February 24, 2022
Mercury is the closest planet to the Sun at approximately 30.4 million miles (48.9 million km) which causes the planet to heat up to extreme temperatures. However, because Mercury has little to no atmosphere, it is not able to hold the heat. This means that as day turns to night, temperatures drop drastically. Daytime temperatures on Mercury can reach up to 800°F (430°C), while nighttime temperatures reach as low as -290°F (-180°C).
This image of Mercury was taken by the MESSENGER mission in 2008. It shows the terminator, which delineates night and day on a planetary body. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
