Which planet is closest to the sun?

Mercury is the planet closest to the Sun. It travels around the Sun on the innermost orbit of the Solar System, completing one revolution in about 88 Earth days.

Because Mercury is nearest the Sun, its surface receives intense sunlight. The planet has a rocky surface covered with craters, a very thin exosphere rather than a substantial atmosphere, and a large iron-rich core. It is also the smallest of the eight planets.

Mercury’s closeness to the Sun does not make it the hottest planet overall. Venus has a much thicker carbon-dioxide atmosphere, which traps heat and gives Venus the highest average surface temperature. Another common mix-up is choosing Earth or Mars because they are more familiar, but both orbit farther from the Sun. Mercury’s orbit also gives it the shortest year, while its slow rotation makes a solar day last far longer than its year.