Our solar system is huge, but compared to the size of Milky Way or other galaxies and the universe, we don't even exist. Once we go beyond the solar system, traditional method of measuring distances like miles doesn't work. So scientists came up with a new measurement unit called Light Year. One light year is the distances light can travel in one year. Light travels 160000 miles /sec. 6 trillion miles a year. Light can travel around earth 230 million times in one year.

So one light year = 6 trillion miles.

Light-year makes the distance slightly easier to understand. But compare to our universe it is still very small.

The furthest planet Neptune is 2.8 million miles away from sun. Milky-way galaxy is 100 thousands light-years across. Universe is much bigger than that.

The size of universe can't be imagined by human mind. It seems beyond the realm of possibility.

Light year is the distance light travel in one year. 1 light years = 6 trillion miles

Light travels faster than anything. It travels 6 trillion miles in one year. Yet compared to our endless universe it is still not enough.

Milky way galaxy is 100 thousands lightyears across

Light takes 100 thousands years to travel from one edge to another of our Milky way galaxy.