Perihelion Day

Celebrate Perihelion Day, the date on which our planet passes its closest point to the Sun in its orbit. The cosmos is multifaceted and fascinating, making it exciting to observe the phenomena taking place. Learn more about this unique holiday!

History

Scientists have learned to determine the moment of perihelion to the nearest minute, but it was quite difficult. The fact is that there is no straightforward way to determine the distance from the Earth to the Sun directly. Auxiliary calculations like measuring the solar disk won’t work because of constantly changing indicators, and goniometric tools do not provide the necessary accuracy. However, researchers found a way out by using Kepler’s laws, which state that the orbital speed of the planet is highest at perihelion (the closest point) and slowest at aphelion (the farthest point). On this date, the distance between the Earth and the Sun is approximately 147 million kilometers.

People often ask, “Will the phenomenon always occur in January?” The answer is no. Precession shifts the axis of rotation in space, causing the points of the solstices to slowly move in the direction of the Sun’s movement. The position of the perihelion also changes over time, sometimes falling in February, then in March, and so on. This process is incredibly slow: we, our children, and future generations will not live to see it.

Interesting facts

Curious moments about the Sun:

• Its diameter is hundreds of times greater than that of the Earth;
• Scientists believe that the star will use up its resources in about 5 billion years;
• It does not have a solid surface;
• Light and heat reach our planet in approximately 8 minutes;
• If viewed from space, it appears white. The yellow color is due to the influence of the atmosphere;
• The Earth’s core has a temperature similar to that of the Sun;
• 35% of people sneeze when looking at the Sun.

How to celebrate

Learn more about the phenomenon on Perihelion Day! This is a unique event observed by astronomers and laypeople from all over the world. Study literature or watch documentaries. Share information with friends and discuss it together. Throw a space-themed party!

When is Perihelion Day in 2025?

Perihelion Day is observed on January 4 each year.

Observations