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 it is not the largest or most famous like the rest of its peers, Mercury holds the keys to many secrets that may contribute to understanding the origin and development of the solar system. The challenges posed by the small planet, such as extreme temperatures and a thin atmosphere, stand as obstacles to space exploration and a deeper understanding of the nature and composition of Mercury.

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 consists of a high percentage of metal concentrated in its relatively massive core, which represents approximately 75 percent of Mercury's 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.

Mercury passes directly between the Earth and the Sun about twelve times every century. This event is called a transit, which is a type of eclipse, as the planet Mercury appears as a small black disc against the background of the bright Sun.

The orbit and rotation of the planet Mercury

Mercury orbits the Sun at a distance of approximately 58 million km. Like the rest of the planets, it revolves around the sun in an elliptical orbit, and its orbit is the most skewed or elongated and the most inclined among the planets, as the plane of Mercury’s orbit is inclined by 7 degrees with respect to the ecliptic or the plane of the Earth’s orbit, and Mercury completes one orbit around the sun approximately every 88 Earth days. That is, one year on Mercury 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 planet's distance from the Sun also varies greatly as it moves along its orbit. The furthest distance from the sun that Mercury reaches is about 70 million kilometers. At that stage of the planet’s orbit, it may be seen that the sun appears about twice its size from Earth, and the closest distance from the sun that Mercury reaches is about 46 million kilometers, where the sun will appear at that stage 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 or seasons on the planet Mercury, because Mercury’s axis of rotation is very perpendicular or perpendicular to the plane of its orbit, and compared to the planet Earth, the Earth’s axis tilts by approximately 24 degrees. This tilt is the main reason for the existence of seasons on Earth.

Atmosphere, internal surface, and climate

Mercury does not contain an atmosphere or a thick layer of gases surrounding it, unlike other planets. The pressure on the surface of Mercury is less than a trillion times the pressure on the surface of the Earth. The layer of very weak mercury gases includes atoms of helium, hydrogen, oxygen, sodium, potassium, calcium, magnesium, and sulfur, where the heat of the sun drives them away. The gases remain near the planet and are partly replenished by the solar wind and a stream of charged particles from the Sun. Other gases come from asteroids, comets, and from the planet's surface.

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

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.

The internal structure of the planet Mercury is similar to the structure of the Earth, as Mercury contains three separate layers: a metallic core in the center, a middle rocky layer called the mantle, and a thin rocky crust. In all planets, the core is mostly made of iron, and Mercury’s core is relatively larger than the Earth’s core, as the core occupies about 61 cm. percent of Mercury's volume compared to only about 16 percent for Earth, and this explains the large density of Mercury.

Observing and exploring the planet Mercury

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

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 planet Mercury. In 2016, scientists released the first global digital elevation model 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 Mercury's equator, 4.48 km above the planet's average elevation, while the lowest point is in the Rachmaninoff Basin, the suspected location of some of Mercury's 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.