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26 Jul 07 - 01:06 PM (#2111905) Subject: BS: 4 suns- Didn't Asimov write a story ? From: beardedbruce about a planet in such a system? Quadruple Sunsets Possible Ker Than Staff Writer SPACE.com Wed Jul 25, 11:00 AM ET Astronomers have spotted a dusty disk in a four-star solar system that could be home to a planet in the making. Using the infrared eyes of NASA's Spitzer Space Telescope, astronomers spotted the swirling disk around a pair of stars in the quadruple-star system HD 98800, located 150 light-years away in the constellation TW Hydrae. If a planet did form in the disk, its sky would be bathed in the light of four suns. One pair of suns would blaze brightly, while the other pair, gravitationally bound to the first pair, would appear as little more than faint pinpoints of light. The finding will be detailed in an upcoming issue of The Astrophysical Journal. So-called "circumstellar" disks like the one that rings HD 98800 can be the birthplace of planets. Most disks are smooth and continuous, but Spitzer detected a gap in the HD 98800 disk that could be evidence of one or more immature "protoplanets" carving out lanes in the dust. "Planets are like cosmic vacuums,' said study team member Elise Furlan of the NASA Astrobiology Institute at the University of California, Los Angeles. "They clear up all the dirt that is in their path around the central stars." Quadruple sunsets The researchers spied two separate belts of material in the circumstellar disk. One belt sits at 1.5 to 2 astronomical units (AU) from the binary stars and likely consists of fine dust grains. The other is located about 5.9 AU away from and is probably made up of asteroids or comets. (One AU is equal to the distance between the Earth and the sun.) A swath of near-empty space separates the two belts, inside of which a budding planet might roam. Alternatively, the researchers think the gap could be caused by a gravitational tug-of-war between the system's four stars. The other two stars are also doubled up, and the two binary pairs are separated by about 50 AU-slightly more than the distance between our sun and Pluto. "Typically, when astronomers see gaps like this in a debris disk, they suspect that a planet has cleared a path," Furlan said. "However, given the presence of the diskless pair of stars sitting 50 AU away, the inward-migrating dust particles are likely subject to complex, time-varying forces, so at this point the existence of a planet is just speculation." Not uncommon The stars that make up each stellar doublet orbit around each other, and the two pairs circle one another as well. Worlds with multiple sunsets are not uncommon. Astronomers used to think that strong gravitational forces from multiple stars might interfere with planet formation, but recent surveys have revealed that the dusty debris disks that function like nurseries for new planets are as common around double star systems as they are around single ones. A few triple-star systems are even known. "Since many young stars form in multiple systems, we have to realize that the evolution of disks around them and the possible formation of planetary systems can be way more complicated and perturbed than in a simple case like our solar system," Furlan said. |
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26 Jul 07 - 01:13 PM (#2111911) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Richard Bridge I think the Asimov story was about two suns and a planet with a figure-of-eight orbit. |
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26 Jul 07 - 01:18 PM (#2111916) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: beardedbruce "Nightfall" - six suns, darkness once every 2049 years. "Because of its six suns, the planet Kalgash is bathed in perpetual sunlight. However, once every 2,049 years all six suns are eclipsed, plunging the planet into total darkness and causing widespread madness that results in the civilization's complete destruction, thus allowing the cycle to begin again. " |
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26 Jul 07 - 01:53 PM (#2111954) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Skivee The star Castor (of the pair Castor and Pollux, the head stars of Geminii), is actually six stars orbiting and dancing about each other in tight formation. They are separable by observing their spectral lines shifting. What an interesting sight that must be close up. At 50 light years distance the effect is somewhat diminished. |
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26 Jul 07 - 02:20 PM (#2111982) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: ClaireBear Jack Vance wrote an unforgettable novella called "Noise" about a multiple-sun system. Highly recommended. |
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26 Jul 07 - 03:40 PM (#2112016) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Rapparee What WAS the story about the planet with a figure-eight orbit? I've been trying to remember for years. |
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26 Jul 07 - 07:24 PM (#2112187) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Mrrzy I always liked Larry Niven's glorious description of Beta Lyrae, twin spiral stars tossing off beautiful ribbons of some particle or other... |
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26 Jul 07 - 07:38 PM (#2112197) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Sorcha MZB had 4 moons.....does that count? |
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26 Jul 07 - 09:07 PM (#2112251) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Naemanson Larry Niven wrote about a 'planet' that was actually a gas torus. |
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26 Jul 07 - 10:05 PM (#2112280) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Don Firth In one of Isaac Asimov's non-fiction books (and he's written a whole bunch of them, in addition to his science fiction), he describes a possible Earth-like planet in the Alpha Centauri system. Sounds like a most interesting place, should such actually exist. The Alpha Centauri system consists of a yellow main-sequence star very much like our sun, but about 20% larger. The second star in the system, Alpha Centauri B, is also main-sequence, but somewhat smaller and cooler. It lies about as far out from Alpha Centauri A as Uranus lies from our sun. Proxima Centauri (Alpha Centauri C), the third star, is a red dwarf, and it lies way out from the other two. If you were to stuff an Earth-like planet into the system, say, orbiting Alpha Centauri A somewhat further out than the Earth orbits the sun (almost as far out as Mars, perhaps), it would lie in the "temperate zone," where water would be in a liquid form. We could quite probably live there very comfortably. The orbit might be a bit egg-shaped, getting pulled toward Alpha Centauri B as Alpha A, the planet, and Alpha B came into conjunction, but that wouldn't drastically affect the livability of the place for humans. There might be some interesting seasonal variations. Alpha B would circumnavigate Alpha A about once every eighty years (Earth years), as Uranus orbits our sun. At times, there would be two suns in the daytime sky, and at other times of the year, Alpha B would be in the night sky. Asimov says that it would be bright enough so you could read a newspaper by its light. Proxima Centauri is far enough out so it would appear as a bright red star, but not as another sun. If you were to look toward the constellation Cassiopeia, you'd notice that it contains one star too many. That would be our sun. It was some time after I read Asimov's description that I found THIS, which pretty shows what he was describing. Don Firth |
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26 Jul 07 - 11:02 PM (#2112291) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Cluin Actually, IIRC, the thing that caused the fall of civilization in Azimov's original short story "Nightfall" was not the darkness per se. It was the appearance of stars. The planet of Kalgash was much closer to the center of the galaxy (which we now know could never support similar life to ouselves) and the sky was far more filled with stars, many of which were larger than we see. This brought home to the population that they were "not alone" in the universe and supposedly that's what drove them mad. |
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27 Jul 07 - 01:44 PM (#2112776) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Joe_F Cluin: The spectacle of the stars contributed to the horrific myths that grew up around the periodic nightfalls, but it was the darkness that did in the successive civilizations. Asimov describes a funhouse ride that consisted simply of 15 minutes of total darkness; it had to be shut down because it drove people crazy. In the mythology, the stars sent fire down and burned up the world, but in reality what happened was that the crazed people set fire to everything they could get at to drive back the darkness. |
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27 Jul 07 - 01:54 PM (#2112780) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Bill D The Asimov story, "Nightfall" has for a long time been regarded as one of the classic short SF stories of all time. It has won all sorts of awards. |
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27 Jul 07 - 06:08 PM (#2112936) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Donuel I remember one where stars were sentient beings but at a rate so slow most life forms never recognized stars as being alive. |
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27 Jul 07 - 06:38 PM (#2112966) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Bill D ??Wasn't that one of Frank Herbert's lesser known novels? |
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27 Jul 07 - 06:48 PM (#2112978) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: ClaireBear You mean Whipping Star? I thought so too and just looked that one up in Wikipedia to check, but I didn't see anything in the entry about the star living such a slow life that its sentience wasn't detectable...of course, maybe that just didn't make it into the Wiki. |
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27 Jul 07 - 07:55 PM (#2113015) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Don Firth Arthur C. Clarke had a doozy of a short story some decades ago about a team of computer experts who had delivered a big super-computer to a Tibetan lamasery and taught the monks how to use it. The monks had the belief that if they could learn all 9 billion names of God, the universe would end. Since, to them, this would mean the end of having to reincarnate onto the tediously repetitive wheel of life and death, they felt that a computer could aid them greatly in the task. They were already hard at it when the computer experts left. On the way back down the mountain, they were laughing up their sleeves at the whole operation, especially the silly beliefs of the monks. Suddenly, one of them pointed at the sky and said, "My God! Look!" The others looked up. One by one, the stars were winking out. Don Firth |
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27 Jul 07 - 10:08 PM (#2113073) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Peace "Nightfall." For those who wish to read or reread this wonderful sci-fi story by a great and prolific writer (about 400 books authored, edited or collaborated on?). |
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28 Jul 07 - 07:45 AM (#2113222) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: GUEST Over 1000... |
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28 Jul 07 - 07:12 PM (#2113635) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Grab Yeah, that's a good one, Don. (Story's called "The 9 billion names of God", coincidentally. :-) IIRC, "Nightfall" is also interesting because it shows religious belief ("our god says it won't happen") against the scientists' discovery that it's going to happen. And the scientists end up as the scapegoats when it *does* happen. Also don't forget "Pitch Black" which was a cracking little film. Graham. |
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28 Jul 07 - 07:34 PM (#2113642) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Cluin Wasn't the one about sentient stars a Pauline Gedge novel called "Stargate" (no relation to the movie/TV series). |
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28 Jul 07 - 07:37 PM (#2113645) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: folk1e In "Whipping Star" the stars were sentient and able to comunicate through a device called a tsipriot(or something similar)it was part of a series that included "Dorsi" unless I am becoming befuddled in my old age! |
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28 Jul 07 - 10:17 PM (#2113733) Subject: RE: BS: 4 suns- Didn't Asimov write a story ? From: Adrianel I think the 2 suns and the figure-of-eight orbiting planet was by Fredric Brown, and involved some awful puns about twins named Ike and Mike Witt. Unfortunately, I can't remember the name of the story just now - I'm definately becoming befuddled in my old age. |