On May 6, the Aquariids, with the "blood" of Halley's Comet, will usher in a maximum period, and the zeni η th is expected to appear up to 50 per hour, and it will not be affected by the moonlight, and the viewing conditions will be better. Since the constellation Aquarius, where the meteor shower's radiant is located, rises before dawn, the mainland public can observe it in the second half of the night from the 3rd to the 7th.
With the naked eye, the meteors we see across the sky seem to be white. But did you know that meteors actually come in many different colors? "When a meteoroid rapidly breaks into the Earth's atmosphere, friction with the atmosphere causes it to heat up, and some elements emit specific wavelengths of light when burned at high temperatures, thus revealing their characteristic colors. Wang Kechao, director of science popularization at the Purple Mountain Observatory of the Chinese Academy of Sciences, said that the chemical composition of the meteor itself is an important factor affecting its color. In addition, when a meteor passes through the atmosphere, the atmospheric oxygen and nitrogen in its path also emit a specific wavelength of light due to heat, adding color to the meteor.
Sodium in meteors glows orange-yellow, iron glows yellow, magnesium glows blue-green, calcium may add a purple hue, and atmospheric nitrogen and oxygen glow red. For example, the Perseid meteor shower, known for its brilliant colors, often has bright, fast meteors, with green or reddish colored meteors in addition to white meteors. Meteors η Aquariids are usually blue-green in color, which is due to the burning of magnesium in the meteoroids.
The chemical composition of a meteor is not the only factor that determines its color, the speed at which it enters the Earth's atmosphere also affects its color. Wang Kechao said that the faster the meteor has more kinetic energy, which will enhance the color effect of the meteor. Meteors that are fast will start to glow at high altitudes and change color at low altitudes. For example, the Perseid meteor shower first emits green light high in the thin atmosphere, and when it reaches the lower part of the atmosphere, oxygen and nitrogen dominate, resulting in a red color at the end of the meteor. Slow meteors, on the other hand, generally do not begin to shine until low altitudes, and their color is generally reddish.
Although most of the time it is impossible to distinguish with the naked eye, we can still see the color of the meteor by taking pictures with a digital camera or a spectrum. The easiest way to shoot spectroscopy is to insert a prism in front of the lens to get the spectrum of a meteor.
Source: Xinhua News Agency