Mar. 26, 2016

Multiple lines of astronomical evidence show the existence of dark matter and dark energy — mysterious stuff whose gravity holds galaxies together and drives the accelerated expansion of the universe, respectively. Physicists have long assumed that this "dark sector" would at least partially consist of new, relatively massive particles, but have not been able to turn up clear evidence for them. A dark sector made of very light particles, however, could have escaped detection, yet is compatible with all astronomical and cosmological evidence. Precision measurements in physics are suitable to searching for such ultralight dark-sector candidates.
Admission is FREE. Bring a flashlight, and, just in case, wear warm clothes in layers. If bad weather threatens, call 415-455-5370 after 4pm. This event is produced by Wonderfest in collaboration with the Mount Tam Astronomy Programs, Mt. Tamalpais State Park, Friends of Mt. Tam, and the San Francisco Amateur Astronomers.