What is the Smallest Planet in the Solar System

What is the Smallest Planet in the Solar System

Four small planets make up the solar system: Mars, Venus, Mercury, and Earth. Since these stars are all less voluminous, they also have very distinct and unique characteristics. But Mercury is the smallest planet in the solar system and is close to the Sun. Indeed, it should be pointed out that the galaxy is home to giant planets, including Uranus, Jupiter, Neptune, and Saturn.

Generally, children often ask their parents about the smallest planet. However, they sometimes do not have the answer. Already, the eight planets that make up the solar system are Jupiter, Mars, Earth, Neptune, Venus, Uranus, and Saturn. And all these space bodies are not the same size.

Mercury, the smallest planet: why?

For a long time, everyone believed that the solar system had nine planets. And the small planet at the edge of the galaxy, called  Pluto, was considered the 9th planet. Indeed, Pluto is small, but it is surrounded by satellites. So many people saw it as a planet. As researchers studied it, they realized it wasn’t actually a planet. Consequently, “Pluto was reclassified in the category of dwarf planets  ”.

By classifying the planets in ascending order according to their size, the established list gives Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, and Jupiter. Since Pluto is no longer an official planet, Mercury is now given the title of the smallest planet in the galaxy.

Mercury: the origin of the name, structure, and surface

The name of this planet comes from the Roman god called Mercury, the swift envoy of the deities, the equivalent of Hermes in Greek mythology. This is because Mercury completes a complete orbit of the Sun in 88 days, faster than any other asteroid or object in the solar system. Furthermore, a year on this planet is equivalent to less than three months on Earth. The rapidity of this rotation prompted the Romans to attribute the name of Mercury to this small planet.

The structure of Mercury

Besides, Mercury is one of the rock stars of the solar system. Its surface is identical to that of the Moon, as it has a considerable mass and several craters. Note that these were formed following the impact of meteorites, blocks of rock or metal, on Mercury. Very large impact basins that have formed include Rachmaninoff (306 km in diameter) and Caloris (1,550 km in diameter). From the point of view of its size, Mercury is very heavy because of the iron core that composes it.

Mercury: composition and temperature

This dwarf planet consists mostly of iron. It has two cores, one internal and the other external, formed of liquid metal, and covered with a mantle and a crust, like the Earth. Its inner core is massive with a size comparable to that of the Earth, although it is smaller.

On the other hand, instead of a full atmosphere, Mercury has an exosphere. NASA explains that the formation of the celestial body’s exosphere resulted from solar winds and meteor collisions that shattered its surface with atoms. This exospheric layer provides Mercury with weak protection against bodies such as asteroids. It contains 22% hydrogen, 0.5% potassium, 29% sodium, 6% helium and 42% oxygen.

Measurements concerning the small planet

The dwarf planet Mercury, with a radius of 2,440 km, is just over a third the size of Earth. If the globe were as big as a nickel, then Mercury would be the size of a blueberry.

Mercury is the closest planet to the sun. Being 58 million kilometers from the Sun, the small Mercury has located about 0.4 astronomical units from the Sun. You should know that an astronomical unit (AU) corresponds to the distance between the Sun and the Earth. With this distance, the sun’s rays only take three and a half minutes to pass from the Sun to Mercury.

Since Mercury is near the sun, some speculate that the heat characterizing the dwarf planet would be high. Unfortunately, unlike Earth, it does not have an atmosphere that can trap and retain heat. The side opposite the sun is therefore constantly cold.

Orbit and rotation of the small planet

With its very eccentric ovoid orbit, Mercury moves 70 million km away from the Sun and approaches it at 47 million km. “This star orbits the Sun once every 88 days,” according to momes.net. It thus crosses space at a speed close to 47 km per second, faster than all the other planets.

Mercury is a retrograde planet.

Mercury’s rotation slowly follows its axis and is once in 59 Earth days. However, as Mercury moves at an accelerated rate in the elliptical orbit around the Sun, each revolution of the satellite is not accompanied by sunrise or sunset. This situation also occurs on other planets. Moreover, Mercury’s axis of rotation is tilted only 2 degrees in the direction of its solar orbit. This means that the star rotates almost vertically without experiencing seasons like many planets.

Mercury retrograde: what is it?

Mercury retrograde occurs when the star seems to move backward across the sky but does not. This optical illusion is explained by the perspective that men have of looking at the smallest of the planets, which compete with the Earth by revolving faster around the sun. Although some astrologers see Mercury retrogrades as disruptive events in everyday life on Earth, there is no scientific evidence for this.

What resemblance between comets and the small planet?

It would seem that Mercury shares a certain affinity with comets, given that it sports a luminous tail. What’s more, it is almost devoid of atmosphere. It’s very low mass (5.5% of the Earth’s mass) and its slight magnetic field mean that it does not benefit from the same gravity as the Earth.

Does Mercury have a resemblance to Comets?

With regard to comets, it should be noted that the ice they contain sublimates as these objects approach the Sun. From the body of the comets will then escape the dust, which solar radiation in the form of a long tail will then project. At the same time, the magnetic force exerted by the solar wind will shape the gases emitted by comets. Therefore, the tail does not appear because of their movement, their approach to the Sun. And obviously, the same observation was made about Mercury.

Is there life on Mercury?

Science still doesn’t know much about the planet Mercury. However, there is no reason to believe that this planet can harbor life. NASA believes that Mercury’s cold and hot temperatures, as well as its exposure to sunlight, are too high for living organisms. Additionally, thanks to space rockets like MESSENGER, “Several areas of Mercury’s surface have been captured in 98% detail,” says MESSENGER’s website.

Also Read: 10 Best Space Movies to Watch in 2022

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