Perihelion Day 2024: When Earth is closest to the Sun | All you need to know about astronomical event

Perihelion Day 2024: This year has just started and we are already set to observe the first astronomical event in January. Though January is packed with spectacular astronomical events, this event will mark the onset of galactic dance. Our planet Earth will make its closest approach to the Sun on January 3, which is called Perihelion Day.

The term “perihelion” is a Greek word that refers to the point in the orbit of a planet or any other astronomical body, at which it is closest to the Sun. “Peri” means around and “helios” means the sun in Greek. The opposite of perihelion is aphelion - a point where an orbiting body is farthest from the Sun.

Here’s more you need to know about the day:

What is Perihelion Day?

The orbit of Earth is not a perfect circle but an elliptical one. It revolves around the Sun in this elliptical path and completes its revolution. As Earth’s orbital velocity decreases it moves away from the Sun, as the Earth does. It travels at its slowest speed as it approaches the farthest point from the Sun, i.e. aphelion.

It accelerates as it begins to move back towards the Sun. Earth then travels at maximum speed as it approaches the closest point to the Sun, or perihelion, almost defying the Sun’s gravitational pull. It is then eventually overpowered by the Sun’s force and falls back into its normal cycle.

However, the process is never exactly repeated and that is why the date for the occurrence of Perihelion Day also keeps changing from year to year.

When is Perihelion Day in 2024?

Perihelion Day generally occurs in early January of every year, which is almost two weeks after the December Solstice. For 2024, our Earth will make its closest appearance to the Sun on Wednesday (Jan 3) at 1:00 UTC.

Early January will see Earth approximately 3 per cent closer to the Sun than early July when Earth is at its aphelion. Thus, during the first part of January, when winter is in the northern hemisphere, Earth comes closest to the Sun annually.

For your understanding, here is a quantification of the perihelion and aphelion of Earth in 2024. It will be 91,404,095 miles away from the Sun at perihelion and 94,510,539 miles away from the Sun at aphelion. So, Earth is about 4,800,000 km (3,000,000 miles) farther from the Sun in July than in January. Isn’t that fascinating?

(With inputs from agencies)