Light year is a measure of distance, not time. It is the distance that light travels during one Earth year
(The speed of light is 300,000km/s, which means that this is a very, tremendously, amazingly huge distance of over 9.5 trillion km)


The biggest known star currently is UY Scuti, a bright red supergiant, located 9500 light years away in the Scutum constellation. It is more than 1,708 times the size of the Sun.


Universe is estimated to be 13.82 billion years old. Even though we know its age we don’t really know its size since it’s always expanding, so the light actually didn’t have time to reach us yet from the furthest reaches of space. Current estimates are that it is at least 46 billion light years across!


A popular comparison that can illustrate these numbers is this: There are more stars in the universe than there are grains of sand on all the beaches and deserts on Earth.