Science news has been a buzz about a whole posse of new black holes discovered in the constellation of Andromeda. The reason for this is not that these have suddenly been discovered, but rather that a new paper on results from Chandra is being published in the Astrophysical Journal last year, and the press releases have been published.
Out of the Blue
The image here is of the very center of the Andromeda galaxy. If you look in the middle of this image, you’ll see a smudge of blue. As first demonstrated in an article in Astrophysical Journal, the central blue region is a collection of about 400 young blue stars. They are concentrated in a region about a light year across, and are moving at about 1,000 km/s.
Eddies in the Space-Time Continuum
We often refer to gravity as a gravitational field because it can be described mathematically as a field. That is, each each point in space and time has certain characteristics, and they are related to each other through field equations. For gravity, the field equations are the equations of general relativity. Lots of physical quantities can be described as fields, including electromagnetism and quantum objects. Fluids are also described mathematically as fields. With a flow of water or air, for example, every point has properties such as pressure and speed, and they are related by equations of fluid dynamics.
Hole In One
Recently there’s been news that scientists suspect the black hole in the center of our galaxy may be a wormhole instead. Needless to say, you shouldn’t get your hopes up. The news is actually based on a preprint published on the arxiv that outlines how one might distinguish between a black hole and a hypothetical “white hole”.
No Doughnut
Within most galaxies is a supermassive black hole. These black holes can have a mass of millions or even billions of Suns. When actively consuming material, these black holes can produce tremendous amounts of energy, and can be seen as quasars, blazars and radio galaxies, depending upon the way they are oriented relative to our vantage point. At least that’s been our understanding. But now a new paper in the Astrophysical Journal has thrown a wrench in one part of that idea.
The Inbetweeners
Yesterday I mentioned the possibility that a mid-sized black hole might explain why the Trapezium cluster is gravitationally bound. If such an black hole were discovered it would be a really big deal.
Non-Singular Black Holes
The basic model of a black hole can be summed up as follows: gravity wins. The root cause of all black holes—be they tiny primordial black holes, solar mass black holes, or supermassive galactic black holes—is gravity. Squeeze enough mass into a small enough volume and gravity does the rest.
Heart of Darkness
Star formation within a galaxy is a complex process. We have models of galaxy formation, but one of the difficulties with these models has been that they predict a greater formation of stars in large galaxies than we observe. This would seem to indicate that there is some mechanism that hinders star formation within large galaxies. Basically at some point in the galaxy’s formation there must be something that pushes gas out of the galaxy, preventing it from forming into stellar nurseries.
Hidden Giants
When WISE completed its full sky survey, about 1.6 million “hidden” black holes were discovered. Some of these are billions of light years away, which will help give us a better understanding of how these supermassive black holes evolve within galaxies.