When we talk about the mysteries of the solar system, Mercury stands out as one of the most surprising and surprising planets. This small constellation, which revolves around the sun at an amazing speed, represents a scientific challenge that continues to arouse the curiosity of scientists and researchers throughout the ages. Mercury, the smallest planet in the solar system, has a set of unique characteristics that make it the focus of interest for scientists and observers alike.

Although not as large or famous as its peers, Mercury holds the keys to many secrets that may contribute to understanding the origin and evolution of the solar system. The challenges posed by the small planet, such as extreme temperatures and a thin atmosphere, represent obstacles to space exploration and a deeper understanding of its nature and composition.

Discussing this article will give us the opportunity to explore more of the secrets of this small planet, starting with the history of its discovery and its unique physical properties, all the way to the challenges facing the mission of exploring it and learning about its role in the formation of the solar system. Thanks to the continuous efforts of researchers and engineers, we look forward to uncovering more secrets hidden by the planet Mercury and delving deeper into its understanding to contribute to our continued development of scientific and technical understanding of the universe in which we live.

Physical properties of the planet Mercury

Mercury is one of the inner planets closest to the Sun. The inner planets are also known as terrestrial planets or Earth-like planets. They are dense, rocky bodies much smaller than the outer planets of the solar system. It is also the smallest planet in terms of mass and diameter, as it is about 18 times less massive than Earth. With a diameter of about 4,879 kilometers, it is about a third larger than Earth's moon.

The solar system contains two larger moons, Jupiter's moon Ganymede and Saturn's moon Titan. However, it has been larger than the dwarf planet Pluto for about 75 years since Pluto was classified as a planet, where it is the second smallest planet.

Mercury is the densest planet in the solar system, followed by Earth, because it is made up of a high percentage of metal concentrated in its relatively massive core, which accounts for about 75 percent of its diameter.

The planet Mercury can be seen from Earth without a telescope, as it always appears close to the Sun at an angle of approximately 28 degrees. For this reason, the planet can only be seen near the horizon. At certain times of the year, the planet appears as the morning star just before sunrise, while at other times it appears as the evening star directly after sunset.

The planet Mercury passes directly between the Earth and the Sun about a dozen times every century. This phenomenon is called a transit, and it is a type of eclipse, appearing as a small black disk against the bright Sun.

The orbit and rotation of the planet Mercury

Mercury orbits the sun at a distance of approximately 58 million kilometers, and it orbits the sun like the rest of the planets in an elliptical orbit. Its orbit is the most eccentric or elongated and the most inclined among the planets, as the plane of its orbit is inclined by 7 degrees relative to the path of the sun or the plane of the Earth's orbit, and it completes one revolution around the sun approximately every 88 Earth days, meaning that one year on it takes about 88 Earth days.

Although Mercury moves along its orbit very quickly, it rotates slowly. It may take approximately 59 Earth days to complete one revolution around its axis, and it rotates on its axis only three times for every two revolutions it makes around the sun.

The distance of the planet from the sun varies greatly as it moves along its orbit. The maximum distance it reaches from the sun is about 70 million kilometers, and at that point in the planet's orbit we may see that the sun appears from Earth to be almost twice its size. The closest distance it reaches from the sun is about 46 million kilometers, where the sun will appear at that point to be three times its size from Earth.

What is even more surprising is that the Sun does not appear to be moving steadily across Mercury's sky. Its apparent speed may change depending on the viewer's location on the planet and the planet's distance from the Sun, and the Sun sometimes appears to reverse its path for a short period.

There are no seasons on Mercury because its axis of rotation is very perpendicular to the plane of its orbit. Compared to Earth, Earth's axis is tilted by about 24 degrees. This tilt is the main reason for the seasons on Earth.

Atmosphere, internal surface, and climate

It has no atmosphere or thick layer of gases surrounding it, unlike other planets. The pressure at its surface is less than a trillion times that at Earth's surface. Mercury's very tenuous layer of gases contains atoms of helium, hydrogen, oxygen, sodium, potassium, calcium, magnesium, and sulfur, which are pushed away by the Sun's heat. The gases remain close to the planet and are partly replenished by the solar wind, a stream of charged particles from the Sun. Other gases come from asteroids, comets, and the planet's surface.

It has a magnetic field similar in shape to Earth's, but much weaker and only about 1% as strong as Earth's. Its temperatures vary, as its proximity to the Sun makes it a hot planet during the day. Daytime surface temperatures exceed 800 degrees Fahrenheit (430 degrees Celsius) in parts of the planet, and because it lacks a thick atmosphere to trap heat, the planet cools dramatically at night, dropping to about -300 degrees Fahrenheit (-180 degrees Celsius) just before dawn. Its average surface temperature is about 332 degrees Fahrenheit (167 degrees Celsius).

The surface of Mercury is dry, rocky, full of craters, and somewhat similar to Earth's moon. It also has areas of flat and slightly rolling plains, and there are hundreds of long, steep slopes called cliffs that define the planet's surface.

Mercury's internal structure is similar to Earth's, with three separate layers: a metallic core in the center, a rocky middle layer called the mantle, and a thin rocky crust. As with all planets, the core is mostly iron, and its core is relatively larger than Earth's, occupying about 61 cm3 of its volume compared to only 16% for Earth, which explains its greater density.

Observing and exploring the planet Mercury

Mercury's proximity to the sun makes it difficult to observe from Earth. Moreover, the Hubble Space Telescope and other instruments orbiting Earth are too sensitive to be pointed close to the sun. Astronomers have used radar to study it, sending radio waves toward the planet and detecting and measuring the waves, which bounce back. The planet's proximity to the sun also presents challenges for space probes, which must deal with the intense heat and enormous pull of the sun's gravity. A spacecraft needs a lot of energy to enter orbit around it.

Among the discoveries about the planet Mercury are that the inner core of Mercury is much larger than previously thought and that the planet has shrunk a long time ago than previously thought. Evidence has also been found of the existence of volcanic vents and that the planet was geologically active even after the formation of the Caloris Basin 3.8 billion years ago.

In 2012, scientists discovered a group of meteorites in Morocco that they believe came from the Menakh. In 2016, scientists released the first global digital model of the altitude of Mercury, which combined more than 10,000 images acquired through the MESSENGER exploration mission. The model revealed the planet's highest and lowest points – the highest point is just south of its equator, at 4.48 kilometers above the planet's average altitude, while the lowest point is in the Rachmaninoff Basin, the suspected site of some of its most recent volcanic activity.

Currently, the mission is making trips through the inner solar system with a flyby of Mercury. The next science mission will begin in 2025 and is scheduled to last one Earth year or four Mercury years.

In conclusion

Amidst the magic and mystery surrounding the planet Mercury, this tiny world remains a landmark in astronomy and an inspiration to humanity. Despite its small size, it holds great secrets that arouse the curiosity of researchers and attract attention. Mercury is distinguished by its amazing brightness in the sky and its rapid movement around the sun, which makes it unique among the planets of the solar system.

In our article, we explored the salient features of Mercury, from the history of its discovery to recent studies that have expanded our understanding of this tiny world. From its complex surface terrain to its thin atmosphere, Mercury remains a source of wonder and wonder.

However, many secrets remain preserved deep within Mercury, and future studies will require more effort and dedication to understand them further. Mercury may hold secrets that may shed light on the evolution of the solar system and on the conditions that prevail in small, dim planets.

As a piece of the essence of the universe, Mercury must remain a continuous station for scientific research and space exploration. Through our understanding of this world, we understand more about the origin and evolution of planets, and thus about our origins and place in the vast universe.