General Relativity is a theory by Albert Einstein that explains gravitation. It proposes that mass causes a curvature in spacetime, creating a gravitational force.
If a basketball is placed in the center of a sheet, it will create a downwards curve in the sheet. A second less massive ball such as a golf ball will roll towards it because of the curvature. Like a ball creating a curvature on a sheet, a star creates a curvature in space time, which attracts the planets around it. A curvature in spacetime creates the force of gravity. The more massive the object, the greater the curvature and the stronger the gravitational force.
Black Holes:
A black hole is a point in space where there is a such a strong gravitational pull that nothing, including light can escape. Black holes have a strong gravitational pull because all the matter is concentrated at a single point called a singularity. The surface of a black hole is called the event horizon. The gravitational pull at the event horizon is infinitely strong. According to general relativity, a black hole can be formed when a massive star runs out of nuclear fuel and collapses under it's own weight into a singularity.
General Relativity:
Define:
General Relativity is a theory by Albert Einstein that explains gravitation. It proposes that mass causes a curvature in spacetime, creating a gravitational force.
If a basketball is placed in the center of a sheet, it will create a downwards curve in the sheet. A second less massive ball such as a golf ball will roll towards it because of the curvature. Like a ball creating a curvature on a sheet, a star creates a curvature in space time, which attracts the planets around it. A curvature in spacetime creates the force of gravity. The more massive the object, the greater the curvature and the stronger the gravitational force.
Black Holes:
A black hole is a point in space where there is a such a strong gravitational pull that nothing, including light can escape. Black holes have a strong gravitational pull because all the matter is concentrated at a single point called a singularity. The surface of a black hole is called the event horizon. The gravitational pull at the event horizon is infinitely strong. According to general relativity, a black hole can be formed when a massive star runs out of nuclear fuel and collapses under it's own weight into a singularity.Source:
http://archive.ncsa.uiuc.edu/Cyberia/NumRel/GenRelativity.htmlhttp://www.nasa.gov/worldbook/relativity_worldbook.html
http://www.nasa.gov/worldbook/blackhole_worldbook.html