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Milky Way Leaves Devastation in its Wake
soulctcher writes "An article on Yahoo! talks aout how a group of scientists now have evidence that the Milky Way galaxy, and others like it, are able to slice and dice their way through older galactic structures."
Would you mind giving a source for your tale of globular formation and evolution? I've never heard any such thing, and I'm working on my Ph.D. in astronomy.
Globulars are indeed old. But 40-50 billion years would make them about 25-35 billion years older than the universe itself. We thought we had issues when they appeared to be a couple billion years older, but even astrophysicists can't ignore 30 billion years.
I'll assume that that was a typo, though. Globulars, according to all I have studied, formed around our galaxy. Either with it or shortly before it started to form. What would a quasar have to do with this? Quasars, sexy as they are, are only big black holes on a binge of eating. These are not the kinds of places you form clusters of stars.
Finally, when a globular passes through the Milky Way's disk, nothing really happens. You can tell because almost all globulars are on disk-crossing orbits. They have to be, since most are orbit nearer the galactic center than we do (this is how Shapley worked out where the galactic center was, after all). And since they've made quite a few orbits in their lives and since they are still around, clearly passing through the disk isn't terribly disruptive. And it shouldn't be expected to be: stars don't collide when galaxies pass through each other. This is easy to understand because galaxies are made of mostly empty space. Stars can find their orbits disrupted, but they seldom collide.
I'd be curious to see where you heard all of this.
Since the popular press tends to use the least familiar name for any given astronomical object, I wondered, "Is there an NGC number for that?" Apparently not. The faint Palomar globular clusters were discovered on photographic plates from an all-sky survey by the 48-inch Schmidt camera. They're supposed to be pretty tough to see visually. Palomar 5 is in Serpens Caput at RA 15h16m Dec -0.1 if you have a big scope and you're up to it.