Gravitational waves
A world-wide network of detectors is now searching for the gravitational waves emitted by astrophysical objects such as black holes or neutron stars. Once they are successful this will open up a completely new way of studying the Universe - letting us 'hear' as well as see (Marcia Barthusiak's Einstein's Unfinished Symphony gives an excellent introduction to this field). A brief description of gravitational waves and the basic principles involved in their detection can be found on this website. Gravitational waves are notoriously hard to detect since they interact very weakly with normal matter, and anything that causes spurious motions of the detector reduces the chances of a detection. This includes everything from earthquakes to local traffic on a nearby highway! Some phenomenally advanced technology is required to overcome these challenges.
API scientists are involved in several different aspects of gravitational wave research. These range from high frequency sources such as neutron star vibrations triggered by starquakes, to very low frequency signals from the cosmic gravitational wave background that can only be detected by using nearby radio pulsars as an enormous detector.
The following people are working on this topic: