The Bridge V Learning Edition 1 ; our solar system | Page 20

Credit: NASA
Mercury is the planet nearest to the Sun. It has no atmosphere and its solid surface, like that of
our Moon, is covered with many craters. Mercury orbits the Sun once in just 88 days and has no
moons. There are severe temperature differences on its surface: 380° C on the side facing the
Sun, and -180° C on the night side! This is because day and night shift very slowly on Mercury,
because of its slow spin. Also, there is no atmosphere to trap the heat at night.
Venus
Credit: NASA
Venus is about as large as the Earth. Carbon dioxide (a greenhouse gas) makes up 99% of its
atmosphere, which causes sunlight to get trapped in this mega greenhouse. Whether it is day or
night, it is always very hot on Venus: almost 500° C! Venus’ spin on its own axis is inverted
compared to the spins of other planets.
Earth