Discussion in 'Astronomy, Exobiology, & Cosmology' started by Norsefire, Dec 13, 2007.
He does have a point mind, you, sir. Please Register or Log in to view the hidden image!
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I keep reading about the expanding universe. What is it expanding into?
Perhaps the universe is a paradox. After all, it IS infinity. This means that every single potential event in space-time has an infinite chance of happening. So, in a strange way, all theories concerning the beginning of the universe and its end are both true and false. This means that the Big Bang happened, but it didn't as well. This means the Big Rip will happen, but it won't either. It means that theres definately intelligent life out there somewhere, and also that it exists nowhere else. Thats the problem with the universe. Its self-contradicting. The very fact that it exists is a wonder.
Yup. Check out the first post in my blog.... Please Register or Log in to view the hidden image!
the big bang is indeed about as 'scientific' as grimm's fairy tales...
but there is a difference...
it's a working theory... the best that could be construed from the evidence at hand... evidence that could be in some way attained, in some way measured, and in some way examined under the scientific method...
anyone who 'signs off' on the big bang theory as 'the way it happened' is short sighted...
but in science one must stay with that theory the method finds and supports... until the method disproves the theory substantially, or produces a hypothesis that 'fits' the data better and supplants the previous theory...
pane collision of M theory is a fascinating idea...
but it's not able to, under the method, supplant the big bang yet...
so we go with the best working theory that science can build on for now... even if it is nonsense... it fits the data...
i have had long conversations on this topic with some highly credentialled folks, including at nifty places like lanl and sandia... always a good discussion...
anyone with any thoughts on Juan Maldacena's ideas?...
The universe contains all space. It doesn't sit in some kind of external space.
What happens as the universe expands is that everything gets further apart. Well, not exactly everything - you don't expand with the universe, for example, because the electromagnetic forces that hold your body together are much stronger than the expansive effects.
One way to think of it is that the universe is like a loaf of raisin bread being baked in an oven. As the bread expands, the raisins all move away from one another, just like galaxies in the universe all move away from one another. The difference is that the raisin bread has edges that expand into the surrounding air, whereas our universe has no edges.
That seems weird. If the universe has no edges how does it expand?
If the universe is infinite in extent, it wouldnt matter.
What do we mean by infinity as applied to a physical thing or space?
With numbers, it means that no matter what number you pick, you can always add 1 (or whatever quantity depending on the kind of number).
With an object like a sphere, that has a definite fixed surface area, there are an infinite number of points on this finite surface. Meaning that, since a point is a dimensionless entity, between any two points can be found another point.
So what about the universe (space)? If space is infinite in 3 dimensions, this would mean that no matter how far you travelled, you could always take another step. And you could always see as far as the expansion rate would allow.
So, if the thing that is expanding is simply the whatever-it-is that defines length scales in the universe, why would an infinite volume of this not be able to accommodate this "metric expansion"?
Think of it another way. I can fairly easily imagine an infinite number line stretching away to my left and right. The numbers have some spacing. I can then easily imagine adjusting the spacing between those numbers without violating the infinite nature of the number line itself.
Does that do any good?
It has no VISIBLE edge. Without being able to view past the horizon..(the light that has had time to reach us) there really is no way to tell if it is infinite or not. In my lifetime, I would like to see a new star popup in the night sky though so I could confirm or deny this "universe came into existence all at once" theory...
Well, going down a dimension, consider the surface of a balloon. If you ignore the thickness of the balloon's skin (which we have to for this lower-dimensional analogy) then the skin has no edges. If an ant crawls along the surface, it never hits an "edge" and it will never fall off an edge. Paint dots on the balloon's surface and blow it up. All the dots move further apart and the surface expands, but there are still no edges.
Really, the image is a lot smaller at the NASA site
Isn't that the raisin-cake theory? Or was that just a pet name given it by my 121 professor before I dropped out? Ah ... here it is:
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Image credit: WMAP Cosmology 101 (NASA.gov)
Note on Edit: Ah, I had missed your prior post using the very phrase. My apologies.
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There is one fundamental difference between scientific and religious origins assertions:
Science isn't done yet. Barring any further revelations from God, religion is done.
Is the importance of this juxtaposition clear, or would you like me to explain a little further?
That is the $64,000 question. Space I believe is an actual material which EMR travels through as waves travel through water. It cannot expand without changing what it is. I think somehow there would have to be ever more of it for expansion to work but I don't know how.
Tiassa. For that to happen, bb-ers need to explain how something can expand in four physical dimensions. A 3D expansion would mean everything moving away from a definite centre.
That's just it. Everything is more powerful than the so-called expansive effects of the universe, even photons. We are led to believe that literally nothing more than space can drag whole galaxies, even super-massive black holes along. The expansion effect (allowing 22 km/s per million light years) works out 1 part in 427,636,363,636,363,636 (per second). It is utter nonsense!
Photons ALWAY travel at light speed. If their journey has become an atom's width longer in the second taken to travel 186,282 miles, they will totally ignore it and still only travel that 186,282 mps.
Walter LW. It could be possible that micro BH's could grab loose particles around them but I don't think they possess the gravitational pull over a large enough area to do anything about it. Very roughly. A proton is reduced on the same scale as the Earth becoming football size. Say it now has the gravitational force of a thousand protons. For it to convert another particle to black hole material, it would have to exert it's force over the whole particle which at maybe many millions of times bigger would be impossible.
I don't know if a particle could be broken down into the fabled "super-strings" but would not think this capable of doing so. I think for a viable Mini-BH which could do serious damage, we are talking one the size of a proton (a few thousand tons of material) which can then suck in atomic material.
Never heard of him. Could you post some of his thoughts/theories here?
And what is the energy that is increasing the speed of that occurence? I hope we can all agree that if there was only one explosion in the beginning, most of the energy was released at the beginning. So most of the expansion would have occured in the beginning and then slowed down until stopped.
Besides, red shif doesn't mean expansion necessarily. All that it means is that galaxy X should be at a certain distance, but instead it is a little bit farther away.
Oh, and what about the blue shift of many galaxies?
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