Mercury
The smallest planet and the closest to the Sun — hard to catch, always near twilight.
Mercury never strays far from the Sun in our sky, so you only see it low in the west just after sunset or low in the east just before sunrise.
It whips around the Sun in just 88 days, so its best viewing windows come and go within a few weeks.
Facts
- Year
- 88 Earth days
- Size
- a little bigger than our Moon
- Temperature
- 430 °C by day, −180 °C at night