A depiction of a black hole
A Black hole is an object that is so massive or so condensed that the escape velocity from its gravity, within a radius known as the event horizon, is greater than lightspeed.
Since not even light can escape from a black hole, they cannot be detected directly, but only by their effects on their surroundings. For instance, stars and other luminous objects may orbit around black holes. A star must be at least three solar masses for a black hole to form naturally by gravitational collapse, much smaller objects could in theory be compressed into black holes by extreme compression.
References and External links
- Black Holes Enchanted learning
- Black Hole Wikipedia
Videos
- Black Holes Tall Grande Venti
- Mysteries of Deep Space: Black Holes This video deals with Neutron Stars and Black holes.
- Violent Universe: Inside a Black Hole
