Surface of the Moon is covered with dust. But this dust is very different from the dust we know on the Earth. It's lunar dust.
Our habitual dust formed as a result of erosion of different rocks by winds and waters. Its particles typically have smooth surfaces. Lunar dust formed as a result of impacts of meteorites, some of them were very large; they formed craters. But a huge number of them are tiny, like small grains of sand, or cosmic dust, moving at the relative speed from 10 to 40 kilometers per second. Eventually bombardment of these tiny meteorites splintered Moon rocks into dust.
Here, on Earth, these tiny meteorites never reach the surface. They burn up in atmosphere. We see them as meteors or shooting stars. The Moon also has an atmosphere, but it is very thin, it is almost like vacuum, and it cannot prevent even tiniest pieces of cosmic dust from reaching the surface.
Particles of lunar dust have very sharp edges. They resemble pieces of glass smashed with a hammer into tiny grains. The first astronauts discovered unpleasant properties of this dust. After walking on the Moon and before returning to the spacecraft they tried to clean dust from their spacesuits and their space boots, but it was practically impossible. Particles of dust stuck to the surface of their suits with their sharp edges and needles. Inside the spacecraft these particles started to flow into the air. When the astronauts took off the spacesuits, they breathed in particles of dust, which made tiny wounds in the respiratory tracts of astronauts causing a medical condition similar to hay fever. It was called the lunar hay fever.
Lunar dust may be the cause of mysterious glow that astronomers see sometimes above the surface of the Moon at the border between lunar day and night. Dust cannot flow in the air, because the atmosphere is so thin, that not only it cannot support particles of dust, but also its own molecules rarely bump against each other. Scientists believe that particles of dust may flow because of electric charges. On the day side the Moon gets charged positively by solar wind, on the night side it gets charged negatively. On the edge between day and night (which is rather sharp, because there is no twilights on the Moon) electric discharges may shoot particles of dust up above the surface, probably, by several kilometers.
Studying lunar dust is a part of the mission, which NASA launched in September 2013. By the end of October 2013 a robotic lunar orbiter reached the orbit of the Moon. It is called LADEE – Lunar Atmosphere and Dust Environment Explorer. It will circle the Moon at the heights between 75 and 25 km.
This is a small vehicle. Its initial mass was 383 kg, of which almost 140 kg was rocket fuel. Even though the atmosphere of the Moon is very rare, it still causes drag. In order to maintain the orbit and prevent the spacecraft from falling, rocket engines will be used. When all the fuel is used up, the vehicle will fall on the Moon and make a small crater on its surface. In total, the mission will last around 100 days.
From the BBC science and technology news.
November, 2013.
Our habitual dust formed as a result of erosion of different rocks by winds and waters. Its particles typically have smooth surfaces. Lunar dust formed as a result of impacts of meteorites, some of them were very large; they formed craters. But a huge number of them are tiny, like small grains of sand, or cosmic dust, moving at the relative speed from 10 to 40 kilometers per second. Eventually bombardment of these tiny meteorites splintered Moon rocks into dust.
Here, on Earth, these tiny meteorites never reach the surface. They burn up in atmosphere. We see them as meteors or shooting stars. The Moon also has an atmosphere, but it is very thin, it is almost like vacuum, and it cannot prevent even tiniest pieces of cosmic dust from reaching the surface.
Particles of lunar dust have very sharp edges. They resemble pieces of glass smashed with a hammer into tiny grains. The first astronauts discovered unpleasant properties of this dust. After walking on the Moon and before returning to the spacecraft they tried to clean dust from their spacesuits and their space boots, but it was practically impossible. Particles of dust stuck to the surface of their suits with their sharp edges and needles. Inside the spacecraft these particles started to flow into the air. When the astronauts took off the spacesuits, they breathed in particles of dust, which made tiny wounds in the respiratory tracts of astronauts causing a medical condition similar to hay fever. It was called the lunar hay fever.
Lunar dust may be the cause of mysterious glow that astronomers see sometimes above the surface of the Moon at the border between lunar day and night. Dust cannot flow in the air, because the atmosphere is so thin, that not only it cannot support particles of dust, but also its own molecules rarely bump against each other. Scientists believe that particles of dust may flow because of electric charges. On the day side the Moon gets charged positively by solar wind, on the night side it gets charged negatively. On the edge between day and night (which is rather sharp, because there is no twilights on the Moon) electric discharges may shoot particles of dust up above the surface, probably, by several kilometers.
Studying lunar dust is a part of the mission, which NASA launched in September 2013. By the end of October 2013 a robotic lunar orbiter reached the orbit of the Moon. It is called LADEE – Lunar Atmosphere and Dust Environment Explorer. It will circle the Moon at the heights between 75 and 25 km.
This is a small vehicle. Its initial mass was 383 kg, of which almost 140 kg was rocket fuel. Even though the atmosphere of the Moon is very rare, it still causes drag. In order to maintain the orbit and prevent the spacecraft from falling, rocket engines will be used. When all the fuel is used up, the vehicle will fall on the Moon and make a small crater on its surface. In total, the mission will last around 100 days.
From the BBC science and technology news.
November, 2013.
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