Viktor says Earth's field at the space station's altitude still has about 90% of its surface strength. Is he correct?
In every video from the space station, astronauts drift and tumble in midair. The usual name for it is 'zero gravity'. Yet at the station's altitude, Earth's field still has about 90% of its surface strength.
This lesson explains how astronauts can float while gravity still acts on them.
From the motion topic: motion under gravity alone is called free fall.
A capsule coasts with engines off, moving under gravity alone. What is this motion called?
An orbiting station moves under gravity alone. No engines fire, and there is no air to drag on it. So the station is in free fall: it is continually falling around Earth.
The astronauts inside also move under gravity alone. So the astronauts are in free fall too, falling along exactly the same path as the station.
You've already seen that everything at one place in a gravitational field accelerates equally, whatever its mass. So the station, the astronauts, and every loose object inside all fall together, at the same rate.
Nothing inside presses on anything else: the floor falls away exactly as fast as an astronaut falls toward it.
An astronaut lets go of a camera inside the orbiting station. What does the camera do?
The camera, the astronaut, and the station are all in free fall, falling along the same path.
All of them accelerate equally, so none gains on another.
The camera floats where it was released, beside the astronaut.
An astronaut releases a wrench inside the orbiting station. What does the wrench do?
Earth still attracts a floating astronaut with hundreds of newtons. Why does she feel weightless?
She and the station fall together, so the floor falls away exactly as fast as she falls toward it.
Nothing inside presses on her.
She feels weightless because nothing presses on her, not because gravity is absent.
'Zero gravity' is a nickname for shared free fall, not a fact about the field.
Osei says Earth's gravity still pulls on astronauts inside the orbiting station. Is he correct?
A supply capsule coasts around Earth. A pencil inside floats in midair. Which statement explains why?
A student claims gravity is absent in orbit. Which fact shows the claim is wrong?
A research airplane flies a steep falling path, and for 20 seconds its passengers float. Why?