The Exquisite Role of Dark Matter
With the dark matter question, which I am a little more actively involved at this moment because there is a brand new dataset that is just incredible, much of the mapping of dark matter that I do is to try and understand how granular dark matter is, in terms of how it’s spatially distributed in the universe.
Both dark matter and visible matter will bend light, but it’s just that dark matter is the dominant matter component, and it’s implicated in much of the light bending that we see.
My group has just finished analysis, and the paper has just been submitted where we are able to chart lumps of dark matter that are as small as the dark matter content of a tiny dwarf galaxy in our neighborhood, about 1 billion times the mass of the sun.
If we see a cutoff in the clump size, that tells you that the nature of dark matter is something fundamentally different from that predicted by the cold dark matter theory.
Essentially, a cluster is a giant blob of dark matter that holds about 1000 galaxies that are swirling around but held in place by the gravity of the dark matter.
It turns out that galaxies are also repositories of dark matter, and you know that there’s a lot of dark matter in them when you map the speeds of stars around a galaxy to figure out how the stars are held together.
Originally published at Cogly.