The coldest place in the solar system was found in the crater of the moon.

According to the BBC, NASA used the divination instrument on the Lunar Reconnaissance Orbiter (LRO) to explore the interior of the crater that was always in the shadow on the moon. In the dead of winter, it found the coldest place in the solar system in the craters at the north pole of the moon, where the lowest temperature can reach MINUS 20 degrees.

Professor David Page, the main researcher of the "fortune teller" project, said: "In any celestial body in the solar system, the most extreme thermal environment includes the moon. At noon during the day, the temperature near the equator of the moon can rise to about 400 absolute temperature scale (127 degrees Celsius), while the polar nights are extremely cold. " Peggy introduced these latest findings in detail at the annual meeting of the American Geophysical Union in autumn. This is the largest meeting that earth scientists attend every year.

"Diviner" is one of many instruments carried by the lunar reconnaissance orbiter launched this year. It has been in operation since it started working in July this year. June 5438+this year1October, the spacecraft found itself in the best position to observe the summer solstice in the southern hemisphere and the winter solstice in the northern hemisphere. The moon has seasonal changes, but it is not obvious. The inclination of the moon axis is 1.54 degrees. So there is no difference in most parts of the moon, but as Pei Jie said, the angle between the polar horizon of the moon and the sun is relatively small all year round, with a change of about 3 degrees.

"This has led to great changes in the length and temperature of polar shadows," Pei Jie said. The lowest temperature observed by "fortune teller" in the darkest crater in Antarctica in summer is about 35 absolute temperature scale (minus 238 degrees Celsius). However, the results observed by the "fortune teller" show that the temperature at the southwest edge of the bottom of the "Hermite Crater" in the northern hemisphere is only 26 absolute thermometers near the winter solstice.

In some areas on the south side of the bottom of the "Piri" and "Bosch" craters, the temperature almost reached this level. The analysis results show that if we want to find such a cold place on the surface of another celestial body, we must go outside the Kuiper Belt, that is, outside the orbit of Neptune.

Peggy said: "To reduce the temperature to such a low level, all other possible heat sources must be removed. The craters in the polar regions of the moon can't get direct sunlight, and even the coldest places can't get indirect sunlight. Perhaps only some radiation from distant cliffs can reach these areas, and they will soon get cold. So these places will reach such a low constant temperature. "

This discovery strongly supports the view that there may always be water ice and some more volatile substances in some craters on the moon, and these more volatile substances even need colder storage temperature.