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#521
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How well can we predict the solar system's far-distant future ?
"G=EMC^2 Glazier" wrote...
in message ... Painius A very clean silver surface is the best reflector of sun light. Mirrors melt iron. They give back a virtual image that easily fools our brain. If we are using a reflector telescope we are seeing a virtual universe. Mirror gives back exactly what is shown to it. It does not reverse words from right to left,when we present the head line of a news paper to it. We did that bert Bert, i'm not getting that last part. If that is true, then why do the letters on the front of an ambulance show up like this when you look directly at them?... E C N A L U B M A Of course, it's for drivers in front of an ambulance to be able to read that it's an ambulance in their rear- view mirrors! happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S.: Thank *YOU* for reading! P.P.S.: http://yummycake.secretsgolden.com |
#522
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what if (on colliding galaxies)
"BradGuth" wrote in message...
... On Aug 19, 3:07 pm, oldcoot wrote: On Aug 19, 2:04 pm, "Painius" wrote: Here we have a star with a blue shift heading for us at a measurable radial velocity. At its present rate of approach, Sirius would reach Earth in 339,000 yrs. Since we do know that Sirius has a proper motion, we also know that Sirius is not approaching Earth. Sirius is headed off in some other direction that is from 0 degrees to 90 degrees (non-inclusive) off from the straight-line radial between us and that star. Sirius will not collide with Earth if it stays on its present path. Uh, before you get pounced on, Sirius' blue hue is not from Doppler shift but from its temperature. It radiates higher in the blue end of the spectrum. So invoking Sirius' blue-ness doesn't really make a valid analogy to the Andromeda issue, although you've effectively made your point with it. In addition to its nearly UV spectrum to start off with, and the 26x visual illumination, the Sirius star/solar system is once again being followed and closed in on by our solar system. Sirius a/b used to be worth 7+ solar mass. 4+ solar mass is currently missing in action. The unanswered question of the day; How many planets and their moon got away from the red giant phase? ~ Brad Guth Brad_Guth Brad.Guth BradGuth Oops, missed this one. To give some idea, though, most scientists agree that at the red-giant phase of our Sun, Mars will probably make it and shoot off quickly out of its orbit, while Venus and Mercury definitely won't make it. The expanding red surface will grow too quickly for those two to do anything but vaporize. Earth? The fate of our beloved homeland is upina air. Some astronomers feel that Earth will make it out like planet Mars, and others say, "No dice." And it seems to be most likely that Earth will wind up like Venus and Mercury... T o a s t e d ! happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S.: Thank *YOU* for reading! P.P.S.: http://yummycake.secretsgolden.com |
#523
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what if (on colliding galaxies)
On Aug 31, 7:17 am, oldcoot wrote:
All BBs expand before eventually turning around and becoming the next SMBH. The question is, which BB cycle are we in? ~ BG WFIW, Gordon Wolter believed that **in present time**, we are slightly past the 'Solstice' point of max expansion and into the beginning of the Contraction phase. *In present time* is the operative term, not in deep- past lookback. The onset of Contraction also marks the beginning of *reversal of thermodynamic entropy* (in contrast to the open-ended heat death notion). Since our universe has supposedly created its physical radius of 50+ billion light years, perhaps in 50 or so billion years we might actually start to discover how much such cosmic things have turned around. ~ Brad Guth Brad_Guth Brad.Guth BradGuth |
#524
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what if (on colliding galaxies)
"Saul Levy" wrote in message...
... On Fri, 22 Aug 2008 12:33:41 -0400, Scott Miller wrote: Timberwoof wrote: In article , "Painius" wrote: Yes, TW, i'm afraid that's exactly what Scott, Saul and pretty much the whole of astronomy are saying when they (without really thinking it out) say that Andromeda WILL collide with our Milky Way someday. It's taking just too damn long for astronomers to sense a proper motion for Andromeda, so they're sliding back into the ancient paradigm of geocentrism. Simple as that! Scott and Saul are not "pretty much the whole of astronomy". "Pretty much the whole of astronomy" is NOT saying that it WILLL happen; they say it might. There's a difference. I take exception to this statement as well, as I have not said it will happen either. But, unlock the nonscience folks here (Brad, Panius, Bert), I did go and see what the most recent measurement attempts of the proper motion of M31 is. Here are three articles of various detail on one of the more recently published findings: http://www.sciencemag.org/cgi/conten...;307/5714/1440 http://arxiv.org/abs/astro-ph?papernum=0506609 http://www.nrao.edu/pr/2005/m33motion/ Note for those attempting to catch me or others here in a lie - these three articles are of the same attempt, worded differently, and are indirect attempts at measuring the proper motion by measuring motions of Triangulum. Very interesting, Scott! The second link says that a dark halo collision will occur in 5-10 billion years. Saul Levy Still haven't had time to adequately digest all three links, but if you're correct, Saul... ". . . W I L L occur in 5-10 billion years"? Riiiiight! So much for the scientific method, eh? happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S.: Thank *YOU* for reading! P.P.S.: http://yummycake.secretsgolden.com |
#525
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How well can we predict the solar system's far-distant future ?
On Aug 31, 7:56 am, "Painius" wrote:
"G=EMC^2 Glazier" wrote... in ... Painius A very clean silver surface is the best reflector of sun light. Mirrors melt iron. They give back a virtual image that easily fools our brain. If we are using a reflector telescope we are seeing a virtual universe. Mirror gives back exactly what is shown to it. It does not reverse words from right to left,when we present the head line of a news paper to it. We did that bert Bert, i'm not getting that last part. If that is true, then why do the letters on the front of an ambulance show up like this when you look directly at them?... E C N A L U B M A Of course, it's for drivers in front of an ambulance to be able to read that it's an ambulance in their rear- view mirrors! Perhaps Bert thinks It's your left/tight brain playing those mind games. ~ BG |
#526
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what if (on colliding galaxies)
On Aug 31, 8:29 am, "Painius" wrote:
"BradGuth" wrote in message... ... On Aug 19, 3:07 pm, oldcoot wrote: On Aug 19, 2:04 pm, "Painius" wrote: Here we have a star with a blue shift heading for us at a measurable radial velocity. At its present rate of approach, Sirius would reach Earth in 339,000 yrs. Since we do know that Sirius has a proper motion, we also know that Sirius is not approaching Earth. Sirius is headed off in some other direction that is from 0 degrees to 90 degrees (non-inclusive) off from the straight-line radial between us and that star. Sirius will not collide with Earth if it stays on its present path. Uh, before you get pounced on, Sirius' blue hue is not from Doppler shift but from its temperature. It radiates higher in the blue end of the spectrum. So invoking Sirius' blue-ness doesn't really make a valid analogy to the Andromeda issue, although you've effectively made your point with it. In addition to its nearly UV spectrum to start off with, and the 26x visual illumination, the Sirius star/solar system is once again being followed and closed in on by our solar system. Sirius a/b used to be worth 7+ solar mass. 4+ solar mass is currently missing in action. The unanswered question of the day; How many planets and their moon got away from the red giant phase? ~ Brad Guth Brad_Guth Brad.Guth BradGuth Oops, missed this one. To give some idea, though, most scientists agree that at the red-giant phase of our Sun, Mars will probably make it and shoot off quickly out of its orbit, while Venus and Mercury definitely won't make it. The expanding red surface will grow too quickly for those two to do anything but vaporize. Earth? The fate of our beloved homeland is upina air. Some astronomers feel that Earth will make it out like planet Mars, and others say, "No dice." And it seems to be most likely that Earth will wind up like Venus and Mercury... T o a s t e d ! I tend to agree, because long before then our Earth will have come to its self cultivated demise at the faith-based hands of the mostly rich and powerful of arrogant, greedy and despicable humans, so there's really nothing to worry about our getting T o a s t e d ! No point in relocating our Selene/moon out to Earth L1, as that would only have extended our terrestrial survivability by a few hundred million years, not to mention having provided unlimited clean energy and making a rather terrific outpost/gateway (in addition to my 256e6 tonne LSE-CM/ISS) for effectively going just about anywhere. Of course eventually moving our Selene/moon once again from Earth L1 to a little past Earth L2 would make a rather nifty gravity tug. There are computer simulations that'll prove this out. ~ Brad Guth Brad_Guth Brad.Guth BradGuth |
#527
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what if (on colliding galaxies)
In article ,
"Painius" wrote: "Saul Levy" wrote in message... ... On Fri, 22 Aug 2008 12:33:41 -0400, Scott Miller wrote: http://www.sciencemag.org/cgi/conten...;307/5714/1440 http://arxiv.org/abs/astro-ph?papernum=0506609 http://www.nrao.edu/pr/2005/m33motion/ Still haven't had time to adequately digest all three links, On other words, you haven't read them. The second one is an abstract an the third one has more detail. but if you're correct, Saul... ". . . W I L L occur in 5-10 billion years"? Riiiiight! So much for the scientific method, eh? Alternatively, maybe you did read the articles. What was wrong with the method used to make the measurements? -- Timberwoof me at timberwoof dot com http://www.timberwoof.com People who can't spell get kicked out of Hogwarts. |
#528
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what if (on colliding galaxies)
In article
, "Painius" wrote: "Timberwoof" wrote in message ... In article , "Painius" wrote: Even so, no separate massive object is needed. Of course it's needed. Don't you understand the 3body problem? Yes, I understand it. I don't think you do. What it means is that while the orbits of two objects can be described with simple equations and parameters, when three objects are involved, you can no longer use just algebra to show the relationships. (Under special circumstances, you can, for a limited period of time.) There are over 30 galaxies in the Local Group that might be orbiting the common barycenter. They would all fly off in random directions if there were no hypermassive object at the barycenter. That is simply not true. First, they *aren't* orbiting a hypermassive object. Any "hypermassive" object would *require* everything near it to show certain accelerations, and those are just not seen. If all there was, was just the Milky Way, Andromeda, and the double handful of smaller galaxies, the system could be gravitationally bound and perfectly happy. Firstly, there are THREE (please get it thru that thick skull of yours) T H R E E gigantic spiral galaxies of similar size in the Local Group: 1) the Andromeda galaxy, 2) the Triangulum galaxy, and 3) the Milky Way galaxy. Most of the rest of the smaller galaxies are satellites of these three spiral galaxies. However, there are at least six or seven rogue galaxies that are also gravitationally bound in the 10 million light year wide Local Group of galaxies. At the very least this is a classic 3-body problem. IE, three bodies of similar mass, which is, oh cosmology guru, very different from the Centauri situation where P. Centauri is so much smaller than ACa or ACb and much farther from the two alphas, as well. That makes the Centauri group a simple 2-body problem. Kryst! It's not even known for certain that Proxima even orbits the two Alphas! Secondly, there is as yet no way of telling anything at all about your "certain accelerations". It could very well be that they're "just not seen" because of the tremendous distances involved. "Barycenter" is just a term of convenience. Consider Alpha Centauri. It is a binary star system; Proxima Centauri is believed to orbit Alpha Centauri. When doing calculations of Proxima's orbit, it's simpler and more convenient to consider Alpha as one mass; its location is taken to be the barycenter of ACa and ACb. However, when you calculate the orbits of ACa and ACb about each other, you treat them separately, and you do *not* invent a third massive object for them to orbit around: the orbits would just not work. Your insistence on "barycenter" implying a real invisible massive object throws an unnecessary and unobserved monkeywrench into all multiple-star orbit calculations. It's just plain wrong. Drop it. Eeeeeee-NOPE! I'm still working on oc's lensing argument, but that's the only monkeywrench worth its salt thus far. But you can drop it if you like. No skin off my nose. Even so, no unknown invisible hypermassive barycenter is needed for a bunch of objects to be gravitationally bond to one another. *Especially* because, as you claim, there's no way to tell anything about the objects' accelerations: you have no basis for claiming the existence of such a thing. -- Timberwoof me at timberwoof dot com http://www.timberwoof.com People who can't spell get kicked out of Hogwarts. |
#529
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what if (on colliding galaxies)
In article
, "Painius" wrote: "Timberwoof" wrote... in message ... . . . If I am moving toward you, my velocity is ... toward you. As I'm whipping about, there's a point where my velocity changes from toward to, through zero, to away from you. That zero point is also the closest point to you. It cannot be any other way. I know how frustrating this can be for you to keep trying to convince me, TW. But you have to allow for the fact that what you describe is not the kind of motion under consideration. But to use your description, try the following... If I am moving toward you, my velocity is... toward you. As I'm whipping about, there's a point where my velocity changes from more toward you to less toward you. As it changes toward "less toward you", it appears to change sign, but it doesn't. It cannot be any other way... http://www.physclips.unsw.edu.au/jw/circular.htm Note in the above that as long as the orbit always curves in one direction, the two tangential velocity vectors will always yield a radial velocity vector that points toward the center. It never changes sign. If you're moving in a straight line that I'm not on, then a component of your motion is toward me. At your closest approach, the component is zero, and then becomes "away". But that's not the kind of motion we're discussion. We're discussing circular motion. If you're moving in a circular orbit around me, you're not moving toward me, you're moving at a right angle to the line between us. You're accelerating along that line, but your movement is tangential. (We're discussing *circular* motion, right? As in moving on a circle. As in that thing which is always the same distance from some point, and that distance is known as the radius of the circle. Which is constant because the size of the circle isn't changing. That kind of circle, right?) -- Timberwoof me at timberwoof dot com http://www.timberwoof.com People who can't spell get kicked out of Hogwarts. |
#530
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what if (on colliding galaxies)
In article ,
"Painius" wrote: It's easy to see how the bullet's upward and downward movement is changing sign with respect to the Earth. But how about with respect to Earth's gravitational field? Whether or not you and i can ever agree upon the nature of a gravitational field, whether it's push or pull, whether or not it's generated by a mass or the result of a spatial energy flowing into mass, the fact remains that a mass possesses a definite gravitational field. And i submit to you, Greg, that the bullet's movement, while obviously changing sign with respect to the surface of the Earth, never changes sign with respect to Earth's gravitational field. You're apparently failing to separate velocity and acceleration. The projectile's acceleration is always toward the Earth. The projectile's velocity depends on the initial angle of the shot, the initial velocity of the projectile, and the time elapsed after that moment. -- Timberwoof me at timberwoof dot com http://www.timberwoof.com People who can't spell get kicked out of Hogwarts. |
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