Tatooine's Double-Sunset a Common Sight 132
anthemaniac writes "Thirty years ago, Luke Skywalker beheld something that scientists are just now realizing is likely quite common in the universe: double sunsets. Astronomers have long known that binary star systems are common. And models suggested that planets could form in these systems, even though there's a double-tug of gravity on the material that would have to form a planet. Observations from NASA's Spitzer telescope, show that binary systems are just as likely to be surrounded by planet-forming debris disks are are lone stars."
This just in (Score:2, Funny)
Force, not tug (Score:3, Funny)
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pre-Quantum viewpoint (Score:2)
Most modern models have a particle, the graviton, exchanged between objects interacting gravitationally. In the Quantum and String Theory models, gravity is a real force, just much weaker (probably because space is warped in the fifth dimension, with gravity only being strong near its brane, and weak out in the bulk).
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Two suns in the sunset? (Score:2, Interesting)
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Great (Score:5, Funny)
Why do we have to drag Republicans into this? (Score:5, Funny)
Why do we have to drag the White House into every science discussion we have on SlashDot?
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One drawback (Score:2)
I love this movie! (Score:2, Funny)
its common knowledge to them.
Planetary Orbit? (Score:3, Interesting)
Would it have to be far enough away so they appeared as one, or go into some crazy chaotic close orbit?
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Earth, Moon, man-made object can make one such trio as can say Sun Jupiter and asteroid.
Mycroft
Re:Planetary Orbit? (Score:5, Informative)
Would it have to be far enough away so they appeared as one, or go into some crazy chaotic close orbit?
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Even if such planets did form, none of them would harboring any life, at least not any life based on carbon. The irregular orbits of all possible planets would preclude any with a stable temperature range. The minimum star spacing for an earth like planet is about 3.8 light years. This specification disqualifies about half of all stars in our galaxy. The mass of any planet harboring life could also not be much different than that of our earth.
This means that the S
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.....In between, no planets will form.......
Even if such planets did form, none of them would harboring any life, at least not any life based on carbon. The irregular orbits of all possible planets would preclude any with a stable temperature range. The minimum star spacing for an earth like planet is about 3.8 light years. This specification disqualifies about half of all stars in our galaxy. The mass of any planet harboring life could also not be much different than that of our earth.
Wow, that's only 50 billion stars left. No chance of finding much there.
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Re:Planetary Orbit? (Score:5, Insightful)
If the second binary star is in a medium-sized orbit (ie, somewhere between where Jupiter and Pluto are in our system), it seems to be the case that this disrupts the planet-forming disk of gas so much that no planets are likely to form.
If you want to see a full list of all known exoplanets, go here: http://exoplanets.org/planets.shtml [exoplanets.org]
The column marked "a (AU)" is orbital radius, where 1 AU is the earth's distance from the sun.
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Is it possible to create an orbit around a binary system where a planet has a stable enough environment for harboring life?
Helliconia got it right... (Score:3, Interesting)
Helliconia by Brian Aldiss had a striking ternary system with a small star (with an inhabited planet) orbiting a binary system, giving a 1,500-year long mega-season that gave it regularly-occuring ice-ages.
That seems quite viable, but it illustr
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What Oort cloud? There is no such thing. It is a mathematical fiction that has never been observed, even with the most powerful telescopes. The reason that such a fiction even exists is because comets should long ago have evaporated into space, having a lifetime of a maximum of about 15,000 years. That of course contradicts the accepted religious evolutionary dogma of the billions and millions of years for the age of the Universe. Hence the proposed fiction of the Oort cloud.
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Picture a long board with an anvil at one end and a small paperweight at the other. If you were to find the balance point between the two, it would certainly a lot closer to (perhaps underneath) the anvil. That st
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It wasn't thirty years ago... (Score:5, Funny)
Luke didn't see the sunset thirty years ago - he saw it "A Long Long Time Ago (in a Galaxy Far Far Away)..."
I can't believe I'm posting to a Star Wars item...feel like I need to take a shower now.
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Psst, I didn't wanna say anything man, but since you brought it up.
Two is Better than One (Score:5, Funny)
anybody remember Risa? (Score:2)
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what about a double-sunset + life? (Score:5, Insightful)
One of the reasons that Earth can support life is that the distance between the earth and the sun remains close to a constant for the duration of Earth's orbit around the sun, so the Earth receives a fairly constant amount of solar energy. This means, for example, that the temperature doesn't go down to -200 in the winter and up to +800 in the summer.
But in a binary system, I would imagine that orbits that provide a constant amount of solar energy in the Earth-normal range would be less likely to occur. (What would such an orbit look like when there are 2 suns?) Are there any astrophysicists out there that can comment on this?
Doug Moen
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Sure planets could support "life". What you're asking is, could they support you? Maybe not.
Earths precarious orbit and presense of the water and the particular temperature make it suitable for our type of life - or is it the other way around, did life suit itself to the rock we happen to be stuck on?
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"life" isn't as delicate as we've once thought, it can be supported in extreme environments,
What, you mean places like volcanoes? Or ocean trenches? Those may be "extreme" compared to where you live, but by cosmic standards they're positively bucolic. Which is why there's no evidence that the other planets in our solar system are anything but sterile. You could maybe introduce life on Mars by being careless with decontaminating your space probes, but it seems unlikely that life ever evolved there.
And Mars is pretty hospitable compared to a planet that gets blasted by a companion star one a yea
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You are wrong there. The complex proteins found in living cells cannot be made with any other element. Silicon is the closest, but its binding energies are too high for really large, complex molecules such as in all life forms. As far as we know, the same elements exist throughout the universe as we have here on earth. Of course if you are talking about non-physical life forms then anything can be conjectured.
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Certainly something like a Von Neumann replicator (at the extreme like the replicators of Stargate SG-1) are a legitimate alternative, and other ideas with nano-technology can some up with some alterantives, but such machines do seem to be unlikely to have been created spontaneously from just raw matter.
Of course even the machinery of life as we know it has not been completely explained through any theories, nor h
Lagrangian (Score:2)
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Yeah I wondered about that too. But it shouldn't be too bad. F'rinstance, if both are suns like ours then the habitable zone would be wider and further out (~1.4 AU I guess). The only problem comes then from one sun occluding the other, so if the planet isn't inclined to the ecliptic too much then there will be brief, but nasty, periods when the light level drops to 50% of normal. If the suns are separated by 3 AU then half a 'cycle' (therefore one occlusion) would be about .... OK too long since I've done
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The mass and distance of the sun and earth are very critical and cannot be changed very much. Making a smaller sun means the earth would need to be closer. At some point, the earth could no longer rotate independently, but its rotation would be the same as its orbit, such as Mercury. That would preclude life, since one side would be very hot and the other extremely cold. Too massive of an earth would
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Um, weren't methane and ammonia the critical components of Earth's atmosphere in the currently accepted theory of abiogenesis? Earth retained those chemicals, too, and they were critical for the rise of anaerobic life.
Also, Venus is actually just slightly smaller than Earth, so if Venus's large size caused it to retain methane and ammonia...
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The biggest problem with that theory, as with evolution in general is that it doesn't tell us where the information stored in the DNA molecule cones from. It takes proteins to make DNA, but it takes the information stored in the DNA to build the proteins. It's the ultimate chicken and egg problem.
It is the surface gravity that determines what gaseous elements are retained, as well as temperature. The core and temperature of Venus are also different.
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The chicken and egg problem was solved a while ago. The egg came first, borne by something that wasn't quite yet a chicken. Similarly, DNA ultimately evolved out of basic self-replicating amino acids - ones tha
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The current theory of how current DNA+protein life came to be is the "RNA World" hypothesis. In this theory, originally all life was based on RNA wrapped in lipid "cell membranes". RNA acted both as the self-replicating genetic material, and as the enzymes that powered the cell. When proteins were first produced, they were produced by RNA enzymes, which is why to this today ribosomes are still made of RNA enzymes (ribozymes), even though the rest of the cellular machinery has been taken over by (more eff
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The problem with this and all other scenarios is that none of them explain where the INFORMATION codes carried came from. It is akin to making educated guesses how a CD or floppy is made, but not addressing in any way the huge amount of information, programming if you will, that is stored on these carriers. DNA and RNA are only carriers of data, they do not generate or produce it, any more than a CD or floppy disks spontaneously come with code and data. These have to or
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What is information? Shannon entropy [wikipedia.org], which is very closely related to thermodynamic entropy [wikipedia.org] (the latter being a specific case of the former).
Information is constantly being created, because entropy is constantly increasing. Mutation — random changes to genetic information — is the process by which information/entropy becomes inheritable. Natural selection is the process by which undesirable information/entropy is weeded out.
In specific application to the RNA World hypothesis, the process
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Shannon only treats information at a statistical level. Information always and ONLY arises in a mind. Information is not a physical quantity and is not constrained by certain laws of physics. It is carried by physical matter or energy, but in and of itself is neither. Norbert Wiener, the originator of the term "cybernetics" said: "Information is information, neither matter nor energy. Any materialism which ignores this will not survive one day."
To reduce entropy, in the sense
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... Information always and ONLY arises in a mind ...
Bullshit. Meaning always and only arises in a mind. Information, however, is not the same thing as meaning.
Information is what it is because it is surprising, i.e. you cannot predict it in advance. Order is the complete absence of information; an orderly system is easily predicted. It makes no sense whatsoever to say that you need "1) energy and 2) information" to reduce entropy. Why would you need information, only to remove it moments later? It
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Such a stable orbit is impossible if the stars are any closer than about 3.8 light years. Half of the stars in our galaxy (and most likely other galaxies) are closer than this. The parameters for a life supporting planet are extremely narrow. The mass, chemical makeup, rotation rate and a number of other specs must be right also. The size of the parent star is also critical. Our earth is a very rare and special place.
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I am not an astrophysicist, but there is some good information at the following link regarding the Alpha Centauri system (which is basically a dual-star system if you discount the temporary incursion of the Proxima Centauri red dwarf star):
http://www.solstation.com/stars/alp-cent3.htm [solstation.com]
Seems the most important factor is not the duration of energy that two stars give, but whether liquid water can exist. Even though Alpha Centauri A and B range between 11 and 35 AU from each other, habitable planets that h
Ooh. Debris fields. (Score:2)
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Can that many science fiction shows be wrong?
(not that 'two suns' has just become a cliche "this is an alien world, not new mexico, really" sort of backdrop)
Old news on slashdot.... (Score:2)
Alaska - already on a planet with two suns (Score:2, Interesting)
Sundog (Score:4, Informative)
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Stereo Sun(s) Tan FTW (Score:2)
Have a nice diurnal anomoly (Score:1)
500 A.U. only _relatively_ tight (Score:5, Insightful)
Remember the inverse square rule:
A companion star even 40 A.U. far out would be just an especially bright star. If it had the same luminosity as the Sun, it would appear 1/1600 as bright (.0625%).
The Tatooine scenario is still romantic fiction: Stars close enough to appear in the sky together as visible disks would probably be close enough that planets in orbit around them to have strange orbits.
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Brings to mind the time when I was about 12 or so and I got my hands on a 40 power telescope. With Alpha Centauri in the field changing to the higher magnification resolved the binary pair for the first time, and they are only 80 AU apart, IIRC. Doing that gives a fantastic feeling of depth. You can feel how far away it is.
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In other space news... (Score:2, Funny)
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Just don't ask Richard Hogland.... he'll give you an interesting response on this one.
It's my thinking (Score:2)
Maybe this would be more conducive to a life sustaining environment, even for planets further out from their sun than ours is. It's an old concept that a planet has to be just the right size, it's sun has to be just
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We will know more about this once we get landers on Europa and Io. Both are models for this type of planet because Juipiter is (really) the second sun we almost got.
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Long experience on the Earth is that life can be found nearly everywhere you can find an energy gradient and water, with a few other trace minerals, with the other elements mainly being carbon and nitrogen that are highly critical.
The dynamics of the Jovian moons, however, are a little different than what causes the molten core of the Earth and Venus, and active geological changes on these two
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There are many specifications of the earth and sun that must be just right. The orbit is only one. The mass of the planet is also critical. Making a smaller sun means the earth would need to be closer. At some point, the earth could no longer rotate independently, but its rotation would be the same as its orbit, such as Mercury. That would preclude life. Too massive of an earth would retain
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It appears as though our sun is unique enough to have a nearly circular orbit around the galactic core... and this is indeed something unusual for most stars that we see in the sky. Most stars have highly elliptical orbits relative to the galactic center.
The advantage of this is that
Shadows of the Empire (Score:2)
Whatever, none of the "improvements" have done it for me anyways. In my day, Han shot first. And we liked it that way.
J
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Besides, the technical problems of trying to cast daylight shadows of two G-class stars is both beyond the experience of most people that it would detract from the film, as well as the fact that the cost would have been perceived as prohibitive as well for everything but the CGI shots. Certainly not something to really have to bother with.
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The only scenario I can think of would require the planet to be inside the orbit of the less massive star about it's companion and be orbiting in the opposite direction and I don't even think that would work without eventually tossing the planet away, probably long before it cooled.
Mycroft
Old news (Score:4, Informative)
This was discovered sometime in 1967.
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Lucas says in the intro to the Special Edition version of the film that the double sunset wasn't a special effect, it was an optical illusion caused by the atmospheric conditions in the desert where they filmed it.
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The Star Wars (A New Hope) novelization by Alan Dean Foster mentions not only the twin suns, but even gives them names and a bit of a mythology behind them by "natives" of Tatooine.
Luke clearly lived in a binary star system, although it should be noted that these "twin suns" were in relatively close proximity to each other, and they were of similar masses. The number of times that this was referenced in movies and other places is too numerous to mention.
If Mr. Luca
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It could be it wasn't sfx, but a valid weather phenomenon that Lucas took advantage of, either intentionally knowing it to be common or by accident and he decided to 'keep' it and add to the mythology of his fictional universe.
If that were the case he might not have bothered to explain it back then and and let the proto ILM get credited for it (makes him and them look
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And due to the popularity of Star Wars in 1977, all of the crew members were interviewed, includin
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At best I figure Lucas saw such and optical illusion once and it influenced him to make it a double star system.
I just like to figure out improbable explanations to explain what didn't really happen sometimes.
Mycroft
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doubles common (Score:3, Funny)
Defenders of the Indefensible (Score:2)
Now all the fan boys need do is tell us why it took 20 years to build the Deathstar and why Luke found Leia such a "Turn-me-on Hot Chicky Mamma ooooh yeah", and their work will be complete.
http://www.chefelf.com/starwars/ [chefelf.com]
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Haliburton.
"Luke found Leia such a "Turn-me-on Hot Chicky Mamma ooooh yeah""
Let's see:
Teenager, in a small confined space with 2 droids, a wookie, and old man, a pirate and a princess.
It was either the princess or the pirate.
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Now as far as Luke being attracted to Lea at first I will present two datum about humans that one may assume applies to Luke and Lea (on the presumption that looks like and behaves like human in other ways is indicative).
Thar she blows... (Score:1)
All is possible with the touch of his noodly appendage.
first reference for two suns (Score:2)
Does anyone have an earlier reference? I suspect that Tatooine is a fairly recent reference, though popularly known it may be.
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Tatooine also predates HHGTTG.
I seem to remember Jules Vernes mentioning the possibility in Off on a Comet, a Journey through the Stars, but I could be misremembering. But considering that he was writing about people traveling to the moon in the 19th century, using 19th century technology, it wouldn't surprise me if he or someone else long before came up with the idea.
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Star Wars film release: 1977
Hitchhiker's Guide to the Galaxy on BBC Radio 4: 1978
(Book first published: 1979)
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Did the first movie discuss the two suns of Tatooine?
(I actually can't remember.)
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One of the greatest early SF stories. Look for it.