something I've always wondered about

If the Universe is expanding, then all the galaxies must be moving
away from one another.

So how come there are such things as 'colliding galaxies'?

"dave blacker" wrote in message
m...
If the Universe is expanding, then all the galaxies must be moving
away from one another.

So how come there are such things as 'colliding galaxies'?

One would assume because 'a' galaxies gravitational pull is great enough to
affect another galaxy...

dave blacker wrote:
If the Universe is expanding, then all the galaxies must be moving
away from one another.

In general, yes. Imagine a load of black dots on an elastic sheet that
is being stretched....

So how come there are such things as 'colliding galaxies'?

Because the expansion is not the *only thing happening. In your mind,
turn those black dots into (live) ants...

(OK, I know it's a lousy analogy, but it ought to do the trick! g)



Best,
Stephen

Remove footfrommouth to reply

--
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+ Stephen Tonkin | ATM Resources; Astro-Tutorials; Astro Books +
+ (N51.162 E0.995) | http://www.astunit.com +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

On Fri, 31 Oct 2003 16:38:39 +0000, Stephen Tonkin
wrote:

dave blacker wrote:
If the Universe is expanding, then all the galaxies must be moving
away from one another.

In general, yes. Imagine a load of black dots on an elastic sheet that
is being stretched....

So how come there are such things as 'colliding galaxies'?

Because the expansion is not the *only thing happening. In your mind,
turn those black dots into (live) ants...

(OK, I know it's a lousy analogy, but it ought to do the trick! g)

What type of ants?
--
Pete Lawrence
http://www.pbl33.co.uk

In message , Dave
writes

"dave blacker" wrote in message
om...
If the Universe is expanding, then all the galaxies must be moving
away from one another.

So how come there are such things as 'colliding galaxies'?

One would assume because 'a' galaxies gravitational pull is great enough to
affect another galaxy...

And because clusters of galaxies aren't expanding, so the members are on
orbits which occasionally intersect.
--
Rabbit arithmetic - 1 plus 1 equals 10
Remove spam and invalid from address to reply.

Pete Lawrence wrote:

In general, yes. Imagine a load of black dots on an elastic sheet that
is being stretched....

So how come there are such things as 'colliding galaxies'?

Because the expansion is not the *only thing happening. In your mind,
turn those black dots into (live) ants...

(OK, I know it's a lousy analogy, but it ought to do the trick! g)

What type of ants?

Black - the red ones are invisible on those rubber sheets. I thought
you'd know that...

Cheers

Martin

--------------
Martin Frey
N 51 02 E 0 47
--------------

Pete Lawrence wrote:

On Fri, 31 Oct 2003 16:38:39 +0000, Stephen Tonkin
wrote:

dave blacker wrote:
If the Universe is expanding, then all the galaxies must be moving
away from one another.

In general, yes. Imagine a load of black dots on an elastic sheet that
is being stretched....

So how come there are such things as 'colliding galaxies'?

Because the expansion is not the *only thing happening. In your mind,
turn those black dots into (live) ants...

(OK, I know it's a lousy analogy, but it ought to do the trick! g)

What type of ants?

Migrants perhaps?

Kay :-)

"dave blacker" wrote in message
m...
If the Universe is expanding, then all the galaxies must be moving
away from one another.

So how come there are such things as 'colliding galaxies'?

I think I remember on a Sky at Night show they said M31 and our own galaxy
will one day pile into each other. You should also remember that the images
of galaxies we see colliding actually took place hundreds of thousands of
years ago. We are looking into the past all the time.

Martin

plutonic wrote:

What type of ants?

Migrants perhaps?

Kay :-)

Selfish. They're ourgrants too.

Cheers

Martin

--------------
Martin Frey
N 51 02 E 0 47
--------------

Martin Frey wrote:

plutonic wrote:

What type of ants?

Migrants perhaps?

Kay :-)

Selfish. They're ourgrants too.

Cheers

Martin

--------------
Martin Frey
N 51 02 E 0 47
--------------

teehee