Mercury’s Atmosphere | Mercury’s Surface
With a diameter of 4876 km, Mercury is only slightly larger than our Moon (3476 km) and is therefore unable to maintain a noticeable atmosphere due to the low force of gravity. Directly on its surface, at the site of greatest gas density, there is a pressure only 2 • 10⁻¹³ times that of terrestrial atmospheric pressure. Due to its almost complete disappearance, we have an unobstructed view of the surface of Mercury, as is the case with our Moon.
As can be seen here in the southwestern part of the planet, it is littered with impact craters that resulted from a bombardment in which all the planets were exposed in the early stages of the Solar System. A walker on the surface will see strange things because of the strange rotation: First, the sun normally rises over the horizon. But here it stops and moves backwards again towards the horizon. Here it stops again and then wanders very rapidly towards another horizon.
Mercury’s atmosphere is made up of a ratio of hydrogen, helium, oxygen as well as sodium and potassium. These elements are certainly not remnants of an earlier atmosphere; Rather, hydrogen and helium are particles trapped by the solar wind. While sodium and potassium are probably leached out of surface minerals by the solar wind, helium can also come from radioactive decay of the rock.
In one cubic centimeter of the atmosphere we find 8 hydrogen atoms, 4,500 atoms of helium and 150,000 atoms of sodium, some of the element potassium. As the lightest elements, hydrogen and helium are filled with relatively high thermal speeds and are therefore very unstable, i.e. they quickly escape into space. On the other hand, sodium and potassium have longer residence time on the planet.
According to NASA, the chemical composition of the atmosphere of the planet Mercury is considered to be the following :- 42% oxygen (O 2 ), 29% sodium, 22% hydrogen (H 2 ), 6% helium, 0.5% potassium, and possibly argon, carbon dioxide, water, nitrogen, xenon, krypton, neon, calcium (Ca, Ca +), and magnesium.
The reason for Mercury’s such atmosphere is the long temperature range found on its surface. Which is a minimum of -180℃ to a maximum of about 430℃ which is more than the temperature range present on the surface of any other planet. The reason for the high temperature of the surface of Mercury facing the Sun is insufficient atmosphere.
Due to which or unable to absorb solar radiation. The reason for the low temperature of the surface on the other side of Mercury that is not in front of the Sun is also due to the lack of sufficient atmosphere, due to which the surface of Mercury does not hold the heat received by the Sun and releases it back into space.
Surface of Mercury
Until 1974, the surface of the planet Mercury remained a mystery to scientists because Mercury was so close to the Sun. Being so close to the Sun, the time to see the surface of Mercury is only just before dawn or just after dusk. But at this time the angle of view of Mercury from Earth is made. In between, a lot of the Earth’s atmosphere goes. Which obstructs the view of the surface of Mercury.
But in 1974, a spacecraft named Mariner 10 captured clear and stunning pictures of the surface of Mercury during three flybys of the planet Mercury. Amazingly, Mariner 10 captured only about half of the surface of Mercury during its mission. It was discovered that the surface of Mercury has mainly three important features.
- The first feature is the sheer number of craters that have been accreted over billions of years on Mercury. The Caloris Basin is the largest of these craters with a diameter of 1,550 km.
- The second feature is the plains found between the craters. These are smooth areas of the surface. which may have been formed from lava flows.
- The third feature is rocks that are tens of thousands of kilometers long and 100 meters to 2 kilometers high.
The presence of lava fields in the planet Mercury suggests that there must have been volcanoes in the planet Mercury at one time or another. From the number of craters present on the planet Mercury and their age, scientists deduce that Mercury must have been geologically inactive for a long period.
The scarves found on the surface of Mercury are giant rocks. These rocks are formed due to buckling in the crust of Mercury. Buckling on Earth is caused by the movement of tectonic plates, while buckling on Mercury is caused by the shrinking of its core. Recent estimates suggest that the diameter of Mercury has exceeded 1.5 kilometers.