The Earth is going through perihelion: what does that mean?

Planet Earth passes perihelion on Saturday January 4, 2025. But there is no need to scan the sky to understand what this expression means: even if the event is indicated in most astronomical calendars, there is no celestial spectacle to observe. So what is it all about?

What is perihelion?

The périhélie designates the point in the trajectory of an object at which its distance from the Sun is minimum. By extension, perihelion also designates the moment when the object reaches this point.

How far is Earth from the Sun? On January 4 at 2:28 p.m. (French legal time), our planet is approximately 147 million kilometers from the star, indicates the Institute of Celestial Mechanics and Ephemeris Calculation (IMCCE) — very precisely, 147 103 686 km.

When is Earth at perihelion?

The Earth is usually at perihelion around January 4. However, the precise date and time of his passage through this point vary slightly depending on the yearfor several reasons. This is particularly linked to the characteristics of our calendar. A calendar year of 365 days does not quite correspond to the time of one revolution of the Earth around the Sun – hence the existence of the leap year.

Are you wondering why we are in winter when the Earth is closest to the Sun during perihelion? Do not hesitate to read our article on the origin of the seasons (which are not explained by the distance between the Earth and the Sun, contrary to popular belief).

What is the difference between perihelion and aphelion?

The antonym of perihelion is aphelion, that is to say the point in the orbit of a body where its distance from the Sun is maximum: for the Earth, the distance from the Sun is then approximately 152 million kilometers.

The diagram above simplifies the Earth’s orbit around the Sun, to clearly show what perihelion and aphelion correspond to. Earth’s orbit around the Sun actually looks much more to a circle.

When is the Earth furthest from the Sun?

This year, aphelion will occur on July 3. Yes, Earth is furthest from the Sun in summer, when it is hottest (in the northern hemisphere).

Does perihelion exist on other planets?

Earth is not the only body that passes through perihelion and aphelion in the solar system. This is also the case for planets and dwarf planets. When our neighbor Mars passes perihelion, for example, it is about 206 million kilometers away. During its aphelion, the red planet is 249 million kilometers from the Sun.