S4F: Black Holes Suck
By David Siegel Bernstein, PhD
If a black hole got married, would it still be considered a singularity?
(joke from astropixie’s blog)
This S4F is dedicated to black holes; a worthy topic for science fiction fans and writers. Black holes come in different sizes—they can be as small as an atom (with the mass of a mountain) or enormous with the mass of over 1 million suns, labeled as supermassive. It is believed every large galaxy contains one of these supermassive black holes in its center. The one in the center of the Milky Way is called Sagittarius A.
Let’s begin with how a black hole is created. The executive summary goes something like this: a star runs out of fuel to puff itself out and, thanks to gravity, it collapses. If it collapses to its Schwarzchild radius it will continue to collapse to a singularity and a black hole is created.
Whoa! What’s the Schwarzchild radius? Or for that matter what’s a singularity? Well since you happened to ask: the Schwarzchild radius (rs) is the radius of a given mass where if the mass could be compressed to fit within this radius, no force could stop it from continuing its collapse to a singularity. A singularity is an infinitely small and dense point—something not clearly defined in physics (darn). When an object is compressed smaller than its Schwarzschild radius it is called a black hole.
Fun facts: the estimated rs of Earth is 9mm and it is 3km for the Sun.
Okay now for the longer “how” of a black hole. The power of a star comes from the nuclear reaction taking place in its core which causes outward pressure. This pressure is balanced by the weight of gravity from the star’s mass. In other words, the nuclear power pushes out and gravity pushes in. As the star gets older it goes from combining hydrogen into helium (where our sun is at) to fusing helium into carbon, and then carbon into oxygen, and then oxygen into silicon and then finally silicon into iron (a cosmic dead-end, more one this in a future post). At this point fusion stops and the outer layers of the created elements (hydrogen, helium, carbon and silicon) burn around the iron core. The core continues to build up until it explodes. This is called going supernova. Now for the interesting bit, after the supernova explosion the core compresses further, ramming atoms against each other, changing protons into neutrons until—voila, a neutron star. But if the neutrons can’t prevent the star from collapsing further, from gravitational forces, it will shrink to beneath its Schwarzchild radius and you get yourself a stellar black hole
Black holes devour anything that dares to pass its outer boundary, called the event horizon. This includes light and electromagnetism. Its core is a singularity.
Now that we have the basics, in my next post I’ll provide some more black hole facts and perhaps a few tips on how to incorporate these stellar objects into science fiction stories.
See you in time and space… and S4F
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Authors: David Siegel Bernstein. Form: Column. Length: 500 words. Editor who accepted this story: Previous Editors.
Author Bio
Abandoned Towers Content: S4F: Go Kardashev not Kardashian for Your Science S4F: Black Holes (Don’t Really) Suck S4F: Black Holes Suck S4F: Can Anyone Intelligent Communicate with Me? Other Than My Earthling Friends. Part II S4F: Can Anyone Intelligent Communicate with Me? Other Than My Earthling Friends. S4F: Do You Know the Time? S4F: Do You Know the Time? Part II S4F: Do You Know the Time? Part III S4F: Fiction by the Numbers S4F: From Higgs to Holograms S4F: Getting More Entangled In Time and Space S4F: I Have Virtually Nothing to Say About Zero-Point Energy S4F: If You are Uncertain—Call a Quantum Mechanic for a Fix S4F: Infinity for Fun S4F: Infinity of Fun, Part II S4F: Invisibility, Science not Magic S4F: Meet David Siegel Bernstein – Forensic Statistician S4F: More or Less Human S4F: Much Ado About Nothing This Month S4F: Now Playing at the Opera—The Faster than Light Particle Experiment S4F: Paradox Found S4F: Paradox Lost S4F: Parallel Worlds S4F: Splicing Science from Fiction S4F: The End of Infinity (Infinity of Fun Part III) S4F: We Hold Universal Truths to Be Not Self-Evident S4F: What’s the Matter with Antimatter?
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March 8th, 2012 at 6:43 pm
Interesting article!
Stealth is easier than cloaking, and we already have the technology.
March 30th, 2012 at 7:41 am
William you are absolutely correct. Invisibility (a descendant of Stealth) is not only easier to achieve, but a future topic. I thought I’d go over invisibility first to please those who enjoy Harry Potter, but want to write hard science fiction.
April 5th, 2012 at 5:39 am
Fascinating post. We are so much empty space and mostly water. Amazing to think how we can be beings of intelligence and creativity.