If Earth is Always Moving, Then How Do We See the Same Constellations Every Night?
6700 mph is nothing in cosmological speeds and distances. Constellations are freakin’ far away.
Get in a car at night and drive on a straight road, then look at the moon. The angle of the moon in respect to your point of view doesn’t change, it seems like the moon is following you wherever you go. Meanwhile, things that are really close to you—like electric poles, roadside buildings, and trees—seem to fly by really fast.
The effect is known as parallax. Things that are close seem to move faster and “travel more distance” (not really) than things [that are] far away.
The sun is only eight light-minutes away; that’s 146 million km on average. At human scale it seems like a lot, but in cosmic distances it is nothing. Orion, for example, has stars that are from 243 to 1360 light years away from us. Imagine traveling at the speed of light for 1360 years. That’s how far these stars are. And these are not even the farthest stars. Some stars are Giga-light years away from us.
Now, with the proper precision instruments you can indeed notice the parallax in distant stars, just not with the naked eye. Furthermore, our solar system has moved so much since the early days of astronomy and astrology, the constellations do not correspond to the early astrology maps. The constellations appear shifted.
As a free info nugget: in case your life is ruled by astrology, whatever sign you think you are, you are not.
This post originally appeared on Quora.