• Creating tiny black holes isn't all that hard

    Matt Choptuik, Will East, Frans Pretorius

    A snapshot from a video showing two particles being slammed into each other and distorting into pancake shapes before forming a black hole.

    By Charles Choi
    LiveScience

    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.

    Matt Choptuik, Will East, Frans Pretorius

    Here, the particles have just collided and are forming a black hole.

    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
    As frightening as black holes might seem, if particle accelerators on Earth can generate them, such infinitesimal entities pose no risk to the planet.

    "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.

    "These black holes would be too small to consume any significant amount of matter," Pretorius said.

    Pretorius and his colleague William East detailed their findings online Thursday in the journal Physical Review Letters.

    Follow LiveScience us on Twitter @livescience, Facebook and Google+. Original article on LiveScience.com.

    Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Black hole's super-fast spin revealed

    NASA / JPL-Caltech

    This artist's concept illustrates a supermassive black hole with millions to billions times the mass of our sun.

    By Mike Wall
    Space.com

    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." 

    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 data from two X-ray space telescopes — the European Space Agency's XMM-Newton observatory and NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. The telescopes observed NGC 1365 in July 2012.

    By zeroing in on the 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 were 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 implied 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.

    That's one interpretation. In the past, some astronomers have put forward a different interpretation of the readings. They suggested 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. 

    How fast a super-massive black hole spins may indicate what it fed on and how often. NASA's NuSTAR X-Ray Telescope is helping to decode the early life story of a nearby active galaxy by timing its rotation and measuring its glow.

    NASA / JPL-Caltech

    This graphic shows two models for the spin of a black hole. Observations from NASA's NuSTAR probe revealed that the prograde rotation model applied in the case of NGC 1365's black hole - and that suggests that the black hole is spinning at an incredibly fast rate.

    Pinning down the spin
    The observations from the $165 million NuSTAR telescope, which launched in June 2012, cracked the case.

    Using NuSTAR's super-sensitive measurements of high-energy X-rays, the astronomers calculated that if there were gas clouds in the way, they would have to be incredibly thick to produce the observed distortion levels. In fact, they'd have to be 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 is the 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. One estimate puts the speed at 670 million mph, or 1.08 billion kilometers per hour. In any case, 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 Wednesday in the journal Nature.

    How a black hole grows
    Astronomers think that 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." 

    Follow Space.com senior writer Mike Wall on Twitter @michaeldwall or Space.com @Spacedotcom. We're also on Facebook and Google+.

    © 2013 Space.com. All rights reserved. More from Space.com.

  • Black hole's burp surprises scientists

    NRAO / AUI / NSF / Gemini / AURA

    A radio image from the High Sensitivity Array shows bright "hot spots" in the galaxy NGC 660. The HSA image, shown in the inset, represents less than a pixel's worth of the larger optical image.

    By Tia Ghose, LiveScience staff writer

    LONG BEACH, Calif. — Astronomers have discovered what appears to be colossal belch from a massive black hole at the heart of a distant galaxy. The outburst was 10 times as bright as the biggest star explosion, scientists say.

    The potential super-sized black hole burp find came as astronomers studied the galaxy NGC 660, which is located 44 million light-years away in the constellation Pisces.

    "The discovery was entirely serendipitous. Our observations were spread over a few years, and when we looked at them, we found that one galaxy had changed over that time from being placid and quiescent to undergoing a hugely energetic outburst at the end," study researcher Robert Minchin of Arecibo Observatory in Puerto Rico said in a statement.

    Minchin presented the research Monday at the American Astronomical Society's winter meeting in Long Beach.

    To determine whether the outburst was from a supernova — the explosive end of a star —  or the galaxy's core, the researchers used the High Sensitivity Array, a global network of telescopes that includes the Very Long Baseline Array, the Arecibo Telescope, the National Science Foundation's 100-meter Green Bank Telescope and the 100-meter Effelsberg Radio Telescope in Germany.

    Instead of an expanding ring of material suggesting a supernova event, the researchers found five locations with bright radio emissions clustered around the galaxy's core.

    "The most likely explanation is that there are jets coming from the core, but they are precessing, or wobbling, and the hot spots we see are where the jets slammed into the material near the galaxy's nucleus," said Chris Salter, also of the Arecibo Observatory.

    Those jets, the researchers said, would mean the outburst likely came from a supermassive black hole at the heart of galaxy NGC 660. As the black hole devours dust and mass, it pulls a whirling disk of matter into its heart that spews jets of particles as it is consumed.

    Supermassive black holes are colossal structures at the cores of galaxies that are between millions and billions of times as massive as the sun. They are much larger than stellar-mass black holes, which are created from the deaths of giant stars and can contain the mass of about 10 suns.

    Follow Space.com on Twitter @Spacedotcom. We're also on Facebook and Google+.

    Copyright 2013 Space.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Scientists to catch a black hole

    Scott Noble / RIT

    A simulation shows superheated plasma swirling around the black hole at the center of our galaxy.

    By Alan Boyle, Science Editor, NBC News

    Astronomers are setting up a virtual telescope as wide as our planet to capture the first picture outlining our galaxy's monstrous black hole. 

    "Everybody's super-excited," one of the leaders of the effort, astrophysicist Dimitrios Psaltis of the University of Arizona's Steward Observatory, told me today. "A couple of years ago, this was science fiction. Now it's becoming a reality."

    Psaltis and his colleagues are calling together researchers from around the world for a conference in Tucson starting Wednesday, with the aim of combining up to 50 radio telescopes from Taiwan to the Netherlands to the South Pole into one big observing instrument they call the "Event Horizon Telescope."

    The observations have to be done by radio telescopes sensitive to millimeter-scale wavelengths, because that's the ideal range for seeing through "the dust and the mess" at the center of our Milky Way galaxy, Psaltis said.

    By combining millimeter-wave radio readings from widely separated antennas, astronomers can produce an unparalleled picture of the region around our Milky Way's central black hole. "We expect to see the swirling of matter going into the black hole in real time," Psaltis said. "What we're really hoping to see is how the black hole is fed."

    Black hole in the neighborhood
    A black hole is an object so massive that nothing, not even light, can escape its gravitational grip within a boundary known as the event horizon. Black holes can be created by the catastrophic collapse of massive stars, and a much larger breed can take root at the center of galaxy during its formation. The black hole at the center of the Milky Way is relatively frugal in its dining habits, and that's probably a good thing for us: Scientists have suggested that the violent galactic environment associated with more ravenous supermassive black holes wouldn't be conducive to life as we know it.

    Even though our galaxy's black hole is thought to have the mass of 4 million suns, and even though astronomers have determined its location by charting its gravitational effect, astronomers have never seen it directly. The black hole itself would be nothing more than a black spot, surrounded by a blazing swirl of inward-falling matter. Its extent is said to be no more than the width of Mercury's orbit around the sun, and astronomers would be watching it from a distance of 26,000 light-years. Actually seeing the "shadow" or silhouette of the black hole's event horizon would be as challenging as spotting a grapefruit on the moon, according to a University of Arizona news release.

    Despite those challenges, the astronomers behind the Event Horizon Telescope believe the observation can at last be made, in part because of promising results from a pilot study conducted using the Steward Observatory's Submillimeter Telescope in Arizona, the James Clerk Maxwell Telescope on Mauna Kea in Hawaii and the Combined Array for Research in Millimeter-wave Astronomy in California.

    "Those three telescopes told us that we can actually observe all the way to the black hole," Psaltis told me.

    Testing Einstein
    Now more telescopes will be brought into the network, including the 50-antenna Atacama Large Millimeter Array in Chile, also known as ALMA. Sheperd Doeleman of MIT's Haystack Observatory, who is the principal investigator for the Event Horizon Telescope, says ALMA's participation will be a "real game-changer."

    "We will be able to actually see what happens very close to the horizon of a black hole, which is the strongest gravitational field you can find in the universe," he said in the news release. "No one has ever tested Einstein's general theory of relativity at such strong fields."

    Observing the bright outline that defines the black hole's shadow could serve as an unprecedented test of general relativity, Psaltis said. If the outline is precisely circular, that would be in line with what Einstein's theory predicts. But if the outline turns out to be elliptical, the theory "must be flawed" in some way, he said.

    Psaltis emphasized that the black hole picture would not take shape all at once. Instead, the details would emerge gradually as more and more readings are sent to the project's central data processing center at MITs' Haystack Observatory.

    "In perhaps three years, we'll be able to have the first complete picture of the black hole," he said.

    More about black holes:

    Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds. 

  • How a black hole throws fastballs

    A NASA animation shows how a black hole sends out powerful "bullets" of ionized gas.

    By Alan Boyle, Science Editor, NBC News




    X-ray and radio observations have revealed how a black hole winds up and pitches fastballs made of ionized gas at a quarter of the speed of light. That's about 1.6 million times faster than the fastest fastball ever pitched on Earth.

    The pitches were clocked during an outburst from the black hole system H1743-322 in mid-2009. using NASA's Rossi X-Ray Timing Explorer and the National Science Foundation's Very Long Baseline Array. The binary system, 28,000 light-years from Earth in the constellation Scorpius, consists of a normal star and a black hole that are gravitationally bound together. The black hole sucks material in a continuous stream from the star, drawing it down in a swirling disk.

    Some of the superheated material radiates away from the black hole's surroundings in two jets that point in opposite directions. Every once in a while, hot ionized gas bunches up into huge "bullets" that are wound up and flung out from the disk. RXTE and the VLBA spotted a couple of the bullets as they sped away in early June 2009.

    "Like a referee at a sports game, we essentially rewound the footage on the bullets' progress, pinpointing when they were launched," Gregory Sivakoff of the University of Alberta said Tuesday in a NASA news release. "With the unique capabilities of RXTE and the VLBA, we can associate their ejection with changes that likely signaled the start of the process."

    By comparing the X-ray observations of H1743-322 and the radio emissions from the blobs of gas, astronomers were able to figure a timeline for the interactions in the disk and the ejection of the fastballs. Sivakoff presented the research team's findings this week in Austin, Texas, at a meeting of the American Astronomical Society, and a paper on the observations will be published in the Monthly Notices of the Royal Astronomical Society.

    "This research provides new clues about the conditions needed to initiate a jet and can guide our thinking about how it happens," said Chris Done, an astrophysicist at the University of Durham in England who was not involved in the study.

    Rest in peace, Rossi
    The study serves as a sendoff of sorts for the Rossi X-Ray Timing Explorer, which was decommissioned last week after 16 years of science operations. "The spacecraft and its instruments had been showing their age, and in the end RXTE had accomplished everything we put it up there to do, and much more," Tod Strohmayer, RXTE project scientist at NASA's Goddard Space Flight Center, said in the space agency's obituary for the probe.

    RXTE played a part in mapping the space-time shift around spinning black holes and neutron stars, detecting a black hole's X-ray "heartbeat," figuring out what's behind our galaxy's X-ray glow, studying a superflare blasted out from the Crab Nebula and observing many other extreme phenomena.

    NASA says the 7,000-pound satellite is expected to re-enter the atmosphere and burn up sometime between 2014 and 2023, depending largely on how solar activity affects the decay of its orbit.

    More from this week's astronomy meeting:

    Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

  • Zoom in on the black hole next door

    T. Lauer / NOAO / NASA / ESA

    A new Hubble Space Telescope image centers on the 100-million-solar-mass black hole at the hub of the neighboring spiral galaxy M31, or the Andromeda Galaxy, one of the few galaxies outside the Milky Way visible to the naked eye and the only other giant galaxy in the Local Group. This is the sharpest visible-light image ever made of the nucleus of an external galaxy.

    By Alan Boyle, Science Editor, NBC News




    The Hubble Space Telescope has captured the best view yet of the Andromeda Galaxy's nucleus — which is actually a double nucleus, thanks to the galaxy's supermassive black hole.

    Andromeda is the nearest spiral galaxy to our own Milky Way, and the only galaxy outside our own that's visible to the naked eye. But it's not easy to see what's going on at the bright center of the spiral. Astronomer Tod Lauer of the National Optical Astronomy Observatory put together several exposures in blue and ultraviolet wavelengths from Hubble's Advanced Camera for Surveys to produce this ultra-sharp view.

    The inset photograph tells the story: The black hole itself can't be seen, but it's near the center of a compact cluster of blue stars at the center of the inset. That cluster is surrounded by the double nucleus, an elliptical ring of older reddish stars in orbit around the black hole.

    "When the stars are at the farthest point in their orbit they move slower, like cars on a crowded freeway," NASA says in its image advisory. "This gives the illusion of a second nucleus."

    NASA notes that the blue stars in the cluster are no more than 200 million years old, and had to have formed close to where they are now. Such stars wouldn't last long enough to form somewhere else and move inward.

    So how can stars form so deep within the black hole's gravitational field? That's what Lauer and other astronomers are trying to figure out.

    Lauer presented the Hubble observations this week in Austin, Texas, at a meeting of the American Astronomical Society.

    This zoom dives deep into the nucleus of the Andromeda galaxy. Credit: NASA, ESA, and G. Bacon (STScI)

    More from the astronomy meeting:

    Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.