Today (3rd), the earth moves to perihelion, which is the moment when the earth is closest to the sun this year. At 8:38, what people see is the "biggest sun" of the year.
Today we have the "biggest sun of the year"
The earth revolves around the sun in an elliptical orbit. At 8:38 on January 3, the earth reaches perihelion, and the distance between the sun and the earth is about 0.983 astronomical units, which is smaller than the average distance from the earth to the sun. , approximately 147 million kilometers. At this time, the apparent diameter of the sun is 32 arc minutes and 31 arc seconds. The surface of the sun that people can see is the largest this year, so it is called the "largest sun of the year." The apparent diameter of the sun is about larger than that of the Earth on July 5 this year. It is 3.4% larger when passing through aphelion. The distance between aphelion and perihelion is about 5 million kilometers.
However, for the northern hemisphere, when the earth reaches perihelion, the direct point of the sun is in the southern hemisphere. The sunlight shining on the ground in the northern hemisphere has a large inclination angle, the sunshine time is short, and the overall solar heat received is less, so the temperature is lower and the weather is cold. . Every year after the "biggest sun of the year" appears, the Xiaohan solar term comes one after another, and people also usher in the coldest time of the year.
The Quadrant Meteor Shower will usher in a huge event tomorrow. In the January night sky, all winter constellations have appeared. Orion, Taurus, and Gemini form the core of the night sky. It is a suitable season for enthusiasts who like to observe deep sky objects.
On January 4, the Quadrantid meteor shower will have its maximum. As one of the three major meteor showers in the northern hemisphere, the Quadrantid meteor shower has received far less attention than the Perseid and Geminid meteor showers due to factors such as its short maximum duration and cold weather. In the past, the maximum flow of the Quadrant meteor shower could reach more than 120, but in the past two years it has been less than 100. The maximum flow this year is expected to be only about 80. In addition, this year's maximum time falls at 17:00 on the 4th in my country, and the radiation The point reaches its highest in the second half of the night, so it can be said that our country has missed the best observation opportunity for this meteor shower. In addition, there is interference from the last quarter moon in the second half of the night. Therefore, it is not recommended that everyone stay up late to observe this year's Quadrant Meteor Shower.
Double stars accompanying the moon will appear in the early morning of January 9th
In the early morning of January 9th, in the southeast before dawn, there will be a waning moon and several bright stars worth watching. The moon phase at this time is a thin waning moon, which is very beautiful.
To the north of the moon is the shining star Venus, which is very conspicuous. If you are in a relatively open southwest location, you can also try to look for Mercury to the left of the moon. At this time, Mercury is close to the western elongation and the horizon is high, which is also the most suitable time for observation. (Source: CCTV News)
Editor in charge: Weiye
Proofreader: Wang Lei
