News Revisited

It turns out that Kip Thorne and John Preskill of the California Institute of Technology have been asserting for more than a decade that it is possible that not all singularities are black.  Perhaps they are visible.  Ok, that’s a weird thought and sounds unlikely.  The question is how can we test this?  So far we haven’t been able to see all the way to the event horizon around a black hole due to all the matter swirling around it.

In papers written in 2005 and 2006, Arlie Petters of Duke University and Charles Keeton of Rutgers University had suggested that the visible black holes could be detected by the way they affected gravitational lensing.  However, their method worked only with singularities that are not spinning.  So far all of the suspected black holes have been spinning rapidly.

Recently Professor Petters and Marcus Werner, a graduate student at the University of Cambridge, managed to generalize the technique such that it can work with spinning singularities as well.  In the event that a singularity is spinning fast enough that its angular momentum is greater than its mass it will in theory shed its event horizon, become a naked (visible) singularity, and split the light from background stars or galaxies in specific ways that could be detected.

This does not prove that naked singularities exist, but gives us a way to start looking for them.

Earlier this month David Denhardt, a cell biologist at Rutgers University, and colleagues reported that microgravity may weaken the immune system.  Now Cheryl Nickerson, a microbiologist at Arizona State University, and colleagues have shown that the bacteria that is the most common cause of food poisoning and typhoid fever, Salmonella typhimurium, actually becomes three times more virulent when in a microgravity environment.