Light Years

• Astronomers use the unit light-years, the distance light can travel in one year to measure vast distances in space.

• The speed of light is 299,792.458 kilometers per second, exactly.

• It takes 8 minutes for light from the sun to reach Earth, and a 4.367 light years for light from the other closest stars (like Proxima Centauri) to get to our planet. (25 trillion miles)