Astronomers investigate a planet orbiting a distant star. Model A predicts a circular orbit. Model B predicts a slightly elliptical orbit.
The table gives the distance predicted by each model and the distance measured at four positions in the orbit. Each measured distance has an uncertainty of ±1 million km. For this question, treat a prediction as consistent with a measurement if they differ by no more than 1 million km.
| Position in orbit | Distance predicted by Model A in million km | Distance predicted by Model B in million km | Measured distance in million km |
|---|---|---|---|
| 1 | 152 | 148 | 147 |
| 2 | 152 | 151 | 151 |
| 3 | 152 | 156 | 157 |
| 4 | 152 | 153 | 153 |
Evaluate which model the astronomers should prefer and whether they should accept this model immediately.
80 exam-style questions on Edexcel GCSE Physics 7.1 The Solar System and gravity, covering 7.1.1 Weight and g on different bodies in space, 7.1.2 The Solar System, 7.1.3 Changing ideas about the Solar System, 7.1.4 Orbits of moons, planets, comets and satellites, and 7.1.5 Gravity and orbital motion. Each one has a worked solution and a mark scheme showing where the marks go.