In January of 2016 we reported that “A globular cluster might be the first place in which intelligent life is identified in our galaxy,” according to Rosanne DiStefano of the Harvard-Smithsonian Center for Astrophysics (CfA). Globular star clusters are extraordinary in almost every way. They’re densely packed, holding a million stars in a ball only about 100 light-years across on average. They’re old, dating back almost to the birth of the Milky Way. And according to new research, they also could be extraordinarily good places to look for space-faring civilizations.
Future Laser Interferometer Gravitational-Wave Observatory (LIGO) alerts may likely come from a globular cluster, with the closest cluster residing about 7,000 light years from Earth. When a gravitational wave transit the Milky Way, it stretches and squashes space-time, making pulsars and the Earth jiggle.
Astronomers using the NASA/ESA Hubble Space Telescope to study some of the oldest and faintest stars in the globular cluster NGC 6752 (above) have made an unexpected finding. They discovered a dwarf galaxy in our cosmic backyard, only 30 million light-years away while studying white dwarf stars within NGC 6752. The aim of their observations was to use these stars to measure the age of the globular cluster, but in the process they made a surprising discovery.
The ultimate firework celebration: gravitational-wave researchers increasingly think that globular clusters –dazzling, celestial “snow globes” populated with hundreds of thousands of closely packed stars– harbor dark “hearts,” loaded with dozens to even hundreds of black holes–by far the greatest concentration of these exotic objects found anywhere in the universe.
