Originally posted by New-Prototype
Hey how's the grid expanding? I thought there were black holes absorbing things, doesn't this shrink the size? And it's not like I didn't listen to chroot when he said that the black holes expand after sucking stuff in. But that would make the even bigger right? So that'll cause more things to get sucked in, right? [?]
Can a black hole contract? Maybe there was once this huge black hole that sucked everything in over a lloonnng period of tim. And then it started collasping because there was nothing more to suck up, however all the previous matter was still within in. So then it was kind of like compaction within the hole and the gravity inside it just kept compacting and building stress, until...BOOM! the Big Bang! hehehe ^_^ do you think that's possible?
Black holes really aren't much different from any other massive object - they are just massive enough (dense enough) that light can't escape. If you compressed our sun into a little black hole without changing its mass, the orbits of the planets around it wouldn't change at all.
The expansion of the universe is a separate issue. The universe isn't a "thing" its just empty (more or less) space. And the empty space is getting bigger. How do we know? Because as discussed in wyzowl's other thread, everywhere we look, everything we see is moving away from us at high speed. And if we map those objects, we see that every object is moving away from every other object at high speed. The only possible explanation for this is that space itself is expanding.
All objects do not move on a radii from some central point. We have also recently discovered "planets" that are considered to "wander" rather than being a part of a "solar" system; and of course we have asteroids and comets that get perturbed from orbital paths from time to time.
Well that's just it - there is no central point. Like the cookie in the other thread (better yet, a balloon with dots on it that you are blowing up) everything is expanding away from everything else - except when things are already very close together. Also, we don't have the capability to see any planets beyond about 50 light years from us. When talking about the expansion of the universe, its not observable within our own galaxy only between galaxies not within our local group.
Some scale (distances from earth):
The Sun: 9 light minutes
Pluto: 4 light hours
Center of Galaxy: 25,000 light years
Nearest local galaxy: 80,000 light years
Andromeda Galaxy: 2.5 million light years
Diameter of the Universe: 20 billion light years
With the Hubble space telescope, we have been able to determine that there are roughly 100 billion galaxies in the universe. In accordance with the description above, if you point the Hubble in ANY direction, you see the same thing:
lots of galaxies