Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Bryan See on December 02, 2015, 11:47:21 am
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From ExtremeTech.com (http://www.extremetech.com/extreme/218715-why-tatooine-is-plausible-the-orbital-mechanics-of-binary-star-systems):
While we’re all waiting for The Force Awakens to hit theaters, the time is again ripe for speculating on the plausibility of the Star Wars universe. Science fiction loves crazy astronomy — think Pandora, Halo, or Tatooine. The home planet of Luke Skywalker orbits a double star. But what do we know about how plausible the astronomy of Star Wars might be? How do you get a planet that has two suns?
Binary star systems are common throughout the observable universe; of the stars nearest our sun, about half are part of binary systems. For a long time, we didn’t even know whether a binary star system would be stable enough to allow matter to accrete to planetary dimensions. In 2014, researchers used gravitational microlensing (http://www.extremetech.com/extreme/203417-this-amazing-map-shows-just-how-little-of-our-galaxy-weve-explored-so-far) to confirm that an exoplanet with the working name OGLE-2013-BLG-0341LBb orbits one star of a binary pair at a distance of some 3000 light-years from Earth.
This particular exoplanet (http://www.extremetech.com/tag/exoplanets) orbits cool, dim stars and is therefore probably too cold to be habitable. But if you stood on its surface at the right time, you would see an unmistakable resemblance to the Tatooine sky: two suns, one bright, one dim. It’s certainly proof of concept. And what if those stars were just a little warmer, a little brighter? These are conditions that are tantalizingly suggestive of a real-life inhabitable planet just like Tatooine, somewhere in the universe we occupy.
(http://www.extremetech.com/wp-content/uploads/2015/12/Binary-Stars-640x360.jpg)
Artist's impression of a binary star system. (Credit: NASA)
Truth may be stranger than fiction, though. It turns out that many multiple-star systems are actually groups of three stars called ternary systems, where one star orbits at some distance around a binary-star pair. It’s suspected that if the outer star had a rocky, Earth-like planet, it might be relatively more likely to harbor life because of the large Goldilocks zone (http://www.extremetech.com/extreme/201671-scientists-most-stars-have-goldilocks-planets-in-the-habitable-zone) created by the arrangement of the three parent stars.
An observer on the surface of a planet in such a system would experience varying night lengths and varying phases of daytime temperature and illumination, related to how many of their stars were in the sky at any given time: one, two, or all three. Or at least they would until the planet inevitably became tidally locked, which means that one side of the planet would face its star forever: a seared, uninhabitable afterscape. Nobody has yet confirmed life on other planets, which means that we don’t know whether it’s more or less likely to find life around a binary or ternary system, but a compelling case can be made for either.
Still more complex stellar systems have been observed. Earlier this year, a five-star system in Ursa Major was announced by researchers from the Open University. Two pairs of its five stars eclipse along our line of sight, consistent with the spin mechanics of a relatively stable system. Scientists believe that a planet in this system might only have one real night per year, since such an event would require all five of the stars to appear in conjunction. Here’s hoping there’s some sort of relationship between stellar radiation and the appearance of the Force in life forms on a given planet.
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If you're just reposting articles, you could do us all a favour and read them first. Note how the sentence "Or at least they would until the planet inevitably became tidally locked, which means that one side of the planet would face its star forever: a seared, uninhabitable afterscape." contradicts your thread title quite handily.
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Yeah, except that's talking about ternary systems, which may be more common, and not binary, if my reading comprehension serves me.. :P
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I thought the problem with Tatooine was that is a was a worldwide desert with very little plant life, so where does all the oxygen come from? Star Wars does this sort of stuff a lot. Mustafar had the same issue. Volcano planet, livable and breathable atmosphere. That planet should look like Venus or Io.
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Rule of cool, or just no thought given to universe mechanics. Take your pick, or both. :sigh:
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lot of oxygen locked up in the mantle.
and tidally locked doesn't mean uninhabitable.
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However, some planets could end up flying free from the gravitational influence of multiple stars they orbit, while some end up crashing at one of them, and others survive at stable orbits.
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Hey guys I have an idea:
It's a movie.
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Lol, we've known for years that planets can form in multiple-star systems, and it is not very difficult for them to be habitable. Consider Gliese 667 Cc for instance -- a potentially habitable planet with three suns.
It's tempting to think that multi-star systems would just be too dynamically crazy for planets, but you have to think about how stable configurations appear in n-body systems. It follows a sort of binary addition rule, with stars grouping into pairs, pairs of pairs, etc. Planetary systems can develop orbiting around a single sun with a distant partner, or orbiting around a close binary (circumbinary planets). Habitability can arise in either scenario, depending on the masses and separations of the stars. You can even have a planet orbiting a binary which forms a binary with another distant binary -- i.e. a quadruple star system.
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Hey guys I have an idea:
It's a movie.
oh, I have an idea too!
What if a detail of that movie might be able to actually work in reality!
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Hey guys I have an idea:
It's a movie.
oh, I have an idea too!
What if a detail of that movie might be able to actually work in reality!
Then nothing would change. At all. Even imperceptibly. Because it's still a movie.
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wow those people who are arguing against you sure must feel foolish right about now. all of them.
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Enough of this, Bob.
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of what exactly? Scotty was the one who came into a thread about the feasibility of a planetary system in a scifi movie and was all "herpder itamovie! nowt reel" as if it was a contribution. what exactly was his point? am I missing something painfully obvious?
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of what exactly? Scotty was the one who came into a thread about the feasibility of a planetary system in a scifi movie and was all "herpder itamovie! nowt reel" as if it was a contribution. what exactly was his point? am I missing something painfully obvious?
You need to understand the binary code of moisture vaporators. Do you also speak bocce?
Oh, and what's your opinion of the singularity
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The singularity is a one-dimensional point which contains infinite mass in an infinitely small space, where gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate. The singularity is at the center of the black hole, beyond the event horizon.
FreeSpace and Star Wars science, in terms of astronomy, is plausible. While the Tatooine star system is common, planets orbiting closely around the stars have been observed.
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The singularity is a one-dimensional point which contains infinite mass in an infinitely small space, where gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate. The singularity is at the center of the black hole, beyond the event horizon.
Not that singularity, but THE SINGULARITY ENGIIIIIIIIIIIIIINE
https://youtu.be/gI8aSJBC9u0?t=15m54s
And the corresponding reference question
https://youtu.be/Lu9dUG3_KNA?t=12m
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The singularity is a one-dimensional point which contains infinite mass in an infinitely small space
Finite mass. Otherwise the horizon would be infinitely big! :eek2:
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Exactly. If you swapped out the Sun for a 1-solar-mass black hole, absolutely nothing would change about the Earth's orbit.
...and then we'd all freeze to death in about 9 minutes. :nervous:
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FreeSpace...in terms of astronomy, is plausible.
Well, except for Capella having several large planets within less than 0.1 AU, more than half of which is occupied by the star itself.
...and then we'd all freeze to death in about 9 minutes. :nervous:
Think of it as free cryogenic stasis. Just don't forget to set your alarm clock for 10^67 years or so, before Hawking radiation makes things too toasty again. And, uh, gamma-y.
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Well, except for Capella having several large planets within less than 0.1 AU, more than half of which is occupied by the star itself.
Any planet orbits at 0.1 AU close to that kind of star is considered hot. Hot Jupiters and hot Neptunes normally reside in that region. These are the ones discovered by Earth-based observations and Kepler space telescope. Think about the tenth transiting "Tatooine" exoplanet Kepler-453b.
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The singularity is a one-dimensional point which contains infinite mass in an infinitely small space, where gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate. The singularity is at the center of the black hole, beyond the event horizon.
I don't think physicists actually expect the singularity to have infinite mass, they expect weird physics to happen at it.
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The quantity that really becomes infinite at the singularity is the strength of the space-time curvature, AKA the tidal forces. You can think of this as a consequence of having finite mass in zero volume -- in other words a point mass. It's just like how the strength of electric field is infinite at a point charge.
All allowed paths through space-time terminate at the singularity in finite proper time, so this implies that all matter that falls into the hole is utterly destroyed there, essentially the mass becoming manifest only as gravitational field. Think of the black hole as being completely empty. It is made not of matter but of warped space-time.
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(Disclaimer: I study mathematics, not physics.) I agree with PH - I don't think the concepts of "infinity" and "point" exist in the real world. When physicists use those words to describe black holes, they're actually saying that our understanding of physics breaks down inside an event horizon.
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Our understanding of physics is actually okay even deep inside the horizon. It only breaks down when you get really close to the singularity (like on subatomic scales), where quantum gravitational effects become important. General relativity, as a classical theory, predicts infinite quantities there, but the reality probably just "approaches" infinity. :)
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Yeah, that's exactly what I was referring to.