• X-ray probe catches a bright blast from Milky Way's colossal black hole

    NASA / JPL-Caltech

    These are the first, focused high-energy X-ray views of the area surrounding the supermassive black hole at the center of our Milky Way galaxy, called Sagittarius A*. The three images on the right side show Sagittarius A* before, during and after an X-ray flare that was spotted in July.

    By Alan Boyle, Science Editor, NBC News


    For years, astronomers have known about the supermassive black hole at the center of our Milky Way galaxy, but these pictures from NASA's NuSTAR telescope show a rare view of the usually sleeping giant gobbling down a cosmic snack.

    "We got lucky to have captured an outburst from the black hole during our observing campaign," Caltech's Fiona Harrison, the $165 million mission's principal investigator, said today in a NASA news release. "These data will help us better understand the gentle giant at the heart of our galaxy and why it sometimes flares up for a few hours and then returns to slumber."

    NuSTAR, also known as the Nuclear Spectroscopic Telescope Array, is an X-ray observatory that was launched in June to study high-energy phenomena such as the tumult that takes place around black holes. Sagittarius A*, which is 4 million times as massive as our sun, is one of the prime targets for observation.

    Supermassive black holes like Sagittarius A* commonly form at the center of big galaxies: In fact, they may be an essential piece of the galaxy formation puzzle, and some of them can get pretty violent. Our galaxy's black hole is uncommonly quiet, however, and that's probably a good thing. Only occasionally does matter from the surrounding area fall into its grip. As that matter is sucked into the singularity, it heats up and emits a blast of radiation.

    NuSTAR happened to be in the right place at the right time to observe Sagittarius A* for two days in July, along with other observatories. NASA's Chandra X-ray Observatory was watching for lower-energy X-rays, while the Keck Observatory on Hawaii's Mauna Kea was taking infrared images.

    During the observations, a bright X-ray flash flared up. The emissions were given off by matter that was heated up to about 180 million degrees Fahrenheit (100 mllion degrees Celsius), NASA said. The high-energy readings are being compared with the images in other wavelengths to deepen astronomers' understanding of how black holes gobble up matter and grow.

    "Astronomers have long speculated that the black hole's snacking should produce copious hard X-rays, but NuSTAR is the first telescope with sufficient sensitivity to actually detect them," Columbia University's Chuck Hailey, a member of the mission science team, said in today's statement.

    Get ready for a gluttonous orgy
    NuSTAR and other black-hole watchers are getting set to watch Sagittarius A*, or Sgr A* for short, go into full gobble mode next year: A huge cloud of dust and gas known as G2 is approaching the black hole, and when it gets close enough, gravitational forces will start pulling material in and heating it up. If July's event was a snack, G2's close encounter will be a gluttonous orgy.

    Just this week, researchers at Lawrence Livermore National Laboratory in California released a supercomputer simulation showing how the cloud will be disrupted as it passes by Sgr A*. That simulation suggests that the close encounter will last several months, and that G2 will be totally gone in less than a decade.

    Fragile et al. via College of Charleston / LLNL

    This three-dimensional volume visualization spans the period 2010 to 2020, showing the cloud of dust and gas known as G2 as it approaches the Sgr A* black hole near the center of the Milky Way galaxy.

    "It will just sort of break up into some sort of incoherent structure," Peter Anninos, a computational physicist at Livermore Lab, said in a news release. "Much of it will join the rest of the hot accretion disk around the black hole, or just fall and get captured by the black hole. It will lose a lot of energy, but not all of it. It will become so diffuse that it's unlikely that any remnant of the gas will continue on its orbital track."

    Check out this Web page for QuickTime animations showing what scientists think will happen to the cloud, and stay tuned for updates on the dietary preferences of our galaxy's not-always-sleeping giant.

    More about black holes:

    The G2 computer simulation is the subject of a paper due for publication in The Astrophysical Journal, titled "3D Moving-Mesh Simulations of Galactic Center Cloud G2." In addition to Anninos, the authors include P. Chris Fragile and Julia Wilson of the College of Charleston, as well as Stephen D. Murray of Livermore Lab.

    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.

  • Countdown to a black hole show

    Video from the European Southern Observatory tells you all about the massive gas cloud that's heading for the supermassive black hole at the center of our Milky Way galaxy.

    By Alan Boyle, Science Editor, NBC News


    Researchers are watching the first scenes of a cosmic show that's expected to heat up over the next year as a giant gas cloud approaches the supermassive black hole at the center of our galaxy.

    The impending collision was the subject of a research paper published in Nature last December, and now Youris.com, the European Research Media Center, is providing an update: By mid-2013, the cloud is expected to pass in the vicinity of the black hole, known as Sagittarius A*, at a distance of 36 light-hours, or less than 25 billion miles (40 billion kilometers).

    Black holes are gravitational singularities so dense that nothing, not even light, can escape their grip. They can only be detected by their gravitational influence on their surroundings, or by the blazing swirl of material being sucked down into their maw.

    Some black holes are thought to be created when massive stars collapse. Others, like Sagittarius A*, are thought to be crushed into existence as part of the galaxy formation process. Sagittarius A* is 4.3 million times as massive as our sun, and is located 27,000 light-years from our solar system. There's no danger that this black hole will gobble up the galaxy — in fact, it's unusually well-behaved, which is one reason why humanity has been able to hang around long enough to detect it.

    Stefan Gillessen, an astrophysicist at Germany's Max Planck Institute for Extraterrestrial Physics, has been observing Sagittarius A* for the past 20 years. He says next year's encounter could provide an unprecedented view of our supermassive black hole at its best ... or at its worst.

    Youris.com

    A computer simulation shows the elongation and breakup of a cloud of gas as it encounters the supermassive black hole at the center of our galaxy. Click on the image for an update and video on the encounter, which is expected to begin in 2013.

    "So far, there were only two stars that came that close to Sagittarius A*," Youris.com quotes him as saying. "They passed unharmed, but this time will be different: The gas cloud will be completely ripped apart by the tidal forces of the black hole."

    Astronomers at the European Southern Observatory say the speed of the cloud's progress has nearly doubled over the past seven years, to more than 5 million mph (8 million kilometers per hour). They report that the cloud's edges are already beginning to shred. During the months to come, it should break up into elongated filaments. "It will look like spaghetti," Gillessen said.

    The cloud is also expected to get much hotter, and will probably start emitting X-rays.

    Reinhard Genzel, who heads the ESO's team of astronomers, said the show won't end with next year's expected encounter.

    "The next few years will be really fantastic and exciting, because we're probing the territory," he said in the Youris.com video report. "Here this cloud comes in, gets disrupted, but now it will begin to interact with the hot gas right around the black hole. We have never seen this before."

    Update for 11:20 a.m. ET June 29: I've added the preferred title for the European media center, Youris.com.

    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.

  • Scientists zero in on black hole

    NASA / ESA / STScI / OSU / SRON

    is image of Markarian 509 was taken in April 2007 with the Hubble Space Telescope's Wide Field Camera 2. Observations reveal bullets of gas being driven away from the galaxy's supermassive black hole, and a corona of hot gas hovering above the disk of in-falling matter.

    By Alan Boyle, Science Editor, NBC News

    Astronomers have taken an unprecedented look at the tumult surrounding a supermassive black hole, using a quintet of space telescopes. And they're finding out that it's a horribly messy eater.

    The black hole in question is at the center of the galaxy Markarian 509, which is nearly 500 million light-years away. Unlike the black hole at the center of our own Milky Way galaxy, Markarian 509's colossal black hole is sucking huge amounts of dust and gas into its gravitational maw. Its mass is 300 million times that of the sun, or roughly 75 times the mass of the Milky Way's central black hole.

    Five space telescopes focused on Markarian 509: the European Space Agency's XMM-Newton telescope and Integral gamma-ray observatory, NASA's Chandra X-Ray Observatory and Swift gamma-ray probe, and the Hubble Space Telescope. The ground-based William Herschel Telescope and PARITEL telescope were also put on the case.

    The telescopes couldn't see the black hole itself, but they could see the strong emissions of radiation in various wavelengths from the wreckage that's swirling around it. The X-ray observatories — XMM-Newton and Chandra — were particularly useful.

    Markarian 509's gravitational monster is known for its variability. During the 100-day observing campaign, its brightness in the soft X-ray band jumped up by 60 percent, signaling a cosmic feeding frenzy. In a news release, the European Space Agency said giant, blobby bullets of gas were stripped away from the whirlpool and ejected at speeds of millions of miles per hour.

    The astronomers were surprised to find that the bullets were coming from a dusty reservoir of matter waiting to fall into the black hole, situated more than 15 light-years away. That's farther away than some astronomers thought was possible.

    "There has been a debate in astronomy for some time about the origin of the outflowing gas," said Jelle Kaastra of the SRON Netherlands Institute for Space Research. Kaastra coordinated the international black-hole research team of 26 astronomers from 21 institutes.

    M. Weiss / CXC / NASA

    In this artist's illustration, turbulent winds of gas swirl around a black hole. Some of the gas is spiraling inward toward the black hole, but another part is blown away.

    The dusty reservoir forms a doughnut-shaped torus around the black hole. Material spirals in toward the black hole, creating a whirling accretion disk. The disk appears to give rise to a "corona" that hovers above it.

    "This corona absorbs and reprocesses the ultraviolet light from the disk, energizing it and converting it into X-ray light," Kaastra said in a SRON news release. "It must have a temperature of a few million degrees. ... This discovery allows us to make sense of some of the observations of active galaxies that have been hard to explain so far."

    The researchers said the corona appears to be the source of the X-rays and gamma rays that drive the bullets outward.

    The initial results are being published as a series of seven papers in the journal Astronomy and Astrophysics, titled "Multiwavelength Campaign on Mrk 509." SRON said still more results are in preparation.

    More about black holes:

    Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding me to your Google+ circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.  

  • Black holes make space-time splash

    Caltech / Cornell SXS Collaboration

    This diagram shows two spiral-shaped vortexes (yellow) of whirling space sticking out of a black hole, plus the vortex lines (red curves) that form the vortexes.

    By Alan Boyle, Science Editor, NBC News

    No one's ever seen a black hole up close, but physicists can nevertheless visualize how two colliding black holes send ripples through space-time like waves on the ocean. They've even invented a new word — "tendex" — to describe the lines of force that stretch the objects caught in a space-time warp.

    A research paper published online this week in Physical Review Letters delves into the effects of black hole collisions in unprecedented detail. "We've found ways to visualize warped space-time like never before," Caltech theoretical physicist Kip Thorne said in a news release.

    Thorne and his colleagues at Caltech, Cornell University and the National Institute for Theoretical Physics in South Africa combined theory and computer simulations to describe the beautiful patterns of gravitation force lines emanating from black holes. Such lines are analogous to the invisible field lines created by electromagnetic forces.

    In some scenarios, warping space-time creates swirls of force lines that twist around each other in a region of space called a vortex. "Anything that falls into a vortex gets spun around and around," said Cornell physicist Robert Owen, the paper's lead author. An astronaut falling through a gravitational vortex would be wrung out like a wet towel.

    Caltech/Cornell SXS Collaboration

    In this simulation, two doughnut-shaped vortexes are ejected by a pulsating black hole. Also shown at the center are two red and two blue vortex lines attached to the hole, which will be ejected as a third doughnut-shaped vortex in the next pulsation.

    Tendex lines describe the stretching effect of a strong gravitational field. "Tendex lines sticking out of the moon raise the tides on the earth's oceans," said David Nichols, the Caltech graduate student who coined the term. When many such lines are bunched together, as in the surroundings of a black hole, that creates a super-stretching region called a tendex. An astronaut passing through a tidal tendex would be pulled apart like taffy — an effect sometimes known as "spaghettification."

    The researchers contend that the vortex and tendex concepts can lead to a clearer understanding of black hole collision modeling. If two black holes smash into each other head-on, that creates doughnut-shaped vortexes and tendexes that emanate from the merged black hole like smoke rings. But if the black holes spiral in toward each other before merging, the field lines swirl outward like sprays of water from a rotating sprinkler.

    Whether they're more like smoke rings or sprinkler jets, the force lines create gravitational waves — the kinds of waves that the Laser Interferometer Gravitational-Wave Observatory, or LIGO, has been built to detect. "With these tendexes and vortexes, we may be able to much more easily predict the waveforms of the gravitational waves that LIGO is searching for," said Caltech physicist Yanbei Chen.

    The researchers suggest that the vortex-tendex model could explain a theoretical phenomenon that other physicists noticed three years ago: Using computer models, the Rochester Institute of Technology's Manuela Campanelli and her colleagues found that a black hole collision could result in a gravitational kick so powerful that the merged black hole is thrown out of its galaxy. The newly published paper proposes that gravitational waves from spiraling vortexes and tendexes are added together on one side of the black hole, but cancel out each other on the other side. The result would be a burst of waves in one direction, creating the kick.

    "Though we've developed these tools for black hole collisions, they can be applied wherever space-time is warped," said Cornell's Geoffrey Lovelace. "For instance, I expect that people will apply vortex and tendex lines to cosmology, to black holes ripping apart, and to the singularities that live inside black holes. They'll become standard tools throughout general relativity."

    More about space-time warps:

    For more about "Simulating Extreme Spacetimes" project, including video visualizations of black hole collisions, check out Black-Holes.org, the Caltech-Cornell collaboration's website. In addition to Owen, Thorne, Chen, Lovelace and Nichols, the co-authors of the paper in Physical Review Letters, titled "Frame-Dragging Vortexes and Tidal Tendexes Attached to Colliding Black Holes: Visualizing the Curvature of Spacetime," include Jeandrew Brink, Jeffrey D. Kaplan, Keith D. Matthews, Mark A. Scheel, Fan Zhang and Aaron Zimmerman.

    Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about my book on Pluto and the search for planets, check out the website for "The Case for Pluto."