Category Archives: black holes

astronomy, black holes

Ruminations about Black Holes

Leave a comment

<

Black Holes: Not Just for Science Fiction Anymore


I’ve always been a sucker for mysterious things in outer space. No, not little green beings or monsters from Cryzalix IV or alien face-things on other planets that turn out to be eroded mesas. I’m talking about the real deal: strange things that really do exist, but when scientists first think about them, or observe them, they kind of scratch their heads and go “huh?” Black holes fit in that category. And, you know what? A LOT of people are really curious about black holes. If you’re a planetarium lecturer or a scientist who does outreach, or a teacher who finds time to fit in some astronomy between all those other unfunded educational mandates you have to follow, you already know this. Black holes are just about the first thing anybody asks about as soon as the topic of astronomy comes up. No, really. It’s true. (Well, sometimes they ask about astronaut love triangles, but I don’t want to go there and neither do you…)Anyway, I wish I had US$5 (or 5 Euros, I’m not picky) for every time I’ve been asked about black holes while standing in a line at the store, or sitting on an airplane talking with somebody, or answering an email from somebody who’s read my site. Black holes are just that popular. Yet, I remember a time when they were pretty much flying beneath the public’s radar.Back when I was a kid a few decades ago, black holes were taken seriously more as theoretical constructs—objects that mathematical and scientific models said could exist, but nobody had actually seen in real life. There are a lot of science fiction stories about using wormholes to ride around the universe in; those are based on some theoretical constructs called Einstein-Rosen Bridges.

Pretty speculative, but interesting to think about. And, certainly TV and movie science fiction stories often depend on spectacular special-effects wormholes to keep people moving. But, right now those remain on the dreamers’ drawing boards while astronomers study the real-life black holes that are turning up everywhere.

So, black holes hide in a lot of places. Astronomers have known for a while that they exist in the hearts of many galaxies, and they’re also the powerful engines under the hoods of quasars. Back when I was a teenager, Quasars were TV sets. Now they’re better known as the bright, distant and extremely active core regions of galaxies. Radiation pours out of these things in many wavelengths of light, including x-rays and radio waves.

Last week at the American Astronomical Society, we heard a LOT about black holes. I was especially intrigued with the story out of Vanderbilt University that there could be hundreds of rogue black holes roaming around our own galaxy. They got the galactic heave-ho from the globular clusters where they formed.

But, for my money, the most interesting black holes are the ones that lurk in the hearts of galaxies like our own. You can’t see the one making its nest in the core of the Milky Way because it’s hidden behind clouds of gas and dust. And, well, you really can’t see a black hole anyway. What you DO see is the chaos that is created when a lot of matter swirls into the black hole. In addition to the stars, gas, dust, and other stuff that is getting sucked into the black hole, powerful and twisted magnetic fields are funneling superheated plasmas out to space, in the form of jets.

All this activity gives off those x-rays and radio waves I just mentioned. And, the heat in the region also warms up clouds of gas and dust, which glow in infrared wavelengths. So, looking for black holes is a multi-wavelength (except for visible light) proposition, particularly for the Milky Way’s black hole.

If you want to read more about the black hole in the Milky Way’s core, I recommend a very cool book called The Black Hole at the Center of our Galaxy by astronomer Fulvio Melia. I reviewed it a while back for Sky & Telescope Magazine, and I still remember what a great read it was. There’s a lot we know about black holes, and they’re not just for science fiction any more. They play roles in everything from the earliest galaxy formation to stellar evolution.

The latest installment of my little vodcast series about all things astronomical is also about black holes, specifically the one at the heart of the Milky Way. Check it out!


To see this video here, you need to tell your browser not to block active content, or you need to get the Flash player. RSS readers who can’t access the video can download it here.


Creative Commons License

This work is licensed under a
Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License.

astronomy news, astronomy research, astrophysics, black holes, cosmology

AAS Day Two

Leave a comment

More Peering at the Cosmos

The Center of Centaurus A and Its Embedded Black Hole, as seen by Chandra X-Ray Observatory

Day two of the AAS meeting is just as frenetic as day one. There are hundreds of talks and papers being given about every aspect of astronomy you can think of— and then some! In addition, there are dozens of exhibit booths featuring astronomy missions, telescopes, contractors, NASA institutes, observatories and publishers.

I made it about halfway through the exhibits hall on Monday; my mean free path went to nearly zero, what with stopping to talk to various and sundry colleagues and friends. I did manage to spend some time talking with the folks at the Thirty Meter Telescope (TMT), a project I worked with briefly a few years back. Also visited with friends at Gemini Observatory, Konica Minolta’s Planetarium division, and Cambridge Press. We’ll see how far I get the next couple of days.

We’re hitting our stride with news stories today—some rather breathless headlines about some breathtaking research. Two very fascinating results we heard about today were papers given on black holes. First, the existence of rogue black holes created in the centers of globular clusters has stirred some interest among black hole researchers. If the observations and models hold up, there could be a hundred of these rogues roaming the Milky Way Galaxy (although not near enough to affect us here on Earth).

The second is about two black holes and their interlocked orbits that have given astronomers a chance to confirm Einstein’s General Relativity theory.

Check out the other big stories for yourself while I head out to the University of Texas for a tour of their supercomputing site, and then on to what has been assured to be Texas’s best barbecue!!

  • The Sloan Digital Sky Survey announced its work studying a once-hidden population of powerful black holes tucked away behind clouds of gas and dust around the cores of galaxies where these strange beasts exist.
  • At the same time, Vanderbilt University astronomers are doing simulations that seem to imply that the Milky Way Galaxy may have hundreds of rogue black holes.
  • In other black hole news, a researcher from the University of Turku, Finland has discovered the most massive black hole ever, some 18 billion times more massive than the Sun. This discovery has implications for yet more confirmation of Einstein’s General Relativity theory. (Note: I’m still trying to track down an URL for this one.)
  • Chandra X-Ray Observatory released a fantastic image of Centaurus A, a nearby galaxy with a supermassive black hole at its heart.
  • Harvard-Smithsonian Center for Astrophysics informs us that when worlds collide it could have resulted in a rather spectacular and mysterious-looking object that lies 170 light-years away. Another team at Harvard tells us that our home planet has been on the edge of habitability since it first formed.
  • Our friends at the Joint Astronomy Centre announced results from an infrared sky mapping project called UKIDSS (UK Infrared Telescope Infrared Sky Survey). Their findings are expanding the infrared sky for astronomers.
  • If high-resolution radio astronomy is your bag, the National Radio Astronomy Observatory (NRAO) announced the latest work they’re doing with very large baseline array interferometry and astrometry.
  • Astronomers at Rutgers and Penn State universities have discovered galaxies in the distant universe that are ancestors of our own Milky Way Galaxy.
  • Hot off the press at European Space Agency is the news that the Earth-orbiting Integral satellite (sensitive to gamma-ray wavelengths) has discovered that the antimatter cloud at the center of our galaxy is lopsided. (More information here.)
  • For the folks at the Department of Astronomy at the University of Texas at Austin, a study of galaxies from HST and Spitzer observations shows that the mad merger-driven rush of galaxy interactions slowed down once the universe hit middle age.
  • The National Optical Astronomy Observatory announced the discovery of dark matter in accretion disks around a variety of astronomical objects.
  • In planet-forming research circles, there’s news that a second wave of planet formation is orbiting two stars hundreds of millions of years after these stars first experienced their first wave of planet formation. (Note: the press release should appear on UCLA’s site within the day.)
  • At the University of Arizona, astronomers point out that they are the first to successfully predict the existence of an extrasolar planet around a star about 200 light-years from Earth.
  • Finally, from my friends at Gemini Observatory, a beautiful image of the dance of two supernova remnants in the Large Magellanic cloud.

Okay, more later! Stay tuned.