Since ancient times scientists, astronomers, mathematicians and Greek philosophers have tried to find the right way to explain the movement possessed by the planets and stars the according as viewed from the Earth . One of these great scientists was Kepler who made Kepler’s laws stable. In his second law, he tells us about the different speeds at which the planets move and in this law mention is made of the perihelion that these celestial bodies have in relation to the sun.

What is perihelion?

It is known by the name of perihelion to the point at which a celestial object or an object in the solar system that is rotating around the sun is at the minimum distance from it.


Jonathan Kepler based his work and research on the laws of planetary movements or in other words, Kepler’s laws , these same laws are responsible for having provided the basis for Newton’s laws . Kepler was responsible for creating two of the most important terms used today within the scientific field , and these terms were the aphelion and perihelion , terms used to define the closest and farthest position that a certain planet has to the Sun respectively. The perihelion is also subject to Kepler’s first law which establishes aapproximately ellipsoidal motion of planets and other bodies around the Sun.

The dates on which the perihelion of the earth can occur are very changeable and diverse, but these changes are practically imperceptible because there are many orbital factors that make them go unnoticed. When the stage of perihelion, the Earth, is given sea or continents receive as much radiation as possible, but in the same way it can change depending on the cycles having the solar activity.

During the perihelion stage, the flow of energy is accompanied by a change in its spectrum, which basically lasts for the entire perihelion. The perihelion then consists of the point that is closest to the orbit that a celestial body has around the sun . It is represented by the letter q.


The word perihelion is considered according to its etymology as a masculine noun . This word is part of the field of astronomy and refers to a point, position or location that has the orbit of a planet that is closer, adjacent or contiguous to the sun . This term in its etymology is composed of the prefix “ peri ” of “ περι ” which has the meaning around and “ ηλιος ” or hēlios, a word that has the sun as meaning .

How perihelion influences the seasons

Perihelion is generally a phenomenon that always occurs in the vicinity of January 4 of each year. The distance between the Sun and the Earth usually does not change considerably throughout the year, however there are some differences that can be measured and considered with respect to the reception of heat from the Sun, which results in a consequence of the slightly elliptical orbit of our planet.

According to the sunlight that falls on Tterra during the month of January , in other words, during perihelion, it is approximately 7% more intense than that which falls during the month of July and added to this, the fact that the northern hemisphere has more land , while the southern hemisphere has more water , tends to contain the impact produced by the differences in sunlight received between perihelion and aphelion .

Sunlight causes the sun’s temperature to rise higher on continents than it does in oceans . In the month of July parts of the land located in the northern half of our planet are more inclined towards the sun.

The perihelion of the different planets

All the planets in our solar system vary according to their perihelion, these are the following:

  • Mercury : 0.31 AU
  • Venus : 0.718 AU
  • Earth : 0.98 AU
  • Mars : 1.38 AU
  • Jupiter : 4.95 AU
  • Saturn : 9 AU
  • Uranus : 18.37 AU
  • Neptune : 29 AU

This taking into consideration that AU is the average distance from the earth to the sun and that it is equivalent to 93 million miles or in other words, 150 million kilometers.

What happens to the structure of a comet at perihelion

What happens to the structure of a comet at perihelion will depend on the heat , radiation and effect produced by photons from the solar surface in the nucleus , producing the sublimation of ice and the ignition of the components that are in solid states and gaseous , causing the incandescence of the core and the formation of the tail , which is the trace of dust, iron, sodium and gases produced by the effect of solar radiation and heat. It also involves a modification in the structure and relief due to wear secondary to the formation of the glue.

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