Even though we can’t feel it and it doesn’t seem like it, and even though we talk about the sun rising and stars moving overhead, what’s really happening is the earth is moving. Fast. Our planet spins at about 1000 miles per hour, and travels through space around the sun at about 67,000 miles per hour! This orbit around the sun (sometimes called a solar year) creates one year on earth.
And here’s something else we don’t usually think about: Our sun is in orbit too, through the Milky Way. The sun travels at a rate of about 500,000 miles per hour as it circles the Galactic Center. One of these orbits is called a galactic year. Of course, we’re all pulled along with the sun in this bigger orbit: planets, moons, meteors, asteroids, and comets.
Now for some perspective on distance: Just how big is our galaxy? Let’s start with the distance between the sun and the earth. This distance, a “mere” 93 million miles, is known as an astronomical unit. Astronomers use the astronomical unit as a way of measuring distances in the solar system. This rather average-sized galaxy of ours is 100,000 light-years across. (A light-year is the distance sunlight travels in a year.) Each incredibly biglight-year is about 63,241 astronomical units. So how wide is our galaxy? About 586,941,600,000,000,000 miles! No wonder it takes us 240 million years to make just one circuit around the galaxy.
But wait, there’s more: our galaxy is also moving through the universe. Our closest galactic neighbor, and the only galaxy we can see with our naked eyes, is the Andromeda Galaxy. Our Milky Way Galaxy is traveling around 270,000 miles per hour, right at it! In the distant future the two will collide, but that’s another story.
Why don’t we feel all this movement? Because we are all moving at the same speed, we don’t feel a thing. We are speed demons many times over and don’t feel it or even know it!
by Greeley Wells
[Note: The above article appears in the SPRING 2017 edition of our local newspaper, THE APPLEGATER. I’ve been writing an article for every edition for years now.
You can view the whole paper at www.applegater.org