Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: pip on 04/12/2008 22:03:18

Title: Will the expansion of the Universe lead to a hole at the centre?
Post by: pip on 04/12/2008 22:03:18
OK big bang first then lots of mass with gravity all flying away from center, each mass has a pull on the other but as the planets become further apart the pull weakens and gravity is stretched, so is it possible that in the end space will become so stretched, and as nothing can never exist at the center where it all began will it be another big bang and so on. Are we just one of many big bangs....
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: Bikerman on 04/12/2008 22:14:30
Er..there is no 'centre'.
You are thinking of the picture of the BB as an explosion. It isn't like that. Everywhere is the 'centre' of the BB. The only useful metaphor I can conjure is the balloon - think of a balloon inflating and imagine the skin of the balloon is space and the radius is time...there is no 'centre'.
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: DoctorBeaver on 04/12/2008 22:25:31
"Big Bang" itself is a misnomer. There would have been no sound.

There is much debate about what the ultimate fate of the universe will be. There is now not much doubt that the universe will continue to expand until everything is so sparse that nothing will be happening. The temperature will drop to almost absolute zero and there will be no light.

A theory known as "The Big Rip" theorises that atoms and even composite particles will eventually break up.

As for whether there will be another Big Bang - we don't yet know why the Big Bang happened so we have no way of knowing if there could possibly be another.
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: pip on 04/12/2008 22:29:41
Ah if the universe will grow cold and we know engery cannot be created or destroyed where will it go.
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: DoctorBeaver on 04/12/2008 22:32:17
Conservation of energy says that all the energy will still be there, but so thinly spread it will barely be noticeable.
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: pip on 04/12/2008 22:36:46
Is it true to say that there is a large amount of hidden mass in the universe
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: DoctorBeaver on 04/12/2008 22:38:12
It certainly seems that is the case. Looking at the rotation of galaxies, there is not enough visible material to stop the galaxies flying apart. There must be more mass there to stop that happening; mass that we cannot yet detect.
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: pip on 04/12/2008 22:42:07
What if gravity both pulled and pushed but the pull was greater e.g.a lorry and a car tied back to back , the lorry would win but in order to calculate the amount of energy used you would have to take into account both vehicles...The car would be hidden energy.
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: DoctorBeaver on 04/12/2008 22:51:49
The exact nature of the force driving the acceleration in the rate of expansion is still unknown. It has been conjectured that there may be a repulsive element in gravity that only acts over very large distances.
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: pip on 04/12/2008 22:55:27
So as mass and gravity are related , opposite gravity should also have a relation maybe making the mass seem less than really exist ..... hidden mass
Title: Re: Will the expansion of the Universe lead to a hole at the centre?
Post by: DoctorBeaver on 04/12/2008 22:58:21
So as mass and gravity are related , opposite gravity should also have a relation maybe making the mass seem less than really exist ..... hidden mass

That is the opposite of what is required to explain why galaxies don't fly apart.

As do many people, you seem to be confusing Dark Matter with Dark Energy.