Table 8.1 shows data about three planets, Mercury, Venus and Earth.
| planet | time for one orbit of Sun / days | distance from Sun / km | average density / kg/m³ | gravitational field strength at surface / N/kg |
|---|---|---|---|---|
| Mercury | 88 | 5.8 × 10⁷ | 5400 | 3.7 |
| Venus | 220 | 1.1 × 10⁸ | 5200 | 8.9 |
| Earth | 365 | 1.5 × 10⁸ | 5500 | 9.8 |
Fig. 8.1 shows these planets in alignment with the Sun. They rotate around the Sun in the direction shown.
Mark and label on Fig. 8.1 the positions of the three planets 110 days after the position shown in Fig. 8.1.