In response to Elaine Hyde's message:

I'm unaware of the "past collision theory"- the last astronomy text I used made no mention of this. I do know that we are traveling toward the Andromeda galaxy now. Maybe someone else knows more about this.

But to say we will "collide" is a bit misleading. Although both galaxies are comparatively large they are mostly empty space. The closest star to ours is more than 4 light years away (Alpha Centauri)- so one might expect few if any actual collisions to occur as the two galaxies pass near each other. Maybe a less misleading term is to say that the galaxies will merge. There is even a term for when a small galaxy is merged with a larger one- galactic cannibalism. I think the milky way and the andromeda galaxy are expected to merge, but it is possible for two galaxies to "collide" causing distortions in each and then move on their separate ways. However, I don't think they could "collide" multiple times without merging.

-Sean Goe (I'm a graduating physics major at PSU. I will be admitted to the MSTS program next fall, also at PSU. I'm currently working on my undergraduate thesis on Inflationary Cosmology- with Todd's supreme guidance:)

-----Original Message-----
From: owner-science@lists.pdx.edu [mailto:owner-science@lists.pdx.edu]On Behalf Of Elaina Hyde
Sent: Friday, June 09, 2000 12:38 PM
To: Todd Duncan
Cc: SII listserv post
Subject: Re: Faster than light?

Hi, I heard something kinda interesting on Science Friday on OPB radio today and thought I'd share. They were talking with a Harvard astronomy professor about the recent maping of the universe that they have been doing and at the end of the talk the professor mentioned that we are falling towards the andromeda galaxy (or vice-versa) and I am wondering if it would discount the previous theories that I've heard that in the past we have collided with the andromeda galaxy. I was under the impression that this was a prevalent theory and if it is no longer valid or if (over a very long period of time) our galaxy and that of andromeda can be expected to collide a number of times. Also if the second is the case our galaxy might well be quite strange looking (perhaps this is an element considered when models for galaxy evolution are formed?). Anyway I thought I'd send this out and give you all something to think about.

- Elaina Hyde