Search found 33 matches
- Tue May 08, 2007 9:19 am
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Dark Matter
- Replies: 113
- Views: 23921
There are some modifications of gravity that could potentially explain both Dark Matter and Dark Energy, that would tiidy things up very nicely. Interesting. It was my understanding that the concept of 'Dark Matter' was invoked to explain anomalously high orbital velocities of stars on the peripher...
- Mon May 07, 2007 2:51 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Star Cluster, Misidentification of Objects (APOD 6 May 2007)
- Replies: 2
- Views: 1580
- Wed Apr 25, 2007 7:09 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Smooth Sections of Asteroid Itokawa (APOD 22 Apr 2007)
- Replies: 18
- Views: 7439
- Sun Apr 22, 2007 6:59 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: NGC 5139 Omega Centauri globular cluster (APOD 19 Apr 2007)
- Replies: 12
- Views: 3373
I have to wonder if it's the presence of large amounts of interstellar gas that leads to the structure of spiral galaxies. Sounds good to me! :wink: If you can figure out how spiral galaxys form I imagine that astronomers would be interested. Right now I'm not sure that anyone has a clue. Elliptica...
- Sun Apr 22, 2007 5:52 am
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: light pollution
- Replies: 12
- Views: 3890
It is likely that the night sky on a planet orbiting a star in a globular cluster would be pretty spectacular because of the clarity. There would be very little interstellar dust and gas to impede your view. But as to the light pollution question; don't forget that stars would be separated by vast d...
- Fri Apr 20, 2007 8:32 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: NGC 5139 Omega Centauri globular cluster (APOD 19 Apr 2007)
- Replies: 12
- Views: 3373
Hi nikki, I goofed in my original calculation for the average distance between stars in the globular cluster, NGC 5139: :roll: With a diameter of 150 ly, the GC has a volume of 1.77 million cubic ly (a sphere) containing 10 million stars. Assuming each star occupies the center of a spherical volume ...
- Fri Apr 20, 2007 8:22 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: NGC 5139 Omega Centauri globular cluster (APOD 19 Apr 2007)
- Replies: 12
- Views: 3373
Thanks astro_uk. Very enlightening. As I understand it, all galaxys appear to have super-massive black holes at their cores, whereas globular clusters do not. If the precursor to galaxy formation was the presence of a SMBH, what if anything was the precursor to the formation of a globular cluster? M...
- Thu Apr 19, 2007 6:55 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: NGC 5139 Omega Centauri globular cluster (APOD 19 Apr 2007)
- Replies: 12
- Views: 3373
NGC 5139 Omega Centauri globular cluster (APOD 19 Apr 2007)
Actually this post refers to all globular clusters orbiting the Milky Way galaxy. My question: If the Milky Way galaxy is embedded is a much larger cloud of Dark Matter, should not the orbits of all globular clusters be affected? That is, shouldn't the orbits be different if there was no Dark Matter?