In the Field a bright sun sits at the centre, and the disc no longer flies straight — its path bends into a curve. That reach across empty space, pulling harder the closer you get, is gravity: the force that turns a straight throw into an orbit, an escape, or a slingshot.
The sun at the centre pulls on the disc across empty space — that is gravity. The closer the disc swings, the stronger the pull and the sharper the bend, and watch the speed readout climb as it nears the sun and drop as it pulls away. Too slow and it spirals in; just right and it orbits; fast enough and it slings past and escapes. The disc never touches the sun — the whole curve is a force reaching across the gap.
Gravity is the attractive pull that every mass exerts on every other mass, reaching across empty space with no touching. It is a non-contact force: the sun tugs the disc from a distance, bending its straight path into a curve. The more massive the body and the closer you are, the stronger the pull. Gravity is what makes things fall, holds the planets to the Sun, and in the Field turns a simple throw into an orbit, a slingshot, or an escape.
Gravity pulls the disc toward the sun, and that inward pull is a centripetal force — it bends the path rather than speeding it along. The strength follows an inverse-square law: halve the distance and the pull becomes four times as strong, so a close pass curves hard while a distant one barely bends. With just enough sideways speed the disc keeps falling toward the sun yet always misses, tracing a closed orbit. Too little speed and it spirals in; beyond escape velocity it breaks free for good.
In the Field a sun sits at the centre and pulls on the disc the whole time it moves. Launch it gently and gravity wins, curling it into a tight loop or spiralling it inward. Launch it just right and it settles into a steady orbit. Launch it fast on a close pass and it whips around, gaining speed as it nears and being flung onward — a gravity assist, or slingshot. The disc never touches the sun: every bit of the curve is gravity reaching across the gap, stronger the closer it gets.
Gravity is easiest to feel when you can change one thing at a time. Launch a world at different speeds to find an orbit, weigh the inverse-square pull, and turn a height into a falling speed.
There is a narrow band of speed that gives a stable orbit. Below it gravity wins and the world spirals in; above the escape speed it breaks free and never comes back.
The Moon is forever falling toward Earth under gravity, but it moves sideways so fast that it keeps missing — so instead of crashing down it loops around us. That endless, curving fall is an orbit, the same balance that holds every planet to the Sun.
Probes like Voyager reach the outer planets with almost no fuel by swinging close past a world and being flung onward faster. A gravity assist borrows a sliver of the planet's motion, turning its gravity into free speed.
Astronauts on the Space Station drift weightless not because gravity is gone — it is still strong up there — but because they and the station are in constant free fall around the Earth, falling together and so feeling no weight.
Gravity is the pull that reaches across empty space to shape everything from a dropped ball to a galaxy. This FAQ travels from the disc curving past the sun to orbits, slingshots, floating astronauts, falling feathers, and Einstein's curved spacetime.
Gravity is the attractive pull that every mass exerts on every other mass, reaching across empty space without anything touching. It is a non-contact force: the Sun tugs the planets from millions of kilometres away, and the Earth pulls a dropped ball straight down. The more massive a body and the closer you are to it, the stronger the pull. Gravity makes things fall, holds the atmosphere to the planet, keeps moons and satellites in orbit, and on the largest scale gathers matter into stars and galaxies.
On the open Field there are no walls, yet the disc's path bends — because the sun at the centre pulls on it the whole time it moves. That steady inward pull is gravity, and it acts as a centripetal force, bending the path toward the sun instead of speeding the disc straight along. The closer the disc swings, the stronger the pull and the sharper the bend. With nothing touching it, the entire curve is a force reaching across the empty gap from the sun.
The inverse-square law describes how gravity fades with distance: the pull is proportional to 1 / distance². Double the distance and the force drops to one quarter; triple it and the force drops to one ninth. This steep fall-off is why a close pass to the sun bends the disc hard while a distant one barely nudges it, and why gravity, though it never truly ends, becomes very weak far away. Light and sound spread out from a source by the same inverse-square pattern.
An orbit is a closed, looping path that a body follows around a massive object under gravity. An orbiting body is actually falling toward the central mass the whole time — but it is also moving sideways so fast that the surface curves away beneath it just as quickly, so it keeps missing. The result is a perpetual fall that bends into a loop. Newton pictured firing a cannonball so fast that it falls all the way around the world and comes back to where it started: that is an orbit.
Escape velocity is the minimum speed an object needs to break free of a body's gravity and never fall back. Below it, the object either orbits or falls back down; at or above it, the object coasts away forever, slowing but never stopping. Earth's escape velocity is about 11 kilometres per second — the speed a rocket must beat to leave for deep space. It depends on the mass and size of the body, so it is much lower on the smaller Moon and enormous near a black hole.
A gravity assist is a manoeuvre where a spacecraft swings close past a moving planet and leaves much faster than it arrived, without firing its engines. The craft borrows a tiny share of the planet's orbital motion: it speeds up relative to the Sun while the planet slows by an immeasurable amount. This lets missions reach the outer Solar System on far less fuel. The Voyager probes chained slingshots past Jupiter and Saturn to fling themselves toward the edge of the Solar System.
On a stretched, oval orbit the body moves fastest at its closest approach and slowest when far away — a pattern Kepler discovered in the planets four centuries ago. As the body falls inward toward the sun, gravity does work on it and speeds it up, just as a ball speeds up rolling downhill; as it climbs back out, gravity slows it again. So a comet whips around the Sun in a blur and then crawls through the cold, distant part of its orbit for years.
A centripetal force is the net inward force needed to keep any object moving in a circle — it constantly bends the path toward the centre instead of letting the object fly off straight. It is not a new kind of force but a role that some real force plays. In an orbit, gravity is the centripetal force: the sun's pull does the bending. Whirl a ball on a string and the string's tension is the centripetal force; cut the string, remove the inward pull, and the ball flies off in a straight line.
| Property | Mass | Weight |
|---|---|---|
| What it is | Amount of matter | Gravity's pull on the mass |
| Units | Kilograms (kg) | Newtons (N) |
| Changes with location? | No | Yes |
| On the Moon | Same | About one sixth |
At the Space Station's altitude, Earth's gravity is still about 90 percent as strong as on the ground, so it has certainly not run out. Astronauts float because the station and everyone in it are in continuous free fall around the Earth — falling toward it but moving sideways fast enough to keep missing, which is an orbit. Since the astronauts, the walls, and every tool fall at the same rate together, nothing presses on anything else, so they feel weightless. True zero gravity exists only far from any mass.
No — in the absence of air, all objects fall at the same rate regardless of mass. A heavier object feels a stronger gravitational pull, but it also has more inertia and needs more force to accelerate; the two effects cancel exactly, so a hammer and a feather hit the ground together in a vacuum. On Earth it only looks otherwise because air resistance slows light, fluffy objects more. Astronaut David Scott dropped a hammer and a feather on the airless Moon to show they land together.
Gravity is astonishingly weak — a small fridge magnet beats the pull of the entire Earth on a pin. But unlike the electric force, which comes in positive and negative charges that mostly cancel out, gravity only ever attracts. Across the vast mass of a planet, a star, or a galaxy, every particle pulls the same way, so the tiny pulls add up into an overwhelming total. That is why gravity, not the far stronger electric force, is what shapes orbits, builds stars, and sculpts galaxies.
Newton described gravity as a pull acting instantly across space, and his law still works beautifully for spacecraft and planets. Einstein went deeper: in his general relativity, mass and energy curve the very fabric of space and time, and objects simply follow the straightest possible paths through that curved geometry. What we feel as a pull is really this curvature. Einstein's picture predicts tiny effects Newton's misses — light bending past the Sun, GPS clocks running fast, and black holes — all since confirmed.
In the Field a sun sits at the centre and pulls on the disc across empty space the whole time it moves, with no walls involved. Launch the disc gently and gravity curls it into a tight loop or spirals it inward; launch it just right and it settles into a steady orbit; launch it fast on a close pass and it whips around, speeding up as it nears and being flung onward in a slingshot. The disc never touches the sun, so the entire curving path is gravity reaching across the gap — stronger the closer it gets.
In everyday physics, no — gravity between masses only ever attracts; there is no known "anti-gravity" that shoves ordinary mass apart. This one-way pull is exactly why gravity adds up so powerfully over large masses. On the grandest cosmic scale there is a subtle twist: the expansion of the universe is speeding up, driven by a mysterious "dark energy" that behaves like a repulsion. But for planets, moons, spacecraft, and the Kinetica disc, gravity is purely a pull toward the mass.
Seven question formats, the way Beyond Dictionary serves them. Every question has layered hints — a quick nudge, the reasoning, then a deeper connection — so a wrong answer opens a door, never a dead end. 32 questions across all seven formats — multiple choice, multiple-correct, fill-in-the-blank, match, sequence, read-think-connect, and write-your-own.