Galaxies Gone Wild!

Tachyon · Post by **Tachyon** » Fri Apr 25, 2008 7:44 pm

Eye candy... check out the videos also!

http://hubblesite.org/newscenter/archiv ... 6/image/a/

Clifford60 · Post by **Clifford60** » Fri Apr 25, 2008 8:30 pm

If galaxies are colliding with one another from different direction, does that means that the big bang theory is not true? That is, it started from a single point and then expand outward. [smilie=confused.gif]

Post by **zong** » Fri Apr 25, 2008 10:11 pm

Not true. Some galaxies move toward each other, but on the whole the galaxies are spreading out.

Back to topic, galaxy collisions are always very erm, eye candy (couldn't find another word). Maybe ChaosKnight can help by making some simulations of galaxy collisions for us to wow over!

Tachyon · Post by **Tachyon** » Sat Apr 26, 2008 1:16 am

zong wrote:Not true. Some galaxies move toward each other, but on the whole the galaxies are spreading out.

Back to topic, galaxy collisions are always very erm, eye candy (couldn't find another word). Maybe ChaosKnight can help by making some simulations of galaxy collisions for us to wow over!

Try this one: http://hubblesite.org/newscenter/archiv ... 6/video/d/

Clifford60 · Post by **Clifford60** » Sat Apr 26, 2008 10:48 am

zong wrote:Not true. Some galaxies move toward each other, but on the whole the galaxies are spreading out.

If there is infinite space and objects are moving outward, why should some galaxies move toward each other? If able, there must be a force that can overcome the outward movement causing some galaxies to move in different directions that result in the collision, what is this force? Inter-galactic gravity that result in some push-pull activities or like comet / asteroid running in a different path (why they run in a different path?) or ...?

Post by **weixing** » Sat Apr 26, 2008 11:57 am

Hi,

If there is infinite space and objects are moving outward, why should some galaxies move toward each other?

This is cause by gravity between the galaxies. When the galaxies are quite close together, the gravity between the galaxies will overcome the expansion of the universe locally and collide.

Have a nice day.

Post by **zong** » Sat Apr 26, 2008 10:23 pm

Tachyon wrote:Try this one: http://hubblesite.org/newscenter/archiv ... 6/video/d/

Couldn't access the link. Maybe it's my side faulty..

Clifford, you're getting the idea wrong. It is not infinite space and things are moving outward, but rather the expansion of spacetime itself. At least, that's what the current idea seems to be.. What in the future we don't know.

The analogy is like the balloon surface being the fabric of spacetime, with dots (aka galaxies) moving slowly in random directions on the surface of the balloon. The expansion of spacetime fabric (simulated by blowing air into the balloon to expand the "fabric" of the balloon) causes the galaxies to "move" away from one another. However, if some galaxies are near enough, the gravity will force them to move toward each other faster than the spacetime fabric can expand and pull them away. But in general, most galaxies will seem to be "moving" away from one another, because of the expansion of spacetime.

Sorry if i'm confusing you... it's quite difficult to explain using words without pictures >.<

Tachyon · Post by **Tachyon** » Sat Apr 26, 2008 10:37 pm

Link works.. .try again.

Clifford60 · Post by **Clifford60** » Sat Apr 26, 2008 10:48 pm

Must be you end is faulty, I downloaded the video, interested?

It is more than the balloon surface analogy. The universe is not just on the surface, the analogy need to include the volume of air within the balloon, a 3D analogy. I did mention the inter-galactic gravity, but there might be more forces in play to cause the collision, so not that simple. Anyway, don't try killing too many of our brain cells. haha