Date: February 22, 2011
Title: Black Holes and the Cosmos
Podcaster: Carolyn Collins Petersen, TheSpacewriter
Organization: Loch Ness Productions (www.lochnessproductions.com)
Music from Stella Novus, a new album from Geodesium. (http://www.geodesium.com)
Description: Carolyn Collins Petersen, TheSpacewriter, talks about those objects that even non-astronomers know have to do with the cosmos… in some way.
Bio: Carolyn Collins Petersen is a science writer and show producer, as well as vice-president of Loch Ness Productions, (http://www.lochnessproductions.com/index2.html) a company that creates astronomy documentaries and other materials. She works with planetariums, science centers, and observatories on products and projects that explain astronomy and space science to the public. Her most recent projects include documentary scripts, exhibits for NASA/JPL, the Griffith Observatory and the California Academy of Sciences, video podcasts for MIT’s Haystack Observatory and podcasts for the Astronomical society of the Pacific’s “Astronomy Behind the Headlines” project.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Greg Dorais, and is dedicated to the Chabot Space And Science Center in Oakland California, home of Bill Nye’s Climate Lab, Space Explorers Summer Camp, and so much more. At Chabot Space And Science Center, the universe is yours to experience. Set amid 13 trail-laced acres of East Bay parkland, with glorious views of San Francisco Bay and the Oakland foothills, Chabot is a hands-on celebration of sights, sounds, and sensations. Find out more about the Chabot Space And Science Center at www.chabotspace.org.
Transcript:
Hello and welcome to the February 22, 2011 edition of 365 Days of Astronomy. This is Carolyn Collins Petersen, TheSpacewriter, and today I’m going to talk about black holes.
I write a blog called TheSpacewriter’s Ramblings, mostly about astronomy and space science. One of the most popular postings of all time was one I made about black holes. It’s called “Mass Holes”, which I admit is a catchy title and probably accounts for many of the hits the entry gets.
Well, the title is suggestive – because black holes ARE holes full of mass. Each black one is a collection of impressive amounts of mass compressed into a tiny pinpoint called a singularity. Everything that ever strayed into the black hole is IN there. For a stellar-mass black hole – that is, one that formed when a giant star exploded and compressed its central region down to a singularity – that “everything” consists of what was left over in the original core of the star.
For a supermassive black hole at the core of a galaxy—the black hole’s mass likely consists of the constituent components of stars, planets, nebulae. Basically, whatever strayed too close to the black hole, and got caught up in the gravitational pull of the ever-growing black hole. It’s stuck in there – forever. And, we have NO way of knowing exactly what’s stuck in there. This is because the identifying characteristics are gone, lost forever along with the mass of the material that got sucked in.
And that’s why we can call these things mass holes. They’re full of mass… and the gravitational pull of all that mass is so strong that nothing – not even light – can escape.
This idea of something getting sucked in that will never escape also explains why the term “black hole” gets used in everyday language to describe something that is sucking in information or time or money or too much of your attention. I’m sure you’ve all heard someone say “Well, that information I send to headquarters just disappeared into a black hole.” Or “Shoveling money into that investment is like throwing it into a black hole.” Or – who hasn’t said THIS one– “These taxes are a black hole sucking up all my available time.”
It’s a fine metaphor to use, especially if you know what a black hole IS and what it does. Most of us do, or at least we get the idea. It sucks stuff in.
Luckily, we’re not close enough to any REAL black holes to experience first-hand what it’s actually like to get sucked into one. But, if you were in a spaceship on a trajectory into a black hole, the experience would likely be fascinating – at first. Then, as you got close to the event horizon – otherwise known as the point of no return – life as you know it would be over. First, the gravitational pull of the singularity would rip your ship – and you – apart. That would happen as soon as you got to the point where the black hole’s gravity would be stronger than your ship’s force field or inertial dampeners or warp core or other technological goodies you have. Second, as the parts of your ship – and you – slide inexorably into the black hole, you’d be stretched out as the gravitational pull on the parts closer to the singularity would experience a greater pull than the parts farther away. That, too, would contribute to your destruction. Third, once you were inside the black hole, you’d be compressed to a singularity yourself.
At least, that’s what we think would be happening. Nobody has ever been in a black hole (that we know of), and if they have been… we’d never get a report back about conditions inside.
So, are there any black holes near us? Well, it depends on how you define “near”. The closest supermassive black hole is in the center of our galaxy, some 26,000 light-years away. We don’t feel its effects here out in the galactic boonies. There’s no cosmic beam emanating from it, and the only way we could really be affected by it for now is if we move Earth 26,000 light-years closer. Of course, that would take millions of years to do. Or, I suppose the black hole could somehow break free and travel all that way out here. Now, I can’t imagine any scenario – other than a galaxy collision – that would be able to do that. Oh, we ARE facing a collision with the Andromeda Galaxy some three to five billion years from now. But, that’s a long time from now, so the thought of YOU or ME becoming one with the galaxy’s central black hole is just that – a thought.
But, you ask, what about those stellar-mass black holes? Could we get sucked into one of those real soon?
Well, there ARE stellar-mass black holes scattered throughout the galaxy, but none of them are close to us to have a gravitational sucking effect. One of the nearest is the Cygnus X-1 black hole which is some six thousand light-years away. It has about seven times the mass of the Sun – a pretty small one, especially compared to the one at the galaxy’s heart, which has the equivalent of a little over four million stellar masses and lies much farther away. And it’s not affecting us either.
There’s not much chance of the Cygnus X-1 black hole plowing through our solar system from its perch over there.
Well, no doubt, these cosmic oddities ARE fascinating. They’re fodder for lots of interesting science fiction stories and movies that use drama to tell a story – and a black hole CAN be very dramatic. The true drama of a black hole isn’t that it’s going to eat you or me or Nero or the Starship Enterprise or the aliens from Proxima Centauri Five. No, their fascination lies more in how they formed, and in the case of the supermassive behemoths at the hearts of galaxies – what role they play in the evolution of their galaxy hosts. While they may be the end state for matter captured into their singularities, black holes are also implicated in the lives of galaxies in ways that astronomers are just learning to measure and understand.
If you’d like to learn more about black holes, point your browser to www.thespacewriter.com/wp and click on the 365 Days of Astronomy tab. Thanks for listening!
End of podcast:
365 Days of Astronomy
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