaking down rocks and incorporates carbon dioxide from the air. On Earth, these types of organisms are most often found near hydrothermal vents on the ocean floor, where they thrive off chemicals emitted into the water.
Obviously, this isn’t direct proof of life, but rather circumstantial evidence that it may have once existed. Still, it’s yet another vindication of Curiosity’s mission, which is to determine the planet’s habitability. Over the coming months and years, the scientists guiding the rover plan to keep sampling sedimentary rocks on the planet’s surface, hoping to find further evidence of potentially-habitable ancient environments and perhaps even direct evidence of now-extinct living organisms.
For more, head over to NASA’s webcast of the press conference announcing the findings, which occurred today at noon EST.
October 31, 2013
For the past 10 years, the European Space Agency’s Mars Express probe has flown around and around the red planet, orbiting it more than 12,500 times in total.
All the while, it’s been collecting detailed topographic data on Mars’ surface with a suite of remote sensing instruments, including high-resolution cameras, radar-sensing devices and spectrometers that can detect the minerals present on the planet by analyzing the spectrum of infrared light they emit.
This video, released earlier this week by the ESA, gives you a look at some of the probe’s most dramatic views to date. The ESA built this simulated flyover from computer graphics based off real-world data, so this clip is (currently) the closest you can possibly get to flying over Mars’ surface yourself.
September 26, 2013
Some 46 Martian days after landing on Mars in August 2012, after traveling nearly 1,000 feet from its landing site, Curiosity came upon a pyramid-shaped rock, roughly 20 inches tall. Researchers had been looking for a rock to use for calibrating a number of the rover’s high-tech instruments, and as principal investigator Roger Wiens said at a press conference at the time, “It was the first good-size rock that we found along the way.”
For the first time, scientists used the rover’s Hand Lens Imager (which takes ultra-high resolution photos of a rock’s surface) and the Alpha Particle X-ray Spectrometer (which bombards a rock with alpha particles and X-rays, kicking off electrons in patterns that allow scientists to identify the elements locked within it). They also used the ChemCam, a device that fires a laser at a rock and measures the abundances of elements vaporized.
Curiosity, for its part, commemorated the event with a pithy tweet:
I did a science! 1st contact science on rock target Jake. Here’s an action shot pic.twitter.com/pzcgH6Bk
— Curiosity Rover (@MarsCuriosity) September 22, 2012
A year later, the Curiosity team’s analysis of the data collected by these instruments, published today in Science, shows that they made a pretty lucky choice in finding a rock to start with. The rock, dubbed “Jake_M” (after engineer Jake Matijevic, who died a few days after Curiosity touched down), is unlike any rock previously found on Mars—and its composition intriguingly suggests that it formed after molten rock cooled quickly in the presence of underground water.
The new discovery was published as part of a special series of papers in Science that describe the initial geologic data collected by Curiosity’s full suite of scientific instrumentation. One of the other significant findings is a chemical analysis of a scoop of Martian soil—heated to 835 degrees Celsius inside the Sample Analysis at Mars instrument mechanism—showing that it contains between 1.5 and 3 percent water by weight, a level higher than scientists expected.
But what’s most exciting about the series of findings is the surprising chemical analysis of Jake_M. The researchers determined that it is likely igneous (formed by the solidification of magma) and, unlike any other igneous rocks previously found on Mars, has a mineral composition most similar to a class of basaltic rocks on Earth called mugearites.
“On Earth, we have a pretty good idea how mugearites and rocks like them are formed,” Martin Fisk, an Oregon State University geologist and co-author of the paper, said in a press statement. “It starts with magma deep within the Earth that crystallizes in the presence of one to two percent water. The crystals settle out of the magma, and what doesn’t crystallize is the mugearite magma, which can eventually make its way to the surface as a volcanic eruption.” This happens most frequently in underground areas where molten rock comes into contact with water—places like mid-ocean rifts and volcanic islands.
The fact that Jake_M closely resembles mugearites indicates that it likely took the same path, forming after other minerals crystallized in the presence of underground water and the remaining minerals were sent to the surface. This would suggest that, at least at some time in the past, Mars contained reserves of underground water.
The analysis is part of a growing body of evidence that Mars was once home to liquid water. Last September, images taken by Curiosity showed geologic features that suggested the one-time presence of flowing water at the surface. Here on Earth, analyses of several meteorites that originated on Mars have also indicated that, at some point long ago, the planet held reserves of liquid water deep underground.
This has scientists and members of the public excited, of course, because (at least as far as we know) water is a necessity for the evolution of life. If Mars was once a water-rich planet, as Curiosity’s findings increasingly suggest, it’s possible that life may have once evolved there long ago—and there may even be organic compounds or other remnants of life waiting to be found by the rover in the future.
August 28, 2013
If the phenomena of Star Trek, Area 51, Ancient Aliens, or War of the Worlds can be taken as anthropological clues, humanity is consumed with curiosity about the possibility of life beyond Earth. Do any of the 4,437 newly discovered extrasolar planets contain traces of life? What would these life forms look like? How would they function? If they came to Earth, would we share ET-esque embraces or would the visit be more a Battle Los Angeles style throw down?
Life outside of Earth has spawned endless interest, but less public interest seems to be given to how life on Earth began 3 to 4 billion years ago. But the two topics, it turns out, might be more connected than one would believe–in fact, it’s possible that life on Earth really began outside of Earth, on Mars.
At this year’s Goldschmidt conference in Florence, Steve Benner, a molecular biophysicist and biochemist at the Foundation for Applied Molecular Evolution will present this idea to an audience of geologists. He’s well aware that half the room will be adamantly against his idea. “People will probably throw things,” he laughs, hinting at a consciousness of how out-of-this-world his ideas sound. But there’s scientific basis for his assertion (PDF), a logical reason for why life maybe truly did begin on Mars.
Science holds a number of paradoxes: If there are an infinite number of stars in the sky, why is the night sky dark? How can light act as both a particle and a wave? If the French eat so much cheese and butter, why is the incidence of coronary disease in their country so low? The origins of life are no different; they, too, are dictated by two paradoxes: the tar paradox, and the water paradox. Both, according to Benner, make it difficult to explain the creation of life on Earth. But both, he also notes, can be solved by placing the creation of life on Mars.
The first, the tar paradox, is simple enough to understand. “If you put energy into organic material it turns to asphalt, not to life,” Benner explains. Without access to Darwinian evolution–that is, without organic molecules having the opportunity to reproduce and create offspring who themselves, mutations and all, are reproducible–organic matter that is bathed in energy (from sunlight or from geothermal heat) will turn into tar. Early Earth was full of organic materials–chains of carbon, hydrogen and nitrogen that are believed to be the building blocks of life. Given the tar paradox, these organic materials should have devolved into asphalt. “The question is, how is it possible that the organic materials on early Earth managed to leap from their asphaltic fate to something that had access to Darwinian evolution? Because once that happens–presumably–you’re off to the races, and then you can manage whatever environment you want,” Benner explains.
The second paradox is the so-called water paradox. The water paradox states that even though life needs water, if organic material could escape its asphaltic fate and move toward Darwinian evolution, you can’t assemble the necessary building blocks in a flood of water. The building blocks of life start with genetic polymers–the well-known player DNA and its less-famous but still very smart friend RNA. Experts agree that RNA was likely the first genetic polymer, partly because in the modern world, RNA plays such an important role in the manufacturing other organic compounds. “RNA is the key to the ribosome, which is what makes proteins. There’s almost no question that RNA, which is a molecule involved in catalysis, arose before proteins arose,” Benner explains. The difficulty is that for RNA to assemble into long strands–which is needed for genetics–you can’t have the assembly taking place in water. “Most people think that water is essential for life. Very few people understand how corrosive water is,” Benner says. For RNA, water is extremely corrosive–bonds cannot be made within water, preventing long-strands from forming.
However, Benner says that these paradoxes can be resolved with the help of two very important groups of minerals
. The first are borate minerals. Borate minerals–which contain the element boron–prevent life’s building blocks from devolving into tar if incorporated into organic compounds. Boron, as an element, is seeking electrons to make itself stable. It finds these in oxygen, and together the oxygen and boron form the mineral borate. But if the oxygen boron finds is already bonded to carbohydrates, the carbohydrates linked with boron form a complex organic molecule dotted with borate that’s less resistant to decomposition.
The second group of minerals that come into play
involve those that contain molybdate, a compound that consists of molybdenum and oxygen. Molybdenum, more famous for its conspiratorial relation to the Douglas Adams classic A Hitchhiker’s Guide to the Galaxy than for its other properties, is crucial, because it takes the carbohydrates that borate stabilized, bonds to them and catalyzes a reaction which rearranges them into ribose: the R in RNA.
Which brings us–however circuitously–back to Mars. Both borate and molybdate are scarce and would have been especially scarce on early Earth. The molybdenum in molybdate is
highly oxidized, meaning that it needs electrons from oxygen or other readily available negatively charged ions to achieve stability. But early Earth was too oxygen-scarce to have readily created molybdate. Plus, returning to the water paradox, early Earth was quite literally a water world–with land making up only two to three percent of its surface. Borates are soluble in water–if early Earth was a flooded planet, as scientists believe, it would have been difficult for an already scarce element now diluted in a huge ocean to find ephemeral organic molecules to bond with. Moreover, Earth’s status as a water-logged planet makes it difficult for RNA to form, because that process can’t easily happen in water on its own.
These concepts become less of an issue on Mars, however. Though water was certainly present on Mars 3 to 4 billion years ago, it was never as abundant as it was on Earth, creating the possibility that Martian deserts–locations where borate and molybdate could concentrate–could have fostered the formation of long strands of RNA. Moreover, 4 billion years ago, Mars’ atmosphere contained much more oxygen than Earth’s. Further, recent analysis of a Martian meteorite confirms that boron was once present on Mars.
And, Benner believes, molybdate was there too. “It’s only when molybdenum becomes highly oxidized that it is able to influence how early life formed,”Benner explains. “Molybdate couldn’t have been available on Earth at the time life first began, because three billion years ago the surface of the Earth had very little oxygen, but Mars did.”
Benner believes that these factors imply that life originated on Mars, our closest neighbor in space equipped with all the right ingredients. But life wasn’t sustained there. “Of course Mars dried out. The process of drying was very important for life originating, but not sustaining,” Benner explains. Instead, a meteor would have to have hit Mars, projecting materials into space–and eventually those materials, including some building blocks of life, might have made it to Earth.
Would the sudden change in environment have been too harsh for the fledgling building blocks to survive
? Benner doesn’t think so. “Let’s say life starts on Mars, and becomes very happy in the Martian environment,” Benner explains. “A meteor comes to hit Mars, and the impact ejects rocks on which your predecessor is sitting. Then you land on Earth, and you discover that there is lots of water that you were treating as a scarce element. Will it find the environment adequate? It certainly appreciated the existence of enough water that it didn’t have to worry.”
So, sorry Lil Wayne, looks like it might be time to relinquish your claim to the fourth rock from the Sun. As Brenner notes, “The evidence seems to be building that we are actually all Martians.”
April 9, 2013
Ever since the collective “YOU” became Time Magazine’s Person of the Year in 2006, campaigns to get our attention have increasingly sought out our digital selves. You can name a Budweiser Clydesdale. You can pick Lays’ new potato chip flavor. And it’s not just retail that wants your online opinions: You can vote for who will win photography contests. You can play the futures market on who will win elected offices. And with enough signatures, you can get the White House to read your petitions.
Many science endeavors rely on such crowdsourcing. With a simple app, you can let researchers know the exact date that your lilacs or dogwoods bloom, helping them to track how seasonal cycles are shifting as a result of climate change. You can join the search for ever-larger prime numbers. You can even help scientists scan radio waves in space to search for intelligent life outside of Earth. These more traditional crowdsourcing efforts allow users to brainstorm ideas and process data from computers at home.
But now, a few projects are allowing us to put our virtual selves beyond Earth’s atmosphere through recently launched space missions. Who said that rovers, space probes, a handful of astronauts and pigs were the only ones in space? No longer are we just bystanders watching spacecraft launch and cooing over images returned of other planets and stars. Now, we can direct cameras, help run experiments, even send our avatars–of sorts–to inhabit nearby planetary bodies or return to us in a time capsule.
Here are a few examples:
Asteroid Chimney Rock: On April 10 (tomorrow), the Japan Aerospace Exploration Agency will open up a campaign that allows visitors to their site the opportunity of sending their names and brief messages to the near-Earth asteroid (162173) 1999 JU3. Called the “Let’s meet with Le Petit Prince! Million Campaign 2,” the effort aims to get people’s names onto the Hayabusa2 mission, which will likely launch in 2014 to study the asteroid. When Hayabusa 2 lands on the asteroid, the names submitted–embedded in a plaque of sorts on the spacecraft–will stand as a testament to the idea that humans (or at least their robotic representatives) were there.
The campaign is reminiscent of how NASA got more than 1.2 million people to submit their names and signatures, which were then etched on two dime-sized microchips and affixed to the Mars Curiosity rover. Sure, it’s a bit gimmicky–what useful function is brought by having people’s names out in space? But the idea of “tagging” a planet or an asteroid–preserving a bit of yourself on what will over decades become space junk–has powerful pull. It is why Chimney Rock, with its etchings from early explorers and pioneers, is the historical marker it is today, and why gladiators scored their names into the Colosseum before they fought to the death. For mission leaders hoping to get the public enthusiastic about space, nothing’s more exciting than a bit of digital graffiti.
Interplanetary time capsules: A key goal of Hayabusa2 is to return return a sample from the asteroid in 2020. Mission creators saw this as a perfect way to get the public to fill a time capsule. Those seeking to participate are encouraged to send to mission coordinators their thoughts and dreams for the future along with their hopes and expectations for recovery from natural disasters, the latter likely a way to get people to express their feelings on the 2011 Tohoku earthquake and tsunami that devastated Japan’s east coast. Names, messages, and illustrations will loaded onto a microchip that will not only touch down on the asteroid’s surface, but will also be a part of the probe sent back to Earth with asteroid dust.
But why stop at a mere 6-year time capsule? The European Space Agency, UNESCO, and other partners are blending crowd sourcing with space technology to create the KEO mission–so named because the letters represent common sounds across all of Earth’s languages–which will bundle thoughts and images of anyone who seeks to participate and will launch this bundle in a probe that will only return to Earth in 50,000 years.
Project operators write on KEO’s website: “Each one of us have 4 uncensored pages at our disposal: an identical space of equality and freedom of expression where we can voice our aspirations and our revolts, where we can reveal our deepest fears and our strongest beliefs, where we can relate our lives to our faraway great grandchildren, thus allowing them to witness our times.” That’s 4 pages for every person who chooses to participate.
On board will be photographs detailing Earth’s cultural richness, human blood encased in a diamond, and a durable DVD of humanity’s crowdsourced thoughts. The idea is to launch the time capsule from an Ariane 5 rocket into an orbit more than 2,000 kilometers above Earth, hopefully sometime in 2014. “50,000 years ago, Man created art thus showing his capacity for symbolic abstraction.” the website notes. And in another 50,000 years, “Will Earth still give life? Will human beings still be recognizable as such?”Another logical question: Will whatever’s left on Earth know what’s coming back to them and will be able to retrieve it?
Hayabusa2 and KEO will join capsules already launched into space on Pioneer 10 and 11 and Voyager 1 and 2. But the contents of these earlier capsules were picked by a handful of people; here, we get to choose what represents us in space, and will get to reflect (in theory) on the thoughts bound in time upon their return.
You, the mission controller and scientist: Short of going to Mars yourself, you can do the next best thing–tell an instrument currently observing Mars where to look. On NASA’s Mars Reconnaissance Orbiter is the University of Arizona’s High Resolution Imaging Science Experiment (HiRISE), a camera designed to image Mars in great detail. Dubbed “the people’s camera,” HiRISE allows you–yes, you!– to pick its next targets by filling out a form specifying your “HiWishes.”
A recently launched nanosatellite is allowing the crowdsourced winners of a crowdsourced screaming contest the chance to test whether screams can be heard in space. Launched in February, the nanosatellite’s smartphone-powered brain will broadcast the screams–no word yet on results. But you may find just listening to the yelling therapeutic! This guy’s roar got the most votes: