“We are a way for the Cosmos to know itself.” -Carl Sagan, Cosmos
You may have noticed that the top-notch Historicalness research team has been away for a bit. But fear not. After climbing the Seven Summits and writing a few novels, the squad is back…and we’re taking on something big…
If you woke up one day and thought to yourself, “I want to see something really old”, where would you go? A museum? Maybe hop on a plane to check out the pyramids?
Turns out, all you need to do is head outside at night and look up (except if you’re in a city…this works better if you’re in some rural spot). When you see the Milky Way, you’re looking at something that was born 13 billion years ago. Well, that’s not entirely true — what you’re actually seeing is light emanated from the Milky Way which has traveled for the past 25,000 years to reach your eye ball.
To try to put this in some context:
- The Great Pyramid of Giza was built about 5,000 years ago — meaning those light beams you’re seeing have been traveling for 5x as long.
- It takes light only 8 minutes to travel the 150 million kilometer distance from the sun to the earth. The light you’re seeing from the Milky Way has traveled for 12.6 billion minutes in its 25,000 years.
Even still, that 25K year distance (called light years) is only a quarter of the 100,000 years it would take something moving at the speed of light to travel across our entire galaxy.
A few other facts I like:
- The edge of our solar system is the Oort Cloud which is 1 light year away
- The middle star in Orion’s belt is 1,500 light years away
- The next closest large galaxy to ours, Andromeda, is 2.5 million light years away
- The edge of the observable universe is 13 billion light years away
Here’s a depiction of the Milky Way in relation to Andromeda used in a Khan video which I found helpful:
It’s hard not to consider the scale of our galaxy and the millions of other galaxies that make up our universe, and agree with Carl Sagan’s comment in his Cosmos series:
“There are a hundred million galaxies and a billion trillion stars. Why should this modest planet be the only inhabited world? To me, it seems far more likely that the Cosmos is brimming over with life and intelligence.”