An orbiting NASA telescope has detected evidence of what may be the youngest black hole yet discovered, relatively__________________________. The object resulted from a supernova first observed by an American amateur astronomer just 3 decades ago.The astronomer, a school teacher named Gus Johnson, first observed the massive explosion that was labeled Supernova 1979C. Observations in the years since found it was a powerful source of X-rays typical of black holes.

__________________________; their gravitational pull is so strong, that not even light can escape. They can form at the end of a star's life. When a star has used up its nuclear fuel, its core can collapse and it becomes a supernova. Daniel Patnaude, of the Harvard-Smithsonian Center for Astrophysics, who led a new study of this presumed black hole, says sometimes the result is a black hole, other times it's a neutron star.

"Results such as this might actually be important because we don't know __________________________those supernova which form black holes, and those which form neutron stars."

(1)close 50,000,000 light years from Earth
(2)Black holes are regions that are so massive
(3)what the dividing line is between