The Big Bang

Arrow · Post by **Arrow** » 2003-01-28 09:38am

Yes, because everywhere we look in the sky galaxies are moving away from us, with increasing speed the farther away they are. Furthermore, the speed is dependant on distance. This was first observed by Edwin Hubble in 1929. Its similar to putting dots on a deflated balloon. Blow up the balloon and watch the dots move away from each other.

Durandal · Post by **Durandal** » 2003-01-28 04:01pm

His Divine Shadow wrote:
Durandal wrote:Space is expanding
Are we sure that space itself is expanding and not just the matter that inhabits space?

Yes, because we have a limited radius of observability due to the expansion. If things were simply flying apart from one another, their relative velocities could never reach c. However, space can expand faster than light, and after a certain distance away, space is expanding too quickly for light to make it to us.

Arrow · Post by **Arrow** » 2003-01-28 04:50pm

Durandal wrote:
His Divine Shadow wrote:
Durandal wrote:Space is expanding
Are we sure that space itself is expanding and not just the matter that inhabits space?
Yes, because we have a limited radius of observability due to the expansion. If things were simply flying apart from one another, their relative velocities could never reach c. However, space can expand faster than light, and after a certain distance away, space is expanding too quickly for light to make it to us.

Furthermore, the only other force that could cause matter to move is gravity. However, gravity can not be the cause as all distant galaxies would fly toward each other, not away from. Therefore, space-time expansion is the only explaination.