Earth has reached the point of maximum proximity to the Sun today


On Wednesday, January 3, the Earth reached its highest orbital speed around the Sun. In the early hours of the day, our planet and its star found themselves at the point of maximum proximity. This phenomenon, known as perihelionwill cause the average speed at which the Earth moves to increase by approximately three thousand kilometers per hour.

The distance of the Earth from the Sun varies depending on the month of the year in which it is measured. This is because the planet’s orbit is not a perfect circle with the star at the center, but is elliptical, with periods of maximum distance (aphelium) and maximum approach (perihelion). The average distance is 149 million km, but each year during aphelion it reaches 152 million km and decreases to 147 million km during perihelion.

Diagram showing Earth’s perihelion and aphelion.


Approaching and receding from the Sun affects the speed of the Earth’s movement. German astronomer John Kepler established in his famous laws that the gravitational pull of a star changes the speed of its reference planets. Specifically, Kepler’s second law suggests that a planet moves faster when it is closer to the Sun and slows down when it is farther away.

During perihelion, the Earth reaches its maximum speed of the year. On January 3, our planet will travel at a speed of 110,700 kilometers per hour sa an increase of 3,420 kilometers per hour over the annual average. Earth’s elliptical orbit and velocity fluctuations are key factors that explain why an astronomical year is exactly 265.2421 days long. I.e partially leading to a leap yeara mechanism that involves adding a day to February every four years to correct the discrepancy between the traditional year and the astronomical year.

The change in Earth’s speed during perihelion is significant from an astronomical point of view, but to most people acceleration is imperceptible. However, at the moment of maximum proximity to the Sun, it is possible to notice a change in temperature and changes in solar radiation.

Aphelion will arrive on July 5, 2024. According to the Spanish National Astronomical Observatory, at that moment the Sun will be 152.090 million kilometers from the Earth, whose speed will drop to 103.536 kilometers per hour.

But January also coincides with another important astronomical event. The early morning hours of January 4th will actually be the best time for sky watching Quadrantids, the first shooting stars of the year.

The article originally appeared on Wired en espa├▒ol.


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