I had to go and pick up my new glasses tonight and after getting home around 8:00p.m. I went looking around the Web. I ended up at the Hubble site and at NASA and found this image taken by Hubble of the double nucleus of the galaxy Messier 31, M31 or the Andromeda Galaxy. In the center is a 100 million solar mass black hole and it is surrounded by relatively young blue mass stars in orbit around it and another older red mass group of stars caught in the black hole's gravity. From the NASA site:
The double nucleus is actually an elliptical ring of old reddish stars in orbit around the black hole but more distant than the blue stars. When the stars are at the farthest point in their orbit they move slower, like cars on a crowded freeway. This gives the illusion of a second nucleus.
Now what is cool about this image is it is the "sharpest visible light image ever made of the nucleus of an external galaxy." That to me is super cool! Next time I view M31 I will be sure to remember this image and think about what I am actually observing here. The other cool item is that Astronomers are using this and observations from the Milky Way to solve a question about massive star formation so close to a black hole. Again, from the NASA site we read:
The blue stars surrounding the black hole are no more than 200 million years old, and therefore must have formed near the black hole in an abrupt burst of star formation. Massive blue stars are so short-lived that they would not have enough time to migrate to the black hole if they were formed elsewhere.To read the entire article and to view their movie of this please go to this link. Also here is the link to the Hubble Site of the image.
Astronomers are trying to understand how apparently young stars were formed so deep inside the black hole’s gravitational grip and how they survive in an extreme environment.
The fact that young stars are also closely bound to the central black hole in our Milky Way galaxy suggests this may be a common phenomenon in spiral galaxies.