NASA Merging Galaxies

For the past twelve years, a group of astronomers have been watching the sky carefully, timing pulses of radio waves being emitted by rapidly spinning stars called pulsars, first discovered 50 years ago. These astronomers are interested in understanding pulsars, but their true goal is much more profound; the detection of a new kind of gravitational waves. With a new, more sophisticated analysis, they are much closer than ever before.

Read More

Distance is one of the most challenging properties to measure in astronomy – it is bootstrapped from nearby objects like the Sun and planets all the way out to galaxies and quasars. The Pleiades, a nearby star cluster, had served as a cornerstone for astronomical distance derivations and set the scale for other clusters.

Read More

Until this year, astronomers have only been able to indirectly determine the presence of gravitational waves -- tiny, wave-like shifts of space and time -- through the measurements of decaying orbits of neutron stars. In January 2016, the LIGO collaboration announced the first direct detection of gravitational waves from a system of black holes orbiting and colliding together. Read More