Tonight’s talk was “Current Research on the Origin of Dark Matter” by Dr. Michelle Shinn from the Jefferson National Lab in Newport News Virginia. In addition to being a physicist, Dr. Shinn is also an amateur astronomer and member of the Back Bay Astronomers.
One of the interesting observations Dr. Shinn talked about tonight was that “regular matter” observed in spiral galaxies would not be enough to make them stable. There must be some kind of other matter present. She discussed three puzzling things:
- Measurements of the rotation speed of the spiral galaxy arms do not behave as expected.
- The motion of clusters of galaxies seems to be “too quick.”
- The effect of gravitational lensing requires more mass than is observed to work.
How do we reconcile what we know about gravity and other physical laws with the observations above? The answer to these puzzles is dark matter. The existence of dark matter was proposed by Fritz Zwicky in the early 1930s. This non-luminous matter is not hydrogen and it is not dust. What is it?
The possibilities are undetected subatomic particles such as axions which are variants of neutrinos, WIMPS, WISPS, and ALPS. Dr. Shinn gave us a primer of the standard model of subatomic particles. She then talked mostly about WISPS which are axion like particles. She also described an experiment where a strong laser is shone on a light tight wall which then creates WISPS which can then pass through the wall and turn back into photons again. She also described the projects BMV, GAMMeV, and LIPSS. She noted that Jefferson Lab studies Quarks.
There was a long question and answer period after her talk
The business meeting was just a series of announcements before the main talk. Ian Hewitt announced the group would be eating at a new restaurant after the meeting, Dr. Dan Reichart would be giving a talk at the Museum on their Halloween event, a new leader is needed for the loaner telescope committee, and he talked about the lack of a November and December regular meeting due to the holidays.
