There are thousands of stars in the night sky. They are so far away that it would take years to travel to a distant star, even at the speed of light. For example, if a star is 4 light years away, then it takes 4 years for light to reach there. It’s the distance light travels in one year; that’s why it’s called a light year. In fact, you are seeing how the star looked 4 years ago since the light is now reaching your eyes; it’s the long distance the light had to travel to reach Earth. In the next quadrennium(that’s a time period of 4 years), you will see how the star looks right now!

Now here’s the interesting part! If you travelled to a distance star and then back to Earth, you would arrive several years in the Earth’s future. It’s because slower objects age faster, time slows down as you go faster, and stops at the speed of light. The time it takes for the planets to revolve around the Sun has something to do with it, too. If you could go faster than the speed of light, time would go backwards! When it comes to travelling to a distant star, at least time travel into the future is possible; but into past is more complex & difficult.

There is a problem with travelling near light speed. The faster something goes, the more energy it needs to keep going or to stop, because it gains mass & momentum. The object’s mass or momentum becomes infinite at light speed, so it would need an infinite amount of force to keep going or stop. It’s as complicated as it sounds.

Anything that travels faster than light is called tachyonic; anything slower is called tardyonic. If tachyons existed in our universe, they would appear to go backwards in time; you would see them reach somewhere before they even moved. Also, they would need an infinite amount of force to slow down to light speed. Tachyons would be a mathematical mirror version to tardyons. Scientists aren’t absolutely sure if tachyons can exist in our universe yet, and unfortunately in our tardyonic universe, nothing can exceed the speed of light.

Finally, if you did travel to a distant star, even at light speed, the trip would take years; you would age but at a slower pace than everyone else left on Earth. Plus, it’s a next trip to come back to Earth. You would need the patience to take such a long trip!