Inside a Keck telescope dome To clarify our view of outer space, astronomers use a new laser-based technology (seen from inside a Keck telescope dome).

Laurie Hatch

Homing in on Black Holes

To gain insight into the most mysterious objects in the universe, astronomers shine a light at the chaotic core of our own Milky Way

  • By Robert Irion
  • Smithsonian magazine, April 2008

Article Tools

  • Font
    		•  Share/Save/Bookmark Share
  • Email
    		•
  • Print
    		•  Digg Digg
  • Comments
    		•  StumbleUpon StumbleUpon
  • RSS
    		•  Reddit Reddit

    Photo Gallery

    Image of our galaxy taken by the Chandra satellite telescope

    Homing in on Black Holes

    Explore more photos from the story

    Related Links

    W. M. Keck Observatory

    Related Books

    Black Holes and Time Warps

    by Kip S. Thorne
    W. W. Norton & Company, 1994

    (Page 2 of 5)

    More from Smithsonian.com

    The Hubble Space Telescope added to the evidence for black holes in the 1990s by measuring how quickly the innermost parts of other galaxies rotate—up to 1.1 million miles per hour in big galaxies. The startling speeds pointed to cores containing up to a billion times the mass of the sun. The discovery that supermassive black holes are at the core of most, if not all, galaxies was one of Hubble's greatest achievements. "At the beginning of the Hubble survey, I would have said black holes are rare, maybe one galaxy in 10 or 100, and that something went wrong in the history of that galaxy," says Hubble scientist Douglas Richstone of the University of Michigan. "Now we've shown they are standard equipment. It's the most remarkable thing."

    Even from Hubble, though, the Milky Way's core remained elusive. If our galaxy harbored a supermassive black hole, it was quiet, lacking the belches of energy seen from others. Hubble, scheduled to be serviced later this year, can track groups of stars near the centers of distant galaxies, but because of its narrow angle of view and our galaxy's thick dust clouds, it can't take the same pictures in our galaxy. Another approach would be to track individual stars in the black hole's vicinity using infrared light, which travels through dust, but the stars were too faint and too crowded for most ground-based telescopes to resolve. Still, some astronomers in the 1990s ventured that observations of the Milky Way's core might be possible, proving beyond doubt that a black hole exists there. A number of tantalizing questions could then be addressed: How do stars live and die in that wild setting? What does a black hole consume? And can we witness, at the heart of the Milky Way, the warped space and time predicted by Einstein nearly a century ago?

    The Keck control room is 20 miles from the telescope, in the ranching town of Waimea. To the researchers there, the spectacular laser is visible only as a wan beam in a live video feed on a computer monitor. The astronomers check their notebooks and watch screens full of telescope data, weather readings and the latest picture of the stars they're targeting. They use a video link to talk to the telescope operator, who will spend all night at the summit. Things are going so smoothly that there isn't much to do. The telescope will stay locked on the same spot in the sky for four hours; the laser's working fine, and a camera attached to the telescope takes one 15-minute exposure after another in an automated sequence. "This is just about the dullest kind of observing there is," University of California at Los Angeles astronomer Mark Morris says apologetically.

    Even so, there's tension in the room. This team of astronomers, led by Andrea Ghez of UCLA, is in a heated competition with astronomers at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. For more than a decade, Garching astrophysicist Reinhard Genzel and his colleagues have studied the black hole at the center of the Milky Way using the New Technology Telescope and the Very Large Telescope array in Chile. Ghez, 42, pushes her students to get the most out of each observation session at Keck. Four years ago she was elected to the National Academy of Sciences—quite an honor for someone still in her 30s. "It's easy to be at the forefront of astronomy if you have access to the best telescopes in the world," she says.

    Several years ago the American and the German teams independently deduced that only a giant black hole could explain the behaviors of stars at the Milky Way's core. Stars circling a hefty mass—whether a black hole or some large star—travel through space much faster than those circling a smaller mass. In visual terms, the larger mass creates a deeper funnel in the fabric of space around which the stars revolve; like leaves circling a whirlpool, the deeper the whirl- pool, the faster the leaves spin. Other astronomers had seen fast-moving stars and clouds of gas near the center of the Milky Way, so both Ghez and Genzel suspected a dense cluster of matter was hidden from view.

    By painstakingly compiling infrared photographs taken months and years apart, the two teams tracked the innermost stars, those within one light-month of the galaxy's center. Combined, the images are like time-lapse movies of the stars' motions. "Early on, it was clear there were a few stars that were just hauling," Ghez recalls. "Clearly, they were extremely close to the center." Something was trapping the stars in a deep whirlpool. A black hole made the most sense.

    The clincher came in 2002, when both teams sharpened their images using adaptive optics, technology that compensates for the atmosphere's blur. The scientists followed stars that orbit perilously close to the galaxy's center and found that the fastest star's top speed was 3 percent of the speed of light—about 20 million miles per hour. That's a startling speed for a globe of gas far bigger than our sun, and it convinced even the skeptics that a supermassive black hole was responsible.

    The blur of Earth's atmosphere has plagued telescope users since Galileo's first studies of Jupiter and Saturn nearly 400 years ago. Looking at a star through air is like looking at a penny on the bottom of a swimming pool. Air currents make the starlight jitter back and forth, just as a penny's image seems to dart around the pool's bottom.

    Editor's Note, Sept. 23, 2008: Smithsonian magazine profiled astrophysicist Andrea Ghez in April, 2008. Today, Ghez was one of 28 recipients of a prestigious MacArthur genius grant, acknowledging her contributions to the study of black holes in the evolution of galaxies.

    VIDEO: Milky Way Moves Observe stars orbiting our galaxy's black hole

    From the summit of Mauna Kea, nearly 14,000 feet above the Pacific Ocean, the Milky Way tilts luminously across the night sky, an edge-on view of our galaxy. Parts of the great disk are obscured by dust, and beyond one of those dusty blots, near the teapot of the constellation Sagittarius, lies the center of the Milky Way. Hidden there is a deeply mysterious structure around which more than 200 billion stars revolve.

    Behind me atop the craggy rocks of this dormant volcano on the island of Hawaii are the twin domes of the W. M. Keck Observatory. Each dome houses a telescope with a giant mirror that is almost 33 feet wide and, like a fly's eye, is made of interlocking segments. The mirrors are among the world's largest for gathering starlight, and one of the telescopes has been equipped with a dazzling new tool that greatly increases its power. Fewer than 100 people have seen this technology in action. I gaze at the nearest of the Milky Way's graceful spiral arms as I wait for technicians to flip the switch.

    Then, suddenly and with the faint click of a shutter sliding open, a golden-orange laser beam shoots into the sky from the open dome. The ray of light, 18 inches wide, appears to end inside one of the blackest spots in the Milky Way. It actually ends 55 miles above the surface of the earth. The signal it makes there allows the telescope to compensate for the blur of Earth's atmosphere. Instead of jittery pictures smeared by the constantly shifting rivers of air over our heads, the telescope produces images as clear as any obtained by satellites in space. Keck was one of the first observatories to be outfitted with a laser guide; now half a dozen others are beginning to use them. The technology provides astronomers with a sharp view of the galaxy's core, where stars are packed as tightly as a summer swarm of gnats and swirl around the darkest place of all: a giant black hole.

    Without question, the Milky Way's black hole is the strangest thing in our galaxy—a three-dimensional cavity in space just ten times the physical size of our sun but with four million times the mass, a virtual bottomless pit from which nothing can escape. Every major galaxy, it turns out, has a black hole at its core. Now, for the first time, scientists have the chance to study the havoc these mind-boggling entities wreak. For the next decade, Keck astronomers will track thousands of stars caught in the gravity of the Milky Way's black hole. They will try to figure out how stars are born close to the black hole and how it distorts the fabric of space itself. "I find it amazing that we can see stars whipping around our galaxy's black hole," says Taft Armandroff, director of the Keck Observatory. "If you had told me as a graduate student that I'd see that during my career, I'd have said it was science fiction."

    To be sure, the evidence for black holes is entirely indirect; astronomers have never actually seen one. Albert Einstein's general theory of relativity predicted that the gravity of an extremely dense body could bend a ray of light so severely that it could not escape. Something the mass of our sun, for instance, could trap light if it shrank into a ball just one and a half miles across. For Earth to become a black hole, its entire mass would have to fit into a sphere no bigger than a pea.

    In 1939, J. Robert Oppenheimer and another physicist calculated that such drastic compression could happen to the biggest stars after they ran out of hydrogen and other fuel. Once the stars sputtered out, the scientists posited, the remaining gas would collapse under its own gravity into an infinitely dense point. Telescope observations backed up the theory in the 1960s and 1970s. Astronomers discovered quasars—extremely bright beacons billions of light-years away. A few researchers suggested the only possible power source for something so luminous would be a concentration of millions of suns in a small volume—pulled together by what scientists later dubbed a supermassive black hole. Astronomers then found stars that seemed to whip around invisible companions in our Milky Way, and they concluded that only the pull of gravity from small black holes could keep the stars in such tight orbits. Containing several times the mass of our sun, these are called stellar-mass black holes.

    The Hubble Space Telescope added to the evidence for black holes in the 1990s by measuring how quickly the innermost parts of other galaxies rotate—up to 1.1 million miles per hour in big galaxies. The startling speeds pointed to cores containing up to a billion times the mass of the sun. The discovery that supermassive black holes are at the core of most, if not all, galaxies was one of Hubble's greatest achievements. "At the beginning of the Hubble survey, I would have said black holes are rare, maybe one galaxy in 10 or 100, and that something went wrong in the history of that galaxy," says Hubble scientist Douglas Richstone of the University of Michigan. "Now we've shown they are standard equipment. It's the most remarkable thing."

    Even from Hubble, though, the Milky Way's core remained elusive. If our galaxy harbored a supermassive black hole, it was quiet, lacking the belches of energy seen from others. Hubble, scheduled to be serviced later this year, can track groups of stars near the centers of distant galaxies, but because of its narrow angle of view and our galaxy's thick dust clouds, it can't take the same pictures in our galaxy. Another approach would be to track individual stars in the black hole's vicinity using infrared light, which travels through dust, but the stars were too faint and too crowded for most ground-based telescopes to resolve. Still, some astronomers in the 1990s ventured that observations of the Milky Way's core might be possible, proving beyond doubt that a black hole exists there. A number of tantalizing questions could then be addressed: How do stars live and die in that wild setting? What does a black hole consume? And can we witness, at the heart of the Milky Way, the warped space and time predicted by Einstein nearly a century ago?

    The Keck control room is 20 miles from the telescope, in the ranching town of Waimea. To the researchers there, the spectacular laser is visible only as a wan beam in a live video feed on a computer monitor. The astronomers check their notebooks and watch screens full of telescope data, weather readings and the latest picture of the stars they're targeting. They use a video link to talk to the telescope operator, who will spend all night at the summit. Things are going so smoothly that there isn't much to do. The telescope will stay locked on the same spot in the sky for four hours; the laser's working fine, and a camera attached to the telescope takes one 15-minute exposure after another in an automated sequence. "This is just about the dullest kind of observing there is," University of California at Los Angeles astronomer Mark Morris says apologetically.

    Even so, there's tension in the room. This team of astronomers, led by Andrea Ghez of UCLA, is in a heated competition with astronomers at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. For more than a decade, Garching astrophysicist Reinhard Genzel and his colleagues have studied the black hole at the center of the Milky Way using the New Technology Telescope and the Very Large Telescope array in Chile. Ghez, 42, pushes her students to get the most out of each observation session at Keck. Four years ago she was elected to the National Academy of Sciences—quite an honor for someone still in her 30s. "It's easy to be at the forefront of astronomy if you have access to the best telescopes in the world," she says.

    Several years ago the American and the German teams independently deduced that only a giant black hole could explain the behaviors of stars at the Milky Way's core. Stars circling a hefty mass—whether a black hole or some large star—travel through space much faster than those circling a smaller mass. In visual terms, the larger mass creates a deeper funnel in the fabric of space around which the stars revolve; like leaves circling a whirlpool, the deeper the whirl- pool, the faster the leaves spin. Other astronomers had seen fast-moving stars and clouds of gas near the center of the Milky Way, so both Ghez and Genzel suspected a dense cluster of matter was hidden from view.

    By painstakingly compiling infrared photographs taken months and years apart, the two teams tracked the innermost stars, those within one light-month of the galaxy's center. Combined, the images are like time-lapse movies of the stars' motions. "Early on, it was clear there were a few stars that were just hauling," Ghez recalls. "Clearly, they were extremely close to the center." Something was trapping the stars in a deep whirlpool. A black hole made the most sense.

    The clincher came in 2002, when both teams sharpened their images using adaptive optics, technology that compensates for the atmosphere's blur. The scientists followed stars that orbit perilously close to the galaxy's center and found that the fastest star's top speed was 3 percent of the speed of light—about 20 million miles per hour. That's a startling speed for a globe of gas far bigger than our sun, and it convinced even the skeptics that a supermassive black hole was responsible.

    The blur of Earth's atmosphere has plagued telescope users since Galileo's first studies of Jupiter and Saturn nearly 400 years ago. Looking at a star through air is like looking at a penny on the bottom of a swimming pool. Air currents make the starlight jitter back and forth, just as a penny's image seems to dart around the pool's bottom.

    In the 1990s, engineers learned to erase the distortions with a technology called adaptive optics. They had computers analyze the jittering pattern of incoming starlight on a millisecond by millisecond basis, and used those calculations to drive a set of pistons on the back of a thin and pliable mirror. The pistons flexed the mirror hundreds of times each second, adjusting the surface to counteract the distortions and form a sharp central point instead of a fuzzy blob.

    The technology had one severe limitation. The computers needed a strong, clear guiding light to track, as a kind of reference point. The system worked only if the telescope was aimed close to a bright star or planet, limiting astronomers to just 1 percent of the sky.

    By creating an artificial guide star in any part of the sky, the Keck Observatory's laser removes that barrier. The laser beam is tuned to a frequency that lights up sodium atoms, which are left by disintegrating meteorites in a thin layer of the atmosphere. Keck's computers analyze the distortion in the column of air between the telescope mirror and the laser-created star.

    Inside the telescope's 101-foot-tall dome, the laser system sits within a bus-size enclosure. The laser starts out with a jolting 50,000 watts of power, amplifying the light beam within a dye solution made from 190-proof ethanol. But by the time the light is adjusted to its correct color and its energy is channeled along a single path, its power dwindles to about 15 watts—still bright enough that the Federal Aviation Administration requires the observatory to shut down the laser if an airplane flies near its path. From several hundred feet away the laser looks like a dim amber pencil beam. A bit farther and it isn't visible at all. As far as the rest of the island is concerned, there is no laser show at Mauna Kea.

    Identifying a black hole is one thing; describing it is another. "It's difficult to paint a picture that relates to the world as we understand it, without using mathematical complexity," Ghez says one afternoon at the Keck control center. The next day, she asks the older of her two sons, 6-year-old Evan, if he knows what a black hole is. His quick response: "I don't know, Mommy. Shouldn't you?"

    Mark Morris thinks that "sinkhole" makes an apt metaphor for a black hole, particularly "a three-dimensional sinkhole. If you were in space near the black hole," he says, "you would see things disappear into it from all directions."

    Both Ghez and Morris like to visualize what it would be like to be near the black hole looking outward. "This is the thriving city center of the galaxy, compared to the suburbs where we are," says Ghez. "Stars are moving at tremendous speeds. You'd see things change on a time scale of tens of minutes." Morris picks up on this theme. "If you look at the night sky from a beautiful mountaintop, it takes your breath away how many stars there are," he says. "Now, multiply that by a million. That's what the sky at the galactic center would look like. It would be like a sky full of Jupiters, and a few stars as bright as the full moon."

    In this magnificent setting, the laws of physics are wonderfully twisted. Ghez and Morris hope to gather the first evidence that stars do indeed travel along the weird orbital paths predicted by Einstein's relativity theory. If so, each star would trace something like a Spirograph pattern over time, gradually altering the point of its closest approach to the black hole. Ghez thinks she and her colleagues are about eight years away from spotting that shift.

    With each new finding, the Milky Way's core becomes more perplexing and fascinating. Both Ghez's and Genzel's teams were startled to discover many massive young stars in the black hole's neighborhood. There are scores of them, all just five to ten million years old—infants, in cosmic terms—and they are roughly ten times as massive as our sun. No one is entirely sure how they got so close to the black hole. Elsewhere in the galaxy, gestating stars require a cold, calm womb within a large cloud of dust and gas. The galactic core is anything but calm: intense radiation floods the area, and the black hole's gravity should shred gaseous nurseries before anything incubates there. As Reinhard Genzel put it at a conference a few years ago, those young stars "have no damn right to be there." It's possible some of them were born farther out and migrated inward, but most theorists think they're too young for that scenario. Morris thinks the intense gravity compresses spiraling gas into a disk around the black hole, creating the new suns in a type of star birth not seen in any other galactic environment.

    These young stars will self-destruct a few million years from now. And when they do, the most massive ones will leave behind small black holes. Morris theorizes that hundreds of thousands of these stellar-mass black holes, accumulated from past generations of stars, swarm around the central supermassive black hole. The stellar-mass black holes are only about 20 miles wide, so collisions between them would be rare. Instead, Morris says, "You'll have black holes swinging past each other in the night, and stars moving through this destruction derby. A near miss between one of the black holes and a star could scatter the star into the supermassive black hole or out of the galactic center entirely." Theorists think the supermassive black hole may gobble a star once every tens of thousands of years—an event that would ignite the center of the galaxy with radiation. "It would be a spectacular event," Morris says.

    Astronomers see signs of these meals by examining the Milky Way's interior with X-ray and radio telescopes, which detect the shock waves of past explosions. Giant black holes in other galaxies are too far away for astronomers to study in such depth, says Avi Loeb, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. That's why he hangs on every announcement from the Ghez and Genzel teams. "The advances made by the observers in such a short time have been truly remarkable," he says. "We theorists are all cheerleaders for them."

    Loeb and others are painting a new picture of how the universe and its 100 billion galaxies have evolved since the big bang 13.7 billion years ago. They believe that all galaxies started with as-yet-unexplained "seed" black holes—tens to thousands of times the mass of our sun—that grew exponentially during violent feeding cycles when galaxies collided, which they did more frequently when the universe was younger and galaxies were closer together. In a collision, some stars catapult into deep space and other stars and gases plummet into the combined black hole at the galaxies' center. As the black hole grows, Loeb says, it turns into a raging quasar with gas heated to billions of degrees. The quasar then blasts the rest of the gas out of the galaxy entirely. After the gas is depleted, Loeb says, "the supermassive black hole sits at the center of the galaxy, dormant and starved."

    It appears that our Milky Way, with its modest-sized black hole, has absorbed only a few smaller galaxies and has never fueled a quasar. However, a fearsome collision looms. The closest large galaxy, called Andromeda, is on a collision course with the Milky Way. The two will start to merge about two billion years from now, gradually forming a massive galaxy that Loeb and his Harvard-Smithsonian colleague T. J. Cox call "Milkomeda." The galaxies' supermassive central black holes will collide, devouring torrents of gas and igniting a new quasar for a short time in this sedate part of the universe. "We are late bloomers in that regard," Loeb notes. "It happened to most other galaxies early on."

    Our galaxy's fearsome future aside, Loeb hopes that soon—perhaps within a decade—we'll have the first image of the Milky Way's supermassive black hole, thanks to an emerging global network of "millimeter wave" telescopes. Named for the wavelength of infrared light they detect, the instruments technically won't see the black hole itself. Rather, they'll act in concert to photograph the shadow the black hole casts on a curtain of hot gas behind it. If all goes well, the image should show a black shadow, possibly with a distinctive shape. Theorists expect the black hole to be spinning. If so, according to the counterintuitive dragging of space predicted by Einstein's general theory of relativity, our view of the shadow will be distorted into something like a lopsided and squashed teardrop. "It would be the most remarkable picture we could have," says Loeb.

    On the fourth and final night of Ghez's planned observations, wind and fog at the Mauna Kea summit keep the telescope domes closed. So the astronomers take another look at their data from the previous nights. Passing the time, graduate student Tuan Do downloads a song to his computer and reads the lyrics to his amused colleagues. It's called "Supermassive Black Hole," by the British rock band Muse, who sing "o, o, you set my soul alight."

    Images from the first two nights ranged from good to excellent, says Ghez; the third night was "respectable." She's says she's content: her students have enough to keep them busy, and Do identified a few more big young stars to add to the team's analysis. "I feel incredibly privileged to work at something I have this much fun at," she says. "It's hard to believe that black holes really exist, because it's such an exotic state of the universe. We've been able to demonstrate it, and I find that really profound."

    She spends most of her time overseeing the command center at Waimea, but she has been to the top of Mauna Kea to see the laser in action. As we talk about the mesmerizing sight, it is clear that Ghez appreciates an irony: astronomers love the dark and often complain about any source of light that might interfere with their observations. Yet here they are, casting a beacon of light into the heavens to help illuminate the blackest thing humanity can ever hope to see.

    Robert Irion directs the University of California at Santa Cruz science-writing program and wrote about planets in October 2006.


    1 2 3 4 5


     
    Comments

    In this day of declining infrastructure, health care and education suffering lack of funds, water increasingly a matter for serious conflict between states and other problems we are evading, how can we continue the outrageous expense of the space programs. This article was generated -- at least partially -- from the island of Hawai`i where I live. I can assure you the lack of revenue from the space program tenants above Mauna Kea -- where this Keck telescope sits on state land -- is not providing anything like the revenue it should. Our children suffer one of the worst school systems in America. Our University of Hawai`i doesn't have enough money to provide adequate laboratory facilities for either teaching or research. Lots of money and attention for sports, however. This nation is in trouble and every article of this kind needs to include the COST of the beauty and science for which many see very little benefit. Or, if there are benefits beyond the satisfaction of "mine is bigger than yours" telescope enthusiasts, share them with the public.

    Posted by Bill Eger on March 26,2008 | 02:12PM

    How Fantastic! Do they need observers going over data picked up by the pictures? Have they " watched" a star or other body actually enter the field of a black hole? do they have a picture of our galexy with the position of the black hole. I took a class on Black Holes, Quarks, and quasars in the 70's at UCSD. It was fasinating then and more so now. Science and space have come a long way! Carolyn

    Posted by Carolyn Monteverde on March 26,2008 | 10:09PM

    Hey i watched a movie today in science 21 about black holes and it has just made me so interested in them. It fasanates me how they are real and how our wonderful univers can create strange but interesting objects.

    Posted by Danni Bright on March 27,2008 | 03:21AM

    Does the laser help take the wiggle out of the image by compensating for distortions in the atmosphere or some more distant function? Charlie

    Posted by Charles Smith on March 29,2008 | 01:18PM

    Nice story. Maybe eventually everything will get sucked into the black holes? Coincidentally, I am almost done with reading the SF books Dragon's Egg and Starquake by Robert L. Forward. Fascinating books with a lot of science based fact intertwined about a hypothetical race of beings called the Cheela that live and build a civilization on a neutron star and can manipulate black holes.

    Posted by Jojo on March 30,2008 | 03:25AM

    Question for Robert Irion: If the universe is expanding, including the distance between galaxies, how can Andromeda and the Milky Way be on a collision course? Are they so close together already that the gravitational attraction is too strong to overcome? How do we know all this?

    Posted by Tim Shank on March 30,2008 | 09:40AM

    In response to Tim Shank's excellent question: The overall universe is expanding. Indeed, this expansion is now accelerating, one of the strangest discoveries in cosmology. This expansion takes place everywhere, but in some parts of the universe galaxies are close enough together so that their mutual gravitational pull toward each other is dominant. There are lots of major clusters of galaxies bound together in this way. Eventually, the largest galaxy at the center of each of these clusters will absorb the smaller galaxies around it. Astronomers see this galactic cannibalism happening everywhere they look. The Milky Way and Andromeda are part of a small cluster, called the Local Group -- it's our small neighborhood island of galaxies resisting the overall tide of universal expansion. Astronomers know this by examining the light emitted by stars in Andromeda. This light, as seen by our telescopes, is "blueshifted," or shifted toward the blue end of the spectrum of light's colors. That's because Andromeda is speeding toward us. In contrast, the light from galaxies moving away from us is "redshifted." (This is the starlight equivalent of the Doppler shift one hears when an ambulance siren or motorcycle approaches you, at a higher pitch, and then recedes from you, at a lower pitch.) Then, astronomers can extrapolate this speed to determine when the collision will happen. The galaxies will "fall" into each other gravitationally, at a quickening pace, with the first interaction about 2 billion years from now. I hope that makes sense! You basically answered your own question, Tim, with your insights. --RI

    Posted by Robert Irion on March 30,2008 | 09:54PM

    For Jojo: Our solar system and most of the galaxy's stars are safe from the central black hole, for the same reason planets don't spiral into the Sun: Their orbits have the momentum needed to keep them at a stable distance. The physical size of the black hole is actually incredibly small compared to the vast scale of the galaxy. If you shrank the Milky Way to the size of the Earth, the supermassive black hole at the center could fit onto the tip of your thumb. So it really can only "devour" the gas -- and occasional unfortunate stars -- that wander too close to it or get scattered into it after interacting with other stars nearby. Bottom line: We're staying put! (When Andromeda and the Milky Way crash, though, our solar system could get flung into intergalactic space by the turmoil.) By the way, Jojo, if you like black holes in science fiction, you should read "Eater" by Gregory Benford. It's about a rogue black hole that enters our solar system and is, well, capable of some dastardly thinking. I won't say more. But Benford is one of the best hard SF writers, with lots of physics wrapped into his plots. (He's a physicist at UC Irvine.) For Charles Smith: The laser provides a reference "point" of light high in the atmosphere, above most of Earth's blanket of air. When the telescope creates an image of this point, computers analyze the patterns of its "jiggles" created by moving currents of air overhead. Then, the computers send instructions to a flexible mirror to exactly counteract those jiggles. When the incoming light bounces off the flexible mirror, the images of real stars are restored to sharp points. It's true optical wizardry.

    Posted by Robert Irion on March 30,2008 | 10:10PM

    Your magazine says, on page 53, "Watch stars orbit our black hole at Smithsonian .com/blackhole" So here am am perusing everything on my screen, and I find nothing to watch. I have been misled.

    Posted by Theresa Enroth on March 30,2008 | 10:49PM

    I am so fascinated by the universe in general and especially intrigued by blackholes. Thank you for the great article and the great reading tips from other readers. I can't get enough of this subject!

    Posted by Sue Wuolukka on April 1,2008 | 08:57PM

    will we live beside the moon and the sun ?!!!! its very exiting what will we use to travel ?!!!

    Posted by hani haleem on April 3,2008 | 03:44AM

    This was a fantastic article to read! Here are some additional links if you want to see some pictures of the data that gets taken and web-movies of the stars orbiting the black hole: UCLA Galactic Center Group: http://www.astro.ucla.edu/~ghezgroup/gc/ Check out the Pictures section for good animations and the Education/Outreach section for even more links. Max Planck Institute for Extraterrestrial Physics Galactic Center Group http://www.mpe.mpg.de/ir/GC/index.php

    Posted by jlu on April 4,2008 | 01:24PM

    This article is awesome, I was so excited as I read it. I wrote my first book, 16 short sci-fi stories and the first story is about collapsing galaxies - as in black holes. Oh I am so very excited. The research confirms much of what I had come to through study and reading over the years. What confirmation you provide with your articles, not even realizing that you touched my galaxy of life, and imploded the heavy darkness in the black holes of experiences. Thank you, and thanks to all the researchers. . .I'm with you and I feel you!!!

    Posted by DrSew on April 8,2008 | 04:34PM

    For Theresa: You can access the animation touted on page 53 by clicking the link in the text after the article's byline at the top of the page. (link embedded in this text: VIDEO: Milky Way Moves Observe stars orbiting our galaxy's black hole)

    Posted by Jess on April 10,2008 | 06:56AM

    Reply to Bill Eger, When we study and learn how we fit in among wonders of the cosmos we nurture and feed the human spirit which treasures learning and shows itself as a sparkle in the eyes of of a healthy and curious human being, a sparkle as powerful and expansive as what we externalize and call the big bang. Collapsing infrastructure and environment should be associated with huge negatives like continuous war, gargantuan subsidies to polluting technologies and centralization of land ownership to corporations which are at war with nature in their area of ownership. Research into the wonders of creation is not the place where money is wantonly burned. Think about how many energy saving light bulbs it takes counteract one take-off and bombing run in the continuous war. There is a long list of negative culprits which absorb and misuse human effort, understanding how human consciousness blossoms with the cosmos is a positive scientific study, it is not on that dark list of negatives which deprive humanity and destroy nature.

    Posted by Garrett Connelly on April 14,2008 | 05:14PM

    Thanks, Garett. I can't contain myself when I see the same old whazzitgoodfo' line.

    Posted by Dihydrogen Monoxide on April 15,2008 | 07:46AM

    I share your concern Bill Eger. As much as I am interested in and find this information so exciting, I cannot help but think that the resources here on earth could and should be better spent on programs that are effective in relieving human persecution, starvation, suffering and inhuman treatment on this planet. From my observatory of life I see this program as well as the decadent NASA program as figurative "black holes" for resources that could/should be more intelligently spent on genuinely real issues here on earth. However, the perceived mis-spending of resources is not caused by the resources themselves or the programs upon which they are spent. Rather, it reflects a deficiency in overall leadership to act upon the important priorities of our time. It is somewhat of a folly that we can point powerful and expensive telescopes at the center of our galaxy while turning a blind eye to fellow members of our species on this planet. As to the reference to the bombing missions made by Mr. Connelly, my little girl oft reminds me that two wrongs do not make a right. And expanding human consciousness cannot fill a stomach or cure the sick. I know this hard since if I had my druthers, I wish we had unlimited resources so that we could do it all...

    Posted by Frank Porta on April 15,2008 | 05:30PM

    NASA Gripes me too. What they do is important in a research perspective; however, i cannot help but think like many in that so many of our tax dollars go down a huge sinking black hole. Like so much government, it ends up just adding to fraud, waste and abuse. Let's explore our ocean floors; now there we go, it's even on our planet. LM

    Posted by Mac on May 2,2008 | 11:46AM

    Comments by Bill Eger regarding Mauna Kea are ironically short-sighted. I am a regular visitor to Hawaii and was on the peak of Mauna Kea when this article was distributed to readers. Multiple countries (non American public monies) have invested millions of dollars creating the most remarkable observatory peak in the world, the Keck observatories were funded by a private foundation, and the 13,000+ foot mountain peak of Mauna Kea could not serve any other practical purpose for the people of Hawaii. As to the issue of Hawaiian education, the culture in Hawaii affords historically little priority to education, and that cultural problem pre-existed any observatory on the Big Island. Astronomy and our space program inspires many to seek answers to the universe ... and that has been far more successful in providing perspective in the universe than the multitude of religious philosophies that have competing explanations for how the universe formed. The key to public funding priorities is to balance the absolute needs of society with our inherit desire to learn, understand and improve ourselves. Let's not return to the dark ages of mental stagnation ... a human mind is a terrible thing to waste.

    Posted by ken bastin on May 2,2008 | 04:51PM

    It has been impossible to find a discussion on black hole collisions. I'm told that all scientists accept the big bang theory. I should think that black hole collisions should get more attention because deriving an entire universe from a singularity seems too far out and I have not seen a plasible explanation for it.

    Posted by Don W Baird on May 2,2008 | 09:50PM

    i think this so called "black hole" is very interesting and i think that we need to do some more research on it because some people don't believe in it. We need more information on the "black hole" because i don't know if it even exists.

    Posted by Jenny on May 3,2008 | 07:26AM

    For Don Baird: Quite a few astrophysicists do study black hole collisions. Some of them use supercomputer simulations to explore what happens when black holes spiral into each other and crash. Those are incredibly violent events, and they literally rattle the universe by sending out "gravitational waves" that distort the fabric of space-time -- just like the ripples you create in a smooth pond by hurling a rock into it. Physicists have built detectors that probably are within a few years of finding and measuring these waves for the first time. Ultimately the detectors will spot most of the collisions of giant black holes throughout the universe. We won't "see" them in the traditional sense because most of the crashes will be inside galaxies much too far away for telescopes to resolve. However, telescopes on the ground and in space have shown astronomers many examples of galaxies in the long process of merging with each other, as our Milky Way and the nearby Andromeda galaxy will do billions of years from now. For instance, the Chandra X-ray Observatory orbiting around Earth has seen evidence of pairs of giant black holes very close to each other inside these "interacting pairs" of galaxies. To my knowledge, no researcher claims that such collisions would create new universes, though. The Big Bang is indeed really difficult to grasp, but it doesn't appear a black hole bangup was involved. --RI

    Posted by Robert Irion on May 9,2008 | 11:33AM

    I have no idea if this comment will be censored, but the concept of black holes or more properly, a singularity, was not accepted by Einstein, and the Schwartzchild interpretation is in error. Warped space-time, a black hole in every galactic core are not required in plasma cosmology. Here's link to the original paper in English: http://www.sjcrothers.plasmaresources.com/schwarzschild.pdf Dr. Jeremy Dunning-Davies is a Senior Lecturer in Theoretical Physics in the Department of Physics at the University of Hull, England. He writes: 'One further point needs stressing, I think. I was initially trained as a mathematician, although my degree did involve two years of subsidiary physics. Over the years, I have come to realise more and more the power of mathematics but also the fact that that power can be misused. Mathematics is a beautiful subject and can be studied, in its own right, as a highly worthwhile intellectual pursuit. However, mathematics has a second role as the language of physics and, in that rôle, it is simply a tool which must always remain subservient to the physics. If the mathematics throws up a result which does not accord with physical reality, it should be studied carefully but not accepted immediately unless a genuine physical interpretation can be found; the physics must never ever be made to fit the mathematics!' http://www.thunderbolts.info/thunderblogs/guest2.htm

    Posted by James Parker on May 10,2008 | 07:04AM

    The use of the term 'hot gas' throughout this article indicates the 'experts' are entirely ignorant of plasma; you are dealing with plasma, not hot gas. Black holes are a mathematical construct that have become an industry; Einstein thought they were improbably, and his writing is ignored; black holes have become a 'faux' industry. If I am not censored, here are links for interested taxpayers to check out. ' http://plasmascience.net/tpu/TheUniverse.html http://www.thunderbolts.info/thunderblogs/guest2.htm As Dr. Dunning-Davies writes: 'As Stephen Crothers has recently pointed out, this final topic should really be a non-starter, based as it is on an incorrect statement of Schwartzschild’s solution of the Einstein field equations. However, again as Stephen has pointed out, even the incorrectly quoted ‘solution’ is included in, and protected by, conventional wisdom. One further surprising aspect of much of conventional wisdom is that the originators of much of this body of knowledge would have welcomed discussion and even criticism, provided that criticism was constructive. In this day and age, however, people who disagree with conventional wisdom do not face discussion and constructive criticism; rather they are either quietly ignored or destroyed. The first of these is possibly the more destructive action occurring in modern science because if something is quietly ignored, it gains no publicity and so remains unknown, except to the favoured few.' If there are 'truth seekers' here, please make up your own mind. The galactic center is a Torus, not a black hole, the focus of intergalactic Birkeland currents. No space time has to be twisted to provide an answer to observations. Electrical forces are at work and plasma physics, demonstrated on laboratories on earth. Cheer!

    Posted by J. Parker on May 10,2008 | 09:34AM

    how long would it take for the sun to explode? what would it look like?

    Posted by sam canne on May 10,2008 | 10:42AM

    Why don't you put the most recent comments at the head of the line. Astronomy should be treated as a hobby, not given grants. Nice pictures of the universe for how much? Colliders should not be given huge grants; what is gained by smashing atoms? Scientist experiment: explode an atomic weapon, and direct its' blast toward a target??? Not a joke. How much money was wasted on that one.

    Posted by tjake13 on May 14,2008 | 12:26PM

    For the Bill Eger comment and those like it. The reasons why our country has healthcare and education problems has nothing to do with NASA. Do you think if the space program was discontinued, then the US would suddenly solve all of these problems. Do you think that the government would change its stance on national healthcare in the US--of course not. Funding for research is perhaps an easy target for people who are concerned about the economy and the state of the country. But research helps our country to advance technologically. Sometimes the direct application of research is not discovered for years, but the impact can be huge. Can you argue that NASA hasn't vastly improved our ability to analyze and predict the weather? It is unfortunate and short sighted to blame research expenditures for this country's problems. Our country has not voted for politicians who support healthcare and education reforms-that's our fault, not NASA's.

    Posted by bright_future on May 22,2008 | 08:51AM

    I really wish the person who complained about the money spent on this excellent research would take a look at the big picture. "Pure" science has probably returned the most benefits per dollar of anything any institution has ever done. If you want to know why the quality of life in the US in general has deteriorated so much, check what the war is costing--one day's worth of expense killing people abroad would probably fund this research for a year.

    Posted by Mary Ellen Ryder on May 22,2008 | 09:09PM

    the Milky way

    Posted by dakota on May 23,2008 | 08:57AM

    I like to know more obaut explosion supernova star first primordial soup

    Posted by supernova star information on May 26,2008 | 05:18PM

    Dones Uranus have a ring

    Posted by ulysses on May 31,2008 | 12:31PM

    All the brilliant minds on the planet including people such as Steven Hawking and the rest should know this,every galaxy in our universe has a black hole or a vortex that spins in a circle or orbit.All the bodies that surround it do exactly the same.It takes un uncalculable amount of time for these bodies to eventually spin towards the center of this black hole or vortex and and die and be reborn at the same time.As they enter the vortex they travel so fast that every element,every molecule,every atom and other unknowns are completely broken down so small that no microscope ever made or any other equipment can even detect them.They exit at the end of this vortex and join the universal cosmic and celestial winds and move at unreal speeds and keep colliding with other particles expunged from other black holes and keep colliding until they gain tremendous mass .They are worn smooth and then get caught in the gravitational pull or a galaxial orbit .The time that it takes for these universal events to happen should prove to all that our universe cannot be quoted as being 13 billion years old since the so called big bang.

    Posted by Vincent Sherman on June 1,2008 | 09:43AM

    how long is the black holes comparing to uor solar system

    Posted by JESSICA on June 5,2008 | 04:03PM

    On the video 3 dots went aross the star,most were headed that way.

    Posted by Breanna on June 10,2008 | 08:18AM

    Dear I want to point out to the objection raised by Mr.Vincent that he has raised to the current description of the age of the universe from big bang to the present times. I want to mention here that the theory of big bang and the consequent age of the universe is measured in the light of relativity. If any one beleives the relativity as the last suitable theory to describe or to predict the events of the universe then it becomes necessary for him or her to beleive about the explanation of relativity for the start of the universe as it is explained in the theory. I did not mean that we should stop to think further about a better theory which can single handedly predict the events of the universe. Moreover it should be recorded that the time after big bang was not as slow it was very fast while we keep the formation of matter after the Big Bang . It is to be noted that in the thousandth part of a second so many events had taken place immidiately after that grand event we call Big Bang. You may argue against my opinion as it a pure scientific to reach the inference after lot of arguments. Yours Sincerely Dr.M.Umar Soomro Hyderabad Pakistan

    Posted by Muhammad Umar Soomro on June 18,2008 | 02:31AM

    Man, that is indeed one very powerful black hole. Just look at all the crazy it's pulling in here.

    Posted by tom rogers on June 19,2008 | 12:17PM

    I find all this extremely interesting of course; even more so that science has accepted the theory of the 'Big Bang.' However, it appears to me that science does not even tiptoe around the question of what it was that went 'bang' back there in the beginning. So then, what was it? Can anyone refer me to any scientific explanation of this question?

    Posted by Russ on June 21,2008 | 12:29AM

    REPLY TO BILL EGER, WE ARE IN AMONG OF WONDERS OF THE COSMOS.IT'S UNBELIEVEBLE, IT'S SO HUGE!IT'S EVERWHERE JUST ALIKE US.AND I LOVE TO SEE HEART OF SKY AND GLOW TO MY EYES TO GET IDEAS! FROM BILL VOS 6/23/08

    Posted by William Vos Jr on June 23,2008 | 12:33PM

    NICE

    Posted by on June 25,2008 | 11:01AM

    Is the budget for space research astronomically (pun intended) high? Possibly, yes. But as others have pointed out, there are many, many other ways researchers and government officials have wasted money on futile research. However, I think this is the stuff man dreams about. The biggest and most important questions arise from studying the universe: Are we alone? What is our galactic fate? Any answer carries huge implications. And the beauty of the heavens is astounding. For me, space study is not just science, but aesthetics, philosophy, and theology. The wonder of our universe is never ending.

    Posted by KB on June 25,2008 | 12:40PM

    what an amaizing gallery..

    Posted by adarsh mohan on July 6,2008 | 01:48AM

    I recently plowed far enough through the "phonebook" GRAVITATION to the point where they explain how to compute the last time, by your clock, that you, a far-away observer, can send a signal (radio, light) to an object falling into a black hole to cause it to go into "rescue mode" (fire a super-powerful engine, engage a STAR TRECK trnaporter, whatever) to save all or part of itself from falling into the hole and coming back to you, eventually. The signal ends up in the in-falling object's time frame, which has a definite time of falling in, even though, you, the far-away observer, will never see that drop-dead point where the object hits the event horizon and is gone forever (at least in one piece). However, since you never see any of this since it takes going faster than light to see inside a black hole, how can you ever see ANYTHING happen after a black hole forms? By "anything" I mean things like changing its motion due to the gravitational attaction of another object (star, for example) that comes close, and so on. To change this momentum, you have to alter the motion of the singularity at its center. This not only should take forever to see, but how does gravity or any other force "grab" an infinitely-dense singularity to make it do anything at all (even gravitons have some size, I assume)? I realize that quantum effects may change this, but, for now, I am assuming classic General Relativity. Somebody please explain how any changes can happen or, the same thing, be observed in a finite time, as seen by a far-away observer (somebody who is not suicidal!).

    Posted by Nathan Okun on August 13,2008 | 09:02PM

    200 billion stars in the Milky Way?? Was that not the estimates of years ago? Are there not 500 billion 700 billion or more??? Jim

    Posted by jim spens on August 19,2008 | 07:41AM

    Black Holes???? Lets figure out a better name! They are not black! Prodigious amounts of light is produced its just we do not see it! Its all kept inside! what a brillent place it must be inside and in no way are they a hole nothing is missing. I would porpose "Great One" as an alternate name. Jim

    Posted by Jim Spens on August 19,2008 | 07:47AM

    wow! Amazing!! I'm studying black holes and may have found the perfect thing. oh and some people say if you go into or close to a black hole you'll get sucked in and stretched. Some scientists call this being "Spaghetified".

    Posted by Alexis on September 13,2008 | 02:34PM

    Could the prevalence of young stars near the black hole be due to smaller masses being easier to attract by the hole's gravity? The young stars (with less mass) could be more easily accelerated because there is less gravitational force from other nearby stars that would otherwise tug the new stars away from the hole ( the older, more massive stars hold each other out of harms way). The gravitational force is thought to be proportional to the 2 masses, but the theories of gravity are just theories, and they may not work in such hole-induced distortions in space/time. For example, what happens if the mass (of the black hole) approaches infinity? The masses of the objects near it would be irrelevant, would they not? And if so, perhaps other unique characteristics of the young star (e.g. rotation, dust drag, elemental make up, etc) now become influential to the black hole.

    Posted by Kevin Keating on September 16,2008 | 09:17AM

    Fascinating piece of reporting on this brilliant work. But, what is on the other side of a black hole? Is there a parallel universe or oblivion or ??? I love contemplating these things.

    Posted by David Kulaas on September 16,2008 | 10:27AM

    All galaxies in the space continuum have a black hole, or remnent of a black hole at the center. It would be theoretically highly unusual to find a galaxy in the Universe, that did not have a negative star (black hole) at the center. Therefore, it is understandable to find a black holes at the center axis of rotating spiral galaxies, they are the only gravitational influence that can attract, and rotate that much mass in the known Universe of mankind. Theoretically speaking, binary black holes may be found at the center axis of large rotating spiral galaxies. SPR

    Posted by S. P. Robertson on September 22,2008 | 07:34AM

    I want to know why black holes are what they are. I mean why do they happen & exist? Is there EVER going to be a black hole that will destroy the sun and earth? When?

    Posted by Gina on October 24,2008 | 12:56PM

    awesome!!

    Posted by Danielle on December 8,2008 | 10:08AM

    could it be possible black holes are a funnel affect such as sink drain produces? could it be possible the universe as we know it know is acutally a blanket around an inner world we know nothing of with immense storms that create these funnels pulling pieces of our univers in to it? could it have a black atmosphere so thick we cant detect it? could it be possible they are both spining around in their own gravitanol field in a ball in space with other worlds like them?

    Posted by henry lee foster on December 29,2008 | 05:43AM

    who ever figured this out is really,really smart.My name is Kaylee Ann Miller,and Morgan Kristian McDonald.

    Posted by on January 31,2009 | 05:51PM

    Post a Comment


    Name: (required)

    Email: (required)

    Comment:



    Advertisement


    - - - Advertisements - - -


    Join Us

    Facebook

    Facebook

    Become a fan of Smithsonian magazine's official Facebook page!

    Twitter

    Follow Smithsonian magazine on Twitter

    Smithsonian magazine presents

    6th Annual Smithsonian Photo Contest Winners

    Out of more than 17,000 entries contributed from around the world, Smithsonian and its readers select the year's best