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Fraser
2007-Mar-13, 09:34 PM
Globular star clusters are gigantic collections of stars formed at the same time, and held together by their mutual gravity. Amazingly, they're some of the oldest objects in the Universe - some are more than 10 billion years old. ...

Read the full blog entry (http://www.universetoday.com/2007/03/13/new-globular-cluster-discovered/)

One Skunk Todd
2007-Mar-14, 07:31 PM
"Living inside the cluster would be an amazing experience. It’s only 7 light-years across. This is only double the distance from the Sun and its nearest star, Proxima Centauri. Instead of just a couple of stars in this volume, you would see more than 100,000 stars blazing in the night sky."

Could you even call it "night" at that point?

GBendt
2007-Mar-15, 12:16 AM
It depends from where you look when you look at the sky.

From the surface of a cloudy planet like Venus, the night sky would look just dull and dark. From the surface of something like our moon, you should see a dark night sky, filled with thousands and thousands of dazzling stars, each of them much brighter than Venus, or Sirius, all shining brilliantly in all colors from red to orange to yellow to white to pale blue, some of them arranged in close doubles, where each of their partners may have a special, different color.
These stars may shine so brightly that everything on the surface casts various faint shadows in their light, each of these shadows being gently lit by multicolored light from so many bright stars above.
Defining white balance may be difficult at such circumstances. But who cares about that when viewing a sky of such wonders!

Regards,

Günther

Mark2
2007-Mar-16, 01:45 PM
I don't understand ... if these stars are that densely packed, why hasn't gravity merged them into one giant star, or a black hole?

Can someone help me out?

Siguy
2007-Mar-16, 03:50 PM
I don't understand ... if these stars are that densely packed, why hasn't gravity merged them into one giant star, or a black hole?

Can someone help me out?

Some giant globular clusters actually have intermediate mass black holes. The stars also occasionally collide to merge into bigger stars. Lots of weird exotic things happen in globular clusters. They're pretty cool.

Mark2
2007-Mar-16, 05:54 PM
I'm sorry, but I still don't get it. This cluster is said to be 10 billion years old and is but a small member of our galaxy, yet it has 100,000 stars packed into the same volume that you would only find our sun ... so why hasn't gravity pulled all these stars together into one mass? It seems like all the planets in our solar system would be pulled into the sun in a matter years (maybe a few hundred years) if they weren't in orbit around it. But nothing is preventing these stars from collapsing together ... so why haven't they?

Siguy
2007-Mar-16, 08:58 PM
No, globular clusters aren't packet THAT dense, but at the heart of some, the stars are only .1 light years apart. But they have a much larger volume than the sun, some are the size of dwarf galaxies.

clop
2007-Mar-16, 09:56 PM
I'm sorry, but I still don't get it. This cluster is said to be 10 billion years old and is but a small member of our galaxy, yet it has 100,000 stars packed into the same volume that you would only find our sun ... so why hasn't gravity pulled all these stars together into one mass? It seems like all the planets in our solar system would be pulled into the sun in a matter years (maybe a few hundred years) if they weren't in orbit around it. But nothing is preventing these stars from collapsing together ... so why haven't they?

If I remember correctly the stars are in constant motion, orbiting the barycentre of the cluster in pointy orbits (not round). The stars travel a variety of paths through the central region of the cluster and out to the other side, then turn round and fall back again. Even though there are a lot of stars they are still far enough apart that they rarely come very close to each other. It's worth remembering that when entire galaxies "collide" the stars rarely collide, they pass straight through the gaps.

Nick4
2007-Jun-07, 05:00 AM
Can you see it from a normal 4-6 inch scope?