One of the biggest obstacles of sending humans to Mars is the exposure to radiation, from cosmic rays and solar particles, that astronauts would experience during the 180-day ride to the Red Planet and back.

A new report from the Southwest Research Institute found that the amount of radiation an astronaut would experience on the trips to and from Mars would "represent a large fraction of his or her career accepted lifetime limit," according to a statement from the American Association for the Advancement of Science (AAAS).

The study was published in the AAAS's journal Science, on May 30. NASA will hold a press conference at 2:30 p.m. EDT to discuss more details.

The Mars Curiosity rover's 253-day journey to Mars, between November 2011 and August 2012 served as dry run for when the first humans are launched into deep space inside a protected vehicle.

The one-ton rover was carried to Mars inside a spacecraft that acted as a partial radiation shield.

A toaster-size instrument placed inside the belly of the spacecraft — which simulates where astronauts would be sitting during their own Mars-bound journey — was used to measure the amount of deep-space radiation penetrating the interior of the spacecraft.

The data is not a greenlight for sending humans to Mars, but it is one of the most realistic assessments to date of the radiation dose an astronaut would receive on his or her Mars-bound flight, meaning we are inching closer and closer to determining whether a manned Mars mission is even feasible. Previously, radiation predictions had been using unshielded instruments. This is a major feat.  

Once on Mars, radiation is still a threat — likely and even bigger one — since the atmosphere of Mars is 100 times thinner than Earth's. The Martian surface, therefore, is much more easily reached by radiation from the sun and outer space.

Last November, some NASA scientists expressed confidence that astronauts could live in the radiation environment on Mars.

Cary Zeitlin, who lead the Southwest Research Institute report, is cautious.

"Radiation exposure at the level we measured is right at the edge, or possibly over the edge of what is considered acceptable in terms of career exposure limits defined by NASA and other space agencies,"he said in a press release. "Those limits depend on our understanding of the health risks associated with exposure to cosmic radiation, and at present, that understanding is quite limited."

SEE ALSO: Mars Or Utah? Scientists Set Up A Fake Space Base In The Desert [PHOTOS]

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Scientists on Friday called NASA's Opportunity rover gimpy and arthritic, but hailed its new discoveries about early water on Mars made almost 10 years after it was launched toward the Red Planet.

The unmanned solar-powered vehicle has just analyzed what may be its oldest rock ever, known as Esperance 6. It contains evidence that potentially life-supporting water once flowed in abundance, leaving clay minerals behind.

"This is powerful evidence that water interacted with this rock and changed its chemistry, changed its mineralogy in a dramatic way," said principal investigator Steve Squyres of Cornell University.

He described the research as "some of the most important" of the decade-long mission because it showcases a very different chemistry than most of the previous discoveries about water on Mars, which is now quite dry.

Scientists believe that a lot of water once flowed through these rocks through some sort of fracture, leaving an unusually high concentration of clay.

The analysis reveals traces of a likely drinkable type of water that dates to the first billion years of Martian history, when clay rocks were forming under a more neutral pH, before conditions became more harsh and water more acidic, Squyres said.

The rover's rock abrasion tool, alpha particle X-ray spectrometer and microscopic imager provided the details to Earth-based scientists, who can learn about the Red Planet's history without bringing its rocks to Earth.

Opportunity and its twin rover Spirit launched in 2003 and landed in January 2004 for what was initially meant to be a three-month exploration. Both discovered evidence of wet environments on ancient Mars.

"What Opportunity has mostly discovered evidence for was sulfuric acid," Squyres told reporters, outlining the major difference detected in the Esperance rock's formation. "This is water you could drink," he said.

The oldest rocks, like Esperance, have a neutral pH, signaling that early Martian water was "probably much more favorable in its chemistry, in its pH, in its level of acidity for things like prebiotic chemistry, the kind of chemistry that could lead to the origin of life."

Squyres said the six-wheeled Opportunity rover "has kind of a gimpy shoulder" and that analysis of Esperance took seven tries over many weeks as the rover endured a dust storm, a lumpy terrain and a period when Mars went behind the Sun and out of contact with Earth.

Now, Opportunity is is slowly making its way -- about 50 meters (yards) per day) -- toward an area 1.5 kilometers (one mile) away known as Solander Point that contains 10 times as many geological layers for study as the area where Esperance was found.

It hopes to arrive by August 1.

Spirit launched on June 10, 2003 and finally stopped working in 2010. Opportunity left Earth on July 7, 2003. Both rovers landed on Mars in January 2004.

"Opportunity is is remarkably good health for her age, especially if you measure that in dog years," said John Callas, project manager for Opportunity at NASA's Jet Propulsion Laboratory in Pasadena, California.

"The rover's health is essentially unchanged since we last reported. There has been some arthritis in a few mechanisms for some time but the drive system is performing well."

In all these years, the rover has traveled 36 kilometers (22 miles) on the surface of Mars. But for the rover, that is the car-equivalent of lasting two million miles without an oil change, scientists said.

The main aging concern is what Callas called occasional "flash memory amnesia," or a wearing out from over use of one of the flash memory cells. Bigger problems loom with Mars' hostile environment and harsh temperature changes, he said.

"The rover could have a catastrophic failure at any moment. So each day is a gift," said Callas.

The Opportunity rover now costs about $14 million per year to operate, NASA scientists said.

Its much bigger cousin, the $2.5 billion nuclear-powered Curiosity rover, arrived on Mars in August 2012 for an anticipated two-year mission and a further hunt for traces that life may once have existed.

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Some gullies scoring the sides of Martian sand dunes were likely carved by frozen chunks of carbon dioxide, also known as dry ice, a new study finds.

"I have always dreamed of going to Mars," lead author Serina Diniega, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. "Now I dream of snowboarding down a Martian sand dune on a block of dry ice."

Diniega and her colleagues studied one type of Martian hillside groove called a linear gully, which does not appear to be associated with liquid water. [The Search for Water on Mars (Photos)]

"In debris flows, you have water carrying sediment downhill, and the material eroded from the top is carried to the bottom and deposited as a fan-shaped apron," Diniega said. "In the linear gullies, you're not transporting material. You're carving out a groove, pushing material to the sides."

After studying images of these features taken by NASA's Mars Reconnaissance Orbiter (MRO), the team determined that they form during the early Martian spring on dunes that spend the winter covered by carbon dioxide frost.

Some MRO photos even show bright objects in the linear gullies, apparently caught in the act of carving them out. The researchers think these objects are chunks of dry ice that are sliding downhill as they thaw, their passage eased by a lubricating layer of gaseous carbon dioxide. (Water ice is an unlikely candidate since it probably stays frozen during the early Martian spring, scientists said.)

To test this theory out, the team took some dry ice out to dunes in California and Utah. The blocks slid down the slopes, creating features similar to the Red Planet's linear gullies.

"MRO is showing that Mars is a very active planet," said co-author Candice Hansen of the Planetary Science Institute in Tucson, Ariz. "Some of the processes we see on Mars are like processes on Earth, but this one is in the category of uniquely Martian."

There are many different types of gullies on Mars, and scientists think some of them — such as features called recurring slope lineae— may be formed by the action of flowing water. The new study doesn't speak to water's potential role in any of these other features, Hansen said.

"Just because this dry-ice hypothesis looks like a good explanation for one type doesn't mean it applies to others," she said.

The new study has been published online in the journal Icarus.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com.

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NASA announced the latest group of Astronaut trainees on Monday.

The eight potential space travelers includes four men and four women, ranging in age from 34 to 39. The first new class of astronauts to be selected since 2009 will join 49 already active astronauts. The recruiting process started in November 2011, and NASA recieved a record 6,100 applications for the spots.

They will get a ton of training at NASA facilities and prepare for possible missions to low-Earth orbit, an asteroid, or even to Mars. Their training starts in August. After Commander Chris Hadfield's retirement after his stint on the International Space Station, we hope it will include social media training.

It will probably be another two to four years before NASA culls another group.

Andrew R. Morgan is a 37-year-old Major in the U.S. Army from New Castle, Pa. He graduated from West Point, and earned a doctorate in medicine from the Uniformed Services University of the Health Sciences. He has experience as an emergency physician and flight surgeon, and is currently completing a sports medicine fellowship.

Christina M. Hammock, 34, calls Jacksonville, N.C. home. Hammock holds undergraduate and graduate degrees from North Carolina State University. She currently is serving as National Oceanic and Atmospheric Administration Station Chief in American Samoa.

Josh A. Cassada, Ph. D., 39, is originally from White Bear Lake, Minn. Cassada is a former naval aviator who holds an undergraduate degree from Albion College, and advanced degrees from the University of Rochester. Cassada is a physicist by training and currently is serving as co-founder and Chief Technology Officer for Quantum Opus, a company developing quantum computing and communication.

Ann McClain's mother was in her front yard rose garden when her daughter called with the news.

"You'll never forget this moment," McClain, a 34-year-old major in the U.S. Army told her mom. "I've been selected as an astronaut candidate."

Her mother's response, to scream so loud that McClain's stepfather ran out of the house thinking his wife had just injured herself, was rivaled only by McClain's. [Photos: Meet NASA's 2013 Astronaut Class]

"She sounded like she had the same reaction as I did," McClain recalled in a video interview released by NASA.

McClain and seven others were announced Monday (June 17) as the United States' 21st class of NASA astronaut candidates ("ascans"). The four men and four women will report to the agency's Johnson Space Center in Houston in August to begin two years of basic training.

Victor Glover, a 37-year-old lieutenant commander in the U.S. Navy pinched himself after getting the call to report for NASA astronaut training. Currently assigned as a Navy Legislative Fellow in the U.S. Congress, he and his wife, Janet, had been waiting for word as to where he would be going next.

"I called her and I was able to tell her that now we know where we are going, it will be to Houston," he said. "And she was ecstatic."

Tyler "Nick" Hague hadn't yet told his parents, but knew they would be excited. His brothers' reaction? Well, that was bound to be different.

"My brothers, as they always do, will give me a hard time and tell me the challenges ahead in the training program," said Hague, a 37-year-old lieutenant colonel in the U.S. Air Force and the current deputy chief of the Joint Improvised Explosive Device Defeat Organization. "But everybody is going to be excited."

Exciting exploration

Other than being thrilled for their selection — the ascans were chosen from among more than 6,000 applicants, the second largest turn out in NASA's history — the eight new candidates said they were really excited at the prospect of contributing to humanity's exploration efforts.

"I'm really excited about being a part of something much bigger than me and working alongside some of the world's best minds, who, thankfully for us, feel the same about being a part of something much bigger than them," said Josh Casada, 39, a high-energy particle physicist and a former naval aviator.

"From my perspective, exploration is the foundation of the human spirit, whether that exploration is at the subatomic level or on the nano scale or even the cosmic scale," Casada added. "I think if society is not exploring, we are really just kind of sustaining, and to be able to contribute to that exploration in any small way is really exciting."

Glover expressed similar sentiments, stating he is excited to be a "part of kindling America's passion for aerospace and space."

"There is something special about flying, and especially flying in space, that it just draws people's fascinations and passions," he said. "Being a part of that is the thing that I think excites me the most."

NASA recruited this class, its first trainees in four years, to prepare for flights to the International Space Station, as well as future missions to an asteroid and Mars. [7 Notable Space Shuttle Astronauts]

"I really look forward to being able to directly contribute to the human spaceflight program," said Christina Hammock, 34, who serves as a National Oceanic and Atmospheric Administration (NOAA) station chief in American Samoa. "I really strongly believe in both the practical aspects of the research being conducted, as well as the larger picture of the human spaceflight program bringing us forward as a human race and uniting us in exploring the universe."

Looking forward

Before they can hope to launch into space though, the candidates will need to first pass basic training. Over the next two months, the eight ascans will need to relocate to Houston, where they will soon join the NASA community at Johnson Space Center.

"I am really looking forward to the people down at NASA and working for that really great organization," 35-year-old Nicole Mann, a major in the Marine Corps, said. "I've had the opportunity to go down [to Johnson Space Center] a couple of times for a visit and really it is just the energy and the excitement."

"The professionals there and our international partners — everybody working towards a common mission, towards science, exploration and that goal of all of humankind — I'm looking forward to being a part of that very important team," she said.

Andrew Morgan, a 37-year-old emergency physician and flight surgeon, shares Mann's admiration for the people at NASA.

"I definitely felt drawn to being surrounded by the people I have encountered at NASA and being part of the astronaut office and being part of the astronaut corps," Morgan said. "It was just a tremendously talented group of people — and to be a part of that, I knew that would be something special."

Jessica Meir said she too, was excited to be part of the NASA team, but was also looking forward to the training she and her seven ascans will soon begin.

"I have my private pilot's license but I am really excited about going to Pensacola [Fla.] for real flight training in jets. That is something that will be really, really incredible for me," the 35-year-old assistant professor of anesthesia at Harvard Medical School in Boston said.

"I am also looking forward to the international component. I really enjoy studying foreign languages and cultures, and so the emergence in the Russian culture and society that we will have as part of the International Space Station and the other international partners as well, I am really looking forward to that."

Follow collectSPACE.com on Facebook and on Twitter at @collectSPACE. Copyright 2013 collectSPACE.com. All rights reserved.

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NASA just released these amazing billion pixel, interactive panoramic photographs of the surface of Mars, taken by the Curiosity rover.

You can access them at NASA's website.

The Curiosity rover has been on Mars for about 10 months now. It's done some awesome things, like the first drilling of Martian rocks and shown that the pebbles in Gale Crater indicate there could have been hip-deep water flowing over the area.

The panoramas were created using almost 900 exposures from Curiosity's cameras.

"It gives a sense of place and really shows off the cameras' capabilities," said Bob Deen of  NASA's Jet Propulsion Laboratory said in a statement. "You can see the context and also zoom in to see very fine details."

You can see the images in either white-balanced, to make the rocks look as they would on Earth, or in the Raw Color. Definitely make the panoramas full screen. (The button is hiding for us, but still clickable —  a sliver is hanging out under the "View All" button.)

There are also snapshots which will zoom you to places of interest, like the rover's landing site, and this bird that looks like a rock:

SEE ALSO: How A Team Of Scientists Dropped A One-Ton Science Lab On Mars Completely Unscathed

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On June 28, NASA's Curiosity rover observed one of Mars' two moons, Phobos, rising over the Red planet.

The video is a compilation of 86 photos taken by Curiosity's navigation camera. It's is only about 30 seconds long, but the moonrise happened over a period of around 30 minutes.

Phobos is the smaller of Mars' two moons, measuring about 17 miles long by about 11 miles across at its smallest dimension. 

Watch the video below:

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The next highly-mobile rover to land on Mars will be designed to return samples from the Red Planet to Earth, according to a 160-page report [PDF] prepared by NASA's Mars 2023 Science Definition Team (SDT) released on Tuesday, July 9.

The team of scientists and other Mars experts was assembled in January to outline a mission concept for the successor to NASA's Curiosity rover, which has been rolling around the Red Planet and searching for signs of microbial life since it landed on Aug. 6, 2012.

Scientists have learned from Curiosity that Mars once had an environment that was potentially habitable for life. What is still not known about our neighboring planet is "the context of when that was in Mars' history or compared to the Earth's history," John Grunsfeld, NASA's associate administrator for science, said in a press conference on Tuesday. 

For the next large mission, the SDT recommends in situ exploration, meaning scientists would select one key site on Mars that has been confirmed to have had potentially habitable conditions. Specifically, the next rover will be looking for evidence of biosignature preservation, or marks potentially left by ancient forms of life.

The next rover is modeled after Curiosity. It would be car-sized with slight modifications to accommodate a new suite of science instruments, including the ability to collect Martian samples to send back to Earth for further analysis.

"The ability to collect and cache scientifically compelling, well-documented samples from in situ rock outcrops is unprecedented in Mars exploration and is the necessary first step in a systematic plan to search for life," the report said. 

Martian dust and rocks collected over the mission would be preserved in a sample tube and placed into a sample cache. The cache can hold up to 31 samples which would be jettisoned back to Earth. 

Back on Earth, scientists would perform sophisticated laboratory measurements — beyond the capability of what could be done on Mars — to further examine the samples.

The mission is expected to cost $1.5 billion not counting the cost of the launch vehicle. The total cost to build, design, and launch Curiosity was $2.5 billion.  

PHOTOS: This Big Ship Is Powered Entirely By The Sun

SEE ALSO: Scientists Spent Weeks In The Desert Pretending They Were On Mars

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Neil deGrasse Tyson thinks aliens might be living among us right now.

So, what does the StarTalk Radio host think about NASA sending a rover to martian land? Well, he was skeptical that Curiosity would safely make it onto Mars because of it's complicated "Rube Goldberg-ian" landing method.

Neil deGrasse Tyson shares his thoughts on Curiosity below:

StarTalk Radio is a podcast and radio program hosted by astrophysicist Neil deGrasse Tyson, where comic co-hosts, guest celebrities and scientists discuss astronomy, physics, and everything else about life in the universe. Follow StarTalk Radio on Twitter, and watch StarTalk Radio "Behind the Scenes" on YouTube.

Produced by Will Wei, Robert Libetti, and Kamelia Angelova

SEE ALSO: Neil deGrasse Tyson Thinks Aliens Might Be Living Among Us

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Martian air samples analyzed by the Curiosity rover provide the most detailed picture yet of how the Red Planet's atmosphere has changed over time.

The findings, discussed in two papers published on Thursday, July 18, in the journal Science, suggest Mars' atmosphere today is very similar to what it was like around 4 billion years ago.

Mars' atmosphere is mostly a mix five gases: carbon dioxide, argon, nitrogen, oxygen, and carbon monoxide.

In this case, scientists are interested in the different possible versions of each gas, called isotopes. All isotopes of the same element have the same number of protons and electrons, but differ in the number of neutrons.

"If each gas is a finger on your hand, for example, the isotope ratios are going to tell us about the fine fingerprints," lead author Christopher Webster of NASA's Jet Propulsion Laboratory said in a podcast with Science.  

Isotopes are important because they are the window into the whole time history of Mars.

"Isotopes of particular forms of gas have a way of remembering the temperature history of the events that they went through," explains Webster.

Previous atmospheric measurements from the Viking lander missions in the 1970s were too crude to provide a definitive map of how Mars' atmosphere evolved over time. Curiosity's readings are more accurate than Viking, and for the first enabled scientists to "nail down the true Mars isotope ratios," says Webster. What's more, the rover's measurements match those that come from meteorites that landed on Earth, which confirms the belief that these rocks are from Mars. 

Measurements from Curiosity's tunable laser spectrometer (TLS) and its quadrupole mass spectrometer (QMS) reveal that Mars went through two stages of evolution.

In particular, the D/H isotopic ratio — which tells us where Earth's water came — shows a "significant early loss of water to space (before 3.9 billion years ago), followed by only modest loss to space during the past 4 billion years," according to the study. 

This indicates that carbon dioxide and water reservoirs on Mars were formed around 4 billion years ago, after the major loss of atmospheric mass. Most atmospheric species probably did not survive this period, the authors write.  

A comparison of ancient meteorites from Mars with the modern Martian atmosphere, showing similar isotopic ratios, suggests that Mars has not changed much over the last 4 billion years.  

WATCH: Neil deGrasse Tyson Didn't Think Curiosity Would Land Safely On Mars

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Scientists have spotted more evidence that an enormous ocean on Mars covered much of the planet's surface billions of years ago.

The latest clues were found in photos from NASA's powerful Mars Reconnaissance Orbiter circling the planet. The images show what appears to be an ancient river delta, which may have emptied into a vast Martian ocean that inundated up to one-third of the Red Planet long ago, a new study reports.

"Scientists have long hypothesized that the northern lowlands of Mars are a dried-up ocean bottom, but no one yet has found the smoking gun," study co-author Mike Lamb, an assistant professor of geology at the California Institute of Technology (Caltech) in Pasadena, said in a statement. [Photos: The Search for Water on Mars]

The new study does not provide the long-sought smoking gun, researchers stressed, but it further bolsters the hypothesis.

The team studied high-resolution images of a slice of the northern lowlands snapped by the HiRise camera aboard NASA's Mars Reconnaissance Orbiter, which can distinguish features as small as 10 inches (25 centimeters) on the Red Planet's surface.

Specifically, the scientists looked at a 39-square-mile (100 square kilometers) area that's part of a larger region called Aeolis Dorsa, which lies about 620 miles (1,000 km) from Gale Crater. (NASA's Curiosity rover touched down inside Gale Crater last August, kicking off a planned two-year surface mission to assess Mars' past and present potential to host microbial life.)

The small section of Aeolis Dorsa features many ridges called inverted channels, which form in river bottoms over time when coarse material, such as gravel, is deposited by flowing water. Inverted channels can linger long after the rivers that created them have evaporated, helping researchers trace the past activity of liquid water on Mars.

HiRise images allowed the study team to do just that in the section of Aeolis Dorsa they examined. They found that the inverted channels spread out markedly and slope steeply downward near their end, just as streams here on Earth do when they approach and empty into the sea.

Ancient river deltas have been discovered on Mars before. But most of them have been spotted inside craters or other geologically bounded regions, providing evidence for lakes but not global oceans, researchers said.

The newfound delta is different.

"This is probably one of the most convincing pieces of evidence of a delta in an unconfined region — and a delta points to the existence of a large body of water in the northern hemisphere of Mars," lead author Roman DiBiase, a postdoctoral scholar at Caltech, said in a statement.

Just how big this body of water was remains an open question. It would at least have flooded all of Aeolis Dorsa, covering about 38,600 square miles (100,000 square km), researchers said. And it might even be the long-hypothesized global ocean, which some scientists suspect covered a third of Mars.

It's possible that the Aeolis Dorsa delta was once confined by a crater or other feature that has since completely eroded. However, this interpretation implies that the Martian surface is more geologically active than scientists think, team members said.

The researchers plan to continue searching for signs of the potential ocean along its coastline, in an attempt to shed more light on the Red Planet's warmer and wetter past.

"In our work and that of others — including the Curiosity rover — scientists are finding a rich sedimentary record on Mars that is revealing its past environments, which include rain, flowing water, rivers, deltas and potentially oceans," Lamb said. "Both the ancient environments on Mars and the planet's sedimentary archive of these environments are turning out to be surprisingly Earth-like."

The study was published online in the July 12 issue of the Journal of Geophysical Research.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com.

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Most stargazers have never seen the planet Mercury because it never strays very far from the sun. This week is one of the rare opportunities to catch the tiny planet just before sunrise —and with two other planets nearby.

Two things about Mercury make it a tough sky target. First and foremost, it never strays far from the sun because of its location in the inner solar system. It is always observed against a bright twilight sky, either half an hour after sunset or half an hour before sunrise, and always low in the sky.

Secondly, it is a tiny object. Now that Pluto has been demoted to "dwarf planet" status, Mercury, at 1550 miles (2440 kilometers) in diameter, is the smallest of the eight planets, with just 38 percent of Earth's diameter. [Latest Photos: Mercury Seen by NASA's Messenger Probe]

The challenge in observing Mercury is to find a tiny speck of light, low in the sky, against bright twilight. This week offers one of the rare opportunities when conditions are at their best.

Mercury will be farthest from the sun in our sky on July 30. The weeks just before and after this date are equally favorable.

The best time to spot Mercury will be about 40 minutes before sunrise, a balance between Mercury's altitude above the horizon and the brightness of twilight. Scanning the sky with binoculars will help to spot the tiny speck of light. Once spotted in binoculars, you should just be able to see Mercury with the unaided eye.

Because of Mercury's low altitude, a low cloudless eastern horizon is necessary. The task is made easier by the presence of two much brighter planets in the dawn sky, Jupiter and Mars. Mercury will be below and to the left of these two objects.

Once you spot Mercury, locate it relative to landmarks on your horizon, and see how high you can follow it as it rises and the sky becomes brighter. If you have a telescope, this task becomes easier.

Seen in a telescope, Mercury will look like a tiny gibbous moon. As it rises higher in the sky, it will clear the turbulence, and the view will improve.

Congratulations! You have succeeded in observing one of the most elusive objects in the sky. It is said that the great 16th-century astronomer Johannes Kepler never managed to see Mercury.

This article was provided to SPACE.com by Starry Night Education, the leader in space science curriculum solutions. Follow Starry Night on Twitter @StarryNightEdu.

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Did life on Earth originate on Mars? Or did Earth dispatch life to Mars aboard a meteorite more than 3.5 billion years ago?

In order to investigate the possible origin of life on Mars and Earth, a team of researchers from MIT, Harvard and Massachusetts General Hospital (MGH) want NASA’s next Mars rover to probe the Red Planet’s surface for genetic material by analyzing soil and ice samples with a DNA-sequencing microchip.

Finding signs of past life has already been set as one of the top priorities for the successor of the Mars rover Curiosity, NASA's most recent ambassador to Mars.

But new research outlined in June in the journal Astrobiology says the new rover, which is slated to launch in 2020, should search instead for existing or recently dead lifeforms — where "recent" means as much as one million years old. [The Search for Life on Mars: A Photo Timeline]

"If there’s life on Mars and it is based on RNA and DNA, you would get not one but many sequences and you’d be able to understand the extent of ‘relativeness’ of any Earth life," said study lead author Christopher Carr, of MIT’s Department of Earth, Atmospheric and Planetary Sciences.

"You could use that to determine whether it’s contamination from Earth — or whether it's actual Martian life," Carr told SPACE.com. "And that would also allow us to say how Martian life is related to Earth life."

A new kind of hunt for alien life

The project is based on the assumption that life on Earth and Mars (if it ever existed) could have shared genetic ancestry. During a period called the Late Heavy Bombardment, about 3.5 billion to 4 billion years ago, there were a high number of major impact events in the solar system. About 1 billion tons of asteroids zoomed through space between Earth and Mars, possibly cross-contaminating the two planets.

"Some of that rock was transferred in a way consistent with life as we know it," Carr said. "It wasn't too hot, it was relatively quickly transferred so that it wouldn’t be damaged by space radiation. If life was around on one planet or the other, it could've hitched a ride and ended up on the other planet … So the question is, if there's life on Mars and we’re related to it, then how can we detect it?"

In order to search for this kind of life, the team wants to equip NASA's 2020 Mars rover with a device capable of sequencing RNA and DNA — very specific indicators of life.

Such a sequencer could "only target life that is there now or recently dead because nucleic acids don't stick around that long; the oldest nucleic acids that people have been able to sequence here on Earth are less than a million years old," Carr said. "Mars is colder, so maybe we can go further back in time, but a million years may be a pretty good limit."

Radiation protection

For a sensitive DNA chip to work on Mars, it first has to survive the months-long space journey, during which the spacecraft will be exposed to high doses of radiation.

The conditions on Mars itself are harsher than on Earth: the Red Planet's atmosphere, made mostly of carbon dioxide, is 100 times thinner than Earth’s. Temperatures on the surface can plummet to minus 195 degrees Fahrenheit (minus 126 degrees Celsius).

But the environment below the Martian surface may be similar to that of our own planet and may hold all the major elements required for life, some scientists say.

The team has tested several sequencing microchips with 1.3 million microwells, each able to hold a single bead containing an amplified fragment of DNA to generate a DNA sequence. The researchers subjected the chips, along with the reagents required for sequencing, to Mars-mission radiation levels and then used the devices to analyze the DNA of E. coli bacteria.

"The main component of space radiation is protons, and you also get a lot of protons from the sun," Carr said. "We tested the chips at the NASA space radiation lab, the Brookhaven National Lab, exposing it to 1 and 5 Gy doses — above what you would expect for a human mission, and of the order of what you would expect or higher for a two-year mission to Mars, with some safety factor."

This means that such a microchip could probably survive the trip to Mars, as well as another year and a half of gathering data on the surface. [The Boldest Mars Missions in History]

Then the researchers loaded the chips with DNA fragments from E.coli, finding that they were still able to analyze DNA and identify the bacterial sequences.

Chris McKay, a planetary scientist with the Space Science Division of NASA's Ames Research Center, who was not involved in the study, said a radiation-resilient DNA-sequencing chip would be important for future missions to Mars and other corners of the universe.

"An instrument that can detect and sequence DNA is definitely something that should be included in any life detection mission," McKay told SPACE.com. "It would have the benefit of being highly sensitive to a fundamentally important bio-molecule. The next step in this technology is to modify the instrument so that it can sequence any long chain of nucleotides with different backbones: DNA, RNA, TNA, PNA, and so on."

Follow Katia Moskvitch @SciTech_Cat. Follow SPACE.com on Twitter @Spacedotcom. We're also on Facebook and Google+. Original article on SPACE.com.

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As of Aug. 5, 2013, the Curiosity Mars rover has spent an whole year on the Red planet.

She's supposed to be there for two years total, investigating if ancient Mars was once habitable — a feat she actually already accomplished a few months ago.

As she touched down on Mars Aug. 5, 2012, after seven unmanned minutes spent in terror, waiting for the culmination of decades of work, a scream of excitement shook the Curiosity rover's control room.

"Touchdown confirmed, we are safe on Mars," engineer Allen Chen said over the radio, eliciting tears of joy and congratulatory hugs between all the blue-shirted Jet Propulsion Laboratory staff.

Curiosity is on Mars to investigate several things, including studying the climate and geology, searching for signs of life and water, and determining if the planet could ever be made habitable for humans. She was made to last for a two-year mission — and is already half way though it.

One of the most nail-biting events was the Rover's entry, descent and landing on the Red Planet — which luckily went off perfectly. See the video below to relive it or experience it for the first time.

Relive The Excitement And Exhilaration Of Curiosity's Landing With This Video

This image taken during the descent by the Mars Reconnaissance Orbiter captured the rover while she was falling to the surface. You can see the parachute slowing her descent in this stunning image.

The rover's own cameras caught the landing from her point of view. The video starts with the heat shield (which protected Curiosity while she was falling through the atmosphere) detaching, and ends with the sky crane blowing up dust and the rover touching down on Mars.

Mars One, a Netherlands-based private spaceflight project, announced April 22 that it would begin accepting applications for a one-way mission to colonize Mars; three weeks later, 78,000 people had already signed up.

We admit we wondered at the sanity of everyone involved. So we tracked down a few of the applicants and asked them: Why do you want to die on Mars?

Katrina Wolfe, 24, is a video game designer who lives in Los Angeles. You can watch her Mars One application video here.

Popular Science: How would your parents feel about you leaving Earth forever?

Katrina Wolfe: My dad is more excited than my mom. She wouldn't want me to go. When I told my dad about it, he said, "That would be awesome, I want a call from Mars!" But it's funny, because I remember growing up, we would always ask each other the hypothetical question: If Captain Picard beamed down right now and said, "I need you to come to the Enterprise, you have three seconds to decide, and you can never come back." Would you go? My family always said yes.

I don't know if I would go if there was, say, a 70 percent chance I wouldn't even get there alive.

PS: What would you do on Mars?

KW: I'd love to do desert sailing on Mars, with a wind sail. [Editor's note: Dunno about wind sailing, but you might be able to snowboard on Martian dry ice!] But I know most of our time there would be spent getting the colony to the point of sustainability.

PS: Aren't you worried about dying?

KW: Of course death is a worry to some degree. It's hard to say now. I don't know if I would go if there was, say, a 70 percent chance I wouldn't even get there alive.

PS: Did you ever want to be a NASA astronaut?

KW: In 8th grade I did a project on how to become an astronaut. I knew that trying to become an astronaut would mean becoming an engineer and going through NASA. It appealed to me, but very few people actually get to be an astronaut through that path. At some point I realized I would also love to go into game design. I actually majored in classics and minored in video game design and management. This Mars opportunity is even more appealing than being a NASA astronaut because it's about starting a new civilization.

PS: Do you think this mission actually has a chance of happening?

KW: I know there are a lot of unanswered questions about how we're actually going to survive on Mars, but there's lots of time to figure that out. I think that Mars One can make it happen. Listening to the founders speak, I'm very impressed with their vision for the company. I like that they see Mars as the next big step for humanity.

PS: What will you do if you have to stay on Earth?

KW: I'm very excited by life expectancy research and the singularity. There are a lot of big questions we need to answer as a society; how are we going to deal with robots in our lives? What if we live to be 200? I would try to be involved with questions like this if I couldn't go to Mars.

Read more about the Mars One program here. And stay tuned on PopularScience.com for more interviews with the applicants.

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On Tuesday, six scientists emerged from an abandoned quarry on Hawaii's Mauna Loa volcano after spending four months simulating what it is like to live on Mars.

The Hawaii Space Exploration Analog and Simulation, or HI-SEAS, is a NASA-funded study led by Cornell University and the University of Hawaii at Manoa.

The goal of the study was to find foods that astronauts would be able eat and prepare on long-term missions to deep space, like a trip to Mars.

For 118 days, mission commander Angelo Vermeulen and his team members cooked, ate, and kept detailed records of meals made from dehydrated and shelf-stable ingredients from their pantry. The list of available foods included everything from freeze-dried chicken to milk powder to crackers.

Based on pictures (unfortunately we weren't able to taste the food for ourselves), the dining on Mars doesn't look to be half-bad.

The space habitat is located 8,000 feet above sea level on the side of a Hawaiian volcano, Mauna Loa.

The isolated setting was ideal because it had no visible plant or animal life.

A two-story dome featured a ground floor with a kitchen, dining room, bathroom, lab, exercise room, and common spaces. Here's a view of the rooms on the day the crew arrived.

Four months after the call for applicants went out, 100,000 people from around the world (including yours truly) have applied for a one-way trip to Mars.

The Mars One group wants to put four humans on the Red Planet by 2022. The first settlers would be followed more groups, arriving every two years.

The first round of a four-part selection process ends on August 31. By September, the selection committee will begin culling through hundreds of thousands of video entries and questionnaires to decide which space enthusiasts will move ahead to Round Two. Ultimately, candidates will be whittled down to a total of 24 to 40 applicants, divided into groups.

"We are selecting groups of four, and not individuals," says Norbert Kraft, the medical director for the Mars One project. "You can be the best, smartest individual, but if you cannot work within your group you are out," he said.

Each group will spend three months every year, for up to eight years, in an isolated habitat. During this time, the group will have to prove that they can work together.

On its press site, Mars One says it's looking for applicants that display five specific psychological traits: resilience, adaptability, curiosity, the ability to trust others, and creativity/resourcefulness. They also want candidates who are mature, interesting, and have a sense of humor.

Most Mars applicants have a public profile and their application videos are available to watch online.

Because the selection process has not started yet, Kraft says he cannot single anyone out now. However, he did leave us one piece of advice: "I always say they fly to Mars when they sit in the rocket and not a minute earlier."

Who do we think should make the cut? Here are five eager applicants that we think balance each other out.

Pietro Aliprandi, 23, from Italy — "The Adventurer"

Pietro, who is studying to be doctor in Italy, seems like a born adventurer. Every summer he attempts to summit at least one mountain in the Alps, according to his profile. And, he's naturally curious. "When I look at the sky, I do dream about airplanes, Starships, and space exploration," he said in his application video. That's the spirit!

Maggie Duckworth, 28, from the United States — "The Caretaker"

Maggie was "raised on a farm in the heart of the U.S." according to her Mars One profile. Maggie has a degree in electrical engineering and makes high-end costumes for a living. We think Maggie, who likes camping and cooking, would be resourceful during a time of crisis. In an interview with Huffpo Live, the creative spirit even said she would be willing to have a baby on Mars.

Kitty Kane, 23, from the United States — "The Comedian"

Kitty says she would like to go to Mars because she "likes eating food out of pouches." Um, Ok. Kitty may not be the rocket scientist of the group, but we admire her silliness, which will be useful as astronauts battle harsh conditions and loneliness on the Red Planet.

Steve Schild, 28, from Switzerland — "The Athlete"

Steve currently lives with his fiancé and two cats in a rural village in Switzerland. But he's no snooze fest! Steve is a three-time Guinness World Record holder for the farthest distance covered on a water slide in 4 hours. Check him out here. At the end of August, Steve plans to beat another world record: he will attempt to cross with a teammate the English Channel in an inflatable water roller.

Andrew Radar, 34, from Canada — "The Intellectual"

Andrew has a Ph.D in long-duration human space flight from MIT. He's also worked as a spacecraft systems engineer on six Canadian space missions. Last month, the charismatic Ottawa native earned the title "Canada's Greatest Know-it-All" on the popular Canadian Discovery Channel show of the same named.

SEE ALSO: The Food On Mars Will Be Delicious

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Kitty Kane, 23, is among the 100,000 men and women who have volunteered to die on Mars.

Kane answered an open call for astronauts put out in April by Mars One, a company that says it will plant the first humans on Mars by 2023. There is no return flight.

The one-way mission doesn't scare Kane, who currently lives in Provo, Utah, a state that she correctly notes has a remarkable resemblance to the dusty red planet.

After watching Kane's endearing video application, we wanted to learn more about the spunky blonde and why she's looking forward to getting off this rock. 

Read our interview with Kane below. 

Business Insider: What do you do on Earth?

Kitty Kane: I am a hairstylist here on Earth. The prospect of going to Mars terrifies the small part of me that doesn't want anyone to see my natural hair color. On the other hand, if I'm selected, everyone on the red planet will have great hair.

BI: Why is Earth no longer exciting to you?

KK: Earth is overrated. I have wanted to abandon it my entire life. In fact, there are a lot of really embarrassing drawings of Mars colony infrastructure in my childhood journals. (No, you can't see them).

BI: What do you know about Mars?

KK: Uh, the sky is butterscotch? How much does anyone really know about Mars? Our collective knowledge is still limited since the human race has yet to set foot there.

BI: What do you think the chances are this trip will happen?

KK: I'm not sure. I truly believe that rests in the hands of the producers. In order for Mars One to raise enough money, the public needs to care. Space travel today just isn't sexy, though. Half of the people watching NASA's rover footage are nut-job, conspiracy-theorist YouTubers combing the landscape for rocks that kind of look like rats/dinosaurs/faces (if you squint).

BI: The mission launches in 2022. What if you have a family by then?

KK: If I am selected to be in the final 24-40, that is something I would delay in my life. If I am actually given the opportunity to colonize Mars, that is something that probably won't ever happen. I really want to be a mom, though. Sacrificing that dream will be the hardest part about this mission. I would be the mother of a new civilization, though.

BI: Have you told your parents/friends? What do they think of your one-way trip to Mars?

KK: My friends and family have actually been really supportive. In fact, my mother is more excited than I am. I can guarantee that she will plaster the link to this article all over Facebook.

BI: Let's say you run in to some Martians. How do you plan on communicating?

KK: If I came in contact with native Martians, I wouldn't say anything. Music is a universal language, so I think I would just hold up a boom box à la Lloyd Dobler. The question I then have to ask myself is, what should I play? It has to be something that highlights the most important things about the human race. It has to be something that reveals both our benevolent heights and our unspeakable depravity. It has to be something that conveys our pursuit of freedom as well as our struggle to survive. It has to be something that illustrates how 6,000 years after we invented the wheel, we went to Space. So, probably T-Pain?

BI: What kind of people would you like to be sent to Mars with?

KK: Hotties. I'm going to be stuck with them for the rest of my life, after all. I'm kidding, but Mars One probably wouldn't have any trouble funding this mission if they produced a trashy reality show where good-looking people hang out in a hot tub. However, I'm hoping Mars One will launch an intelligent show in which trustworthy, capable people work together for the betterment of humanity … that is also insanely popular. Honestly, that would be a giant leap for mankind.

BI: How do you fit into the group?

KK: I'm a people person. Many of the applicants are science people or machine people or math people. Those types of people are great and absolutely necessary. However, due to the nature of this project, we also need people people. I'd like to think I can bring that to the table.

BI: In your application, you say, once on Mars, you'd like to spend your time juggling and painting the landscape. I have to ask — how serious are you about this trip?

KK: I had a lot of fun with my application video. I definitely don't regret that because I feel like I received a lot more attention than I would have if I had just talked to the camera in my bedroom about how I've always wanted to go to space blah blah blah. That's boring. I am serious about this, but I'm never going to be the type of person who takes everything seriously.

SEE ALSO: The Food On Mars Will Be Delicious

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We may all be Martians.

Evidence is building that Earth life originated on Mars and was brought to this planet aboard a meteorite, said biochemist Steven Benner of The Westheimer Institute for Science and Technology in Florida.

An oxidized form of the element molybdenum, which may have been crucial to the origin of life, was likely available on the Red Planet's surface long ago, but unavailable on Earth, said Benner, who presented his findings today (Aug. 28; Aug. 29 local time) at the annual Goldschmidt geochemistry conference in Florence, Italy. [The Search for Life on Mars (Photo Timeline)]

"It’s only when molybdenum becomes highly oxidized that it is able to influence how early life formed," Benner said in a statement. "This form of molybdenum couldn’t have been available on Earth at the time life first began, because 3 billion years ago, the surface of the Earth had very little oxygen, but Mars did. It’s yet another piece of evidence which makes it more likely life came to Earth on a Martian meteorite, rather than starting on this planet."

Organic compounds are the building blocks of life, but they need a little help to make things happen. Simply adding energy such as heat or light turns a soup of organic molecules into a tarlike substance, Benner said.

That's where oxidized molybdenum comes in. Inserting it or boron, another element, into the mix would help organics make the leap to life, Benner added.

"Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidized form of molybdenum was there, too," he said.

Another point in Mars' favor is the likelihood that the early Earth was completely covered by water while the ancient Red Planet had substantial dry areas, Benner said. All of this liquid would have made it difficult for boron, which is currently found only in extremely dry places, to form in high enough concentrations on Earth when life was first evolving.

Further, Benner added, water is corrosive to RNA, which most researchers think was the first genetic molecule (rather than DNA, which came later). 

No indigenous Red Planet organisms have ever been discovered. But it is possible that life on Mars — if it ever existed — may have made its way to Earth at some point, many scientists say.

Some microbes are incredibly hardy, after all, and may be able to survive an interplanetary journey after being blasted off their home world by an asteroid impact. And orbital dynamics show that it's much easier for rocks to travel from Mars to Earth than the other way around.

Wherever Earth life originated, Benner is glad it put down roots on our blue planet.

"It’s lucky that we ended up here nevertheless, as certainly Earth has been the better of the two planets for sustaining life," Benner said. "If our hypothetical Martian ancestors had remained on Mars, there might not have been a story to tell."

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com.

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If you haven't already applied for a one-way trip to Mars — you've officially missed your chance. Sorry. 

The application phase of the Mars One Astronaut Selection program is now closed. The open call for space settlers went out in April and received interest from 78,000 people in less than one month.

According to Mars One, 202,586 people from 140 different countries filled out online applications by the deadline on Aug. 31. The program also requires participants to make an application video, which is made available for the public to watch.

Here are some of our favorite candidates. 

The majority of applicants — 24% — come from the United States, followed by India, China, and Brazil.

A group of 40 astronauts, in groups of four, will ultimately be chosen to live on Mars. The plan is for the first group to leave Earth for the Red Planet in 2022 and then be followed every two years by more groups.

Mars One is developed by Dutch entrepreneur Bas Lansdorp and will be funded in part by by turning the event into a reality TV show. Lansdorp estimates that the mission will cost $6 billion.

SEE ALSO: This Young Blonde Signed Up For A One-Way Trip To Mars Because Earth Is Overrated

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