Learn the secret of Mercury formation

Being the closest planet to the sun, Mercury has an extremely harsh surface climate.

>>>Discover Mercury from Messenger spacecraft

Among the planets in the solar system, Mercury suffers the most miserable fate. Only about 4,880km in diameter and in 4.5 billion years of existence, it constantly burned under the heat of the sun. This star is only about 58 million kilometers from the sun.

Mercury (black dots) is too small and very close to the sun.

The environment is extremely harsh and the barren surface on Mercury is far from Earth. Except for the three approaches of the Mariner 10 in 1974 and 1975, no other NASA satellite survived and sent home signals. Until March of this year, NASA's Messenger probe launched in 2004 approached Mercury's orbit and began surveying the planet for at least a year. Last week, the latest information about Mercury was published in the Science newspaper and helped people better understand the mysterious world on Mercury.

Compare the size of Earth, Mercury and the moon.

Although Mercury looks outwardly similar to the moon, the environment on the surface is very harsh. The huge impact of the solar gravity makes Mercury spin very slowly. According to the latest report, during the first rotation around the sun, Mercury only turns around it 3 times. The sun-facing surface of this planet has a temperature of up to 510 ° C, while the back surface is 210 ° C negative. Its core is also very special, metal and has a diameter greater than its own radius. While the Earth's core only accounts for 9.5% of the diameter.

Mercury's core is huge compared to the planet itself.

The special structure of Mercury can be explained as follows: it used to be as large as Venus or Earth, but because the distance is too close, it has been gradually blown away by the sun. Or there is another theory that collisions with meteorites have caused the surface of Mercury to wear out a lot. But Science has recently suggested new theories.

The Mercury survey of Messenger ships includes the use of gamma rays and X-rays to analyze its surface material. The key element that scientists are looking for is potassium and thorium. Both of these elements are abundant in the solar system, but they are also very volatile and can only exist in certain conditions. Temperature is one of the factors that make potassium and thorium the most volatile.

Both hypotheses were subjected to heat and abrasive meteorites, both based on predictions that Mercury had a surface temperature of 3,200 ° C. At this temperature, potassium and thorium both evaporate, uranium is also burned, combined with oxygen to produce UO ₃ . But Messenger ships deny this. The proportions of Mercury's elements are very similar to most other planets like Venus, Earth and especially Mars.

These volatile elements are separated in the face and help scientists come up with another theory: the dispersion of elements causes the surface of Mercury to be eroded. Scientists have studied data from gamma rays and X-rays, suggesting that this surface erosion comes from volcanic eruptions of volatile materials on the surface. Over time they evaporate and create huge holes that satellites can observe from outer space.

The surface of Mercury has many large holes and volcanoes.

'This supports the hypothesis that Mercury contains an abundance of volatile substances, and rejects other theories about its formation.' In other words, it is not possible to hypothesize that collisions with meteors and surface scorching heat.

Another Science article also revealed new information: Mercury has the same magnetic field as the Earth, but is weaker, and its magnetic pole deviates 3 degrees from the geographic axis. It also has enough particles to charge itself, but its magnetic field is not strong enough to produce a phenomenon similar to the Earth's Van Allen belt. The northern hemisphere of Mercury is formed by volcanoes, indicating that the geographical activity on this planet is stronger than we thought.

These new findings are making the research very eager, especially the puzzle solving process of Mercury formation. Still more information is needed from Messenger to get to the final conclusion. All are still at the hypothetical level, and if they are all wrong, we have to find a backup hypothesis.

It is a case of frequent occurrence in science, an old argument collapsed but it is unlikely that there has been a new argument to replace it. This does not mean we fail, just a new step in finding knowledge.