30+ Mercury Facts Every Space Lover Must Know! (Free Printables)

Mercury is the smallest planet in our solar system and the nearest planet to Earth. It is also smaller than some moons in our solar system.

Though humans have observed this planet for more than 2000 years, little has been discovered about it compared to the other planets in our solar system.

Mercury cannot be seen easily due to its closeness to the Sun. Only it can be seen easily during the twilight of sunset and sunrise. So, in this article, we will now discuss some amazing Mercury Facts.

Interesting Mercury Facts

The Temperature on Mercury Varies Considerably

Many people think that Mercury’s temperature is really hot due to Mercury’s closeness with the Sun. However, Mercury’s temperature varies a lot during the day and night.

Mercury’s temperature during the day may reach 427 degrees Celsius. However, the temperature at night can hit -173 degrees Celsius. 

Mercury Has the Second-Largest Core After Earth

Planet Mercury has the second core after Earth in our solar system. The core of Mercury is completely molten and encompasses molten iron. In this core of Mercury, the available iron content can surpass any other planet’s iron content in our solar system.

On Mercury, One Year Lasts Just 88 Days

Mercury A Short Year

On Earth, one year is equivalent to 365 days. In contrast, on planet Mercury, one year means just 88 days. Moreover, one solar day on Mercury is equivalent to 176 days on Earth. So, 88 days is the fastest orbit of any planet located in our solar system.

Also, the sun’s rays hitting planet Mercury are about seven times stronger than Earth’s sun rays. Moreover, Mercury has a very slow rotation, requiring 59 Earth days to complete one rotation on its axis, meaning one day on Mercury is longer than a year on this planet. 

Mercury Is a Very Small Planet

Planet Mercury is very small, as its width is just 4878 km. This means this planet is a little bigger than the Moon of our Earth. However, before Mercury became the smallest planet, Pluto had this honor. However, later, Pluto was scratched from this list.

Furthermore, humans have known Mercury for more than 5,000 years. The Sumerians associated this planet with their god of writing, Nabu.

The Hubble Space Telescope Has Never Observed Mercury

The HST, or the Hubble Space Telescope, is a powerful device. It is used to find out almost invisible planets and the distance of planets in our solar system.

However, this telescope has never tried to observe Mercury and is not directed to do so because planet Mercury is too close to the Sun. Hence, any attempt to do so could damage the electronics and optics due to light.

The Gravitational Force on Mercury Is Very Low

Mercurys Weak Gravitational Force

Mercury’s gravitational force is much weaker than Earth’s gravitational force. This means if you weigh 38 kg on Mercury, you would weigh 100 kg on Earth.

Mercury also has the record for the highest temperature swing of any planet in our solar system. It can register a temperature swing of more than 1100 degrees Fahrenheit or 600 degrees Celsius daily.

How Planet Mercury Is Named

Planet Mercury is named after the Roman messenger god Mercury. This Roman god is often depicted with wings on his sandals and helmet, symbolizing his agility and speed.

In Greek mythology, the god Mercury was also known as Hermes. This planet’s symbol is a stylized version of the caduceus, a staff with two snakes that Hermes carried.

Mercury is a rocky planet with a heavily cratered surface and no significant atmosphere. It is just 36 million miles from the Sun.

Mercury Has a Magnetic Field

Mercurys Magnetic Field

Mercury has a weaker magnetic field than Earth. Mercury’s magnetic field is only 1% of Earth’s magnetic field.

However, in 2004, when MESSENGER was launched to Mercury, it revealed some interesting facts that indicated that one million years ago, Mercury’s magnetic field might have been much stronger, similar to Earth’s magnetic field.

Mercury Lacks an Atmosphere

Mercury lacks an atmosphere compared to Earth, so it cannot absorb or even keep any amount of heat from the Sun. This tells why Mercury’s temperature can plummet to -275 degrees Fahrenheit or -170 degrees Celsius.

Furthermore, as Mercury has no atmosphere, asteroids that come near this planet can strike this planet without any resistance. This results in the formation of large craters. 

The Caloris Basin Is a Massive Impact Crater on Mercury

The Caloris Basin is an example of a crater that resulted from the impact of an asteroid 4 billion years ago. It was 100 km wide and believed to have hit Mercury with a force of one trillion bombs, each with the power of one megaton.

This basin is 960 miles wide and can swallow up the entire Texas Estate.

Mercury Has a Long Tail of Particles

Mercurys Long Tail

According to many scientists, planet Mercury glides with a long tail resembling a comet. This tail of Mercury is composed of Sodium atoms and is constantly pushed off by the incredible pressure from the Sun’s radiation.

Mercury’s Surface Is Not Smooth

Earlier, people thought that Mercury’s surface was smooth. However, in the mission of November 1973, when the spacecraft Marine 10 passed near Mercury, some contrasting images were revealed.

According to those images, Mercury’s surface has so many craters that it can be called the most cratered planet in our solar system.

Mercury Can Only Be Seen While It Crosses the Sun’s Surface from Earth

Planet Mercury can be seen just once when it crosses the surface of the Earth. This phenomenon, known as transit, occurs only every seven years.

Moreover, ancient people believed they saw two different celestial objects when they saw Mercury twice daily. They didn’t know that they were seeing the same planet, Mercury, twice because Mercury orbits the Sun incredibly fast.

Mercury Spins Anticlockwise

Like other solar system planets, Mercury spins west to east or anticlockwise when observed from its north pole. Actually, Mercury’s axis is a lot vertical, contrary to the axis of Earth, which is tilted at 23.5 degrees. 

Observations from Mercury’s radar indicate that this planet revolves only once every 58.65 days. Thus, only three rotations of Mercury occur every two of its years, a relationship usually called a 3:2 spin-orbit resonance.

This phenomenon is thought to be caused by the difference in the gravity pull of the Sun on Mercury when this planet rotates.

Mercury’s Smooth Appearance Is Due to Its Lack of An Atmosphere

According to scientists, the smooth appearance of the northern plains of Mercury may be because of volcanic activities.

This part might have been covered with dried lava, which had smoothened the surface. However, today, there is no sign of volcanic activity on Mercury’s surface.

Mercury is also a planet that is not characterized by seasons. Its axis has the smallest tilt compared to any other planet in our solar system. Furthermore, according to several reports, Sumerians knew about Mercury from 3000 BC.

According to Astronomers, Its Craters May Have Ice

Many astronomers believe that Mercury’s craters contain ice. Mercury’s north and south poles are cold and shadowy, which could allow them to hold back water ice.

Also, they think that meteorites and comets could have transported ice and then dumped it in the craters, or water vapor that came from the interior parts of Mercury could have leaked out and frozen.

Mercury’s Core Is Liquid

Though small planets usually have solid nuclei, the core of planet Mercury is liquid due to the presence of Sulfur. Also, its orbit is the most elongated and tilted among all solar system planets.

Also, Copernicus was the first human to find out about orbiting Mercury in the 16th century. In contrast, Galileo was the first person to notice Mercury during the 17th century.

Only Two Spacecraft Have Visited Mercury

Mercury’s closeness to the Sun and good speed make visiting the planet difficult. Thus, till now, only two spacecraft, MESSENGER and Mariner 10, have visited Mercury.

Mercury’s thin atmosphere comprises 29% sodium, 42% oxygen, 6% helium, and 22% hydrogen; the remaining 1 percent comprises other components. Scientists call Mercury’s atmosphere an exosphere. 

Mercury’s Atmosphere Has Streams of Particles

According to scientists, Mercury has streams of particles that slough off its surface, similar to a comet.

They believe these things are produced when the sodium in Mercury’s atmosphere glows because sunlight excites them. Also, sunlight can free these molecules from the surface of this planet and push them away into space.

Mercury Has the Highest Density Among the Terrestrial Planets

The density of planet Mercury is the highest among all planets. Almost two-thirds of Mercury’s mass is contained in the iron core of this planet. This core extends from the planet’s center to a radius of around 1300 miles to its surface. 

However, this planet’s rocky outer shell, surface crust, and underlying mantle are just around 200 miles thick.

Therefore, Mercury’s unique position and interesting geological features make It a significant planet for studying the evolution and formation of the solar system and the procedures that shape the surfaces of rocky planets.

Mercury Facts
Free Mercury Facts Printables

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Free Mercury Facts Printables
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