There’s a chance that NASA’s Kepler space telescope can recover from the malfunction that has halted its wildly successful search for alien planets, mission team members say.
The second of Kepler’s four reaction wheels — devices that allow the observatory to maintain its position in space — has failed, depriving Kepler of the ability to lock precisely onto its 150,000-plus target stars, NASA oficials announced Wednesday (May 15).
But mission engineers are not conceding that Kepler’s planet-hunting days have come to an end, vowing to try their best to recover the failed reaction wheels over the coming weeks. [Gallery: A World of Kepler Planets]
“I wouldn’t call Kepler down and out just yet,” NASA science chief John Grunsfeld told reporters Wednesday.
Balky reaction wheels
The Kepler spacecraft spots exoplanets by detecting the tiny brightness dips caused when they pass in front of their parent stars from the instrument’s perspective.
The observatory needs three working reaction wheels to do such precision work. When Kepler launched in March 2009, it had four — three for immediate use and one spare.
One of the wheels, known as number two, failed in July 2012, giving Kepler no margin for error. And the loss this week of another one (called number four) puts an end to the spacecraft’s exoplanet hunt, unless a fix can be found.
Engineers have begun considering strategies for bringing the wheels back into service. They’ll likely try a light touch at times and a brute-force approach at others, officials said.
“Like with any stuck wheel that you might be familiar with on the ground, we can try jiggling it,” said Kepler deputy project manager Charlie Sobeck, of NASA’s Ames Research Center in Moffett Field, Calif. “We can try commanding it back and forth in both directions. We can try forcing it through whatever the resistance is that’s holding it up.”
It’s also possible that wheel number two will spring back to life if turned on again now, rested and restored after its long break, Sobeck and others say.
“It was putting metal on metal, and the friction was interfering with its operation, so you could see if the lubricant that is in there, having sat quietly, has redistributed itself, and maybe it will work,” Scott Hubbard of Stanford University said in a statement. (Hubbard served as director of NASA Ames during much of Kepler’s development and helped guide the mission.)
It will take a few weeks to put together a recovery plan, Sobeck said. It’s unknown if any potential fixes will do the trick, but Kepler team members are keeping their fingers crossed.
“There is a reasonable possibility that we will be able to mitigate that problem,” said mission principal investigator Bill Borucki, also of NASA Ames. “So I don’t think I’d be a pessimist here.”
There’s no chance of sending astronauts out to service Kepler, as was done five times with NASA’s Hubble Space Telescope over the years. Kepler orbits the sun rather than the Earth, and it’s currently about 40 million miles (64 million kilometers) from our planet.
Kepler has already outlasted its prime mission life of 3.5 years. And even if both reaction wheels are beyond help, Kepler’s science work may not come to an end.
It’s possible Kepler could still gather valuable data by switching to a scanning mode, as opposed to the “point and stare” operations that defined its first four years in space. If neither failed reaction wheel is recovered, NASA will carry out studies addressing possible new missions for Kepler.
It’s too soon to speculate what such missions might look like, officials said.
“We need to know more about the performance of the spacecraft before we can assess what kind of science we’ll be able to do with that performance,” Sobeck said.
More discoveries to come
Kepler has spotted more than 2,700 potential exoplanets to date. Just 132 of them have been confirmed by follow-up observations so far, but mission scientists expect that more than 90 percent will end up being the real deal.
And the flood of Kepler finds won’t slow for a while even if the instrument can no longer lock onto its target stars. The mission team has only had time to go through about half of Kepler’s enormous dataset, which team members say is certain to contain many more gems — including, possibly, the first-ever “alien Earth.”
“We have excellent data for an additional two years,” Borucki said. “So I think the most interesting, exciting discoveries are coming in the next two years. The mission is not over.”
The planet-hunting days of NASA’s prolific Kepler space telescope, which has discovered more than 2,700 potential alien worlds to date, may be over.
The second of Kepler’s four reaction wheels — devices that allow the observatory to maintain its position in space — has failed, NASA officials announced Wednesday (May 15).
If one or both of those failed wheels cannot be brought back, the telescope likely cannot lock onto target stars precisely enough to detect orbiting planets, scientists have said. [Gallery: A World of Kepler Planets]
Staring at stars
The $600 million Kepler spacecraft spots exoplanets by flagging the tiny brightness dips caused when they pass in front of their host stars from the instrument’s perspective. The mission’s main goal is to determine how common Earth-like alien planets are throughout the Milky Way galaxy.
Kepler needs three functioning reaction wheels to stay locked onto its more than 150,000 target stars. The observatory had four wheels when it launched in March 2009 — three for immediate use, and one spare.
One wheel (known as number two) failed in July 2012, giving Kepler no margin for error. And now wheel number four has apparently given up the ghost as well, after showing signs of elevated friction for the past five months or so.
“This is something that we’ve been expecting for a while, unfortunately,” NASA science chief John Grunsfeld told reporters today.
Grunsfeld is a former astronaut who flew on five space shuttle missions, including three that serviced or upgraded NASA’s Hubble Space Telescope in Earth orbit. But in-space repair is not an option for Kepler, which circles the sun rather than Earth and is currently about 40 million miles (64 million kilometers) from our planet.
A new mission?
The Kepler team is not taking the wheel failures lying down. Engineers will try to recover number two and number four, perhaps by turning the wheels to power through any deterioration in their mechanisms, team members have said.
“I wouldn’t call Kepler down and out just yet,” Grunsfeld said.
If this and other measures don’t work, however, Kepler will probably get a new mission, likely one that emphasizes scanning the heavens over its previous “point and stare” operations.
The team is already thinking about what a new scanning mode might be able to accomplish. Researchers are also trying to figure out ways to conserve fuel, so Kepler can keep operating for as long as possible if it needs to start using its thrusters to help point at targets.
Whatever the future holds for Kepler, the mission will go down in history as an incredible success, researchers say.
While just 132 of Kepler’s 2,700-odd planet candidates have been confirmed by follow-up observations to date, mission scientists estimate that more than 90 percent will end up being the real deal.
Further, the telescope’s discoveries have allowed researchers to take an unprecedented, systematic look at worlds beyond our solar system — learning, for instance, that small, rocky planets are much more common throughout the Milky Way galaxy than gas giants like Saturn or Jupiter, at least in close-in orbits.
“Kepler has opened up the next set of questions in exoplanets,” said Paul Hertz, astrophysics director at NASA Headquarters in Washington, D.C.
“Before we flew Kepler, we didn’t know that Earth-sized planets in habitable zones were common throughout our galaxy,” Hertz added. “We didn’t know that virtually every star in the sky had planets around them. Now we know that.”
Kepler also outlasted its prime mission life of 3.5 years; it has been working on an extended mission that takes it through at least fiscal year 2016.
While the observatory may not spot any more exoplanets from here on out, that doesn’t mean the flood of Kepler discoveries will slow down anytime soon.
“We’ve really only sort of looked at half the dataset so far. We just haven’t had the time and the processing hours to go through it all,” Kepler deputy project manager Charlie Sobeck, of NASA’s Ames Research Center in Moffett Field, Calif., told SPACE.com late last month.
Once Kepler stops finding planets, he added, “the scientific output of the mission would continue for at least another year or two before you would see a dropoff.”
The Kepler spacecraft has detected more than 2,700 potential alien planets since its March 2009 launch, revolutionizing scientists’ understanding of worlds beyond our solar system. But the second of the telescope’s four reaction wheels — devices that maintain the observatory’s position in space — may be about to fail, putting the prolific mission’s future in doubt.
While no instrument is likely to replace Kepler or its capabilities anytime soon, reinforcements are on their way to the launchpad. The first is scheduled to blast off this October, in fact — the European Space Agency’s Gaia mission. [Gallery: A World of Kepler Planets]
Gaia is designed to create an extremely accurate 3D map of about 1 billion Milky Way stars — 1 percent of our galaxy’s total. This work could detect tens of thousands of new planetary systems, scientists say.
“Researchers hope that Gaia will tell them more about the distribution of exoplanets around the galaxy: Are there more near the center or in the spiral arms? Are planets more common in areas rich in heavy elements?” reporters Yudhijit Bhattacharjee and Daniel Clery write in a special exoplanet section in the journal Science released online today (May 2).
Europe aims to loft another exoplanet mission in 2017. ESA’s Characterizing Exoplanets Satellite, or CHEOPS, will stare at nearby stars known to host planets, watching for these worlds to cross their stars’ faces. (Kepler uses this technique, known as the transit method, to detect alien worlds.)
“High precision measurements by the satellite should help astronomers nail down planet sizes,” Bhattacharjee and Clery write. Data gathered from the ground should provide these worlds’ masses, allowing astronomers to figure out their density, the reporters add.
NASA plans to launch a planet-hunter of its own in 2017, the Transiting Exoplanet Survey Satellite. TESS will use the transit method to search for worlds orbiting nearby stars, with a focus on Earth-size planets that may be capable of supporting life.
Astronomers hope to then point NASA’s powerful James Webb Space Telescope— an $8.8 billion instrument slated for launch in late 2018 — at the most promising of these newfound worlds, scanning their atmospheres for water vapor and gases that may have been produced by living organisms, such as oxygen, nitrous oxide and methane.
Additions to the planet-hunting picture get a bit murky beyond 2017. But many researchers are hopeful that NASA will be able to build and launch a roughly $1.5 billion observatory called the Wide-Field Infrared Survey Telescope.
In 2010, the U.S. National Research Council deemed WFIRST the top priority for the next decade of astronomical research. The telescope would not only hunt for exoplanets but also probe the mysteries of dark energy and galaxy evolution, among other phenomena.
If approved and funded, WFIRST could potentially launch in a decade or so. But the proposed mission remains in a sort of limbo at the moment.
All this talk about exoplanet space missions is not to discount, of course, the many finds that have been made from the ground.
A number of research groups around the world have employed Earth-based instruments — the HARPS spectrograph, on a telescope in Chile, and the HIRES spectrograph, on Hawaii’s Keck Telescope, are two examples — to spot exoplanets. These scientists often use the radial velocity method, which picks up tiny gravitational wobbles that orbiting worlds induce in their parent stars.
But Kepler’s success has spurred some of these researchers to change tacks temporarily, according to Bhattacharjee and Clery.
“Since the Kepler space mission began detecting new candidate exoplanets by the thousands using the transit technique, radial velocity teams have changed focus from discovering new planets to confirming Kepler detections and measuring their mass,” they write.
The huge, hot mess of cosmic gas that feeds the colossal black hole at the center of our Milky Way galaxy may be getting “cooked” before being devoured, a scientists say.
Before its retirement earlier this year, the European Space Agency’s (ESA) Herschel Space Observatory found that clouds of molecular gas near the galaxy’s center are much hotter than expected, possibly due to the gigantic black hole at the Milky Way’s heart.
Called Sagittarius A* (pronounced “Sagittarius A-star”), the humongous black hole holds about 4 million times the mass of the sun and sits about 26,000 light-years from the solar system. Emissions from collisions between gas clouds sparked by the galaxy’s turbulent core could help account for the high temperatures of the gas and dust closest to the black hole, ESA scientists have found. [See amazing photos by the Herschel Observatory]
“The observations are also consistent with streamers of hot gas speeding towards Sgr A*, falling towards the very center of the galaxy,” astronomer Javier Goicoechea, of Spain’s national Astrobiology Center and lead author of the study, said in a statement. “Our galaxy’s black hole may be cooking its dinner right in front of Herschel’s eyes.”
Herschel found that some of the molecular gas collected in an area around one light-year from the black hole was about 1,832 degrees Fahrenheit (1,000 degrees Celsius) — much hotter than an average interstellar cloud, ESA officials said.
Most of these kinds of molecular clouds are usually pretty cold, with temperatures only a few tens of degrees above absolute zero, ESA officials added.
“The black hole appears to be devouring the gas,” Paul Goldsmith, the project scientist for Herschel at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. “This will teach us about how supermassive black holes grow.”
The research is detailed in the May 7 issue of Astrophysical Journal Letters.
In September, scientists may get the chance to see Sagittarius A*’s feeding in action. Astronomers have their eyes on a different blob of gas (not studied by Herschel) that is expected to fall into the galaxy’s center later this year. The cosmic cloud is about three times the mass of Earth and even closer to the galactic center than the gas studied by the ESA spacecraft.
The gas blob’s destruction will give researchers an unprecedented chance to see what Sagittarius A* looks like when gobbling up matter, scientists have said.
Last month, the $1.4 billion Herschel Space Telescope completed a planned shutdown after running out of the vital coolant needed to chill its sensitive instruments. The Herschel observatory launched in 2009 and collected a massive amount of data that is still being processed by scientists around the world.
Alien worlds resembling giant eyeballs might exist around red dwarf stars, and researchers are now proposing experiments to simulate these distant planets and see how capable they are of supporting life.
Red dwarfs are small, faint stars about one-fifth as massive as the sun and up to 50 times dimmer. They are the most common stars in the galaxy and are thought to make up to 70 percent of the stars in the universe — vast numbers that potentially make them valuable places to look for extraterrestrial life.
Indeed, the latest results from NASA’s Kepler space observatory reveal that at least half of these stars host rocky planetsthat are half to four times the mass of Earth. [Gallery: A World of Kepler Planets]
Tidally locked ‘eyeball Earths’
When looking for alien life as we know it, scientists typically focus on worlds that have water, since there is life virtually everywhere there is water on Earth. As such, they concentrate on the habitable zone of a star — the area surrounding a star where it is neither too hot nor too cold for liquid water to exist on a planet’s surface.
Since red dwarfs are relatively cool, their habitable zones are often closer than the distance at which Mercury orbits the sun. This makes it relatively easy for astronomers to spot worlds in a red dwarf’s habitable zone — the exoplanets’ orbits are small, meaning they complete them quickly and often, and researchers can in principle readily detect the way these worlds regularly dim the light of these stars.
When a planet orbits a star very closely, the gravitational pull of the star can force the world to become tidally locked with it.
“This means that they always show the same side to their star just as our moon does to the Earth, which means they have one permanent day and one permanent night side,” study lead author Daniel Angerhausen, an astronomer and astrobiologist at Rensselaer Polytechnic Institute, Troy, N.Y., told Astrobiology Magazine.
This scenario of permanent day and permanent light could lead to a striking kind of world — one resembling an eyeball. Its night side would be covered in an icy, frozen shell, while its day side would host a giant ocean of liquid water constantly basking in the warmth of its star. [9 Exoplanets That Could Host Alien Life]
These are just one example of the plethora of crazy things we are finding out there in space,” Angerhausen said. “In the field of exoplanets we find hot Jupiters, highly eccentric planets that light up like comets when they come close in to their host star, or evaporating Mercurys — all of them planets that we don’t have in our solar system and that astronomers did not even dream about 10 or 20 years ago.”
The idea of an eyeball Earth, as such a world is called, was spurred by the detection of an exoplanet called Gliese 581g about 20 light-years away, which may be the first known potentially habitable alien world (although scientists continue to debate whether the planet really exists). Planetary geophysicist Raymond Pierrehumbert of the University of Chicago suggested that if Gliese 581g is real, it could be an eyeball Earth.
“We already have telescopes that detect planets that might be eyeballs,” Angerhausen said.
Given the profound differences between the day and night sides of eyeball Earths, “they are potentially the easiest habitable terrestrial planets to detect and distinguish,” Angerhausen said. However, little is known about precisely how easy they are to detect and how habitable they really are.
“Our proposal will find out how common and stable these eyeballs are,” Angerhausen said.
Modeling eyeball Earths
To learn more about what eyeball Earths might be like, Angerhausen and his colleagues are proposing a project they hope to carry out in Brazil dubbed HABEBEE, short for “Exploring the Habitability of Eyeball-Exo-Earths.” The plan is to for the first time see what a stable eyeball Earth needs to support life.
The scientists first aim to construct a variety of eyeball Earth models that vary in mass, distance from their stars, how much radiation they receive, magnetic field strength and their ice composition and density. By providing general and extreme cases of stable and transient eyeball Earths, they can help predict how well existing and future telescope surveys can detect and characterize them.
An eyeball planet is one of several possible scenarios for planets in a red dwarf’s habitable zone.
“A little bit closer to the star — that is, hotter — they would completely thaw and become water worlds; a little bit further out in the habitable zone — that is, colder — they would become total iceballs just like [Jupiter's moon] Europa, but with a potential for life under the ice crust,” Angerhausen said. “These planets — water, eyeball or snowball — will most probably be the first habitable planets we will find and be able to characterize remotely. Thats why it is so important to study them now.”
The ocean of an eyeball Earth will likely span a range of temperatures. “It’s probably pretty hot in the center of the eye and then gradually gets colder towards the edge of the ice crust,” Angerhausen said. Still, much remains uncertain — for instance, if the ocean transports heat well, the planet might warm enough all over to turn into a water world without ice, he suggested. [Two Oceanic Earth-like Exoplanets Found? (Video)]
The researchers also plan an expedition to the Antarctic Peninsula to gather specimens of microbes at transition zones between ice and water that might be analogous to oceans on eyeball Earths. The aim is to see what metabolism of life on the alien worlds might be like.
The researchers finally aim to see how well life can survive on eyeball Earths using an existing planetary simulation chamber originally designed to imitate Mars at the Brazilian Astrobiology Laboratory. Antarctic microbe samples can be tested in atmospheric, radiation and other conditions that simulate a number of possible eyeball Earth scenarios. The researchers can test the survival and genetic activity of the microbes to see how well they behave.
“I like the idea of having a few cubic meters of space that mimic another world in a chamber,” Angerhausen said. “It’s like having a probe from a world light years away in a jar.”
Over the course of their lifetimes, red dwarfs can go from barely to highly active when it comes to dangerous bursts and flares, causing ultraviolet radiation to jump by 100 to 10,000 times normal levels and potentially sterilizing the surface of a nearby planet or even helping to strip off its atmosphere.
To see what harm such radiation might wreak on the habitability of eyeball Earths, the researchers plan to monitor the radiation levels of known red dwarfs over time and investigate previously gathered red dwarf radiation data, knowledge that can help them simulate red dwarfs better.
They also plan on understanding the effects of streams of energetic particles from red dwarfs on the surfaces and atmospheres of eyeball Earths by using the Brazilian National Synchrotron Light Source at Campinas to blast ice with radiation.
“It is not obvious that these planets could be stable for long periods, which we believe is necessary for the origin, maintenance and evolution of life,” said astrobiologist Douglas Galante at the Brazilian Synchrotron Light Source, who organized the Sao Paulo Advanced School of Astrobiology where Angerhausen and his colleagues initiated the HABEBEE proposal.
“Many more studies have to be done, theoretical, experimental and observational, so that we better understand the habitability of these planets,” Galante added.
Upcoming and current telescopes such as NASA’s James Webb Space Telescope might be able to see if planets have eyeball structures. When telescopes improve further, astronomers could look for molecular signs of life on eyeball Earths, researchers said.
“To finally detect life or what we call ‘biomarkers,’ we probably have to wait for next-generation telescopes, such as the 30-meter-class ground-based telescopes that are currently getting built and future space-based platforms such as the Terrestrial Planet Finder,” Angerhausen said. “However, history shows that astronomers are quite creative using current available instruments and telescopes, so maybe one of my colleagues may come up with a new exciting observation strategy that will make it even possible earlier.”
That moniker won an online people’s choice contest organized by space-funding company Uwingu to choose a more exciting, approachable name for the Earth-size alien planet Alpha Centauri Bb, a scorching-hot world that lies just 4.3 light-years away.
Jay Lark, who nominated “Albertus Alauda,” said he chose the exoplanet name to honor his late grandfather.
“It is his name in Latin (Albert Lark),” Jay Lark wrote in his submission to the contest. “My grandfather passed away after a lengthy and valiant battle with cancer; his name in Latin means noble or bright and to praise or extol. I think this is an apt description as my grandfather was a noble man and bright of character, and in this nomination I wish to honour (extol) him.” [Earth-Size Planet In Nearest Star System (Video)]
The Alpha Centauri Bb naming contest ran from March 19 through April 22. Proposing a name cost $4.99, while voting for one cost $0.99. Uwingu (whose name means “sky” in Swahili) will use the proceeds to fund grants in space exploration, education and research, which is the company’s chief purpose, officials said.
“Albertus Alauda” came out on top with 751 votes, scoring Jay Lark a commemorative plaque, a 12-month subscription to Astronomy Magazine, a shout-out on the Uwingu website and a phone call from Uwingu CEO (and former NASA science chief) Alan Stern and famed planet-hunter Geoff Marcy, an adviser for the company.
“Rakhat” and “Caleo” came in second and third place, garnering 684 and 622 votes, respectively.
Astronomers have confirmed more than 800 planets beyond our own solar system, and the discoveries keep rolling in. How much do you know about these exotic worlds?
contest found its way into the headlines two weeks ago, after the International Astronomical Union issued a press release stressing its authority as the sole arbiter of the exoplanet-naming process and reminding readers that it’s impossible to buy an “official” name. While Uwingu wasn’t mentioned by name, the release seemed aimed at the Alpha Centauri Bb competition.
Stern and other Uwingu officials fought back, saying the company had always maintained that the contest aimed to pick a popular or common name, not an “official” IAU one.
The Alpha Centauri Bb contest, and Uwingu’s related “Baby Planet Name Book,” are meant to get people excited about science and astronomy while also raising money for research and education, said Stern, who also leads NASA’s New Horizons mission, which will fly by Pluto in 2015.
“We’re engaging the public with the sky and astronomy in a way that’s never been possible before,” Stern told SPACE.com. “And it’s for a good cause.”
The picture, released last week by the European Southern Observatory, gives the viewer an up close and personal view of the NGC 2547 star cluster — a relatively young group of stars shining in the constellation .”
“Although their exact ages remain uncertain, astronomers estimate that NGC 2547’s stars range from 20 to 35 million years old,” officials from the ESO wrote in a statement. “That doesn’t sound all that young, after all. However, our Sun is 4,600 million years old and has not yet reached middle age. That means that if you imagine that the Sun as a 40 year-old person, the bright stars in the picture are three-month-old babies.”
Stars usually form in clusters like this one. They can have as few as 10 stars or as many as several thousand, ESO officials wrote.
This star cluster is not only populated by young stars. While the brightest, blue stars are the youngest, there are also a few yellow and red stars further along in their stellar evolution that round out this cluster.
Over the course of several hundred million years, the stars in NGC 2547 will drift apart, moving into new parts of the galaxy. Monitoring these stars now could help scientists understand how stars evolve.
“The members of a cluster were all born from the same material at about the same time, making it easier to determine the effects of other stellar properties,” ESO officials added.
The cluster is not the only celestial wonder in this image. Other, faint stars that are not part of the cluster appear in the background, while fuzzy, distant galaxies that are perhaps millions of light-years away can also be soon.
Scientists used a telescope at the La Silla Observatory in Chile to take the incredible cluster’s photo.
The ESO is run by 15 different countries and is the most productive ground-based astronomical observatory in the world.
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.”
The supermassive black hole didn’t finish off its meal, which scientists say was either a huge Jupiter-like planet wandering freely through space or a brown dwarf, a strange object that’s larger than a planet yet still too small to trigger the internal fusion reactions required to become a full-fledged star.
“This is the first time where we have seen the disruption of a substellar object by a black hole,” study co-author Roland Walter, of the Observatory of Geneva in Switzerland, said in a statement. “We estimate that only its external layers were eaten by the black hole, amounting to about 10 percent of the object’s total mass, and that a denser core has been left orbiting the black hole.”
Researchers made the discovery using the European Space Agency’s Integral space observatory, which noticed an X-ray flare coming from the center of a galaxy 47 million light-years away called NGC 4845. [Black Hole Snacks on Super Jupiter (Video)]
Follow-up observations by several other instruments — including ESA’s XMM-Newton and NASA’s Swift space telescopes and Japan’s MAXI X-ray monitor on the International Space Station — allowed the team to trace the outburst’s maximum to January 2011, when NGC 4845 brightened by a factor of 1,000 before dimming again over the next year or so.
“The observation was completely unexpected, from a galaxy that has been quiet for at least 20–30 years,” lead author Marek Nikolajuk, of the University of Bialystok in Poland, said in a statement.
By studying the flare’s properties, the team determined that the emission likely resulted when NGC 4845′s central black hole — which is as massive as 300,000 suns — fed on an object with a mass between 14 and 30 times that of Jupiter.
That mass range corresponds to a brown dwarf, also known as a failed star. But it’s also possible that the unfortunate object is quite a bit smaller, with a mass just a few times that of Jupiter, researchers said. If that’s the case, then the galaxy’s black hole was probably ripping apart a free-floating gas giant planet.
Such “rogue planets,” which have been ejected from their native solar systems by gravitational interactions, are thought to be incredibly common throughout the universe. One recent study, for example, estimated that rogues outnumber “normal” planets with obvious parent stars by at least 50 percent in our own Milky Way galaxy.
The Milky Way’s enormous central black hole is set to have a meal of its own soon. A gas cloud as massive as several Earths is spiraling toward the black hole and should be gobbled up later this year, astronomers say.
Observing more such events should help researchers better understand how black holes feed.
“Estimates are that events like these may be detectable every few years in galaxies around us, and if we spot them, Integral, along with other high-energy space observatories, will be able to watch them play out just as it did with NGC 4845,” said Christoph Winkler, ESA’s Integral project scientist.
The new study was published this month in the journal Astronomy & Astrophysics.
Creating microscopic black holes using particle accelerators requires less energy than previously thought, researchers say.
If physicists do succeed in creating black holes with such energies on Earth, the achievement could prove the existence of extra dimensions in the universe, physicists noted.
Any such black holes would pose no risk to Earth, however, scientists added.
Black holes possess gravitational fields so powerful that nothing can escape, not even light. The holes normally form when the remains of a dead star collapse under their own gravity, squeezing their mass together.
A number of theories about the universe suggest the existence of extra dimensions of reality, each folded up into sizes ranging from as tiny as a proton to as big as a fraction of a millimeter. At distances comparable to the sizes of these extra dimensions, these models suggest gravity may become far stronger than normal. As such, atom smashers could cram enough energy together to generate black holes. [5 Reasons We May Live in a Multiverse]
When the most powerful particle accelerator in the world, the Large Hadron Collider, was coming online, scientists wondered if it might become a “black hole factory,” generating a black hole as often as every second. Particles zip at high speeds around the 17-mile (27 kilometer) circular atom smasher before colliding into one another to create explosive energies. At its maximum, each particle beam the collider fires packs as much energy as a 400-ton train traveling at about 120 mph (195 km/h).
How to create a black hole
So far, researchers have detected no black holes at the Large Hadron Collider. Still, theoretical interest in this possibility remains alive. Now, using supercomputers, researchers simulating collisions among particles zipping near the speed of light have shown that black holes could form at lower energies than previously thought.
This new discovery is rooted in Einstein’s theory of relativity. First, through his famous equation E = mc2, Einstein revealed that mass and energy are related. This means the greater the energy of a particle — say, the faster a particle gets accelerated in a collider — the greater its mass becomes.
Next, Einstein’s theory explains that mass curves the fabric of space and time, generating the phenomenon known as gravity. As particles zip along within particle colliders, they warp space-time and can focus energy much as glass lenses focus light.
When two particles collide, each one can focus the energy of the other. If scientists use models based on classical relativity that exclude notions of extra dimensions, “one might expect black hole formation at one-third the energy” than previously expected, researcher Frans Pretorius, a theoretical physicist at Princeton University, told LiveScience.
Still, conventional physics suggest it would take a quadrillion, or a million-billion, times more energy to form a microscopic black hole than the Large Hadron Collider is capable of, so even a third of that is beyond human reach. Scenarios based on extra dimensions could have black holes form at a lower energy, “but they make no concrete predictions on what it should be,” Pretorius said.
Risk-free black holes
“The one common misconception about the small black holes that may form at the Large Hadron Collider is that they would swallow the Earth,” Pretorius said. “With about as much confidence as we can say anything in science, this is completely impossible.”
To start with, theoretical physicist Stephen Hawking calculated all black holes should lose mass over time, giving it off as so-called Hawking radiation. Tiny black holes should shrink via such evaporation faster than they grow by gobbling up matter, dying within a fraction of a second, before they could engorge on any significant amount of matter.
Even if one assumes Hawking is wrong and that black holes are more stable than that, the tiny black holes would pose no danger. Because the microscopic black holes would be created within a particle accelerator, they should keep enough speed to escape from Earth’s gravity. Moreover, if any get trapped, they are so tiny it would take each one more than the current age of the universe to destroy even a milligram of Earth matter.
The different temperatures of the sun’s layers have long intrigued solar scientists. The outer atmosphere, or corona, is millions of degrees hotter than the sun’s surface, or photosphere, where temperatures are about 10,000 degrees Fahrenheit (5,537 degrees Celsius).
But the temperatures don’t simply rise the further away you get from the surface. There is actually a cooler layer sandwiched between the photosphere and the corona called the chromosphere, where temperatures dip as low as 7,300 degrees F (4,000 degrees C).
Now scientists have found a similarly cool layer around Alpha Centauri A using the European Space Agency’s Herschel space observatory to look at the nearby star in far-infrared light.
“The study of these structures has been limited to the sun until now, but we clearly see the signature of a similar temperature inversion layer at Alpha Centauri A,” study leader René Liseau of the Onsala Space Observatory in Sweden said in a statement. [Alpha Centauri Stars Explained (Infographic)]
Scientists believe the extreme heating of the sun’s corona is likely related to the twisting of magnetic field lines that give rise to explosions known as solar flares. Studying Alpha Centauri A could help scientists better understand the atmospheric phenomenon, especially since the star is almost a twin to the Sun in mass, temperature, chemical composition and age.
“Detailed observations of this kind for a variety of stars might help us decipher the origin of such layers and the overall atmospheric heating puzzle,” Liseau said.
The discovery may also help astronomers better estimate the amount of dust in the cold debris disks surrounding sun-like stars, the scientists said. The research is detailed in a recent edition of the journal Astronomy & Astrophysics.
The three stars of the Alpha Centauri system are the nearest to Earth beyond the sun. The two main stars are the binary pair Alpha Centauri A and Alpha Centauri B. They are about 4.37 light-years from Earth.
The third star, a faint red dwarf named Proxima Centauri, is the closest at just 4.22 light-years from Earth.
In 2012, astronomers announced the discovery of an Earth-size alien planet orbiting Alpha Centauri B.
The European Space Agency’s Herschel observatory used to make the new Alpha Centauri A discovery is the largest infrared space telescope ever launched into space. The observatory launched in May 2009 to map the universe in the far-infrared and submillimeter light wavelengths.
Astronomers have made the first reliable measurement of a supermassive black hole’s spin, showcasing a technique that could help unravel the mysteries of these monsters’ growth and evolution.
The enormous black hole at the center of the spiral galaxy NGC 1365 is spinning about 84 percent as fast as Einstein’s general theory of relativity allows it to, researchers determined. The find demonstrates that at least some supermassive black holes are rotating rapidly — a claim previous studies had hinted at but failed to confirm.
“It’s the first time that we can really say that black holes are spinning,” study co-author Fiona Harrison, of Caltech in Pasadena, told SPACE.com. “The promise that this holds for being able to understand how black holes grow is, I think, the major implication.”
Staring at a black hole in X-ray light
Supermassive black holes are almost incomprehensibly huge, with some containing 10 billion or more times the mass of our sun. Scientists think one lurks at the heart of most, if not all, galaxies. [Gallery: Black Holes of the Universe]
NGC 1365, located about 56 million light-years from Earth in the constellation Fornax, does indeed harbor a gigantic black hole — one as massive as several million suns. And this behemoth is blasting out enormous quantities of energy as it gobbles up gas and other nearby matter, making it an intriguing target for astronomers.
In the new study, researchers analyzed observations two X-ray space telescopes — the European Space Agency’s XMM-Newton observatory and NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) — made of NGC 1365 in July 2012.
By zeroing in on high-energy light emitted by iron atoms, the telescopes were able to trace the motion of the flat, rotating accretion disk that circles NGC 1365′s black hole and funnels gas and dust into its greedy maw.
Astronomers found that the emissions are strongly distorted, suggesting that the inner edge of the accretion disk may be quite close to the black hole — close enough for gravitational effects to wreak havoc with the X-rays streaming from the disk. This in turn implies a rapidly rotating black hole, since general relativity states that the faster a black hole is spinning, the closer its disk can come to it, Harrison said.
But that’s just one interpretation. Another holds that such distortion, which has been observed in accretion disk emissions before, could be caused by clouds of gas that hang between a supermassive black hole and the telescopes observing it. [The Strangest Black Holes in the Universe]
“This has been a big controversy — which of the two is going on?” Harrison said.
Pinning down a black hole’s spin
The $165 million NuSTAR telescope, which just launched in June 2012, finally cracked the case.
Using NuSTAR’s super-sensitive measurements of high-energy X-rays, the astronomers calculated that the purported gas clouds would have to be incredibly thick to produce the observed distortion levels — so thick as to make the whole idea untenable, at least in the case of NGC 1365′s black hole.
“To shine through these thick clouds, the black hole would have to be so bright it would basically blow itself apart,” said Harrison, who’s principal investigator for the NuSTAR mission. “So what has to be happening is, what we’re seeing is these relativistic distortions. And that means that the disk is coming close to the black hole, which means the black hole must be spinning rapidly.”
The research team, led by Guido Risaliti of the Harvard-Smithsonian Center for Astrophysics and the Italian National Institute for Astrophysics’ Arcetri Observatory, calculated this rotation rate to be 84 percent of that allowed by general relativity.
It’s tough to comprehend this figure, since it doesn’t translate well into miles per hour. But it’s safe to say that the black hole is spinning incredibly fast.
“The analogy of an actual velocity is not quite right,” Harrison said. “But what you can say is that spinning black holes twist space-time around them. And if you were standing near the black hole, basically your space-time would be twisted, or dragged, around such that you would have to rotate once every four minutes just to be standing still.”
The new study was published online today (Feb. 27) in the journal Nature.
Learning about black hole growth
Astronomers think supermassive black holes acquire most of their spin as they grow, rather than being born with it. So studying their rotation rates can yield insights into how these monsters have evolved over time.
The superfast spin of NGC 1365′s black hole, for example, implies that it did not grow via numerous small black-hole mergers, Harrison said, since the odds are very low that many such chaotic events would spin it up in the same direction.
Rather, it’s more likely that NGC 1365′s central black hole acquired its spin from one major merger, or simply by gobbling material from an accretion disk that has remained stable over the long haul.
The new study represents a first step toward a better understanding of the nature and evolution of supermassive black holes, Harrison said.
“We will make more measurements like this,” she said. “Eventually what you’d like to do is have a bigger telescope that can actually measure more distant black holes so we can, using the statistics of the sample, understand how they grow over cosmic time.”
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.
NASA’s Kepler space telescope has resumed its search for alien planets after resting for 10 days to work out kinks in its attitude control system, mission officials announced on Jan. 29th.
Kepler went into a protective “safe mode” on Jan. 17 after engineers detected elevated friction levels in one of its reaction wheels — devices that maintain the observatory’s position in space. Engineers spun the wheels down to zero speed, hoping the break would redistribute lubricant and bring the friction back down to normal.
That phase is now over and Kepler is back in action, though it will take time to determine if the problem is solved.
Kepler began coming out of safe mode at 2:30 p.m. EST (1930 GMT) Sunday (Jan. 27) and started collecting science data again at 8 p.m. EST Monday (Jan. 28; 0100 GMT Jan. 29), officials wrote in a mission update today. [Gallery: A World of Kepler Planets]
“The spacecraft responded well to commands and transitioned from thruster control to reaction wheel control as planned,” Kepler mission manager Roger Hunter wrote in the update. “During the 10-day resting safe mode, daily health and status checks with the spacecraft using NASA’s Deep Space Network were normal.”
Kepler flags exoplanets by detecting the telltale brightness dips caused when they pass in front of their parent stars from the instrument’s perpsective. The telescope requires three functioning reaction wheels to stay locked onto its roughly 150,000 target stars.
When Kepler launched in March 2009, it had four reaction wheels — three for immediate use, and one spare. But one wheel (known as number two) failed in July 2012, so a major problem with the currently glitchy wheel (called number four) could spell the end of the $600 million Kepler mission.
It’s unknown at the moment if the 10-day rest period will bring wheel number four back into line.
“Over the next month, the engineering team will review the performance of reaction wheel #4 before, during and after the safe mode to determine the efficacy of the rest operation,” Hunter wrote.
The wheel has acted up before without causing serious problems.
“Reaction wheel #4 has been something of a free spirit since launch, with a variety of friction signatures, none of which look like reaction wheel #2, and all of which disappeared on their own after a time,” Hunter wrote.
To date, Kepler has discovered more than 2,700 exoplanet candidates. While just 105 of them have been confirmed by follow-up observations so far, mission scientists estimate that more than 90 percent of them will end up being the real deal.