The smallest and the innermost planet of our solar system is called Mercury. This crater riddled rocky body is one of four rocky planets in our solar system (Mercury, Venus, Earth and Mars (we miss you Pluto!)) Named after the Roman god of financial gain, commerce, and communication, Mercury completes its orbits around the Sun in a speedy 87.97 days. Below are some more interesting facts about Mercury.
1. Mercury is the second hottest planet in our Solar System
Despite being closest to the heat of the Sun, Mercury comes in second to Venus when looking at surface temperatures. Venus has average surface temperatures of 462 °C (863.6 °F) while the Sun facing side of Mercury sees temperatures of around 427 °C (800.6 °F).
The side of Mercury that faces away from the Sun has temperatures as low as -173 °C (-279.4 °F). That’s a shift of 600 °C (1,080 °F)!
2. Mercury rotates three times for every 2 revolutions around the sun
Proved in 1965, scientists demonstrated that Mercury has a 3:2 spin-orbit resonance. This means that for every two times it goes around the sun, it rotates three times.
3. You would weight 38% of your Earth weight on Mercury
The gravity on Mercury is 38% of that on Earth. Even though Mercury has an atmosphere, the harsh solar winds from the sun blow it away. Interestingly, these same winds also bring in new gases and dust that replenish the atmosphere.
4. Only two man made spacecraft have visited Mercury
The extreme heat and gravity brought on by its proximity to the Sun, has made Mercury a difficult place for us to visit. The Mariner 10 flew by Mercury in 1975, while the MESSENGER (“MErcury Surface, Space ENvironment, GEochemistry, and Ranging) probe orbited Mercury from 2011 to 2015.
Although the Mariner 10 ran out of fuel at the end of its mission, it is still believed to be orbiting the Sun.
5. We have known about Mercury since ancient times.
Although we’re not sure who discovered Mercury, the earliest written records are by a Babylonian astrologer around 1900 BC.
The Greeks thought Mercury was two stars and called it Apollo in the morning and Hermes at night. Later they discovered that these were the same object.
6. Mercury has water and organic compounds!
Discovered by the MESSENGER team in 2008, large amounts of water were found in Mercury’s exosphere. Later additional analysis showed carbon-containing organic compounds and ice inside craters near Mercury’s north pol.e
7. Mercury has the most craters of any planet in the Solar System
Due to its small atmosphere, asteroids that approach Mercury, hit the planet without breaking down. This leads to large and frequent craters on its surface.
8. Mercury is a third the size of Earth
9. Mercury is the fastest planet in the solar system
Rotating around the Sun, Mercury moves at 112,000 miles (180,000 km) per hour!
10. Mercury can be seen traveling across the Sun’s surface
About thirteen times ever century, we can see Mercury travel across the Sun. It last happened on November 11, 2019 and isn’t predicted to occur again until 2032.