When is the sun closest to us?

1.4438+0000000 km At the beginning, the earth is closest to the sun, which is called perihelion. At the beginning of July, the farthest distance of the earth from the sun was 65.438+0.52 billion kilometers, which was called apohelion. In fact, when the earth is at perihelion, it is winter in the northern hemisphere and summer in the southern hemisphere, and it is summer in the northern hemisphere and winter in the southern hemisphere when it is at aphelion.

The revolution speed of the earth is fast at perihelion and slow at apohelion. For the lunar calendar, perihelion is the hardest place to have a leap month. At perihelion, the solar radiation received by the earth is stronger (closer), and the average temperature of the whole atmosphere of the earth reaches the highest in the whole year at 65438+ 10. But the lowest temperature is not at apohelion, but in 10 month (occasionally in September).

Extended data

Proximal precession:

Due to the perturbation of other planets (mainly Jupiter), the perihelion of the earth's orbit also precesses, with a period of about 265,438+0,000 years and an annual period of about 65,438+0.03', which means that the earth reaches perihelion one day later every 58 years. For example, in 65,438+0,250 AD, the time for the earth to reach perihelion was near the winter solstice, but now it is every year.

In the long run, although the precession of perihelion is small, it is also one of the important factors that cause the cold and warm changes of the earth's climate. 1930, Yugoslav astronomer Milankovic proposed that the climate change in geological period was related to the change of inclination angle of the earth axis, eccentricity of the earth orbit and perihelion position.

Baidu encyclopedia-perihelion