2023-07-20 08:08:02
▲ Photo taken at a distance of 2,536 km from Mercury right following the European Mercury probe BepiColombo passed the closest point (236km). On the third flyby, we captured a stunning close-up image of the crater-filled surface. Launched in 2018, the joint European-Japanese Mercury exploration mission is approaching the final leg of a seven-year voyage through the inner solar system. BepiColombo is performing a gravity-assisted flight, flying by Earth, Venus, and Mercury to decelerate enough to transition from solar orbit to Mercury orbit in late 2025. BepiColombo’s next flyby is September 5, 2024. , followed by close flights in December 2024 and January 2025 to enter Mercury orbit. Bepi Colombo is named following Giuseppe Bepi Colombo, a 20th-century Italian scientist who developed navigation for space probes that are widely used today. This navigation, known as gravity assist, is a ‘planetary orbital approach and passage’ (Fly-by) technology that uses the planet’s gravity to change its course or speed. ▲ Graphic of Mercury probe BepiColombo flying by Mercury. ESA) BepiColombo consists of two probes: the Mercury Planet Orbiter (MPO) of the European Space Agency and the Mercury Magnetic Field Orbiter (MMO) of the Japan Aerospace Exploration Agency (JAXA). The two probes are expected to separate from 2026, each orbiting an elliptical orbit at an altitude of 480 to 1500 km, independently explore Mercury for one to two years, and then gradually lower the altitude to collide with the Mercury surface. The basic mission of BepiColombo is It is to photograph the surface of Mercury and analyze its magnetic field. It also analyzes the iron components that make up Mercury’s huge nucleus. Mercury is 64% iron. Scientists speculate that Mercury became a planet with a large core and a thin crust because a massive celestial body collided with Mercury and blew away most of the mantle. Which planet is Mercury closest to the sun?Mercury, the first planet closest to the sun For every two orbits around the sun, it rotates three times, with an orbital period of 88 days. It is also the smallest inner planet with a radius of 2,440 km and a circumference of 43,924 km. The average distance between Mercury and Earth is 77 million km, regarding half the Earth-Sun average distance. However, it is greatly affected by the sun’s gravity, its orbital speed is 47 km/sec, 1.5 times faster than Earth’s, and its surface temperature fluctuates between 400 degrees during the day and 170 degrees below zero at night. It’s not easy. ▲ Mercury, the first planet in the solar system, shows a tail like a comet. In the 1980s, studies predicting that Mercury would have a tail were published, and in 2001, Mercury’s tail was discovered for the first time. (Source: Sebastian Voltmer) Mercury is the most dense object among the planets in the solar system. The Earth’s density is numerically high, but in fact the interior is compressed due to its own gravity, whereas the volume of Mercury is much smaller than Earth’s and the interior is not so compressed. Such a high density of Mercury is due to the large internal core size , which means that the iron content contained in the nucleus is rich. Geologists estimate that the volume of Mercury’s core is 42% (compared to 17% for Earth), and recent studies have shown that Mercury’s core is molten. Despite its small size and slow rotation of 59 days, Mercury has a magnetic field. As a result of measuring the magnitude of the magnetic field of Mercury by Mariner 10, it was found that it is 1.1% of the Earth. ‘Yunseondo Crater’ with a diameter of over 70 km The surface of Mercury has many impact craters similar to the moon, and it is formed when the planet cools and contracts. cliffs exist. There is a little atmosphere, but the atmospheric pressure is very thin, one trillionth of the Earth’s. This is because gravity is too weak to hold the atmosphere in place. Therefore, there is no wind on Mercury. Numerous impact craters on the surface do not undergo weathering, so their shapes are preserved even following tens or millions of years. Overall, Mercury’s surface has plains similar to lunar oceans, and large craters that have been inactive for billions of years. From 4.6 billion years ago to 3.8 billion years ago, there was a period when comets and asteroids collided with the surface of Mercury, and this period is called the Late Great Bombardment. During this period, Mercury was heavily bombarded and the impact craters increased dramatically. This is because, unlike Earth, Mercury has a thin atmosphere, so the speed of the collider did not decrease. ▲ As a result of numerically simulating Mercury’s orbit, the eccentricity of Mercury’s orbit gradually increases, resulting in orbital resonance with Jupiter for the next 5 billion years. (Source/ESA) Also, volcanic activity was active during this time. That’s why the basin is full of magma. In October 2008, data from Messenger on Mercury’s surface were of great assistance to researchers. This data revealed that the surface of Mercury is more heterogeneous than that of Mars or the Moon. Mercury, which receives enormous energy as it is close to the sun, is a melting pot with an average surface temperature of regarding 452K (179℃), but the temperature change is very severe, ranging from regarding 90K (-183℃) to 700K (427℃). In other words, it is a planet that is both hot and cold. Nevertheless, surprisingly, in 1992, radar observations found water and ice in the north pole of Mercury. The ice is thought to have been water from comet impacts or ejected from Mercury’s interior, which was left at the bottom of a polar crater where sunlight didn’t reach for a year. The lack of air on Mercury actually helps to preserve the icy water. This is because there is little conduction of heat by air. Impact craters on Mercury range from small bowl-shaped holes to impact basins thousands of kilometers across. The states also vary, from newly formed craters to already heavily weathered craters. The largest crater on Mercury’s surface is the Caloris Basin with a diameter of 1,550 km. The impact on the basin was so strong that lava erupted and a concentric ring 2 km high spread out around the crater. In addition, 15 impact basins have been identified in partial images of Mercury. A notable basin is the 400 km wide Tolstoy Basin. The Beethoven Basin is regarding the size of an eruption canopy and is 625 km wide. There are also craters named following Koreans. It is Yunseondo Crater with a diameter of over 70 km. In the past, when naming planetary surface features, European names were often chosen, but as Korea became active in the global scientific community in the late 20th century, the number of cases in which Korean names were used as extraterrestrial place names increased. It is said that Mercury also has a topography named following Jeong Cheol, a poet and politician representing the mid-Joseon period. Because Mercury is tidally stationary, held by gravity by the sun’s strong force, it always faces the same side as the sun, just as the moon does to the earth. there is. However, in 1965, radar observations proved that it has a 3:2 orbital resonance effect, in which it rotates twice while rotating three times. Besides this, Mercury hides one more great secret. Numerical simulations of Mercury’s orbit show that as the eccentricity of Mercury’s orbit increases gradually, an orbital resonance with Jupiter will cause it to collide with the neighboring planet Venus in the next 5 billion years. In 5 billion years, the sun will be nearing the end of its life and will enter the stage of a red giant, and the earth will be heated by the sun and the seas will all evaporate and become charred. Lee Kwang-sik, science columnist [email protected]
1689842711
#이광식의 #천문학 #amazing #secret #Mercury #combines #cold #hot #water