A NASA satellite detected the first sign of a black hole 8,000 light years away from Earth on Jun 15, 2015. Astronomers around the world are studying the event.
NASA's rover Curiosity captured incredible images of a blue sunset on Mars. CNN's Rachel Crane reports.
After taking a 26-year nap, a waking black hole released a burst of X-rays that lit up astronomical observatories on June 15. Astronomers identified the revived black hole as an "X-ray nova" — a sudden increase in star luminosity.