When is the sun closest to us?

In early January, the Earth is closest to the sun, which is 147.1 million kilometers. This point is called perihelion. In early July, the earth is farthest from the sun, which is 152 million kilometers. This point is called aphelion. In fact, when the earth is at perihelion, it is winter in the northern hemisphere and summer in the southern hemisphere. When it is at aphelion, it is summer in the northern hemisphere and winter in the southern hemisphere.

The Earth rotates faster at perihelion and slower at aphelion. For the lunar calendar, the location near perihelion is the most difficult place for a leap month to appear. At perihelion, the earth receives stronger solar radiation (closer), and the average temperature of the entire atmosphere of the earth reaches the highest in the year in January; but the lowest temperature is not at aphelion, but in October (occasionally) will be in September).

Extended information

Perihelion precession:

Due to the perturbation of other major planets (mainly Jupiter), the perihelion of the Earth’s orbit also precesses. Phenomenon, the period is about 21,000 years, about 1.03' per year, which means that the earth reaches perihelion one day later every 58 years. For example, in 1250 AD, the earth reached perihelion near the winter solstice, but now it is January 3 or 4 every year. Arrive at perihelion on the day.

In the long term, although the precession of the Earth's perihelion is small, it is also one of the important factors causing changes in the Earth's climate. Yugoslav astronomer Milankovich proposed in 1930 that climate changes during geological periods are related to changes in the tilt of the Earth's axis, changes in the eccentricity of the Earth's orbit, and changes in the position of perihelion.

Baidu Encyclopedia-Perihelion