30 Essential Mercury Facts You Should Know!

In our Solar System, the planet closest to our Sun is Mercury. Being the closest planet, it revolves around the Sun way faster than any other planet in our entire Solar System.

But we believe that it’s a very common piece of information and most of us are aware of this. So, let us today embark on an incredible journey to learn 30 interesting Mercury facts.

Mercury Facts: 1-5

1. The name Mercury was actually given by the Romans. They actually named the planet after their messenger God who was considered to be very swift-footed.

2. This planet has been known to humans for at least 5,000 years. Sumerians associated the planet with their god of writing called Nabu.

3. Heraclitus, a Greek philosopher before the time of Socrates, strongly believed that Mercury as well as Venus revolved not around the Earth, but around Sun.

4. Mercury is the closest planet to Sun, and hence, its surface temperature during day can reach 450 degrees Celsius or 840 degrees Fahrenheit.

5. Unlike Earth, Mercury has no atmosphere, and hence, it is not capable of trapping any heat from Sun. This is exactly the reason why temperature of Mercury can fall to minus 170 degrees Celsius or minus 275 degrees Fahrenheit.

Mercury Facts: 6-10

6. The temperature swing of Mercury is the highest in entire Solar System. In a single day, the temperature of Mercury can swing more than 600 degrees Celsius or 1,100 degrees Fahrenheit.

7. Though the temperature on Mercury can reach up to 840°F during the day, this planet is still believed to have water ice on it. Radar observations in year 1991 revealed that the South and the North Pole of the planet may have ice deep inside the craters, because those areas always remain in shadow and are always cold.

8. There are two distinct possibilities for ice to exist in those places. Some astronomers say that the ice reached the planet through asteroids that crashed on it. Others believe that gas trapped at the planet’s interior somehow escaped but got frozen near the poles.

9. Because Mercury has no atmosphere, asteroids approaching the planet hit it without any restriction forming big craters. One such crater is known as Caloris Basin that was created some 4 billion years ago by an asteroid impact.

The asteroid is believed to have been around 100 kilometers or 60 miles wide and is thought to have hit Mercury with a force equal to that generated by 1 trillion bombs of 1 megaton each.

10. The Caloris Basin is roughly 1,550 kilometers or 960 miles wide and is capable of accommodating the entire Texas state.

Mercury Facts: 11-15

11. While Earth ranks first in terms of being the densest planet, Mercury isn’t far behind and is the second-most densest planet in our Solar System with a metallic core spanning between 3,600 and 3,800 kilometers or 2,200 and 2,400 miles.

12. The diameter of the metallic core is about 75% of the planet’s diameter. The outer shell of Mercury on the other hand is merely 500 to 600 kilometers or 300 to 400 miles wide.

13. Mariner 10, the first spacecraft to visit Mercury, made a stunning discovery. The spacecraft found that Mercury had its own magnetic field.

14. Prior to the discovery made by Mariner 10, scientists believed that only planets that have molten core and spin rapidly can have magnetic fields. Weirdly, Mercury completes one rotation (spins once around its axis) in 59 days (days as counted on Earth).

15. Mercury is only 1/3rd the size of Earth and scientists believed that Mercury’s core cooled off and was solidified long ago because of its small size.

Mercury Facts: 16-20

16. In 2007, however, radar observations from Earth found that the core of Mercury may still have molten mass, which in turn explains the presence of feeble magnetism of the planet.

17. The strength of the magnetic pull of Mercury is just 1% of that of Earth. However, it is interesting to note that the magnetic field of Mercury is pretty active.

Magnetic field produced by solar wind often touches Mercury’s magnetic field producing very powerful magnetic tornadoes.

These tornadoes are responsible for sending gushes of hot plasma solar wind to Mercury’s surface. Solar wind is nothing, but streams of charged particles ejected from the Sun.

18. Mercury’s crust is full of lobe-shaped cliffs. These can run for several hundred miles on surface and soar up to a mile high in air.

19. These cliffs were formed when the surface of Mercury cooled off some billions of years ago and shrank the overall size of Mercury by anywhere between 0.6 miles and 1.2 miles which is approximately between 1 and 2 kilometers. Because of the contraction, the surface crumbled and formed the cliffs.

20. Mercury completes one complete revolution around our Sun in 88 days (days as on Earth and are referred to as Earth days).

Mercury Facts: 21-25

21. Mercury travels around the sun at a speed of 180,000 kilometers per hour or 112,000 miles per hour. This makes Mercury the fastest planet in entire Solar System.

22. The orbit of Mercury is elliptical in shape. The closest the planet gets to the Sun is 47 million kilometers or 29 million miles. This closest point is known as Perihelion.

23. The greatest distance of Mercury from the Sun during one complete revolution is 70 million kilometers or 43 million miles. The farthest point is known as Aphelion.

24. When Mercury reaches its closest point to Sun, if anyone can stand on Mercury at that moment, the Sun will appear at least 3 times bigger than what it actually appears from Earth.

25. Sunrise and sunset, if observed from Mercury, are pretty odd. During sunrise, the Sun appears to rise and then set for some time and then again rise.

During sunset, the Sun will appear to set and then rise for a brief time period and then again set. This happens because of the weird elliptical orbit and also because of the slow rotation speed of the planet, which is 59 Earth days.

Mercury Facts: 26-30

26. We said that Mercury has no atmosphere. This is not entirely true. Mercury has an atmosphere which is extremely thin. This very thin atmosphere consists of 0.5% potassium, 6% helium, 22% hydrogen, 29% sodium, 42% oxygen and trace amounts of neon, krypton, xenon, nitrogen, carbon dioxide, water and argon.

27. Because of the weak gravitation of Mercury (approximately 38% of the gravitation pull of Earth), the gases from its atmosphere constantly escapes to outer space. However, solar winds keep replenishing the atmosphere.

28. The inner metallic core of Mercury is iron while the external shell is silicate.

29. One day on Mercury is equivalent to 58.646 ≈ 59 days on Earth.

30. The average distance maintained by Mercury from Sun is 57,909,175 kilometers or 35,983,095 miles.

Bonus fact: 13 times in every 100 years, Mercury can be seen traveling across Sun’s face. This event can be seen directly from Earth. The event was last seen on 9th of May, 2016.

That concludes our 30 interesting facts about Mercury. Do you have anything else to share? We will love to learn!

Sources: 1, 2, 3

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