Edexcel GCSE Astronomy Topic 8 Planetary motion and gravity overview quiz quiz

Claudius Ptolemy

Copernicus

Tycho Brahe

Isaac Newton

Proposing the Sun-centred heliocentric model of the Solar System

Discovering gravity and the laws of motion

Making very precise naked-eye observations of the planets

Inventing the very first astronomical telescope

They are perfect circles with the Sun at the exact centre

They are slowly winding inward spirals

They are straight lines through space

They are ellipses with the Sun at one focus

The point in a solar orbit furthest from the Sun

The point in a solar orbit that is closest to the Sun

The point in an orbit that is closest to the Earth

The exact geometric centre of an elliptical orbit

All of the planetary orbits are actually perfect circles centred exactly on the Sun

A line from the Sun to a planet sweeps equal areas in equal times

The force of gravity on a planet stays exactly constant

All planets orbit the Sun with exactly the same period

T x r = constant

T divided by r = constant

T squared divided by r cubed = constant

T cubed divided by r squared = constant

4 years

16 years

64 years

8 years

It depends inversely on the mass of the central body

It does not depend on the central body in any way at all

It is directly proportional to the mass of the central body

It depends on the colour and size of the orbiting planet

It is exactly the same size for all bodies, no matter what their masses are or how far apart they happen to sit

It is proportional to the product of their masses and inversely proportional to the square of their separation

It increases steadily as the distance between the two bodies gets larger and larger

It depends only on the size of the larger one of the two masses involved

It doubles to twice the value

It falls to exactly one half

It falls to one quarter

It stays exactly the same

Magnetism

The solar wind

Radiation pressure

Gravity