Fact: General facts about Mercury
In our solar system of planets the 5 closets planets to the Sun are made largely of rocky material. The smallest of these is Mercury, and it also happens to be the planet in closest orbit to the sun. It is grey in color, and has no atmosphere on its very hot surface. Here are some quick facts about Mercury!
Facts About Mercury
Name Origin: Roman. Mercury was named by the ancient Romans, who named the planet after their messenger god because the planet moves more quickly across the sky than any other planet.
Size: Average Diameter of 4,800km, Mass of approximately 3.3 x 10^23 Kg. Mercury is less than 40% the diameter or Earth, but is only about 6% of the total mass of the earth!
Temperature: During the day Mercury’s surface can be as hot as 426 degrees C, but on the night side of the planet it averages a very cold -163 degrees C!
Days: Rotational period 58.6 days. Even though the planet is much smaller than the Earth, it rotates so slowly that a day on Mercury is almost two months long!
Orbit: Semi Major Axis: 57.9 million km, Orbital Period 87.9 days. Mercury is less than half the distance away from the sun, than the earth is, and it travels around the sun so quickly, that a ‘year’ on Mercury takes less than 3 months!
Gravity: 0.38g. Because mercury is smaller than the earth, it has less gravity to hold objects onto it. If you weighed 150lbs on Earth, you would only weigh 57lbs on Mercury!
Atmosphere: None. Although Mercury does have trace gasses that have been detected above its surface, the planet it too small and too hot to hold any atmosphere of consequence.
Surface structures: Craters, Plains, Volcanoes. Mercury is a rocky planet, that is similar in color to the moon. Its surface is covered mostly by craters caused by meteorites and some volcanoes.
To learn more about Mercury Visit the NASA planetary Page
- Planet Mercury