Everything in the universe is made up of atoms, just like us! A light year is 9.5 trillion years away, and light can travel up to 300,000 km/second, plus, light stay even after a star has died (It used up all of it's gases so it's burned out). Speaking of stars, a circle of light in the night sky is actually multiple star's light clumped together, and the distance around the Sun or our Earth is called the circumference. Then, in 12,000 years, Polaris, our "North Star", will actually no longer be the North Star, Vega will. Another cool fact is that around 10 tons of meteors hit the ground each day, but most are only as big as a grain of sand (Lotta grains).