The speed of light is the universal speed limit, at approximately 186 thousand miles per second. Nothing can go faster, even with infinite energy.

At that speed, you could travel around the Earth 7 times in one second and go to the Moon and back in 3 seconds

Light is very fast, and yet it is so slow

If you wanted to make a round-trip to the nearest star, it would take 8 years. If you wanted to go from one side of our galaxy, the Milky Way, to the other, it would take you 100,000 years. 

Light is also the unit of measurement of stellar objects. One light year is the distance light can travel in 1 year, which is about 5.88 trillion miles

This is the universe’s speed limit. Einstein's laws of relativity say that nothing can go faster than the speed of light. As a result, some interesting things begin to happen as a result.

If you look at a Betelgeuse, a star in the night sky, you see it as it was 800 years ago, because since it is 800 light years away, the light the star emitted 800 years ago is just reaching us. If it were to go supernova today, and explode, we would only see the explosion 800 years later

On Mars, the Curiosity Rover, which has been exploring since 2012, needs commands to be inputted in advance, since those commands can take 3 to 24 minutes to reach the rover. This is quite literally, lag in real life.