Time travel is the idea of going back in time to the past or forward to the future. Time travel can not be done with the technology we have now. However, physicists say that there is a chance that time travel will be possible in the future.
The speed of light [change]
Light moves very fast, faster than anything else in the universe. The speed of light is very high: 670,616,629 miles in one hour. Light can go around the earth three times in one second. Most cars can only travel about 100 miles in one hour. Most people can only run 12 miles in one hour.
Scientists say that if a person gets close to going as fast as the speed of light, time will seem to move slower to the person. To give an example, if a rocket ship flew through space at the speed of light for one day, by the time they came back, it is possible that years could have passed. Albert Einstein was famous for his ideas on time.
Movies and television shows [change]
Many Science fiction, fantasy movies and television programs have been based on stories of people who travel through time. For example, the American movie "Back to the Future" tells a fictional story about a professor who builds a machine that can take people into the future or back in the past. The popular British TV program Doctor Who is about an alien who has adventures by time traveling.