A question for those less ignorant that I:

The Big Bang theory...could it be possible to have two "big bangs" occuring the the same universe at the same time, just in different places? Our universe is said to be expanding, but is that just the mass from the big bang?

According to the GR model, the Big Bang happened everywhere at once.

could it be possible to have two "big bangs" occuring the the same universe at the same time, just in different places?

There are no places outside the universe :eek:

According to the GR model, the Big Bang happened everywhere at once.
Not too familiar with this theory...it suggests that all mass/energy just spontaneously came into existance?

There are no places outside the universe

I would agree. But what are you talking about? In the same universe, mass went through a big crunch in two seperate places, very far apart.

I know I have a very limited knowledge of phyics, but I really would like to learn more, and I don't have the cash now to take classes. I would be a great help if you would enlighten me on a few things, or at least tell me of some good books on the subject? (just know that advanced books will probably go over my head :( )

And another quick question...are there limits to gravity? If you had two atoms a hundred billion light years away, moving in a vacuum at 1000 light years a second, would they ever touch each other again (asking if they would ever be drawn back to each other)? Even if they had an infinite amount of time? I know it would probably take a VERY long time, but what if they had eternity? Would they slowly, slowly decelerate, and even start going towards each other, after so much time?

it suggests that all mass/energy just spontaneously came into existance?
No - it suggests that that time had a definite beginning, and that at the beginning of time, the Universe was very very hot and very very dense.

Hi again,
And another quick question...are there limits to gravity? If you had two atoms a hundred billion light years away, moving in a vacuum at 1000 light years a second, would they ever touch each other again (asking if they would ever be drawn back to each other)? Even if they had an infinite amount of time? I know it would probably take a VERY long time, but what if they had eternity? Would they slowly, slowly decelerate, and even start going towards each other, after so much time?

There's no limit to gravity's distance (according to the best current models), but there are limits to the total pulling power of a particular object. Essentially, it doesn't take infinite energy to separate two masses by an infinite distance.

So, if two objects are separating fast enough, they will never stop and return. They will keep slowing down, but asymptotically toward a particular value.

Conversely, if something is falling toward a massive object, there is a limit to how fast that object will end up falling (this is different to terminal velocity or the light speed limit), because there is a limited potential gravitational energy difference.

For example - The escape velocity of Earth is 11.18km/s. This means that if you fire a bullet straight up at 11.18km/s, it will never fall back down (ignoring air resistance. You'd also better fire it from a Pole, so we can ignore Coriolis effects).

Feel free to ask more about these things - it's wonderful stuff! You can also do some reading on your own if you prefer by looking out for 2nd hand physics texts (see if you can track down some slack Physics majors at a university), or have a browse at Hyperphysics (http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)

Pete

Ah, that is interesting. So there is a terminal velocity that goes both ways?

So I'm guessing that it's just all the other factors that slow down a bullet enough to make it return to earth?

And thanks a bunch, everyone.

Bullets return to Earth because they're not fast enough in the first place. If you could fire a bullet at 12km/s or so, it would leave Earth and never return. It wouldn't even hang around in orbit.

Bullets return to Earth because they're not fast enough in the first place. If you could fire a bullet at 12km/s or so, it would leave Earth and never return. It wouldn't even hang around in orbit.

You might want to try a rocket.......They seem to work a little better when it comes to space travel......

Atta Boy :)

You may check this link that eliminates even one Big Bang
http://www.world-mysteries.com/toi_esavov.htm

But escape velocity calculation simply assumes that the object is fired straight up, right?
Gee, I was about to ask this thing and kept bumped...... maybe it's easy to calculate 'escape velocity' if the object were to be fired 'horizontally' (earth is spherical afterall)

It doesn't matter which direction u fire it in (other than into the ground :D ), if it is 12 km s^-1 then it will leave the gravitational influence of the earth.

Note that you can get into orbit without hitting escape velocity. Actually, if you go at escape velocity, you can't stay in orbit without braking.

If there was a big bang. I would have definetley been in it.

Note that you can get into orbit without hitting escape velocity. Actually, if you go at escape velocity, you can't stay in orbit without braking.

Because an orbit is not escape