Milky Way 'Ate' Smaller, Weaker Galaxy

Kierthos writes: "In a true sign of survival of the biggest, astronomers and scientists now believe that the Milky Way 'ate' a smaller galaxy billions of years ago. They believe that this could shed some light on the origin of the universe, although their search only included 1500 "sun-like" stars (far short of the 10,000 stars they want to search). Check out the article here."

Re:Galaxy's aren't "solid"?

[tolan's my name]

I realise it's a vast oversimplification but look at the way moons orbit planets, or better the way saturn etc have a miniture 'asteriod belt' in the form of their rings..

My point is that its essentially perfectly plausible to have a small galaxy, with its stars all orbiting relative to its center orbitig around the central point of a large galaxy. In fact I find it hard to believe that galaxies arnt full of baby clusters of stars, orbiting common central point that in turn orbit the center....

..but then I havent studied cosmology since i was 18...

Re:Galaxy's aren't "solid"?

[drudd]

You're absolutely right about the fact that no stars collide when galaxies merge. The distances are so large, the probabilities are very low.

Galaxies do merge, however. There are certain theories that the spiral instabilities in galaxies similar to our own can be triggered by mergers.

There are two interesting point about our largest galactic neighbor, Andromeda. Not only is it on a collision course with the Milky Way (~1 Gyr if I remember correctly), but it has an interesting "double core" feature, which some have speculated is the result of a merger.

I'm just starting to study such mergers in computer simulations, but I'm still catching up on the math and the theory.

Doug

Re:Galaxy's aren't "solid"?

[tooth]

I'm just starting to study such mergers in computer simulations...

hehe :) When I read this article I fired up the "galaxy" screen saver in X and watched them rip each other apart. Not very realistic, but still fun :)

Re:Galaxy's aren't "solid"?

[Verteiron]

Well, this actually touches upon one of the odd facts about the universe. Galaxies like our milky way do not behave as scientists and simulations expect them too; they behave more like spheres than discs/flat spirals. If you take this into account, then merging galaxies make more sense. They do have center of gravities as a unit, and therefore can orbit each other, spiralling inward until they merge. You're right about it having to be a fairly "gentle" meeting, though. If it went too fast, it would rip right through, disrupting the path of many stars in both galaxies... and moving on.

Galaxy's aren't "solid"?

[tooth]

Seeing as there are virtually no posts here, I'd thought that I'd chip in with my meager little post.

hmmm, the article wasn't very descriptive and fairly light weight, but hey, it's cnn. What I don't understand is how could two galaxies "merge" unless they were heading in very similar directions. As the distance between stars is so great, wouldn't most pass through and not touch anything? Of course there's gravity, which is where this seems strange -- How could the milky-way retain so much ot it's spiral structure? Wouldn't they rip each other apart and send stars left and right?

So, I'm guessing for this to happen one galaxy would be very much smaller than the other, and that they would have to been heading on very similar paths in the universe (3 dimensional thinking? gawd hadn't thought of any more).

The article stated that finding the stars still with the other galaxys' orbit. If this is posible, wouldn't they keep moving straight through? No, gravity would probably change the orbits. So I guess that they are looking for stars with non-normal orbits, but as to keeping the original orbit? I kinda doubt it. Okay, he said "similar", but still? Could merging galaxies settle down, buy a nice quite lot out in the suburbs of the universe and raise thier own little satellite universes?

-- tooth, trying to post something on topic :)