I’m not the kind of guy who takes pleasure in just sitting around. In fact, one of my mantras is “Motion is Lotion.” However, due to a bout with influenza last week, I’ve spent the last ten days being relatively still.
But, was my body truly at rest? I’ve been thinking about this notion for quite some time, wondering how fast my body is traveling even when sitting still. Within the universe, bodies at absolute rest don’t really exist. It might surprise you to learn that your body is traveling through space at remarkable speeds. You can’t feel it, but it is true nonetheless. In fact, it is hard to say exactly how fast your body is moving at any given time because you are moving at vast speeds in multiple directions at once.
Let me break it down for you.
Earth’s Rotation on its Axis.
- Depending on where you are on Earth (latitudinally speaking), the speed of the Earth’s rotation varies. At the Equator the rotational speed is about 1000 Miles per Hour (MPH) and at the latitude of New York City, it is about 800 MPH.
- That spin is what is responsible for the rising and setting of the sun.
- For most of human history it was assumed that the sun revolved around the Earth because we couldn’t feel the movement of Earth’s rotation. That lack of “feel” lead to erroneous conclusions and complicated theories about our solar system. Now we know that the Earth rotates on its axis AND orbits around the Sun.
Earth’s Orbit Around the Sun
- As the Earth orbits around our Sun (which gives rise to our annual seasons), you are traveling at roughly 67,000 MPH.
The Sun’s Orbit around the Milky Way Galaxy
- Like in all gravitationally bond systems, the Sun orbits the center of the Milky Way Galaxy. Relative to the super massive black hole in the center of our galaxy, the Sun is dragging our solar system along in its orbit around the Milky Way Galaxy at somewhere between 450,000 and 515,000 MPH.
Movement Within Our Local Group of Galaxies
- Within our Local Group of galaxies, a collection of 50 plus galaxies in our relative corner of the universe, we are traveling on a collision course toward the Andromeda Galaxy at a speed of around 720,000 MPH.
Our Local Groups Movement toward the Great Attractor
- Our Local Group of galaxies, as a unit, is traveling toward the Great Attractor (a mysterious gravity well in our broader corner of the universe), at a velocity of 1,343,000 MPH.
- This rate of travel is relative to the Cosmic Microwave Background (CMB).
- I repeat, that velocity is over 1.3 MILLION Miles per Hour!
The Expansion of the Universe
- On top of all that, the Universe is expanding at a pretty substantial pace. Because space is literally stretching in all directions, there is no relative stationary benchmark to use in order to calculate a relative speed. I’m not going to get into translating the concept of kilometers per second per megaparsec. It’s way too complicated for this exercise.
These speeds are hard to imagine, let alone grasp. But, given that we are gravitationally bound to Earth and that there have been no relative changes in any of these rates or trajectories, they remain undetectable to us. Much like when you are traveling in an airplane, once at speed and altitude, you cannot discern the speed of your travel. You only notice acceleration, deceleration, and sudden changes in direction (turns) or altitude (turbulence).
Now, all these speeds are not in the same direction or even on the same plain, and each speed is relative to a specific frame of reference. Some speeds in one direction may cancel out or partially cancel out other speeds. The opposite is also true, depending on where we are in the relative position in each system’s rotation and orbit. Regardless, it is safe to assume that when your body is at rest on planet Earth, your actual speed exceeds a million miles an hour. Let’s just consider our galaxy’s speed relative to the CMB (1.3 Million MPH). In the five minutes it just took you to read this article, you will have traveled over 108,000 miles, or the equivalent of 4.35 times around Earth’s Equator.
Body at rest, nope, it’s just an illusion.
If you need a visual of how the solar system is really traveling through space relative to the center of the Milky Way Galaxy, check out this YouTube video. This video is a bit redundant and has the feel of being a product of an AI, but it captures the general essence of what I’m trying to share here.
Notes:
I used the most commonly cited number or range for the velocities reported here. In some cases there were substantial differences between sources. Generally, however the velocities were drawn from reputable sources with references cited. I converted the speeds reported herein from the more scientific metric of kilometers per second to miles per hour, which is generally more accessible for folks in the United States.
