Violent supernovas may have caused two of Earth’s largest mass extinctions that have never been completely explained, according to a theory put forward in new research.

People in Sioux Falls are marveling at Tuesday’s safe return of the two American astronauts who were stuck in space for nine months. The homecoming of Suni Williams and Butch Wilmore has been on the ...

Astronauts Sunita Williams and Butch Wilmore, stranded at the International Space Station (ISS) for over nine months, have ...