The universe as we know it in space and time began about 13.7 billion years ago. That’s a very very long time, but at least it’s a compact number that, with a little effort, most of us can at least remember.
How big is the universe is a much more challenging concept to get our human minds around. The numbers are mind-boggling. And to make matters even trickier, the universe is still getting bigger.
Space in the universe is measured in light years because scientists are pretty sure that nothing can travel faster than light can. To us that is very very fast. Here are some examples, all of which are so far beyond human experience that some people are reduced to laughter when they try to grasp the concept.
In a second, light travels:
- almost 300 million meters (a meter is 40 inches, so just a little more than a yard),
- which is equal to 186,282 miles
- which is equal to 299,792 kilometers
Light travels from
- the moon in 1.3 seconds
- the sun in 8.3 minutes
- across the Milky Way in 100,000 years
- from the Andromeda Galaxy to Earth in 2.5 million years.
Light that first appeared after the Big Bang 13.7 billion years ago has not yet reached us.
It’s a very big place we live in.