Mercury Facts: 33 Facts About The Planet Mercury

Among the eight planets in the Solar System, Mercury is the closest to the Sun and has a lot of significant information that can be collected. With these 33 facts about Mercury, let’s learn more about it.

Mercury’s characteristics and composition

1. Mercury is closest to the Sun as compared to other planets.

2. It is the fastest planet to travel through space, at an incredible speed of 50 km per second (180,000 km/h). It completes one revolution around the Sun in 88 days.

3. Impact basins (an approximately circular depression in the surface of a planet, the moon, or another solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body.) as larger as 1550 km, in diameter, can be found on the surface of Mercury.

4. Did you know that Mercury’s outer shell is only 400 km thick?

5. Mercury is greyish-brown in color. This is the color that has been recorded from the ground and space-based observations.

6.  Mercury is a terrestrial planet. Mercury’s magnetic field is just 1% of that of the Earth.

7. Mercury can be observed 13 times every 100 years from Earth. The event of the passing of Mercury across the face of the Sun is called “transit.”

8. Mercury is devoid of any moons or rings. Mercury and Venus are the only planets in the Solar System that do not have moons. Thus, it has no moons during the night to illuminate it like Earth.

9. Mercury is named after the Roman messenger of gods. The name was chosen because of the high speed with which Mercury revolves around the Sun.

10. Mercury is the smallest planet in the solar system. In size, Mercury is comparable to Earth’s moon but slightly larger than it.

11. Mercury is the second densest planet after Earth. This is mainly because of its composition of heavy metals and rock.

12. Just like old age humans, Mercury has also developed wrinkles that can be up to a mile high and hundreds of miles long.

13. Mercury is not as hot as you would think because of its proximity to the Sun. In fact, it is the second hottest planet in the Solar System. The planet’s side facing the Sun can be as hot as 427 degree Celsius but its opposite side, at the same time, has a temperature of minus 173 degree Celsius. The difference in the temperature is mainly because of the lack of environment/atmosphere to regulate the planet’s temperature.

14. Mercury has the largest range of surface temperature found on any planet – “minus 170 degree Celsius to 430 degree Celsius.”

15. Mercury’s surface has three significant features – craters, plains, and cliffs.

16. If one would stand on the Sun-facing side of Mercury when it is closest to it, the Sun would appear three times as large when viewed from Mercury as compared to when viewed from Earth.

17. Mercury’s surface is similar to that of Earth’s moons.

18. Mercury is also called a morning or an evening star because it is brightly visible in the sky just before the sunrise and just after the sunset.

19. Mercury is one of the five planets in the solar system that are visible to the naked eye. The other four are – Venus, Mars, Jupiter and Saturn.

20. NASA’s spacecraft “MESSENGER” crash landed on Mercury in April 2015. The spacecraft provided a lot of detail about the planet through images that will be used by the scientists to known more about this terrestrial planet in the future.

statistics on the MESSENGER mission.
Statistics on the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) mission. Image credit: NASA

Research and exploration

21. Galileo Galilei observed mercury for the first time in 1631.

22. Mercury has seen only two guests from Earth – “Mariner 10 and the Messenger probe.” The reason behind limited space crafts being sent to Mercury: its close proximity to the Sun which makes it difficult for the space crafts to survive in the intense heat.

23. Mariner 10 is the first spacecraft to reach one planet by using the gravity of another planet (in this case, Venus) to alter its speed and trajectory. The spacecraft lifted off from Cape Canaveral, Florida, on 3 November 1973.

24. As suggested by the images that were collected by space crafts, the surface of Mercury is formed mainly by impacts and volcanic activities.

25. There are no seasons on Mercury. All it has is a weak atmosphere that has 38% the gravity as experienced on Earth.

26. Mercury does not complete one revolution around the sun in a year and is the only planet to do so. It actually completes two revolutions on its own axis during the time it completes two revolutions around the sun.

27. The least circular and the most eccentric orbit in the solar system belongs to Mercury. And remember, a planet’s orbit has a lot to do with other conditions on it including temperature and atmosphere.

28. The presence of some ancient lava fields on the planet’s surface suggests that there was some volcanic activity on Mercury in the past.

29. As per the observations made and data collected by the scientists, mercury has shrunken in size. It has lost 1.5 km of its diameter since its formation. This is mainly due to the solidification of its core as it cools down.

30. Mercury is also a tectonically active planet like Earth. As the core cools down, it causes changes in its surface and produces scarfs and cliffs.

31. “BepiColombo” — named after a famous Italian mathematician and scientist – Giuseppe (Bepi) Colombo (1920-1984) — is ESA’s mission to mercury that will be launched in 2018. The multi-spacecraft mission will take at least 7 years to reach its orbit around Mercury. This will be a joint mission between Japan Aerospace Exploration Agency and ESA. During its journey to Mercury, the mission will see 9 flybys of Earth, Venus, and Mercury.

32. Scientists have imaged Mercury almost entirely with the help of the space crafts that were sent on various exploration missions.

33. Mercury is not tidally locked to the Sun. This fact is clear from the fact that it makes three revolutions on its own axis during the time it makes two revolutions around the Sun. Moon, however, is tidally locked to Earth as it takes the same amount of time to rotate on its own axis as it takes to revolve around the Earth.

Quick facts about Mercury

Date of discoveryUnknown
Discovered byKnown by the Ancients
Orbit Size Around Sun57,909,227 km
Mean Orbit Velocity170,503 km/h
Equatorial Inclination0 degrees
Equatorial Radius2,439.7 km
Volume60,827,208,742 cubic km
Mass330,104,000,000,000,000,000,000 kg
Density5.427 grams per cubic centimeter
Surface Area74,797,000 square km
Surface Gravity3.7 meter per second square
Escape Velocity15,300 km/h
Surface Temperatureminus 173 to 427 °C
Atmospheric ConstituentsNitrogen, Oxygen and others

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