What is the Twin Paradox?
The Twin Paradox is a thought experiment in special relativity in which a person traveles into space in a high-speed rocket, and when they return home they will find that they have aged less then thier identical twin who stayed on Earth for the duration of the journey.
History of the Twin Paradox:
In 1905, Albert Einstein made a prediction about time. When two clocks are brought together and sychronised, then one is moved away and brought back, the clock that was moved away will be lagging behind the clock that stayed in the same place. This is due to the acceleration of the moving clock.
For this paradox to occur, the twin traveling will have to move at an exteremely fast rate. Due to the acceleration of the traveling twin, time around them will slow down, thus causing them to age at a slower rate then the twin that stays on Earth.
http://www.pbs.org/wgbh/nova/einstein/hotsciencetwin/
Megan G. and Leah E.
http://mentock.home.mindspring.com/twins.htm
http://en.wikipedia.org/wiki/Twin_paradox