Black hole

[ATOB2]

What is a black hole?

[dmaude]

A collapsed star from which no light can escape

[caramba]

Once a giant star dies and the concentrated mass that is left becomes a 'black hole'. They are hard to detect because they are completely black and do not reflect light. Because of the intense mass, a black hole has a hugely powerful gravitational pull and anything passing in range of the gravity field will be sucked into the black hole - even light. But anything at a safe distance will not be sucked in. Planets far enough away would merely circle the black hole like the planets circle round the Sun.