Field Guide · 01
The physics of gravity, from a moonbase to orbital flight.
A gravity simulator is only interesting when the rules are honest. This guide walks through the core physics behind GravityNerd's two interactive worlds — FloatSpin and GravityFlight — so you can build intuition for how mass, weight, inertia, and orbital motion actually behave.
Weight vs mass
Mass is the amount of matter in an object; it does not change when you travel. Weight is the force gravity exerts on that mass — and it absolutely does. A 100 kg astronaut weighs about 981 N on Earth (9.81 m/s²), 162 N on the Moon (1.62 m/s²), and 371 N on Mars (3.71 m/s²). Same mass, three very different feelings.
Inertia is stubborn
Objects resist changes in motion in proportion to their mass, not their weight. Pushing a floating wrench in the FloatSpin moonbase takes the same effort as pushing it on Earth — it just doesn't fall while you do it. That's why low-gravity environments feel surprisingly heavy the moment you try to stop something.
Vacuum spin
In a vacuum, there is no air drag to bleed off angular momentum. A spinning object keeps spinning until something touches it. The 0.16 g FloatSpin chamber is airless, so tumbling objects trace long, clean rotations — a useful reminder that gravity and drag are separate forces.
Orbital mechanics
An orbit is a fall that keeps missing the ground. Give a craft enough sideways velocity and its trajectory curves around a body instead of into it. In GravityFlight, launching from Earth, Moon, or Mars changes both the escape velocity and the shape of the resulting path — thicker atmospheres punish shallow angles, airless bodies reward precision.
Ready to feel it? Try the FloatSpin moonbase or the GravityFlight orbital launchpad.