Researchers announced their discovery of the deep watery ocean on Enceladus on Thursday (April 3) in the journal Science, confirming suspicions held by many scientists since 2005, when NASA’s Cassini spacecraft spied geysers of ice and water vapor erupting from Enceladus’ south pole.
The discovery vaults Enceladus into the top tier of life-hosting candidates along with Europa, an ice-sheathed moon of Jupiter that also hosts a subterranean ocean. Both frigid satellites bear much closer investigation, researchers say.
“I don’t know which of the two is going to be more likely to have life. It might be both; it could be neither,” study co-author Jonathan Lunine of Cornell University told reporters yesterday (April 2). “I think what this discovery tells us is that we just need to be more aggressive in getting the next generation of spacecraft both to Europa and to the Saturn system once the Cassini mission is over.”
Cassini arrived in orbit around Saturn in 2004 and is currently scheduled to go out in a blaze of glory in September 2017, when it will dive headlong into the giant planet’s thick atmosphere.
Enceladus’ geysers blast material hundreds of miles into space, offering a way to sample the moon’s subsurface ocean from afar. (Researchers think the ocean is feeding the geysers, though they can’t be sure of this at the moment.)
Cassini has already done some of this work with its mass spectrometer, detecting salts and organic compounds — the carbon-based building blocks of life as we know it — in Enceladus’ plumes during flybys of the moon.
But Cassini’s mass spectrometer can detect only relatively light organics. A follow-up mission to Enceladus should sport a more advanced and more sensitive version of this instrument that could spot a wider range of organics, Lunine said.
“You could actually do this by making flybys of Enceladus, the way that Cassini does now,” he said. “I think you could learn quite a bit about the organic inventory in the plume by flying this device.”
Interestingly, astronomers announced in December that they had discovered plumes of water vapor erupting from Europa’s south polar region as well. So that moon’s ocean could be sampled during flybys, too — perhaps by a mission called the Europa Clipper.
NASA is developing the Europa Clipper as a concept mission at the moment. Recent estimates have pegged the mission’s cost at around $2 billion. That’s pretty steep in these tough economic times, so a scaled-down version might have the best chance of getting it off the ground, NASA officials have said.
Enceladus and Europa aren’t the only icy moons that harbor subsurface oceans; Jupiter’s enormous moon Ganymede also has one, for example. But Ganymede’s appears to be sandwiched between layers of ice, while the seas of Enceladus and Europa are in contact with rocky seafloors, making possible all sorts of interesting chemical reactions, researchers say.
The oceans soured into a deadly sulfuric-acid stew after the huge asteroid impact that wiped out the dinosaurs, a new study suggests.
Eighty percent of the planet’s species died off at the end of the Cretaceous Period 65.5 million years ago, including most marine life in the upper ocean, as well as swimmers and drifters in lakes and rivers. Scientists blame this mass extinction on the asteroid or comet impact that created the Chicxulub crater in the Gulf of Mexico.
A new model of the disaster finds that the impact would have inundated Earth’s atmosphere with sulfur trioxide, from sulfate-rich marine rocks called anhydrite vaporized by the blast. Once in the air, the sulfur would have rapidly transformed into sulfuric acid, generating massive amounts of acid rain within a few days of the impact, according to the study, published today (March 9) in the journal Nature Geoscience.
The model helps explain why most deep-sea marine life survived the mass extinction while surface dwellers disappeared from the fossil record, the researchers said. The intense acid rainfall only spiked the upper surface of the ocean with sulfuric acid, leaving the deeper waters as a refuge. The model could also account for another extinction mystery: the so-called fern spike, revealed by a massive increase in fossil fern pollen just after the impact. Ferns are one of the few plants that tolerate ground saturated in acidic water, the researchers said.
The Chicxulub impact devastated the Earth with more than just acid rain. Other killer effects included tsunamis, a global firestorm and soot from burning plants. [The 10 Best Ways to Destroy Earth]
The ocean-acidification theory has been put forth before, but some scientists questioned whether the impact would have produced enough global acid rain to account for the worldwide extinction of marine life. For example, the ejected sulfur could have been sulfur dioxide, which tends to hang out in the atmosphere instead of forming aerosols that become acid rain.
Lead author Sohsuke Ohno, of the Chiba Institute of Technology in Japan, and his co-authors simulated the Chicxulub impact conditions in a lab, zapping sulfur-rich anhydrite rocks with a laser to mimic the forces of an asteroid colliding with Earth. The resulting vapor was mostly sulfur trioxide, rather than sulfur dioxide, the researchers found. In Earth’s atmosphere, the sulfur trioxide would have quickly combined with water to form sulfuric acid aerosols. These aerosols played a key role in quickly getting sulfur out of the sky and into the ocean, the researchers said. The tiny droplets likely stuck to pulverized silicate rock debris raining down on the planet, thus removing sulfuric acid from the atmosphere in just a matter of days.
“Our experimental results indicate that sulfur trioxide is expected to be the major sulfide component in the sulfur oxide gas released during the impact,” Ohno told Live Science in an email interview. “In addition to that, by the scavenging or sweeping out of acid aerosols by coexisting silicate particles, sulfuric acid would have settled to the ground surface within a very short time,” Ohno said.
A study of teeny-tiny meteorite fragments revealed that two essential components of life on Earth as we know it, could have migrated to our planet on space dust.
Researchers discovered DNA and amino acids components in a smidgen of a space rock that fell over Murchison, Victoria, in Australia in September 1969. Previous studies of the meteorite revealed organic material, but the samples examined then were much larger. This study would lend more credence to the idea that life arose from outside of our planet, researchers said in a statement.
“Despite their small size, these interplanetary dust particles may have provided higher quantities and a steadier supply of extraterrestrial organic material to early Earth,” said Michael Callahan, a research physical scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. [5 Bold Claims of Alien Life]
Amino acids are the basis of proteins, which are structures that make up hair, skin and other bits of living creatures. DNA is a molecule that contains information on building and running an organism.
Meteorites such as Murchison are rare types of space rocks: the carbonaceous chondrites make up less than 5 percent of meteorites found on Earth, NASA said. Further, the molecules discovered in these space rocks are usually in miniscule concentrations of parts-per-million or parts-per-billion.
These factors have researchers questioning how significant the carbon-rich rocks themselves were in bringing life to Earth. Space dust, however, is more plentiful as it is constantly available from comets and asteroids shedding debris in their travels through the solar system.
The Murchison study (a proof of concept for further work, the researchers say) found life’s building blocks in a sample that weighed about the same as a few eyebrow hairs. The 360-microgram sample was about 1,000 times smaller than a typical sample analyzed by researchers.
Samples from space
This micro-sample required a more sensitive technique than usual to extract the information scientists needed. A nanoflow liquid chromatography instrument organized the molecules, which were then ionized with a nanoelectrospray for analysis in a mass spectrometer.
NASA and other agencies have dealt with small sample sizes before, such as on the Stardust mission that collected particles from Comet Wild-2 and returned them to Earth in 2006. Researchers anticipate the techniques they are using today could be used for other missions in the solar system, especially for sample-return missions.
“This technology will also be extremely useful to search for amino acids and other potential chemical biosignatures in samples returned from Mars and eventually plume materials from the outer planet icy moons Enceladus and Europa,” said Goddard astrobiologist Daniel Glavin, who was co-author on the research.
The study, led by Callahan, was recently published in the Journal of Chromatography A.
A NASA asteroid-hunting spacecraft has opened its eyes in preparation for a renewed mission, beaming home its first images in more than 2.5 years.
The Near-Earth Object Wide-field Infrared Survey Explorer spacecraft, or NEOWISE, has taken its first set of test images since being reactivated in September after a 31-month-long hibernation, NASA officials announced today (Dec. 19). The space agency wants NEOWISE to resume its hunt for potentially dangerous asteroids, some of which could be promising targets for future human exploration.
“The spacecraft is in excellent health, and the new images look just as good as they were before hibernation,” Amy Mainzer, principal investigator for NEOWISE at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. [Photos: Asteroids in Deep Space]
“Over the next weeks and months we will be gearing up our ground-based data processing and expect to get back into the asteroid-hunting business, and acquire our first previously undiscovered space rock, in the next few months,” Mainzer added.
NEOWISE began its scientific life as WISE, which launched to Earth orbit in December 2009 on a 10-month mission to scan the entire sky in infrared light. WISE catalogued about 560 million celestial objects, ranging from faraway galaxies to nearby asteroids and comets, NASA officials have said.
WISE ran out of hydrogen coolant in October 2010, making two of its four infrared detectors inoperable. But NASA didn’t shut the probe down at this point; rather, the agency granted a four-month mission extension known as NEOWISE, which focused on hunting asteroids. (The satellite could still spot nearby objects with its other two detectors, which did not have to be super-cooled).
NEOWISE discovered more than 34,000 asteroids and characterized 158,000 space rocks before being shut down in February 2011, NASA officials said.
And the spacecraft is now gearing up for another three-year space-rock hunt, partly to help find potential targets for NASA’s ambitious asteroid-capture project. This “Asteroid Initiative,” which was announced in April, seeks to drag a near-Earth asteroid to a stable orbit around the moon, where it would be visited by astronauts using the agency’s Space Launch System rocket and Orion crew vehicle.
The plan represents a way to meet a major goal laid out by President Barack Obama, who in 2010 directed NASA to get astronauts to a near-Earth asteroid by 2025, then on to the vicinity of Mars by the mid-2030s.
NEOWISE employs a 16-inch (40 centimeters) telescope and infrared cameras to find previously unknown asteroids and gauge the size, reflectivity and thermal properties of space rocks, NASA officials said.
“It is important that we accumulate as much of this type of data as possible while the spacecraft remains a viable asset,” said Lindley Johnson, NASA’s NEOWISE program executive in Washington. “NEOWISE is an important element to enhance our ability to support the [asteroid] initiative.”
The explosive collisions of icy comets with planets and moons generated the vital building blocks of life, spreading these necessary ingredients throughout the solar system, researchers say.
“The important implication is that the complex precursors to life are widespread, thus increasing the chances of life evolving elsewhere,” study co-author Mark Price, a space scientist at the University of Kent in England, told SPACE.com.
Comets are known to possess organic compounds. Scientists have long suggested that comets helped bring the ingredients of life to the early Earth. [7 Theories on the Origin of Life]
Astronomers have detected ammonia and other compounds in comets such as Halley’s Comet that are the precursors of amino acids, the basic components of proteins. Indeed, the simplest amino acid, glycine, was recently discovered in samples of the Comet 81P/Wild-2 collected by NASA’s Stardust spacecraft.
However, more complex amino acids are needed for life. Computer models from physical chemist Nir Goldman at the Lawrence Livermore National Laboratory in California suggested impacts could form complex amino acids, and Price and his colleagues set out to replicate these simulations, while astrobiologist Zita Martins at Imperial College in London and her colleagues helped look for any resultant amino acids.
“Impacts are ubiquitous in the solar system — we see impact craters on every solid surface in the solar system,” Price said. “Due to gravity, we know these impacts must occur at very high velocities, kilometers per second. During such impacts, pressures and temperatures get very high, providing an environment that can induce chemical changes in target and projectile materials. One such change is that simple molecules can become more complicated ones.”
In experiments, the researchers fired steel projectiles at speeds of up to 16,000 mph (25,200 km/h) at ice mixtures similar to ones found in comets. The targets could be difficult to work with — “a mix of carbon dioxide ice, ammonia and methanol gets extremely cold, minus 80 degrees Celsius (minus 112 degrees Fahrenheit), and handling the ices and containers meant using several layers of clean gloves, face masks and coveralls,” Price said. “Even so, this still resulted in frostbitten fingers!”
The results included several amino acids, including L-alanine, an important component of proteins on Earth. Martins, Price, Goldman and their colleagues detailed their findings online Sunday (Sept. 15) in the journal Nature Geoscience.
Price cautioned, “We have not created life. Not even close. What we have done is demonstrate a process that takes molecules that were present at the time of the birth of the solar system and made them into molecules that are required for life. It’s like taking simple LEGO bricks and sticking two together. You are a long way from building a house, but it is a start.”
The researchers suggest that icy impacts — whether from icy comets against rocky planets or rocky or icy bodies against icy surfaces such as the moons of Jupiter and Saturn — could have manufactured complex organic molecules.
“As impacts occur everywhere we look, this implies that complicated molecules are also widespread throughout the solar system,” Price said. “We have managed to generate a result that may increase the chance of life being present in an environment outside of the Earth, such as under the ice of Enceladus or Europa.”
Future research can analyze what other compounds might form during such impacts — for instance, whether complex molecules can be altered into even more complex molecules.
The dwarf planet Ceres, which orbits the sun in the asteroid belt between Mars and Jupiter, is a unique body in the solar system, bearing many similarities to Jupiter’s moon Europaand Saturn’s moon Enceladus, both considered to be potential sources for harboring life.
“I think of Ceres actually as a game changer in the solar system,” Schmidt said.
“Ceres is arguably the only one of its kind.”
The innermost icy body
When Ceres was discovered in 1801, astronomers first classified it as a planet. The massive body traveled between Mars and Jupiter, where scientists had mathematically predicted a planet should lie. Further observations revealed that a number of small bodies littered the region, and Ceres was downgraded to just another asteroid within the asteroid belt. It wasn’t until Pluto was classified as a dwarf planetin 2006 that Ceres was upgraded to the same level.
Ceres is the most massive body in the asteroid belt, and larger than some of the icy moons scientists consider ideal for hosting life. It is twice the size of Enceladus, Saturn’s geyser-spouting moon that may hide liquid water beneath its surface.
Unlike other asteroids, the Texas-sized Cereshas a perfectly rounded shape that hints toward its origins.
“The fact that Ceres is so round tells us that it almost certainly had to form in the early solar system,” Schmidt said. She explained that a later formation would have created a less rounded shape.
The shape of the dwarf planet, combined with its size and total mass, reveal a body of incredibly low density.
“Underneath this dusty, dirty, clay-type surface, we think that Ceres might be icy,” Schmidt said. “It could potentially have had an ocean at one point in its history.”
“The difference between Ceres and other icy bodies [in the solar system] is that it’s the closest to the sun,” Castillo-Rogez said.
Less than three times as far as Earth from the sun, Ceres is close enough to feel the warmth of the star, allowing ice to melt and reform.
Investigating the interior of the dwarf planet could provide insight into the early solar system, especially locations where water and other volatiles might have existed.
“Ceres is like the gatekeeper to the history of water in the middle solar system,” Schmidt said.
Studying the surface
As large as Ceres is, its distance has made it a challenge to study from Earth. Images taken by the space-based Hubble Space Telescope provided some insight to its surface, but to be sighted, features could be no larger than 25 kilometers (15.5 miles) in diameter.
Several round circular spots mar the terrain, features which Schmidt said could be any one of a number of geologic terrains, including potentially impact basins or chaos terrains similar to those found on Europa. The largest of these, named Piazzi in honor of the dwarf planet’s discoverer, has a diameter of about 250 km (155 miles). If this feature is an impact basin, it would have been formed by an object approximately 25 km (15.5 miles) in size.
But for Schmidt, this is another possible indication about the dwarf planet’s surface.
“It doesn’t mean that Ceres hasn’t been hit by something bigger than 25 kilometers,” she said. “It just means that whatever is going on on Ceres has totally erased [the topographic signature of that event].”
Ceres may have suffered major impacts, especially during periods of heavy bombardment early in the solar system’s history. If the surface contained ice, however, those features may have been erased.
Telescopes on Earth have also been able to study the light reflecting from the planet and read its spectra.
“The spectrum is telling you that water has been involved in the creation of materials on the surface,” Schmidt said.
The spectrum indicates that water is bound up in the material on the surface of Ceres, forming a clay. Schmidt compared it to the recent talk of mineralsfound by NASA’s Curiosityon the surface of Mars. [The Search for Life on Mars (A Photo Timeline)]
“[Water is] literally bathing the surface of Ceres,” she said.
In addition, astronomers have found evidence of carbonates, minerals that form in a process involving water and heat. Carbonates are often produced by living processes.
The original material formed with Ceres has mixed with impacting material over the last 4.5 billion years, creating what Schmidt calls “this mixture of water-rich materials that we find on habitable planets like the Earth and potentially habitable planets like Mars.”
A prime site for life?
Water is considered a necessary ingredient for the evolution of life as we know it. Planets that may have once contained water, such as Mars, as well as moons that could contain it today, like Enceladus and Europa, are all thought to be ideal for hosting or having once hosted life.
Because of its size and closeness, Schmidt calls Ceres “arguably more interesting than some of these icy satellites.”
“If it’s icy, it had to have an ocean at some point in time,” she said.
Castillo-Rogez compared Earth, Europa, and Ceres, and found that the dwarf planet bore many similarities to Earth, perhaps more than Jupiter’s icy moon. Both Earth and Ceres use the Sun as a key heat source, while Europa takes its heat from its tidal interaction with Jupiter. In addition, the surface temperature of the dwarf planet averages 130 to 200 degrees Kelvin, compared to Earth’s 300 K, while Europa is a frosty 50 to 110 K.
“At least at the equator where the surface is warmer, Ceres could have preserved a liquid of sorts,” Castillo-Rogez said.
Liquid water could exist at other points on the dwarf planet known as cold traps, shadowed areas where frozen water could remain on the surface. Such icy puddles have been found on Earth’s moon. [Photos: Europa, Mysterious, Icy Moon of Jupiter]
“The chemistry, thermal activity, the heat source, and the prospect for convection within the ice shell are the key ones that make us think that Ceres could have been habitableat least at some point in its history,” Castillo-Rogez said.
The future of Ceres
As scientists develop more information about Europa and Enceladus, there has been a greater call to investigate the two prime sites for life. But Schmidt and Castillo-Rogez think that Ceres could also be a great boon for astrobiology and space exploration.
“It’s not a difficult environment to investigate,” she said. “As we think about the future of landed missions for people and rovers, why not go to Ceres?”
Though it would be more challenging to drill into than Europa, which boasts an icy surface layer, the dwarf planet would make a great site to rove around on. Schmidt also noted that it could make a great launching point when it comes to reaching the outer solar system. Its smaller mass would make it easier to land on — and leave — than Mars, which could make it a good site for manned missions.
“We have such a big planet bias, we have such a bias for things that look exactly like us,” Schmidt said.
“In this kind of special place in the solar system, we have a very unique object that might be telling us a lot about what we don’t know about building a habitable planet.”
NASA’s Dawn mission launched September 27, 2007. It traveled to the asteroid Vesta, where it remained in orbit from July 2011 to July 2012 before heading to Ceres. It is slated to spend five months studying the dwarf planet, though Schmidt expressed hope that the craft would continue working beyond the nominal mission, allowing the team to study the icy body even longer.
Castillo-Rogez pointed out that not only will Dawn reach Ceres in 2015, the European Space Agency’s Rosetta spacecraft will be escorting the comet Churyumov-Gerasimenko around the sun that year, while NASA’s New Horizons mission will be reaching Pluto and its moon Charon.
“’15 is going to be a great year for icy bodies,” Castillo-Rogez said.
“I think when we get to Ceres, it’s just going to be an absolute game changer, a new window into the solar system that we wouldn’t have without going there,” Schmidt said.
3D printing could help the asteroid-mining industry get off the ground.
Billionaire-backed asteroid-mining company Planetary Resources is teaming up with 3D Systems, whose 3D printing technology will help craft components for the Arkyd line of prospecting spacecraft, officials announced Wednesday (June 26).
The collaboration should help Planetary Resources build certain parts of its Arkyd 100, 200 and 300 probes more cheaply and efficiently, officials said. [Planetary Resources' Asteroid Mining Plan (Photos)]
“We are excited to work very closely with Planetary Resources’ engineering team to use advanced 3D printing and manufacturing technologies to increase functionality while decreasing the cost of their Arkyd spacecraft,” 3D Systems CEO Avi Reichental said in a statement.
“In success, we will create the smartphone of spacecraft and transform what has been an old-style, labor-intensive process into something very scalable and affordable that will democratize access to space, the data collected from space and off-Earth resources for scientists and the public,” Reichental added.
Planetary Resources co-founder Peter Diamandis said that the use of 3D printing in the production of the Arkyd spacecraft series could help the company achieve its lofty goals.
“We are absolutely thrilled to partner with 3D Systems, the world’s pioneer and leader in 3D printing and advanced manufacturing, as we pursue our vision to expand the resource base beyond Earth,” Diamandis said in a statement. “3D Systems has a long history of inventing, advancing and democratizing manufacturing – and our vision of mass producing the Arkyd 100, 200 and 300 line will greatly benefit from their thinking and technology.”
Planetary Resources officials hope to launch a series of robotic spacecraft into Earth orbit and, eventually, to near-Earth asteroids in order to mine them for resources such as precious metals and water.
The company, which counts Google execs Larry Page and Eric Schmidt among its investors, hopes its efforts help open up the solar system to further human exploration.
The Arkyd 200 and 300 spacecraft will be able to both search for asteroids and fly toward promising targets for closer inspections. Once an asteroid is spotted, Planetary Resources plans to send a group of about five Arkyds out to the space rock, Diamandis said during a recent Google+ Hangout.
The Arkyd 100, on the other hand, will scout for space rocks from Earth orbit.
The first Arkyd 100 is expected to launch in 2015. Planetary Resources has pledged to make one of these satellites the first publicly accessible space telescope ever sent into orbit. The telescope will search for asteroids and take “space-selfies” crafted from user-submitted photos.
Nearly 15,000 people have contributed more than $1.2 million to help build Planetary Resources’ Arkyd 100 through the crowdfunding website Kickstarter. Planetary Resources’ Arkyd 100 Kickstarter campaign ends on June 30 at 10 p.m. EDT (0200 July 1 GMT). To mark the end if the Kickstarter campaign, Planetary Resources will hold a three-hour webcast Sunday beginning at 6 p.m. EDT (3 p.m. PDT/2200 GMT) to present its asteroid-mining efforts to the public.
If the campaign reaches $1.7 million, Planetary Resources has pledged to create an “Asteroid Zoo” project in cooperation with Zooniverse, a citizen-science website that helps connect the public with projects in different fields. According to the company, the Asteroid Zoo is envisioned to be “a program to allow students, citizen scientists and space enthusiasts to find potentially hazardous asteroids (PHAs) at home and help train computers to better find them in the future.”
“Planetary Resources values the power of the connected mind; when working together, we can accomplish much more than any of us can do alone,” Chris Lewicki, President and Chief Engineer for Planetary Resources, said in a statement. “We’re creating this program to harness the public’s interest in space and asteroid detection, while providing a very real benefit to our planet.”
That conclusion, published in the June 20 issue of the Journal of Physical Chemistry A, was based on a computer model of such an impact’s effect on a comet crystal initially made up of water, carbon dioxide and other simple molecules.
“Comets carry very simple molecules in them,” said study co-author Nir Goldman, a physical chemist at Lawrence Livermore Laboratory in California. “When a comet hits a planetary surface, for example, that impact can drive the synthesis of more complicated things that are prebiotic — they’re life-building.”
The notion that life-building molecules were carried to Earth via comets or asteroids, a hypothesis known as panspermia, has been around for decades. But the idea that the comet impact itself could have created the molecules is newer.
When the Earth was young, comet bombardments may have brought 22 trillion pounds (10 trillion kilograms) of carbon-based material to the planet every year, Goldman said. That would have provided a rich source for the building blocks of life to form. In a separate recent study, scientists zapped a mini-comet in the lab to prove that precursor molecules could form far from Earth. [7 Theories on the Origin of Life]
To test their hypothesis, Goldman and his colleagues used a computer model to simulate a single comet crystal of hundreds of molecules. Comets are mostly “dirty snowballs,” Goldman said, so the simulated crystal started with mostly water molecules, but also included methanol, ammonia, carbon dioxide and carbon monoxide.
The researchers then simulated the effects of the crystal hitting the Earth’s surface at various angles, from crashing into it directly to making a glancing blow. They followed the chemical changes in the crystal for about 250 picoseconds, about the amount of time the system needed to reach a steady state, where the proportion and type of chemicals in the system is stable. The huge jolt from the impact provided the energy needed to make complicated chemicals.
“Certain conditions were a sweet spot for complexity,” Goldman told LiveScience.
For instance, at pressures of about 360,000 times the atmospheric pressure at sea level and temperatures of 4,600 degrees Fahrenheit (2,538 degrees Celsius), the molecules in the crystals formed complex species called aromatic rings. These types of circular, carbon-based molecules could have been precursors to the letters in DNA.
At higher pressures, the molecules produced methane, formaldehyde and some long-chain carbon molecules.
“Every time there was an impact hard enough to get chemical reactivity, it produced interesting stuff,” Goldman said.
As a follow-up, Goldman and his colleagues want to test different initial chemical concentrations in the comet to see how that affects the formation process.
No way to prove
The findings are fascinating, said Ralf Kaiser, a physical chemist who studies astrochemistry at the University of Hawaii at Manoa.
“It opens another pathway to explain how these biological, or precursor molecules can be formed,” Kaiser, who was not involved in the study, told LiveScience.
The team has shown that such precursor molecules “absolutely could be formed this way, no question,” Kaiser said.
But it’s not all or nothing: Some molecules could have been carried here by comets from outer space, while some formed on impact, and still others formed completely from home-grown materials. The tricky question is to determine what percentage of life’s building blocks arose during each process, Kaiser said.
It is time for the private sector to aid in the search for potentially city-destroying asteroids and meteors, lawmakers said during a hearing Wednesday (April 10).
The House Committee on Science, Space and Technology made the call while hearing from NASA scientists and private-sector asteroid hunters during a hearing entitled “Threats from Space,” with both groups agreeing that something more needs to be done.
“Detecting asteroids should not be the primary mission of NASA,” Rep. Lamar Smith (R-Texas), chairman of the House Committee on Science, Space and Technology, said at the hearing. “No doubt the private sector will play an important role as well. We must better recognize what the private sector can do to aid our efforts to protect the world.” [Meteor Streaks over Russia, Explodes (Photos)]
The meeting Wednesday was the second of three aimed at understanding the threat to Earth posed by asteroids in space. The first hearing took place in late March, and addressed the ways governmental entities, like NASA and the Air Force, are mitigating the risks posed by close-flying space rocks. The meetings were scheduled in response to a surprise meteor explosion over Russia and the close flyby of asteroid 2012 DA14 — both of which occurred on Feb. 15.
Astronomers have mapped the orbits of more than 90 percent of the potentially world-ending asteroids in close proximity to the Earth; however, tracking anything smaller than 0.6 miles (1 kilometer) in diameter is more difficult, said Ed Lu, the CEO of the B612 Foundation, a nonprofit organization in the early stages of building a near-Earth-object-hunting space telescope scheduled for launch in 2018.
“NASA has not even come close to finding and tracking the 1 million smaller asteroids that might only just wipe out a city, or perhaps collapse the world economy if they hit in the wrong place,” Lu said at the hearing.
B612′s space telescope, dubbed Sentinel, will be built to aid in the search for smaller asteroids near Earth. Less than 10 percent of asteroids measuring around 459 feet (140 meters) in diameter have been found, while only 1 percent of all asteroids measuring around 131 feet (40 meters) — or “city killer” range — have been tracked, Lu said.
These city-destroying asteroids are notoriously difficult to track with the ground-based methods used by NASA today because the space rocks are relatively small and dark, said Don Yeomans, the head of NASA’s Near-Earth Object Program.
“A dramatic increase in near-Earth asteroid-discovery efficiencies is achievable using space-based infrared telescopes,” Yeomans said at the hearing.
Searching for space rocks in infrared light — as the $240 million Sentinel is expected to do — could allow astronomers to find a larger number of smaller objects that are too dark to be seen in visible light, Yeomans said.
A space-based asteroid hunter is also helpful because it can seek out space rocks at all hours of the day, as opposed to just at night, Yeomans added.
All of these hunting efforts should be put in place to find near-Earth objects well before they could hit the Earth, the panelists said.
At the moment, we have the technology to deflect an asteroid, but scientists won’t be able to use those methods without ample time to implement them, Michael A’Hearn, an astronomer working with the National Research Council, said at the hearing.
But first, the asteroids have to be found, Lu said.
“You can’t deflect an asteroid that you haven’t yet tracked,” Lu said. “Our technology is useless against something we haven’t yet found.”
NASA’s bold plan to drag an asteroid into orbit around the moon may sound like science fiction, but it’s achievable with current technology, experts say.
President Barack Obama’s 2014 federal budget request, which will be unveiled today (April 10), likely includes about $100 million for NASA to jump-start an asteroid-capture mission, U.S. Senator Bill Nelson (D-FL) said last week.
The plan aims to place a roughly 23-foot-wide (7 meters) space rock into a stable lunar orbit, where astronauts could begin visiting it as soon as 2021 using NASA’s Space Launch System rocket and Orion capsule, Nelson said.
While challenging, the mission is definitely doable, said Chris Lewicki, president and chief engineer of billionaire-backed asteroid-mining firm Planetary Resources. [NASA's Asteroid-Capture Plan (Video)]
“Return of a near-Earth asteroid of this size would require today’s largest launch vehicles and today’s most efficient propulsion systems in order to achieve the mission,” Lewicki, who served as flight director for NASA’s Spirit and Opportunity Mars rovers and surface mission manager for the agency’s Phoenix Mars lander, wrote in a blog post Sunday (April 7).
“Even so, capturing and transporting a small asteroid should be a fairly straightforward affair,” Lewicki added. “Mission cost and complexity are likely on par with missions like the [$2.5 billion] Curiosity Mars rover.”
Spurring solar system exploration
NASA’s idea is similar to one proposed last year by scientists based at Caltech’s Keck Institute for Space Studies in Pasadena.
The Keck study estimated that a robotic spacecraft could drag a 23-foot near-Earth asteroid (NEA) — which would likely weigh about 500 tons — into a high lunar orbit for $2.6 billion. The returns on this initial investment are potentially huge, the researchers said.
“Experience gained via human expeditions to the small returned NEA would transfer directly to follow-on international expeditions beyond the Earth-moon system: to other near-Earth asteroids, [the Mars moons] Phobos and Deimos, Mars and potentially someday to the main asteroid belt,” the Keck team wrote in a feasibility study of their plan.
The mission would also help develop asteroid-mining technology, advocates say, and advance scientists’ understanding of how our solar system took shape more than 4.5 billion years ago.
Asteroids “probably represent samples of the earliest matter that was made available to form our solar system and our Earth,” Caltech’s Paul Dimotakis, a member of the Keck study team, told SPACE.com in February.
“We learned a lot about the moon by analyzing the moon rocks that Apollo astronauts brought back,” he added. [NASA's 17 Apollo Moon Missions in Pictures]
Asteroids are fascinating for lots of reasons. They contain a variety of valuable resources and slam into our planet on a regular basis, occasionally snuffing out most of Earth’s lifeforms. How much do you know about space rocks?
Unmanned probes have successfully rendezvoused with asteroids in deep space multiple times. Japan’s Hayabusa craft even snagged pieces of the near-Earth asteroid Itokawa in 2005, sending them back to our planet for study.
But bagging an entire asteroid and dragging it to our neck of the cosmic woods is unprecedented, and it presents several daunting challenges.
For example, the target asteroid will be spinning, which doesn’t make for a smooth ride to lunar orbit. After the spacecraft captures the asteroid and brings it into a hold of sorts, the space rock will have to be de-spun, likely with thrusters, Dimotakis said.
“You might use reaction jets to take out most of it [the spin],” he said. “You would give you yourself a lot of time to do this, because there’s no second chance in any of this.”
Further, bringing the asteroid onboard greatly increases the spacecraft’s mass, making propulsion and navigation much more difficult. And precise navigation will definitely be required to deliver the space rock to its desired orbit, Dimotakis said (though he also stressed that any asteroid chosen would pose no danger to humanity even if it somehow struck our planet).
But ion thrusters like the ones powering NASA’s Dawn mission to the huge asteroid Vesta and dwarf planet Ceres should be muscular enough to make the journey, likely taking a few years to reach the asteroid and somewhat longer to come back. And the asteroid-laden probe could probably still be guided with great care, he added.
“My guess is that all of these are not insurmountable challenges, and you would be able to calibrate yourself after you snagged it and adjust your controls,” Dimotakis said.
Choosing a target
Perhaps the biggest challenge of the entire mission is picking a suitable space rock to retrieve, Lewicki wrote in his blog post.
The Keck study recommends going after a carbonaceous asteroid packed full of water and other volatiles. Carbonaceous asteroids can be very dark, and it’s tough to spot and characterize a 23-foot asteroid in the vast depths of space whatever its color.
So both Lewicki and Dimotakis stressed the importance of searching for potential asteroid targets sooner rather than later. Planetary Resources plans to begin launching a line of small prospecting space telescopes in 2014 or 2015, and these “Arkyd-100″ craft could aid NASA’s mission, Lewicki wrote.
Dimotakis, for his part, is engaged in a follow-up to the Keck study that’s looking for potential targets in observations made by current telescopes.
“We are developing software in collaboration with JPL [NASA's Jet Propulsion Laboratory] that is going to exploit the observational digital record and essentially flag things that could be of interest and might be in this class,” he said. “This has never happened before.”
Still, mission scientists and engineers shouldn’t just sit on their hands until an asteroid selection is made, he added.
It’s important “to start developing the spacecraft before you even know where you’re going,” Dimotakis said. “If you do these things in parallel, then the mission timeline shrinks.”
Mars is farther away than any near-Earth asteroid that NASA would target, but this disadvantage may be outweighed by the greater knowledge scientists have gained of the Red Planet thanks to the many Mars missions that have launched over the years, experts say.
Further, mapping out an asteroid mission is nearly impossible at this point, since NASA does not yet know where it’s going.
“There are still no good asteroid targets for such a mission, a necessary prerequisite for determining mission length and details such as the astronauts’ exposure to radiation and the consumables required,” states a December 2012 report from the U.S. National Research Council (NRC). [How NASA Will Explore Asteroids (Gallery)]
The road to Mars
Landing astronauts on Mars has been the long-term goal of NASA’s human spaceflight program for decades, but the agency’s vision of how to get there was shaken up recently.
NASA had viewed the moon as a stepping stone, working to get humans to Earth’s natural satellite by 2020 under a program called Constellation, which was initiated during the presidency of George W. Bush. But President Barack Obama cancelled Constellation in 2010, after an independent review panel found it to be significantly under-funded and behind schedule.
instead directed NASA to send astronauts to a near-Earth asteroid by 2025, then on to the vicinity of Mars by the mid-2030s. The agency is developing a new crewed capsule called Orion and a huge rocket called the Space Launch System to make it all happen.
The new “asteroid-next” plan has not been enthusiastically embraced by NASA or the broader space community, the NRC report concluded.
“Despite isolated pockets of support for a human asteroid mission, the committee did not detect broad support for an asteroid mission inside NASA, in the nation as a whole or from the international community,” write the authors of the report, which is called “NASA’s Strategic Direction and the Need for a National Consensus.”
A tough proposition
The NRC report was based on research, interviews, site visits and analysis conducted by a 12-member independent committee over the course of about five months in 2012.
One of the people the study team met with was Bill Gerstenmaier, NASA’s associate administrator for human exploration and operations.
Gerstenmaier “talked about how NASA had discovered, in the two years that had elapsed by the time he was speaking to us, just how hard [a manned asteroid mission] was,” committee member and space policy expert Marcia Smith said during a presentation with NASA’s Future In-Space Operations working group on Jan. 30.
“He said in many respects, it’s easier to go to Mars, because we know a lot about Mars,” Smith added. “We know where it is, and we’ve done all these reconnaissance missions already, so we have a knowledge base from which to work in terms of sending humans, whereas no particular asteroid has been selected yet.”
While sending astronauts to an asteroid has never been done before, unmanned probes have successfully rendezvoused with the objects in deep space multiple times.
For example, NASA’s Dawn spacecraft orbited the protoplanet Vesta — the second-largest body in the main asteroid belt between Mars and Jupiter — for more than a year before departing to head to the belt’s largest denizen, Ceres, last September. And in 2005, Japan’s Hayabusa probe plucked some pieces off the near-Earth asteroid Itokawa, sending them back to Earth for analysis.
NASA plans to launch its own asteroid-sampling mission, called Osiris-Rex, in 2016. And two private companies — Planetary Resources and Deep Space Industries — intend to loft reconnaissance spacecraft over the next few years, kicking off an ambitious efforts to mine water, metals and other resources from asteroids.
The more stars a system of alien worlds starts with, the more likely those planets will orbit those stars at odd tilts, scientists say.
The discovery, based on a study unveiled today (Nov. 14), suggests that even Earth’s own sun may have had a companion star early in its development.
In recent years, astronomers have detected hundreds of exoplanets — worlds circling distant stars. Many of these are “hot Jupiters” — gas giants like Jupiter or Saturn that are closer to their stars than Mercury is to the sun.
Researchers had thought hot Jupiters arose when giant planets were dragged inward by protoplanetary disks of gas and dust falling toward stars. However, this idea was recently cast into doubt by the surprising discovery that a major fraction of hot Jupiters have orbits that are tilted in respect to their stars’ rotation.
Stars all spin, just as Earth’s does, and their worlds often line up with this spin — they orbit around the equators of their stars and revolve in the same direction. However, sometimes alien planets have misaligned orbits instead, ones that are at slight or even sharp angles around their stars. The orbits of some exoplanets are so far tilted that they are actually backwards — they move in retrogradeorbits in exactly the opposite direction of their stars’ spin.
Scientists had thought if hot Jupiters were dragged toward their stars by protoplanetary disks, they would all end up in relatively normal orbits around the equators of their stars. However, astronomers recently discovered that a whopping 25 to 50 percent of these planets actually may have misaligned orbits.
“The misalignments seemed to point towards a much more volatile, violent evolutionary path for hot Jupiters,” said study author Konstantin Batygin, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics.
For instance, perhaps it was a gravitational tug of war between exoplanets that hurled some inward at their stars. Still, it seemed unlikely such processes were responsible for all these misaligned planets.
“A crude and oversimplified analogy is taking a machine gun, shooting in every direction possible, and hitting the correct target about 1 percent of the time,” Batygin said. “Surely not impossible, but it seems unlikely.”
Now Batygin has discovered protoplanetary disks can indeed produce such tilted orbits if these systems each harbored multiple stars. [Photos: Alien Planet With Twin Suns Found]
Although the solar system has only one sun, most stars like Earth’s sun are binaries— two stars orbiting each other as a pair. Increasingly, astronomers are discovering planetary systems with twin suns (like Luke Skywalker’s fictional home planet Tatooine in “Star Wars”). There are also many three-star triples in the universe, at least one of which is known to host planets, and the number of stars a system has can even climb as high as seven.
Through computer modeling, Batygin found that the complex system of gravitational pulls that binary stars exert on protoplanetary disks would disrupt them enough to misalign the disks. He added that the more stars a system has, the more likely its planets orbits would be tilted.
This idea does not require that a system have multiple stars for billions of years, Batygin added.
“It is generally believed that 85 to 100 percent of stars form as multiples,” he said. Many times, stars then get stripped from these systems during the first 1 million to 10 million years of their lifetimes.
Batygin noted the orbital plane of the solar system’s planets is misaligned from the sun’s equatorial plane by 7 degrees. Given this skew, “I think it is safe to say that the solar system falls into the misaligned category.” In other words, the sun once may have had a companion star very early in its history.
Future research can analyze other details about the interactions between planets, their stars and protoplanetary disks. “For instance, the magnetic coupling between the disk and the host star should be looked at more carefully,” Batygin said.
Batygindetails his findings in the Nov. 15 issue of the journal Nature.
Amateur astronomers have helped discover an alien planet with two suns and a twinkling twist: The entire twin-sun setup, a real-life version of Tatooine from “Star Wars,” is orbited by two more stars — a solar system that is the first of its kind known.
The alien planet, called PH1, is a gas giant planet slightly bigger than Neptune. Its discovery in the midst of a strange, four-star planetary system is the first confirmed world discovered as part of the Yale University-led Planet Hunters project, in which armchair astronomers work with professional scientists to find evidence of new worlds in the bountiful data collected by NASA’s Kepler space telescope.
“Planet Hunters is a symbiotic project, pairing the discovery power of the people with follow-up by a team of astronomers,” said Debra Fischer, a professor of astronomy at Yale and planet expert who helped launch Planet Hunters in 2010, in a statement. “This unique system might have been entirely missed if not for the sharp eyes of the public.”
Since its March 2009 launch, Kepler has found evidence of more than 2,300 candidate alien worlds. [Gallery: More Alien Planets with Twin Suns]
Finding a strange, new world
Since its initial discovery via Planet Hunters, the existence of PH1 has been confirmed by a team of professional astronomers, who will present their work today (Oct. 15) at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society in Reno, Nev.
With a radius about 6.2 times that of Earth’s, PH1 is a smidge bigger than Neptune. The gassy planet spends 138 days completing a single orbit around its two parent stars, which have masses about 1.5 and 0.41 times that of the sun. The stars circle each other once every 20 days.
The two other stars orbiting the PH1′s twin suns are about 1,000 astronomical units (AU) from the parent stars. (One AU is about the distance between the Earth and sun, about 93 million miles or 150 million kilometers.)
If you’re hoping to catch the quadruple sunset, this may not be your best bet. The researchers estimate PH1′s temperature would range from a minimum of about 484 degrees Fahrenheit (524 Kelvin, or 251 degrees Celsius) and a maximum of 644 degrees F (613 Kelvin, or 340 degrees C), too hot to be in the habitable zone.
“Although PH1 is a gas giant planet, even if there is a possibility of rocky moons orbiting the body, their surfaces would be too hot for liquid water to exist,” researcher Meg Schwamb of Yale University and colleagues write in a draft of their research article.
Alien Planet Quiz: Are You an Exoplanet Expert?
Astronomers have confirmed more than 700 planets beyond our own solar system, and the discoveries keep rolling in. How much do you know about these exotic worlds?
A planet with two suns
Until now, scientists had identified just six planets orbiting two parent stars, called circumbinary planets, and none of these have stellar companions orbiting them. Until their discovery, circumbinary planets were once the realm of science fiction with Tatooine, the fictional homeworld of Luke Skywalker in “Star Wars,” among the most famous.
“Circumbinary planets are the extremes of planet formation,” Schwamb said in a statement. “The discovery of these systems is forcing us to go back to the drawing board to understand how such planets can assemble and evolve in these dynamically challenging environments.”
The Planet Hunter volunteers, Kian Jek of San Francisco, Calif., and Robert Gagliano of Cottonwood, Ariz., spotted PH1 using the transit method, noticing faint dips in light as the plant passed in front of, or transited, its parent stars.
Gagliano said he was “absolutely ecstatic” about the finding. “It’s a great honor to be a Planet Hunter, citizen scientist, and work hand in hand with professional astronomers, making a real contribution to science,” he said.
Jek, too, expressed his amazement.
“It still continues to astonish me how we can detect, let alone glean so much information, about another planet thousands of light-years away just by studying the light from its parent star,” he said in a statement.
Schwamb led the team of professional astronomers who confirmed the discovery and characterized the planet, following observations from the Keck telescopes on Mauna Kea, Hawaii.
The research was supported by NASA and the National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship.
The discovery of the first alien planet with two suns — like the “Star Wars” world Tatooine — residing in its parent star’s habitable zone is good news for the search for life beyond Earth, scientists say.
The planet, known as Kepler-47c, is a gas giant and therefore probably not suitable for life as we know it. But its existence hints that smaller, rockier worlds may inhabit other two-star systems’ habitable zones —that just-right range of distances where liquid water can exist.
And that’s important, because there are a lot of binary systems out there, scientists say.
“Roughly half of the stars in the galaxy are in binary systems,” study lead author Jerome Orosz, of San Diego State University, told SPACE.com. “I thought it would only be a matter of time before we found a system like Kepler-47 where a planet is in the habitable zone.” [Gallery: The Tatooine-Like Kepler-47 System]
The Kepler-47 system, whose discovery was announced Tuesday (Aug. 28), dwells about 5,000 light-years away, in the constellation Cygnus (The Swan). It is a close binary system, with two stars orbiting near each other at its center. Around these stars whirl two planets known as Kepler-47b and Kepler-47c.
They make Kepler-47 the first system seen with multiple worlds circling a pair of stars.
“If single stars and close binary stars can host planetary systems with an equal probability — that is not at all clear at the moment — then it would follow that life could be just as common on circumbinary planets as on planets with single stars,” Orosz said.
Kepler-47c, which appears to be slightly larger than Uranus, is the outer world. It takes the planet 303 days to complete an orbit, placing it squarely in the system’s habitable zone. (Kepler-47b is a bit smaller than its planetary sibling but much closer-in, making it likely too hot to host life.)
Kepler-47c itself is likely not a good bet to support life. But any large moons of the planet — if they exist — would be very intriguing to astrobiologists, said study co-author William Welsh at San Diego State University.
Scientists have already found several exoplanets that are Earth-size or smaller, and they hope to discover many more. NASA’s prolific Kepler space telescope, which discovered Kepler-47b and c, is a key tool in this search.
Indeed, Kepler’s main mission is to determine just how commonly Earth-size planets occur in their stars’ habitable zones throughout the galaxy. The telescope detects alien planets by flagging the telltale brightness dips caused when they cross in front of, or transit, their stars’ faces from the instrument’s perspective..
“I expect that the transits of an Earth-sized planet will be very hard to spot by eye, so we will need to refine our automated search programs to work for binary systems,” Orosz said. “As Kepler gets more and more data, the chances go up that we can identify the smaller transits due to terrestrial planets.”
The scientists published their findings online Aug. 28 in the journal Science. They also detailed their results Aug. 29 at the General Assembly of the International Astronomical Union in Beijing.
Fleeing from the scene of a violent supernova explosion, a compact runaway star may be the fastest traveling pulsar yet discovered, scientists say. The small but powerful star is rushing away from the source of the blast almost 25 times faster than most similar objects move.
When the dust clears from a supernova, the outer layers of the dying star blow into space, leaving behind a neutron star, which is a city-sized object with a mass comparable to the sun.
“In a lot of cases, when the neutron star is not moving fast, you’ll find it right in the middle of the supernova remnant,” John Tomsick of the University of California, Berkeley, told SPACE.com.
Not so for IGR J11014-6103, a special type of rotating neutron star known as a pulsar. The explosion that created this object came with a kick that sent it flying away from its birth location at blistering speeds of between 5.4 and 6.5 million miles per hour.
According to Tomsick, most neutron stars travel anywhere between 225,000 to a mph (100 to 600 kilometers per second), with only a few exceeding 2.2 million mph (1,000 km/s). [Supernova Photos: Great Images of Star Explosions
An uneven explosion
In order for a neutron star to travel after a supernova, there must be some kind of push created by the stellar death, the researchers said. In a symmetrical explosion, the forces pressing on the new neutron star cancel each other out, and the star remains in the center, where the initial explosion occurred.
But if there is any type of asymmetry in the explosion, the stronger force imparts a kick to the compact star, sending it flying through space.
Scientists are still uncertain what causes these asymmetric explosions. Tomsick explained that there could be a correlation between the magnetic field of the neutron star and its strong kick, but nothing conclusive has been demonstrated yet.
Tomsick hopes that a closer look at the atypical IGR J10014-6103 pulsar could shed some light on the mystery.
“If we found that this neutron star had a high magnetic field, it would provide some evidence that it’s related to the velocity,” he said.
Lying in a bed of dust and gas about 30,000 light-years away from Earth, the energetic source first turned up in a survey of hard X-ray objects by the European Space Agency’s Integral satellite. Tomsick and his team have performed follow-up studies of several of Integrals’ new objects.
Initially, nothing about IGR J10014-6103 stood out. But, after examining the object using NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton satellite, as well as the Parkes radio telescope in Australia, they realized a tail 3 light-years long trailed behind the source.
“When (the neutron star) plows through, it accelerates the particles that are in the interstellar medium,” Tomsick said.
This creates a bow shock effect, much like a boat breaking through water. A slow-moving star forms a wider shock, while a fast-moving star produces a narrow one, such as the one formed by IGR J10014-6103.
A curious pulsar
Knowing that the supernova is 15,000 years old, and logging the distance the neutron star had traveled in that time, Tomsick and his team were able to calculate its speed.
Pulsars are a special type of neutron star that rotates rapidly, emitting a beam of high-energy that spins much like the bulb in a lighthouse. But astronomers have not yet been able to actually detect this signature beam from IGR J10014-6103.
According to Tomsick, the radio emission from the gas and dust surrounding the star make those pulses more difficult to read. In fact, the only way the pulses could have been seen with the current observations would be if the flashing neutron star was excessively bright.
“It could be a typical pulsar, and we still wouldn’t be able to detect it,” Tomsick said.
But the scientists are confident the object is a pulsar, rather than a regular neutron star, because of its high-energy emission and the fact that it doesn’t show up in optical wavelengths. They intend to do more in-depth observations of the object in the near future, searching for details about its pulsation and its magnetic field.
“If we do a study in X-rays and still don’t see pulsation, then we’ll be pretty surprised.”
Detailed results of the study were published in the May edition of the Astrophysical Journal Letters.