1. There are an unfathomable number of stars in the observable universe.
So you know when you’re in a rural area at night and the moon isn’t visible and you can see a ton of stars? In those optimal circumstances, you’re looking at around 2,500 stars at most. That’s about 1/100,000,000th of the total stars just in our own galaxy.
Speaking of which, take another look above at our gorgeous Milky Way. To help understand just how insanely big it is, here are a few facts:
- The diameter of the Milky Way is 100,000 light years. A light year is the distance light travels in a year. Considering light can travel around the Earth seven times in a second, a light year is a mind-bogglingly large distance. It would take our fastest spacecraft 18,000 years to travel one light year. And with the Milky Way, we’re talking about 100,000 of them.
- That also means that if you use a telescope to see a star on the far side of the galaxy, you’re actually seeing what the star looked like 100,000 years ago, since the light that left the star then is just reaching us now. Likewise, if at this moment, someone on the other side of the galaxy is checking out the Earth with a telescope, they’ll see a bunch of early humans and Neanderthals running around clubbing each other like fools.
- You might think that when you look closely at that above picture of the Milky Way, one of those little dots might be our sun. In fact, if you expanded the above photo to be the size of the Earth, you’d still need a microscope to be able to see our pinprick of a sun — if the Milky Way were the size of the Earth, the sun would be about 1/50th of a millimeter in diameter.