Watched a doco on the universe, which looked at its scale in particular. The model of dark matter connections was of particular interest to me so I decided to post up some screen caps. This post might be a work in progress with updates to come.

3rd May update:

I read an interesting article where bloggers asked a physicist ‘why believe in Dark matter?’

What I like about Dark matter in the context of my assignment topic area is that it hasn’t been ‘seen’ at this stage, yet it has been theorised to exist when the laws of physics are brought into the equation of explaining the physics of the universe. It ties everything together, preventing it from flying apart some believe.

1.) Gravitational Lensing
Light gets deflected as it travels past massive objects. We can use the distorted images of background galaxies to make mass maps. For those interested in Dave Goldberg background info, this is the area that I work in.  Lensing reconstruction has been done (and found lots of extra mass) for tons of galaxy clusters, but one system has gotten a lot of attention in the press.

Lensing does double duty in the Dark Matter game. We can use a different effect, called “microlensing” to look for dark stars (or black holes, perhaps) in our own Galaxy. Whenever one of those passes in front of a more distant star, the star gets magnified. Cool idea, but we can now definitively say that our Galaxy (and presumably the others) isn’t filled with enough black holes to solve the Dark Matter problem.

This is the only ‘suggested image’ taken of what scientists believe Dark matter to be (in action).

In the image of the “Bullet Cluster” up top, two clusters of galaxies have recently collided with one another, stripping out the gas (shown in red).  The blue indicates where gravitational lensing shows the mass to be. Whatever is making up the mass is neither gas nor stars. This image is the closest to “seeing” Dark Matter so far.