Astronomers have detected eight new exoplanet candidates circling nearby red dwarf stars, which make up at least 75 percent of the galaxy’s 100 billion or so stars. Three of these worlds are just slightly bigger than Earth and orbit in the “habitable zone,” the range of distances from a parent star where liquid water could exist on a planet’s surface.
The new finds imply that virtually all red dwarfs throughout the Milky Way have planets, and at least 25 percent of these stars in the sun’s own neighborhood host habitable-zone “super-Earths,” researchers said.
“We are clearly probing a highly abundant population of low-mass planets, and can readily expect to find many more in the near future — even around the very closest stars to the sun,” study lead author Mikko Tuomi, of the University of Hertfordshire in the United Kingdom, said in a statement.
Tuomi and his colleagues spotted the exoplanet candidates after combining data gathered by two instruments — the High Accuracy Radial velocity Planet Searcher (HARPS) and the Ultraviolet and Visual Echelle Spectrograph (UVES), both of which are operated by the European Southern Observatory in Chile.
Both HARPS and UVES employ the radial-velocity technique, which detects exoplanets by noticing the tiny wobbles they induce in their parent stars’ motion toward or away from Earth.
“We were looking at the data from UVES alone, and noticed some variability that could not be explained by random noise,” Tuomi said. “By combining those with data from HARPS, we managed to spot this spectacular haul of planet candidates.”
The eight newfound candidates circle stars located between 15 and 80 light-years away from Earth. The worlds orbit their parent stars at distances ranging from 0.05 to four times the Earth-sun distance (which is about 93 million miles, or 150 million kilometers), researchers said.
The new detection bolster observations made by NASA’s prolific Kepler space telescope, which launched in 2009 to hunt for alien worlds around stars that lie considerably farther away from Earth.
“This result is somewhat expected in the sense that studies of distant red dwarfs with the Kepler mission indicate a significant population of small-radius planets,” said study co-author Hugh Jones, also from the University of Hertfordshire. “So it is pleasing to be able to confirm this result with a sample of stars that are among the brightest in their class.”
Every black hole conceals a secret — the quantum remains of the star from which it formed, say a group of scientists, who also predict that these stars can later emerge once the black hole evaporates.
The researchers call these objects “Planck stars” and believe that they could solve a very important question in modern physics: the information paradox, or the question of what happens to information contained in matter that falls into a black hole.
The idea could also finally reconcile quantum mechanics and Albert Einstein’s general theory of relativity that describes gravity, thus showing how a theory of quantum gravity might solve longstanding puzzles in the world of physics. [The Strangest Black Holes in the Universe]
Warping space and time
Black holes are regions of space so incredibly dense that nothing, not even light, can escape from them. Most are thought to form at the end of a big star’s life, when its internal pressure is insufficient to resist its own gravity and the star collapses under its own weight.
Most scientists believe that, since there is nothing to stop this collapse, eventually a singularity will form — a region where infinite densities are reached and Einstein’s general relativity ceases to be predictive.
But this “singularity theory” has flaws. Since the laws of physics no longer apply in a region of infinite density, no one knows what could possibly happen inside a black hole.
Stephen Hawking suggested in the early 1970s that black holes can slowly evaporate and disappear. But in this case, what happens to the information that describes an object that falls into a black hole? According to general relativity, information cannot simply disappear; inside a black hole, however, information apparently does. This “information paradox” has puzzled researchers for decades.
Carlo Rovelli at the University of Marseille in France and Francesca Vidotto at Radboud University in the Netherlands have attempted to answer this question by exploring the idea that the universe, which is assumed to have started with the Big Bang, actually emerged — because of quantum gravitational effects — from a “big bounce,” following an earlier contracting phase.
“The quantum gravitational effects produce an effective repulsive force, so that matter wouldn’t have collapsed into a singularity, but it would have just reached a maximal compact state,” Vidotto said.
This way, the universe would “bounce” when the energy density of matter reached the Planck scale, the smallest possible size in physics, causing the universe to expand again, and then possibly collapse again, and so on, back and forth. [Alternatives to the Big Bang Theory (Infographic)]
A similar idea has now been proposed for the fate of the collapsing matter of a dying star.Researchers say that quantum effects — similar to those that prevent an electron falling into the nucleus of an atom — would stop the collapse of a star before it could shrink to a single point, or singularity. The star would then become a super-compact object, bounce back during the evaporation process of the black hole and finally explode. Eventually, everything that would have fallen into the black hole would be released.
The researchers say that, as the black hole evaporates and shrinks, its boundary will at some point meet that of the Planck star as it expands after the bounce. When that happens, there is no black hole horizon any more, and all information trapped inside the black hole can escape.
In this case, the information paradox would be solved; the information would simply be re-emitted into the universe.
“The black hole has a huge remnant — a Planck star — and this allows us to understand the evaporation of black holes, their final stage of life, without paradoxes. Paradoxes are not part of nature; they are the sign of some incomplete knowledge,” Vidotto said.
Rovelli agrees: “Information is never too concentrated, and it can escape with the explosion of the star.” This release of information, he estimates, would generate radiation with a wavelength of about 10^-14 cm — the wavelength of gamma rays.
“Now we glimpse a tantalizing possibility: If, in the black holes, matter collapses and then bounces, the expansion can be a very dramatic event, a big explosion,” Vidotto said.
And possibly, the scientists add, astronomers have already observed Planck stars releasing the information into space, in the form of extremely bright events called gamma-ray bursts.
No ‘end of physics’
Finally, if the theory is confirmed, it could be a solid proof that quantum gravity exists, said Aurelien Barrau of the Joseph Fourier University in Grenoble, France, who was not involved in the study.
“The paper shows that there might be experimental consequences of quantum gravity,” he said. “This would be fascinating.”
The next step would be to get a more accurate description of the quantum gravitational process that should lead to the “big bounce,” possibly with the help of an accurate computer simulation of a realistic collapse, said Stefano Liberati, a physicist at SISSA (International School for Advanced Studies, Trieste, Italy), who did not take part in the research either.
“If the idea [is confirmed] with more detailed calculations, it will be further evidence that what we call singularities in general relativity are just situations where our current theory lack predictability, but are resolved successfully by quantum gravity,” he said. “At that point, the Big Bang or the center of black holes would not be ‘the end of physics’ but just another door to be disclosed, leading us to a quantum leap in understanding the nature of our universe.”
The discovery will help better model the evolution of black holes over time, and help uncover the huge influence they can have on their host galaxies.
Black holes are objects with gravitational pulls so powerful, not even light can escape. Black holes grow when gas and dust in space flows or accretes onto them — this matter gets so hot it glows hot with radiation such as X-rays. [Strangest Black Holes in the Universe]
The amount of radiation flowing out from a black hole cannot exceed a certain level known as the Eddington limit or this radiation will blow gas flowing inward away. This limit is based on the black hole’s mass.
However, whether the amount of kinetic energy from a black hole, in the form of jets and winds, was constrained by the same limit was unclear. Insights on these jets and winds is crucial for understanding the critical role black holes can play in their host galaxies — for instance, they could blow on gas hard enough to keep stars from forming.
To help solve this mystery, scientists investigated the black hole called MQ1 at the center of its host galaxy, M83, for more than a year. The galaxy lies about 15 million light-years away from Earth in the constellation Hydra, and is one of the closest and brightest spiral galaxies in the sky, visible with only binoculars.
“This powerful black hole is in a famous nearby galaxy that has been looked at gazillions of times, but was never spotted or never noticed,”study lead author Roberto Soria, an astrophysicist at the International Center for Radio Astronomy Research located in Perth, Australia, told Space.com.
It took a combination of optical, X-ray and radio observations from the Hubble Space Telescope, the Chandra X-ray Observatory and the Australia Telescope Compact Array to find MQ1. “Only when you put all three images together does this black hole really stand out,” Soria said.
By analyzing the gas flowing into the black hole, they inferred its weight as less than 100 times that of the sun. The researchers compared the mass of the black hole with its outgoing kinetic power, which they estimated by looking at how bright its surroundings are with infrared and radio waves — the brighter the surroundings, the more kinetic energy jets and winds from the black holes must be slamming them with.
The scientists discovered the amount of kinetic energy flowing out from this black hole was perhaps two to five times higher than the Eddington limit for a black hole of this mass. “The little mass that is squirting out travels at a speed approaching the speed of light,” Soria said.
Scientists had suspected that even small black holes such as MQ1 could produce huge amounts of kinetic energy. Now they have proof.
“We have finally shown that even a small one can be so powerful,” Soria said. “In our models, we will have to pay more attention to the huge influence black hole jets have in the evolution of young galaxies, even small black holes that maybe would have been ignored in the past.”
Black holes with such a huge jet power are very rare in the nearby universe “so finding one is exciting and helps us understand them better,” Soria said. “We will look at more galaxies a bit further away, up to 50 million light years, to try and discover more of those.”
The scientists detailed their findings online Feb. 27 in the journal Science.
NASA’s planet-hunting Kepler space telescope may be down, but it’s far from out.
Though a glitch ended Kepler’s original operations last May, the mission continues to discover distant worlds, adding a whopping 715 new exoplanets to the tally on Wednesday (Feb. 26). Several thousand more will likely follow in the years to come, and a new mission could get Kepler scanning the heavens again in the near future.
“Kepler is the gift that keeps on giving,” Sara Seager, a professor of physics and planetary science at the Massachusetts Institute of Technology, told reporters Wednesday during a NASA press conference that announced the 715 newfound worlds.
Revolutionizing exoplanet science
Astronomers have discovered about 1,700 exoplanets to date (the exact number depends on which of the five main alien-world catalogs is consulted). Kepler has found more than half of them; Wednesday’s announcement brought its current tally to 961.
And the finds should keep rolling in from the $600 million Kepler mission, which launched in March 2009. The observatory has detected about 3,600 planet candidates, and mission scientists expect that about 90 percent of them will eventually be confirmed as bona fide alien worlds.
But Kepler is about much more than just sheer numbers. The main goal of the spacecraft’s original mission was to determine how commonly Earth-like planets occur throughout the Milky Way galaxy. Team members are confident they will be able to answer this question using the data Kepler has already gathered, which takes some time to get through.
“We have confidence that there will be planets like Earth in other places,” Seager said.
Indeed, one research team recently used Kepler observations to estimate that about 20 percent of sun-like stars have at least one Earth-size planet orbiting in the habitable zone— that just-right range of distances where liquid water, and perhaps life as we know it, could exist.
Kepler has revolutionized the field of exoplanet science in other ways as well, teaching astronomers that multiplanet systems are common in the Milky Way and that small, rocky planets like Earth are much more abundant than gas giants such as Jupiter and Saturn.
A new mission?
Kepler’s original planet hunt ended in May 2013 when the second of its four orientation-maintaining reaction wheels failed, robbing the observatory of its ultraprecise pointing ability.
But team members say that Kepler remains extremely capable with two good wheels, and they’ve proposed a new mission called K2, which would allow the spacecraft to keep hunting for exoplanets, as well as other phenomena and objects such as supernova explosions, asteroids and comets.
The K2 proposal is currently under review at NASA headquarters, and a final decision is expected by May or so, officials have said.
Kepler team members announced Wednesday (Feb. 25) that the telescope had lost a second detector, leaving it with 19 operational “science modules” with which to gather data. But the failure shouldn’t affect the spacecraft’s performance much if at all, mission officials said.
“We were surprised by the loss of module 7, but it appears to have failed randomly, much like module 3 did,” said Kepler deputy project manager Charlie Sobeck, of NASA’s Ames Research Center in Moffett Field, Calif. “It will have very little impact on [Kepler's] ability to continue doing science.”
The new findings, based on data collected by NASA’s X-ray mapping NuSTAR space telescope, may be a clue into what exactly happens in the hearts of stars as they explode as supernovas, the researchers added.
Elements from carbon on upward that make up stars, planets and people are synthesized within massive stars. These elements are spread throughout the universe by the explosions that end the lives of these stars, supernovas that are bright enough to momentarily outshine their entire galaxies.
Stars that are born with more than about eight times the sun’s mass end their lives as so-called core-collapse supernovas. When the core of such a massive star runs out of fuel, it collapses to an extraordinarily dense nugget in a fraction of a second. Further material falling onto this collapsed core can bounce off it, causing a violent shock wave that blasts matter outward.
For decades “our best model of supernova explosions forced the stars to collapse symmetrically,” said study lead author Brian Grefenstette, an astrophysicist at the California Institute of Technology in Pasadena. “Stars are big spherical balls of gas, so it made sense that they should collapse in some kind of spherical way.”
“The problem is that when you try to make a star explode by forcing it to collapse symmetrically, the star doesn’t explode,” Grefenstette told Space.com. “You get a dud.”
This failure apparently happens in symmetrical models because that shock wave that starts at the center of the star and is supposed to destroy it gets trapped by all of the material above it. This mean the shock wave “can’t find a way out,” Grefenstette said.
As such, astrophysicists have explored ways to put ripples in the material of a dying star they call asymmetries “that can let the shock wave out and rip apart the star,” Grefenstette said. However, it was uncertain how exactly core-collapse supernovas should look — the predicted shape could differ significantly depending on which models one used of the explosions.
Now scientists have confirmed that supernovas can be asymmetric by looking at the nearby remnants of such an explosion.
“Our results are really the first step in being able to see what was going on in the center of the star,” Grefenstette said.
Researchers investigated Cassiopeia A, a remnant about 11,000 light-years away of a supernova that happened about 350 years ago. They focused on the distribution of the radioactive titanium isotope Ti-44, which is produced deep in the cores of stars.
The supernova tossed out titanium-44 just like a bomb would scatter debris.
“We’re like forensic scientists studying the radioactive ash that the explosion left behind to try to understand what happened during the explosion,” Grefenstette said.
Since titanium-44 is radioactive, “it glows in a very specific color of light,” Grefenstette said — high-energy X-rays. The researchers looked at this glowing matter using the NuSTAR space telescope (short for Nuclear Spectroscopic Telescope Array), which is “the first telescope that makes detailed images in this color of light, which lets us unlock a lot of the information that was hidden to us before,” Grefenstette said.
These images revealed the radioactive isotope was spread around in an uneven manner. This revealed the explosion was more asymmetrical than could be produced by a spherical explosion, although it was not completely lopsided in nature.
“What our results are pointing toward is the idea that the explosion happens because the core of the star sloshes around a bit during the collapse,” Grefenstette said. “In this case, we think that what happens is like when you boil water on a stove top, where bubbles are made near the bottom of the pot and rise up, making the surface of the water slosh around and letting some steam escape.”
“In the supernova, the heat, instead of coming from the burner on your stove, is coming from small particles called neutrinos, which are produced in the intense pressure at the center of the explosion,” Grefenstette said. “These neutrinos heat the material in the center of the collapse and make large bubbles of hot gas that rise up through the material and cause the core of the star to slosh around a bit.
This sloshing “lets the shock wave escape the material that’s holding it back, and once this happens, it’s kind of like if you punched a hole in the top of a pressure cooker and the whole thing explodes,” Grefenstette 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.
An international team of scientists used the giant ALMA radio telescope in Chile’s Atacama Desert to detect significant chemical changes in the star’s dust cloud along a region known as the centrifugal barrier, where the pull of gravity no longer overcomes the centrifugal force rotating the gas.
“Spectral lines of these minor [chemical] species are faint, because of their low abundances,” lead scientist Nami Sakai of the University of Tokyo told Space.com in an email. Sakai led the team of scientists that studied the young star and its gas cloud about 450 light-years from Earth. [Amazing Images from the ALMA Radio Telescope (Gallery)]
“But we were able to observe them, thanks to the high sensitivity of ALMA, and succeeded in discovering the drastic chemical change at the centrifugal barrier. No such exploration has been done before.”
Gravity draws clouds of gas in space together to form new stars at their center. The gas left behind after the stellar birth continues to rotate around the new star, forming a disk that is further surrounded by an envelope of gas. Using the changing chemistry that exists at the border, the team could precisely mark the boundary of the two.
Scientists can probe these regions by studying the spectral lines emitted by simple molecules such as carbon monoxide. As technology has improved, other simple gases have been observed within such clouds, and the completion of ALMA and its high sensitivity and spatial resolution is expected to result in even more molecules, such as the cyclic-cyclopropenylidene (C3H2) and sulfur monoxide (SO) detected by Sakai’s team.
Cyclic-C3H2 has been detected in a variety of regions of space, where it plays a key role in producing other hydrocarbons, but the highly-reactive molecule can only be found on laboratories on Earth. It survives in environments like interstellar clouds because the density and temperatures are lower than those of Earth.
Sakai had previously studied the young star, which is located in the Taurus molecular cloud. The dense cloud is about 450 light-years from the sun, making it the closest large star-forming region to Earth. Her team had previously found rich carbon-chain molecules, and was eager to use ALMA to explore their origin and fate. [Video: Nursery of Baby Stars Spotted By Chandra]
“In the course of this observation, we unexpectedly found the chemical change at the centrifugal barrier,” she said.
The rotation that helped birth the young star continues after its formation. Gravity pulls the gas toward the star, but distance limits its reach. At the centrifugal barrier, the force of rotation outweighs the force of gravity, and the star can longer fall inward.
Gas containing cyclic-C3H2 piles up at the outer edge of the barrier, increasing the density. Temperatures of the jammed up gas spike suddenly from minus 243 degrees Celsius (minus 405 degrees Fahrenheit) to temperatures of minus 213 C (minus 351 F) or higher. The heat increase allowed the particles of SO to jump directly from the solid to gas phase in a process known as sublimation. The complex chemicals only exist outside of the barrier; inside, both would be frozen out on dust grains, causing their spectral lines to disappear and marking the boundary between the disk and the envelope.
The research was published online today (Feb 12) in the journal Nature.
Solar system insights
The system resembles the early solar system. The young star has a mass of only 0.18 times that of the sun. The flattened envelope of gas around the young star stretches out to a thousand times the Earth-sun distance, known as an astronomical unit (AU). The disk, the future birthplace of planets, reaches 90 AUs, a distance that corresponds with the nebula of gas around the sun.
“The radius of the centrifugal barrier corresponds to the outer edge of the solar nebula,” Sakai said. “Hence it may have a potential relation to the size of the planetary system to be formed.”
Sakai doesn’t anticipate that the complicated chemistry of the outer envelope is unique. The chemical change at the centrifugal barrier is caused by fundamental physics. It may help to not only understand the formation of other stars and planetary systems but also that of the early solar system.
Observations of the young star were made by ALMA radio telescope — the name is short for Atacama Large Millimeter Array — in 2012. At the time, the telescope comprised up to 25 antennas. In March 2013, all 66 antennas in the ALMA radio telescope array became fully active, allowing for even more detailed studies to be made.
Sakai hopes to put the full power of the telescope to good use.
“We need to observe other molecular species in this source at a higher spatial resolution to clarify the total view of the chemical change. It is also necessary to confirm whether similar situations are found in other protostars,” she said. “These can be done with ALMA in its full operation.”
The Hubble Space Telescope has captured a striking new photo of a doomed star poised to explode in a devastating supernova event.
The Hubble photo of the star, known as SBW2007 1 (or SBW1 for short) reveals the star surrounded by its own expelled gas to create what appears to be a “lidless purple eye, staring back at us through space,” NASA officials wrote in an image description. SBW1 is located more than 20,000 light-years away from Earth.
“The star was originally 20 times more massive than our sun, and is now encased in a swirling ring of purple gas, the remains of the distant era when it cast off its outer layers via violent pulsations and winds,.” NASA officials wrote. “But the star is not just any star; scientists say that it is destined to go supernova.”
Scientists suspect SBW1 will ultimately die violently as a supernova because of its close resemblance to the famed supernova SN 1987A, a star that exploded in 1987. Both stars were travelling at comparable speeds, had the same brightness, and had very similar rings of the same size and age.
“At a distance of more than 20 000 light-years it will be safe to watch when the supernova goes off,” NASA officials wrote. “If we are very lucky it may happen in our own lifetimes.”
Five rocky planets are among a slew of newly discovered alien worlds found by NASA’s prolific Kepler spacecraft. The planets, which range in size from ten to eighty percent larger than Earth, were announced Monday (Jan. 6) at the 223rd meeting of the American Astronomical Society in Washington, D.C.
Two of the newfound rocky planets, named Kepler-99b and Kepler-406b, are both 40 percent larger than Earth and have densities similar to lead, the researchers said. But, the chances of finding life on these exoplanets are slim, they added, since the two planets orbit their respective stars in less than five days, making these worlds sweltering and unable to support life as we know it.
Geoff Marcy, a professor of astronomy at the University of California, Berkeley, presented the findings, which included the masses and densities of 16 new planets — so-called mini-Neptunes — that are between one and four times the size of Earth.
“Kepler’s primary objective is to determine the prevalence of planets of varying sizes and orbits,” Natalie Batalha, Kepler mission scientist at NASA’s Ames Research Center in Moffett Field, Calif., said in a statement. “Of particular interest to the search for life is the prevalence of Earth-sized planets in the habitable zone. But the question in the back of our minds is: are all planets the size of Earth rocky? Might some be scaled-down versions of icy Neptunes or steamy water worlds? What fraction are recognizable as kin of our rocky, terrestrial globe?”
Scientists used the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in Chile to make the discovery while observing supernova 1987A, an exploded star in the Large Magellanic Cloud — a dwarf galaxy companion of the Milky Way located about 168,000 light-years from Earth.
Astronomers have long thought that supernovas are responsible for creating some of the large amounts of dust found in galaxies around the universe, yet they haven’t directly observed the process until now, ALMA officials said. [See more amazing images from the ALMA telescope]
“We have found a remarkably large dust mass concentrated in the central part of the ejecta from a relatively young and nearby supernova,” astronomer Remy Indebetouw, of the National Radio Astronomy Observatory (NRAO) and the University of Virginia, said in a statement. “This is the first time we’ve been able to really image where the dust has formed, which is important in understanding the evolution of galaxies.”
If enough of the dust created by 1987A and other supernovas like it transitions into interstellar space, it could explain part of why many galaxies in the early universe got their copious amounts of dust, Indebetouw said.
“If at least one third of it makes it out, then we’re in good shape,” Indebetouw said here at the 223 meeting of the American Astronomical Society.
“1987A is a special place since it hasn’t mixed with the surrounding environment, so what we see there was made there,” Indebetouw said in a statement. “The new ALMA results, which are the first of their kind, reveal a supernova remnant chock full of material that simply did not exist a few decades ago.”
Astronomers have observed small amounts of hot dust in 1987A before, however, the research didn’t reveal the large amounts of cold dust seen by ALMA radio telescope recently. The telescope’s sensitive instrumentation was able to pick up on the cold dust in millimeter and submillimeter wavelengths, ALMA officials said.
1987A now holds about 25 percent of the mass of the sun in new dust, ALMA officials said.
“Really early galaxies are incredibly dusty and this dust plays a major role in the evolution of galaxies,”
Mikako Matsuura, a scientist associated with the study of the University College London, said in a statement. “Today we know dust can be created in several ways, but in the early universe most of it must have come from supernovas. We finally have direct evidence to support that theory.”
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.”
Scientists have captured their best view yet of how extreme magnetic fields shape superfast jets from the most powerful explosions in the universe.
The new research tracked polarized light from cosmic explosions, known as gamma-ray bursts, and offered an unprecedented glimpse into how intense magnetic fields shape the evolution of the outbursts.
“Gamma-ray bursts are the most extreme particle accelerators in the universe,” said Carole Mundell, a professor of extragalactic astronomy at Liverpool John Moores University, who led the new study. “They’re objects of all kinds of extremes: extreme speeds, extreme gravity, extreme magnetic fields. So they’re the ultimate laboratory for testing or laws of physics.” [10 Strangest Things in Space]
Gamma-ray bursts are believed to form at the end of a massive star’s life, just as the body of the star collapses in on itself, creating a black hole. As this happens, the matter surrounding the black hole may release two jets of gamma-rays and highly energetic particles, in opposite directions away from the black hole. A single gamma-ray burst may radiate more energy in a few minutes than the star radiated in its entire lifetime.
Mysterious origins of cosmic explosions
Scientists still don’t understand how the particles surrounding a black hole can generate the intense bursts of light and particles seen in gamma-ray bursts.
One theory suggests that an organized magnetic field will accelerate particles on an invisible track around the black hole, causing them to radiate light (what’s known as synchrotron radiation). As the black hole rapidly contracts, so do the particles and the magnetic field, causing the particles to accelerate even faster. The theory suggests that it is this rapid bump in acceleration, combined with energy stored in the particles themselves, that creates two massive jets of gamma-rays and particles.
If the energy in a gamma-ray burst was at least partly due to synchrotron radiation, then scientists could expect to see an imprint of that magnetic field in the light produced by this violent event.
New telescope tool’s magnetic find
Mundell and her colleagues designed an instrument named RINGO2 to measure the polarization of optical light that is produced as a byproduct of a gamma-ray burst. RINGO2 observed gamma-ray bursts for two years on the Liverpool optical telescope.
On March 8, 2012, NASA’s Swift satellite — which tracks gamma-ray bursts — alerted the Liverpool telescope to a cosmic explosion dubbed GRB 120308A. The subsequent study, which was detailed in the Dec. 5 edition of the journal Nature, found that optical light emitted early on by GRB 120308A was 28 percent polarized, and decreased to 10 percent polarization over time.
“If you take optical light and you scatter it from dust, as it comes through our Milky Way galaxy, you might observe a few percent polarization,” Mundell said. “Really the only way to produce this high degree of polarization is to have large-scale ordered magnetic fields that are producing the synchrotron radiation with the electrons spiraling around the magnetic field.”
Mundell said the reduction in the polarization of the light over time demonstrates that the light is polarized upon its creation near the black hole, and loses its polarization as it travels through space. For this reason, RINGO2 must observe the optical light almost immediately after the start of the gamma-ray burst, in order to observe the polarity.
More observations of polarized light in future gamma-ray bursts are needed to confirm the findings, the researchers said. RINGO2 operated on the Livermore telescope for two years and collected data on multiple gamma-ray bursts.
“We’re in the process of working on a sample paper about those other gamma-ray bursts,” Mundell said. “Obviously, we want to look at more of them and really prove that this is a universal case and not just a special object. [GRB 120308A] wasn’t special in any other way, and that’s one good reason to suggest that it was typical.”
With the second spacecraft this month now on its way to Mars, you could be forgiven for thinking we’ve forgotten that there is a number of other planets in our solar system.
Due to arrive in orbit about the red planet in September 2014, MAVEN will be the first probe to explore the upper reaches of the Martian atmosphere. It will do this by taking a number of dives into the upper atmosphere, dipping to only 125 km about the Martian surface from its home orbit of 6,000 km.
The hope is that to find clues to a possible warmer and wetter past.
But with Opportunity still trundling along, Curiosity, the Mars Orbiter Mission, MAVEN, the Mars Reconnaissance Orbiter, Mars Express, 2001 Mars Odyssey and the planned InSight, ExoMars and Mars 2020 rover missions, are we forgetting that there’s more to the solar system than Mars?
Sure it is the most viable planet that we, the human race, could go and walk on but it’s probably not the best hope for the discovery of biological activity.
Don’t get me wrong, I’m a massive fan of any space mission, and every step we make in space is a “giant” leap for us down here on Earth. Every endeavour we have undertaken on Mars has thrown up yet more intrigue, and we’ve barely scratched the surface.
But let’s not kid ourselves; it looks pretty dead up there. If we do find any biology on Mars, it going to be most interesting working out how it has hung on for billions of years (and try and get some survival tips).
I admit “The Mars Overload” is a bit of misrepresentation, as we are currently exploring (or travelling to) pretty much every other planet in our solar system right now (with two notable exceptions). So what are they all up to?
The Messenger craft is currently 3,400 days into its mission in orbit about Mercury, and has now imaged the whole surface of the Sun’s closest neighbour. It’s currently in a bit of a limbo, with it’s extended mission finishing in March this year.
Venus currently has the European Space Agency’s Venus Express spacecraft in orbit and the Japanese mission Akatsuki hopefully en route. Venus Express has returned the strongest indications yet that Venus is geologically active, and if confirmed would be the first planets (other than our own Earth) to be discovered so.
Akatsuki, which was planning to study Venus’ extreme climate, unfortunately failed to insert into Venutian orbit in 2010. But hope is not lost, and it is currently held in an elliptical orbit with plans to make another attempt into a closer orbit in 2015.
The asteroid belt
The asteroid belt is the museum of the solar system, and the Dawn mission has been the first to traverse it and focus on some of its biggest exhibits. Dawn’s first stop was orbiting about the asteroid Vesta, and has now left to journey to the largest body in the belt – Ceres – due to arrive in 2015.
At Vesta, Dawn discovered this body’s large metallic core revealing it to be the “last of its kind” as a failed planet.
Any mission to Jupiter has a lot to live up to, with the enduring data set that the Galileo spacecraft collected, coupled with its dramatic ending.
The Juno mission is currently on its way, arriving in 2016 will concentrate on the gas giant’s poles and magnetic and gravity field. The hope that such a detailed mission will reveal more about our largest neighbours interior.
On the cards is more of a successor of Galileo, the European Space Agency’s JUICE mission. But we’re playing the waiting game on this one – with arrival at Jupiter not anticipated to be before 2030.
The most longstanding of current planetary missions is Cassini, launched in 1997. It’s currently in the second phase of its mission and has performed a Galileo-like job on Saturn, returning data on the planet, its rings and moons that will be mulled over for decades.
Like Messenger, is waiting confirmation of its next extended mission, which will keep it running until 2017.
There has been worrying news that cuts to NASA’s budget will force them to choose between extending Cassini or the Mars-roving Curiosity. A terrible choice by all accounts, but given the massive effort taken to get Cassini out there, I really hope that there is some way of keeping them both going.
New Horizons is going to be a science highlight of 2015 when it arrives at the far reaches of our solar system to study Pluto. Since it was launched in 2006 it has seen it’s primary target kicked out of the planet club, but promoted to be the “king” of the dwarf planets.
New Horizons will pass Pluto and it’s companion Charon before heading deeper into the Kuiper belt. Being the first probe to explore this new class of planets in detail, it’s almost guaranteed to return some very exciting stuff.
And the rest …
Uranus and Neptune are the notable exceptions. These gassy icy giants still lie pretty much unexplored with humankind only waving hello in 1986 and 1989 with the respective fly-bys of the Voyager 2 spacecraft.
The biggest difficulty in exploring these planets is that they are so far away that to reach them takes a spacecraft travelling at massive speeds – so fast that by the time they get there you need a massive amount of energy to kick them into orbit. With current technology missions to the outer fringes of the solar system, like New Horizons, are likely only to be fly-bys.
So, contrary to what you might think from recent media coverage, there really is so much more planetary exploration going on than that focused on Mars. To undertake these feats we’ve had to overcome technological hurdles and travelled massive distances at outrageous speeds.
I, for one, very much hope that we can continue to explore our solar system, Mars and beyond, at the same – or even faster – rate.
NASA’s hobbled Kepler space telescope may be able to detect alien planets again, thanks to some creative troubleshooting.
Kepler’s original planet hunt ended this past May when the second of its four orientation-maintaining reaction wheels failed, robbing the spacecraft of its ultraprecise pointing ability. But mission team members may have found a way to restore much of this lost capacity, suggesting that a proposed new mission called K2 could be doable for Kepler.
Engineers with the Kepler mission and Ball Aerospace, which built the telescope, have oriented the spacecraft such that it’s nearly parallel to its path around the sun. In this position, the pressure exerted by sunlight is spread evenly across Kepler’s surfaces, minimizing drift. [Gallery: A World of Kepler Planets]
This strategy is returning some promising results, mission officials say. During a 30-minute pointing test in late October, for example, Kepler captured an image of a distant star field that was within 5 percent of the image quality achieved during Kepler’s original mission.
“This ‘second light’ image provides a successful first step in a process that may yet result in new observations and continued discoveries from the Kepler space telescope,” Charlie Sobeck, Kepler deputy project manager at NASA’s Ames Research Center in Moffett Field, Calif., said in a statement.
The Kepler team is currently conducting tests to see if the spacecraft can maintain such pointing stability over periods of days and weeks — a necessity for discovering exoplanets.
Kepler launched in March 2009 on a mission to determine how frequently Earth-like planets occur around the Milky Way galaxy. The spacecraft finds exoplanets via the “transit method,” noting the telltale brightness dips caused when an alien world crosses the face of, or transits, its host star from the instrument’s perspective.
Kepler has been remarkably successful, spotting more than 3,500 planet candidates to date. Just 167 of them have been confirmed so far by follow-up observations, but mission scientists think 90 percent or so will end up being the real deal.
Researchers are still sifting through the mountains of data Kepler returned during its four years of science operations. Kepler team members have expressed confidence that they’ll find Earth analogs in these databases, allowing the mission’s primary goal to be achieved.
The proposed K2 mission would continue Kepler’s exoplanet hunt, albeit in a modified fashion. K2 would also gather data about supernova explosions, star formation and solar-system bodies such as asteroids and comets, among other things, team members have said.
The Kepler team has officially presented the K2 mission concept to NASA Headquarters, which is expected to decide by the end of the year if the idea progresses to a vetting stage called “senior review.” The ultimate fate of K2, and the Kepler spacecraft, will likely be known by the middle of next year, Kepler officials have said.
A mysterious blast of light spotted earlier this year near the constellation Leo was actually the brightest gamma-ray burst ever recorded, and was triggered by an extremely powerful stellar explosion, new research reports.
On April 27, several satellites — including NASA’s Swift satellite and Fermi Gamma-ray Space Telescope — observed an unusually bright burst of gamma radiation. The explosion unleashed an energetic jet of particles that traveled at nearly the speed of light, researchers said.
“We suddenly saw a gamma-ray burst that was extremely bright — a monster gamma-ray burst,” study co-author Daniele Malesani, an astrophysicist at the Niels Bohr Institute at the University of Copenhagen in Denmark, said in a statement. “This [was] one of the most powerful gamma-ray bursts we have ever observed with the Swift satellite.” [Top 10 Strangest Things in Space]
The gamma-ray burst was described in a series of studies published online today (Nov. 21) in the journal Science.
Gamma-ray bursts, or GRBs, are the most powerful type of explosions in the universe and typically mark the destruction of a massive star. The original stars are too faint to be seen, but the supernova explosions that signal a star’s death throes can cause violent bursts of gamma radiation, researchers said.
Gamma-ray bursts are usually short but extremely bright. Still, ground-based telescopes have a tough time observing them because Earth’s atmosphere absorbs the gamma radiation.
The extremely bright gamma-ray burst seen earlier this year, officially dubbed GRB 130472A, occurred in a galaxy 3.6 billion light-years away from Earth, which, though still far away, is less than half the distance at which gamma-ray bursts have previously been seen. This closer proximity to Earth enabled astronomers to confirm for the first time that one object can simultaneously create a powerful GRB and a supernova explosion.
“We normally detect GRBs at great distance, meaning they usually appear quite faint,” study co-author Paul O’Brien, an astronomer at the University of Leicester in the United Kingdom, said in a statement. “In this case, the burst happened only a quarter of the way across the universe — meaning it was very bright. On this occasion, a powerful supernova was also produced — something we have not recorded before alongside a powerful GRB — and we will now be seeking to understand this occurrence.”
The jet produced by the gamma-ray burst was formed when a massive star collapsed on itself and created a black hole at its center. This generated a blast wave that caused the stellar remnants to expand, producing a glowing shell of debris that was observed as an extremely bright supernova explosion.
After analyzing properties of the light produced by the gamma-ray burst, scientists determined that the original star was only three to four times the size of the sun, but was 20 to 30 times more massive. This extremely compact star was also rapidly rotating, the researchers said.
The GRB was the brightest and most energetic ever witnessed and triggered dynamic internal and external shock waves that are still not well understood. Though scientists have a clearer view of the violent explosion, mysteries remain. For instance, space telescopes detected more photons and more high-energy gamma-rays than theoretical models predicted for a gamma-ray burst of this magnitude.
Researchers are still investigating why the energy levels seen with GRB 130472A do not quite match predictions from existing models of gamma-ray bursts. Their results could lead to more refined theories about how particles are accelerated, which could help astronomers better predict the behavior of cosmic events.
“The really cool thing about this GRB is that because the exploding matter was traveling at [nearly] the speed of light, we were able to observe relativistic shocks,” study co-author Giacomo Vianello, a postdoctoral scholar at Stanford University in California, said in a statement. “We cannot make a relativistic shock in the lab, so we really don’t know what happens in it, and this is one of the main unknown assumptions in the model. These observations challenge the models and can lead us to a better understanding of physics.”