Which Planet is the Smallest?

Mercury is the smallest planet by both mass and volume.

The solar system is made up of eight planets which are grouped into terrestrial (Venus, Mercury, Earth, and Mars) and the giant planets (Uranus, Saturn, Neptune, and Jupiter). Six of these worlds are orbited by natural satellites while they all revolve around the sun. The surface of Mercury resembles that of the Moon with extensive plains and cratering which means that it has been inactive for thousands of centuries. The biggest planet in the solar system by volume and mass is Jupiter while the smallest is Mercury. The best way to measure the size of something is by estimating its volume and how much matter it has.

What Is the Mass and Size of Mercury?

With a mean radius of 3031.67 miles, Mercury is the smallest of all the planets in the solar system. Mercury is equivalent to 38% of the Earth’s size, and since it has no flattened poles, it is entirely spherical. The radius of Mercury is the same at the equator as it is at the poles. The diameter of Mercury is 2.5 times smaller than that of the Earth. Although it is smaller than some of the natural bodies in the solar system like Titan and Ganymede, Mercury is way more extensive. Mercury is twenty times less massive than planet Earth. The size of Mercury is closer to the size of the Moon than Earth.

What Is the Density and Volume of Mercury?

Mercury is way denser than some of the planets in size. Mercury has the 2nd highest density of 338.8 pounds per cubic feet right after Earth with a density of 344.3 pounds per cubic feet which results in a 0.0023 miles per squared second gravitational force. The gravitational force of Mercury is 0.38 times that of Earth which means that if you stand on Mercury, your weight will be 38% heavier than you would be on Earth. Mercury's volume is approximately 0.056 times smaller than the Earth's volume.

What Is the Structure and Composition of Mercury?

Mercury is a terrestrial body which is composed of metals and silicate minerals. The metals are differentiated from the crust, silicate mantle, and metallic core. In comparison to other planets, Mercury has an oversized centre with a radius of 1,118.5 miles which occupies approximately 42% of the volume of the Mercury. Mercury’s core has high iron content as compared to the all the planets, and there are numerous theories proposed to explain the iron content. One of the most accepted hypothesis states that Mercury was once very large, but it was affected by the planetesimal which reduced most of the original mantle and crust leaving only the main components of the core.

Another theory stipulates that this planet might have been created from the solar nebula before the stabilization of the energy output of the Sun. Initially, it was twice its current size, but as the protosun reduced in size Mercury was vaporized by the high temperature thus forming the rock vapour atmosphere which was blown away by the wind. Another theory stipulates that the nebula caused a drag on the particles from which this planet was accreting, which meant that Mercury did not gather the light particles.

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