The Mercury-bound MESSENGER spacecraft captured several stunning images of Earth during a gravity assist swingby of its home planet on Aug. 2, 2005. Several hundred images, taken with the wide-angle camera in MESSENGER’s Mercury Dual Imaging System (MDIS), were sequenced into a movie documenting the view from MESSENGER as it departed Earth. (NASA / MESSENGER MISSION)

Ask Ethan: Why Can’t We Feel Earth Flying Through Space?

Our motion through space is undeniable. So why can’t we feel it?

Our planet isn’t the stationary place we feel it to be beneath our feet, but rather moves in an incredibly complex fashion through the Universe. We rotate on our axis once every 24 hours, revolve around the Sun once per year, while the entire Solar System orbits at 220 km/s around the Milky Way, which accelerates towards Andromeda in the Local Group, which itself moves relative to the radiation left over from the Big Bang. That’s a lot of cosmic motion! And yet, we cannot feel it at all. This troubles many, including reader Annie Bennett, who asks:

I desperately need your help! Please help me explain to my husband why you can’t feel earth flying through space!

There’s a simple reason why we cannot feel it in our bodies, but it won’t be intuitive to anyone who’s used to their experiences here on Earth.

If you stick your limbs out of a moving car, you’ll feel a force as the air rushes past. If you double your speed, the force quadruples. Yet, if you’re at rest relative to the air, you’ll experience no force at all. (PXHERE / PHOTO NUMBER 151399)

If you’re in a car that moves at 15 miles per hour (mph) and you stick your limbs out the window, you’ll feel the wind blow mildly against it. It’s true that the faster you go, the greater the force…