Ground-based observations suggest the former geostationary inspector satellite suffered a fragmentation event months after retirement, raising new concerns about debris in high Earth orbit.
The US National Reconnaissance Office (NRO) has just declassified a pioneering spy satellite program ...
Astronomers have found thousands of exoplanets around single stars, but few around binary stars—even though both types of stars are equally common. Physicists can now explain the dearth.
Cosmic radio pulses repeating every few minutes or hours, known as long-period transients, have puzzled astronomers since ...