sunset from behind the wire

sunset from behind the wire

Friday, January 13, 2017

Science/Sci-Fi Fodder

There are a few who follow this blog who write Science Fiction and still more who read it. For those writers among you who are looking for the factual basis for a "strange and interesting planet", you need look no further afield.

Every few thousand years, an unlucky star wanders too close to the super-massive black hole at the center of the Milky Way. The black hole's powerful gravity rips the star apart, sending a long streamer of gas whipping outward. That would seem to be the end of the story, but it's not. New research shows that not only can the gas gather itself into planet-size objects, but those objects then are flung throughout the galaxy in a game of cosmic 'spitball.'
Harvard-Smithsonian Center for Astrophysics. "Our galaxy's black hole is spewing out planet-size 'spitballs'." ScienceDaily. 11 January 2017. 
"A single shredded star can form hundreds of these planet-mass objects. We wondered: Where do they end up? How close do they come to us? We developed a computer code to answer those questions," says lead author Eden Girma, an undergraduate student at Harvard University and a member of the Banneker/Aztlan Institute.

Girma presented her findings at a Wednesday poster session and Friday press conference at a meeting of the American Astronomical Society.

Girma's calculations show that the closest of these planet-mass objects might be within a few hundred light-years of Earth. It would have a weight somewhere between Neptune and several Jupiters. It would also glow from the heat of its formation, although not brightly enough to have been detected by previous surveys. Future instruments like the Large Synoptic Survey Telescope and James Webb Space Telescope might spot these far-flung oddities.

She also finds that the vast majority of the planet-mass objects -- 95 percent -- will leave the galaxy entirely due to their speeds of about 20 million miles per hour (10,000 km/s). Since most other galaxies also have giant black holes at their cores, it's likely that the same process is at work in them.

"Other galaxies like Andromeda are shooting these 'spitballs' at us all the time," says co-author James Guillochon of the Harvard-Smithsonian Center for Astrophysics (CfA).

Although they might be planet-size, these objects would be very different from a typical planet. They are literally made of star-stuff, and since different ones would develop from different pieces of the former star, their compositions could vary.

They also form much more rapidly than a normal planet. It takes only a day for the black hole to shred the star (in a process known as tidal disruption), and only about a year for the resulting fragments to pull themselves back together. This is in contrast to the millions of years required to create a planet like Jupiter from scratch.

Once launched, it would take about a million years for one of these objects to reach Earth's neighborhood. The challenge will be to tell it apart from free-floating planets that are created during the more mundane process of star and planet formation.

"Only about one out of a thousand free-floating planets will be one of these second-generation oddballs," adds Girma.


22 comments:

  1. It still boggles my teensy brain as to exactly how these guys know all of this. Big gobs of 'star stuff' zipping through space at a 20 million mph...and I want to know who clocked these big gobs of star stuff, and what kind of radar gun did they use?

    All of it sounds iffy to me. Then again, see above about the teensy brain thingy I got going on...

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    1. Fredd, there is considerably more documentation in astronomy than there is in theoretical physics where you read about string theory and claims of two, twelve, heck, why not 47 multiple universes parallel to ours. There's not much math to back up these claims and that bugs me.

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    2. This is the stuff that Dr. Sheldon Cooper spends his time pondering, and yet this brainiac barely knows how to screw in a light bulb.

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    3. Cube, everyone including Einstein and before him, Heisenberg was looking for a unified field theory in which the same laws apply both in the universe we experience and what's going on in the universe described by Planck. (In physics, the Planck length, denoted ℓ P, is a unit of length, equal to 1.616229(38)×10−35 meters. The Planck length can be defined from three fundamental physical constants: the speed of light in a vacuum, the Planck constant, and the gravitational constant.

      I would argue with you that the math is solid, but the results we see don't square with anything intuitive that we experience. Things are simply different in the quantum foam. I have an MS in math, but the work that I did at the Naval Postgraduate School has nothing to do with Planck equations. Which is a pity. If I had the time, I'd work on that sort of thing all the time because I find it so interesting.

      The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate. This is the the smallest measurement of length with any meaning. And roughly equal to 1.6 x 10-35 m or about 10-20 times the size of a proton. The day will come when we will be able to experiment with items even smaller, but I will not live to see it. That's the stuff that everything is made of, but who knows how small it will go before we get to the bottom of the well?

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    4. Fredd, we are all living in the same prison on the third rock from the Sun and it may be for good reason. None of us seem to be all that bright. A friend of mine believes that human beings are a type of virus. I hope that's not true, but he presents a convincing argument.

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    5. There's nothing wrong with your brain, Fredd. And you're right to question such things. The brainiacs who write for a lot of the "Science!" publications would rather not think about it, but the stuff we don't know (and can't know) about the Cosmos dwarfs what we do know. We don't even have a workable theory for how the Sun works, and it's only 500 seconds away in light time.

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    6. I know some Buddhists who doubt that the Sun is real - and given that hypothesis, they would explain that's why you can't figure out how it works...

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  2. Fascinating. I hope to be around in a million years to see one of these second gen planetoids.

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    1. When you consider that they could have been ejected from any galaxy and end up here, the exotic possibilities are endless.

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  3. All of this boggles my pea-brain. Once the speed goes beyond my F-150, I am agog and lost in wonderment. And with all the millions/billions of years attributed to the objects in space and the making of stars and stuff, you tell me that a black-hole can rip apart and devour a star in a day???? Pitcher me googled eyed.

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    1. The super-massive black hole keeps the entire galaxy together gravitationally. My sense is that a star to it is no more than a pebble in a driveway is to you.

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  4. Interesting, like pinball on a galactic scale...

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  5. "Only about one out of a thousand free-floating planets will be one of these second-generation oddballs," is reasonably comforting to a second-generation oddball...

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  6. Perhaps the reason I don't read science fiction is I don't understand the science. I can navigate from maps but that is the limit of my math skills.

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    1. Good science fiction is set in at least a semi-factual setting that exudes a feeling that it might happen that way. Much of the genre is taken up with fantasy sword fights in space and silliness. Good Science fiction is like any other good fiction to me.

      You might enjoy listening to Steven Hawking's "A Brief History of Time" while you drive. It's a good book on the basics of how it all works. Brian Green's "The Elegant Universe" is another book of science fat that explains more or less the same thing with Green's spin on it.

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  7. Soooo... Are 'we' the corner pocket? :-)

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    1. I thought of you. One of these would be a cool planet for the Rimworld.

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