How Time Travel Works
Wanna hear something cool?
The light from the sun, as fast as light is, takes 8 minutes to reach us. That means the sun that you are looking at is actually the sun 8 minutes in the past. If the sun exploded you wouldn’t see it until 8 mins after it happened.
If we had the ability to send a satellite near the sun and turn it towards earth and start filming then somehow (this part is not possible just yet) we could send those images back to us faster then light, we would be able to see 8 min into the future.
Time Travel Into the Future
If you want to advance through the years a little faster than the next person, you’ll need to exploit space-time. Global positioning satellites pull this off every day, accruing an extra third-of-a-billionth of a second daily. Time passes faster in orbit, because satellites are farther away from the mass of the Earth. Down here on the surface, the planet’s mass drags on time and slows it down in small measures.
We call this effect gravitational time dilation. According to Einstein’s theory of general relativity, gravity is a curve in space-time and astronomers regularly observe this phenomenon when they study light moving near a sufficiently massive object. Particularly large suns, for instance, can cause an otherwise straight beam of light to curve in what we call the gravitational lensing effect.