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Black Crunch jams Universal cycle [Cosmology]
Nature Magazine ^
| 23 Decemeber 2002
| PHILIP BALL
Posted on 12/22/2002 6:07:08 PM PST by PatrickHenry
click here to read article
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To: Doctor Stochastic
placeholder bump
161
posted on
12/23/2002 7:33:20 AM PST
by
js1138
To: All
Oh, dear. Dear lurkers:
The answer given by MacDorcha (8.6 ft) was right, but only the good Lord knows how MacDorcha computed it. The simplest way is to look up the sine of a 60 degree angle. If you're not equipped for that, there's another way. The other angle is 30 degrees, and most can remember enough high school trig (sine of 30 degrees is 5) to know how far the base of that the ladder is from the wall -- an even 5 feet. So even without some handy trig tables (or a slide rule which has them built in), one could rely on the ol' Pythagorean theorem to bang out the height, as we already know two of the sides of the triangle.
To: Sentis
Not all that much use speculating about this until we know for certain what the shape of the universe is. I think we can safely conclude that it's Bush's fault for not following the Kyoto protocols.
To: PatrickHenry
The simplest way is to look up the sine of a 60 degree angle. If you're not equipped for that, there's another way.Even $5 calculators have "SIN" buttons nowadays. But I'd give him the points: usually when a student pokes the "SIN" button, the answer he writes down is 0.8666666.
To: Physicist
Even $5 calculators have "SIN" buttons nowadays. You wippersnappers have it too darned easy! Buncha button pushers! Snort, grumble, harumph ...
To: RadioAstronomer
Depends if you are looking for area or diameterSigh! See what happens when you post late at night after a long weekend! :-(
Should have read circumference. (feel like a fool! LOL)
To: PatrickHenry
What is it that some people, when they solve an equation for a given geometry they then have to have an article in Nature and say what will ultimately happen to the universe?
To: RightWhale
"Everybody wants to get into the act!"
-- Jimmy Durante
To: MacDorcha
if it has no sides, how do you know it's expanding? The isotropic 2.7 deg. K Cosmic Microwave Backround radiation is consistent with a Universe that is expanding...
The recession of distant galaxies (again, isotropic), is consistent with an expanding Universe.
"sides" of the universe have nothing to do with it.
how do we know it isnt just some phenomonom that causes movements around us?
Because if it were a localized motion effect, it wouldn't be isotropic; we would appear to be moving away from some distant celestial objects, but towards others.
or... that this system is contracting?
Because we don't see any evidence for an isotropic blue shift.
saying it has no sides down plays the big bang theory
BB Cosmology says nothing about the Universe having "sides" (boundaries). An unbounded Universe is entirely consistent with BB Cosmology.
To: PatrickHenry
Are you sure that wasn't a NESTLE's Crunch??
To: MacDorcha
i happen to be in college, and could not have gotten there without passing algebra, geometry, and trigonomitry. You passed Trigonometry?
"Bump" to an entertaining read. Although, it would be nice to read some discussion regarding the substance of the original article.
RadioAstronomer, you are a class act.
Square root of three, divided by two will get you the ladder answer, exactly.
172
posted on
12/23/2002 10:52:22 AM PST
by
Cboldt
To: VadeRetro
You passed Trigonometry? Hard to believe he passed English. Maybe he slept away in those classes too.
To: Physicist
"Is this not also true of the gravitational force on the moon? Why doesn't it stop?"
actually, it is slowing down. very slowly, but it is doing so. it's about as noticeable as glass ripples.
To: VadeRetro
look, it was 1100 pm when i wrote that. cut me a break. i do things besides listen to people whine about the occasional typo.
To: MacDorcha
5 cubed root.. sorry, just now read the babble i wrote at 2 am... man, it's been a long day
To: MacDorcha
There would be nothing to drive another Big Bang, and nowhere else to go Who says? It all started spontaneously in the beginning, why couldn't it do it again huh?
ahem...
To: LibWhacker
the point of speculation, is that no one is wrong. its jsut the accounts of individuals over time, but everyone's accounst differm, along with mind-set, and society surrounding them. i dont mind you knocking me, but please, let me know its in fun if it's in fun.
To: Terriergal
"Who says? It all started spontaneously in the beginning, why couldn't it do it again huh?"
well, if there is a crunch, then there is a force slowing the expansion of the universe enough to bring the universe crashing into itself again. if there is something acting against the explosion, then the universe is losing energy with each passing moment. if two opposite powers work against each other of equal strength, then the median is the only outcome. the median in this case would be no expanding, no contracting, nothing.
To: Cboldt
it would be nice to read some discussion regarding the substance of the original article. We see the DOE supported some of this work. Aside from that, would the assumption of an infinite, flat universe make this any more than an academic exercise?
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