While it could be superior for folks to have the ability to dwell in house, a “weightless” environment poses some critical challenges. Humans perform finest on Earth’s floor, the place they’re affected by a relentless gravitational drive. Without it, there are well-known consequences of long-term publicity to microgravity, together with bone mass loss and muscle atrophy.

So if we need to dwell in house, we’ll have to create a man-made gravity surroundings. We solely have one methodology for doing that: Build a car that strikes with a relentless acceleration. The most typical idea is to create a spacecraft that spins. But that’s not fairly as straightforward because it sounds. Here’s why.

Feeling Weight

First, let’s go over the fundamentals of gravity and what it means to really feel your weight.

Gravity is an attraction between objects which have mass. Since each your physique and the Earth have mass, there’s a horny drive that pulls you towards the Earth and retains you on the bottom. Even although this drive is continually appearing on you, you don’t really feel it, as a result of the Earth concurrently pulls on all components of your physique, making the impact undetectable.

I do know what you might be considering: “I’m sitting here on this chair, and I can absolutely feel my weight.” Actually, what you feel isn’t gravity. It’s the drive of the chair (and the bottom) pushing up on you. We name this upward-pushing drive your “apparent weight.”

We can get an excellent really feel for the idea of obvious weight by taking a fast journey in an elevator. The elevator begins at relaxation. But once you push a button, it begins shifting upwards. That means it should have an upward acceleration—at the least for a really quick period of time, till the elevator will get as much as its touring pace. During this upward acceleration, you’re feeling a bit heavier. Then as soon as the elevator will get close to its programmed flooring, it has to decelerate. That means it accelerates within the downward course. During this time, you’re feeling lighter.

But, in fact, your precise weight by no means fluctuated. Your actual weight is a measure of how a lot drive gravity exerts in your physique, and it’s the results of the interplay between your mass (m) in addition to the mass of the Earth and your distance from its heart. On Earth, gravity exerts a drive of 9.8 newtons per kilogram. (Mass and weight are different things, so on a planet with totally different gravity, your weight can be totally different, though your mass can be the identical.)

Riding an elevator adjustments none of those elements. What it does change is your obvious weight. It’s a little bit unusual, however this impact is tremendous helpful for a spacecraft.

Linear Acceleration

Let’s say you might be in house the place there’s no gravity—and even in low Earth orbit, the place there’s microgravity, which is the identify we give to a “weightless” surroundings. What in case your spacecraft had an enormous elevator that continually accelerated upwards? If the acceleration of the elevator had the identical worth because the gravitational subject on the floor of the Earth, your weight would really feel precisely prefer it does now.

Of course, a spaceship with an infinite elevator is impractical. It can be simpler to only make the entire car speed up. That would completely create synthetic gravity. In reality, that is the first methodology used on ships within the science fiction sequence The Expanse.