Why do astronauts float if gravity is still there?
They are not beyond gravity — they are falling, continuously, and so is their spacecraft, so nothing pushes back against them.
Simple intuition
The plain reason, in everyday words
The International Space Station orbits about 400 kilometres up. That sounds far, but the Earth is 6,400 kilometres in radius, so the station is only about 6% further from the centre than you are — and gravity there is still about 90% as strong as at ground level. So gravity is not switched off. What is missing is the floor. Standing on the ground, you feel your weight because the ground pushes up on you; the sensation of weight is that push, not gravity itself. In orbit, the station and everyone in it are falling together, with nothing pushing back. There is no floor resisting the fall because the floor is falling too. You feel exactly what you feel in the instant after jumping off a diving board, except that in orbit the fall never ends.
There is no gravity in space.
Gravity at the space station's altitude is about 89% of its strength at the ground. It is what holds the station in orbit — without it the station would fly off in a straight line.
Astronauts float because they are so far away that gravity is negligible.
Distance is not the reason. They float because they are in free fall along with their spacecraft, which would produce the same sensation at any altitude, including in a falling lift.
Orbit means being beyond the pull of the Earth.
Orbit is a continuous fall that keeps missing the ground because of sideways speed. Escaping the Earth's influence entirely is a completely different and much more demanding manoeuvre.
Weightlessness means the body is unstressed and comfortable.
The absence of load causes bone density and muscle loss, fluid shifts toward the head, and vision changes. It is a demanding environment that requires hours of daily countermeasures.
It corrects one of the most widely held physical misconceptions, and the correction contains a genuinely deep idea: what you feel as weight is the force pushing back on you, not gravity itself. That reframing is the first step toward the equivalence principle and general relativity — and it explains why a falling lift, a parabolic aircraft and an orbiting station all produce the same sensation for exactly the same reason.
Who worked it out
Isaac Newton posed the thought experiment in the Principia: a cannon fired from a high mountain with increasing charge lands further away each time, until at sufficient speed the ball never lands at all and circles the Earth.
What problem forced it
That picture unified falling apples and orbiting moons under a single law, but the sensation of weightlessness was not observed directly until human spaceflight in 1961.
How it changed since
Einstein reframed the whole matter in 1907 with the equivalence principle — his 'happiest thought' was that a person in free fall does not feel their own weight — which became the foundation of general relativity in 1915.
Why orbits decay and need reboosting
Even at 400 kilometres there is enough atmosphere to matter, which is why orbit is not maintenance-free.
What the equivalence principle led to
The observation that free fall feels like no gravity is the starting point of general relativity.
Written for Curio rather than collected from a forum — it is part of the curated corpus that ships with the platform. The references it draws on are listed under Sources.