What's Next in the Hunt for Dark Matter?

This past July, the US Department of Energy and National Science Foundation announced which next-generation dark matter projects they'll be supporting.

Dark matter takes a lot of equipment, people, time, and creativity to detect. It also requires being in just the right conditions. For example, the XENON experiment is buried under Italy's Gran Sasso Mountain to eliminate any stray radiation from interfering with the detector.

The winning next-generation projects are

1. The Super Cryogenic Dark Matter Search, which uses "a collection of hockey-puck-sized integrated circuits"to find Weakly Interactive Massive Particles (WIMPs), a prominent dark matter candidate.
2. The LUX-Zeplin experiment, which can find WIMPs of a wide range of masses.
3. The next iteration of the Axion Dark Matter eXperiment, which uses magnetic fields to convert axions (another dark matter candidate) into photons.

Finding Dark Matter using Gravitational Lensing

A couple weeks ago, we talked about gravitational lensing, and how it's used to find black holes. When the earth, a black hole, and a galaxy are lined up just right, a black hole bends light around itself the same way a lens bends light to form an image. 

Well, this technique can also be used to find dark matter, as described in a recent article on phys.org.

Want to learn more about dark matter? Be sure to join us at today's Society of Physics Students meeting (12:15, PENT 125) for a TED talk video about dark matter. Hope to see you there!

Dark Matter: How do we know it's there?

This week is all about dark matter - the stuff that physicists have concluded fills interstellar space that doesn't interact with light (hence the reason we can't see it). The search is on for what types of particles this matter might be made of.

But every time a new search is launched, the question arises: How do we know that dark matter is there, to begin with?

Starts with a Bang offers five reasons why physicists are certain that dark matter exists:

1. Galaxies tend to group together in clusters, and observed cluster don't have enough mass to explain this clustering.
2. Galaxies tend to spin like a top, and the rotational velocities of the stars don't match up with what you'd expect if the only mass present was the mass you could see.
3. Dark matter in the early universe left an imprint of oscillations on the Cosmic Microwave Background.
4. Galaxies can collide with each other, and the resulting distribution of stars can't be explained if the visible mass is all that's present.
5. The large-scale structure of galactic clusters has imprints of dark matter in the early universe.

Dark matter, the article concludes, offers an explanation for all these observations, while alternatives (such as modifying our understanding of gravity) cannot explain more than one.