A light-year is the distance that light travels in one year. It's a vast distance used to measure the incredibly long distances between stars and galaxies.

The distance to Mars varies depending on the orbits of Earth and Mars, but it's significantly less than a light-year. At its closest, Mars is about 34 million miles (55 million kilometers) from Earth.

In comparison, a light-year is about 5.88 trillion miles (9.46 trillion kilometers).