Overview
Today, January 1st, Earth has reached perihelion, the point in its orbit when it is closest to the Sun. This astronomic event occurs once a year in early January as the Earth travels along its elliptical orbit around the Sun. At perihelion, Earth is about 91.4 million miles from the Sun, around 3 million miles closer than its farthest point, aphelion, in July.
While perihelion marks the closest proximity of Earth to the Sun, it does not directly impact temperatures or seasons on Earth. Seasons are determined by the tilt of Earth’s axis, not its distance from the Sun. However, perihelion aligns with the northern hemisphere’s winter, meaning the hemisphere tilted away from the Sun experiences slightly warmer winters and cooler summers.
This annual event offers a chance to understand Earth’s relationship with the Sun and how our planet’s tilted orbit shapes seasons and climate. As Earth begins its new revolution around the Sun, perihelion also serves as an opportunity to reflect on our planet’s intricate celestial motions and our place in space.
Lead Up to Perihelion
Earth’s orbit around the Sun is not perfectly circular, but elliptical in shape. This causes the distance between the two celestial bodies to vary by around 3 million miles over the course of a year. Earth reaches perihelion in early January when it is at the closest point to the Sun along its orbital path.
In the weeks leading up to perihelion, Earth slowly approaches its closest proximity to the Sun. During December, Earth orbits at an average of around 94 million miles away from the Sun. As the new year begins, our planet finally attains its minimum distance of 91.4 million miles from the Sun’s surface.
The exact timing of perihelion changes slightly each year, occurring roughly around January 2nd or 3rd. This year, Earth reached its perihelion point right at the start of 2024 on January 1st.
Explaining the Impact on Earth
Although perihelion marks Earth’s annual closest approach to the Sun, it has a negligible effect on the planet’s climate and seasons. Seasonal weather patterns on Earth are driven by the 23.5° tilt of its rotational axis, not variations in its distance from the Sun. The northern hemisphere is tilted away from the Sun during its winter months, resulting in less direct sunlight and cooler temperatures.
However, perihelion does subtly impact the contrast between seasons in each hemisphere. When the North Pole is tilted away during winter, perihelion slightly warms the cold temperatures. Six months later during summer, aphelion slightly cools the warmer weather. The opposite effect takes place in the southern hemisphere.
So while perihelion makes northern winters somewhat warmer and southern summers mildly cooler, its influence is minor compared to the solar exposure created by Earth’s axial tilt. Overall global average temperatures do not change dramatically between perihelion and aphelion. The 3 million mile difference only changes the sunlight received by about 6.9%.
| Season | Hemisphere | Effect of Perihelion |
|---|---|---|
| Winter | Northern | Slightly warmer |
| Summer | Northern | Slightly cooler |
| Winter | Southern | Slightly cooler |
| Summer | Southern | Slightly warmer |
Perihelion in History & Culture
The concept of Earth’s changing distance from the Sun has been studied by astronomers for thousands of years. Ancient Greek philosopher Parmenides was the first to propose Earth’s orbit as circular in the 5th century BC. Two centuries later, the Hellenistic astronomer Aristarchus of Samos put forth the first known heliocentric model of the universe, with the Sun at the center and a sphere of fixed stars.
In the 13th century AD, medieval Persian astronomer and mathematician Nasir al-Din al-Tusi developed the Tusi couple, a mathematical model that showed how linear motion could be converted into circular motion. This groundwork paved the way for Nicolaus Copernicus’s heliocentric model in 1543, which resonates with the modern understanding of Earth revolving around the Sun in an elliptical orbit.
Prior to modern astronomy, many ancient cultures charted the Sun’s annual cycle and made efforts to track the seasons. Several historical festivities and observances coincide with perihelion, including winter solstice celebrations around December 21. Some holidays, like the Roman Mithra and Persian Shab-e Yaldā festivals tied to the winter solstice, celebrate the renewal and victory of light over darkness.
These ancient traditions reflect humanity’s long effort to make meaning of Earth’s celestial dance and the corresponding ebb and flow of seasons. Modern science has since revealed the physical causes behind the planet’s orbital variations, giving new perspective on age-old astronomical phenomena like perihelion.
What Happens Next for Earth’s Orbit
As Earth passes its proximate perihelion point, it will continue orbiting the Sun at varying distances on its elliptical path. The planet’s velocity also changes along its orbit, faster when nearer the Sun at perihelion and slower when farther away at aphelion.
Over the next six months, Earth will traverse to the opposite side of its orbit, reaching aphelion on July 4th at a distance of 94.5 million miles from the Sun. As the planet travels outward, the northern hemisphere will transition from winter to summer. The south pole tilts increasingly toward the Sun, resulting in warmer temperatures.
When Earth arrives at aphelion in July, the Sun’s rays will strike the top half of the planet at their most direct angle. The northern hemisphere will be angled fully toward the Sun, bringing peak temperatures for the year. After six more months orbiting the Sun, Earth will return once again to its perihelion point in early January 2025.
Conclusion
On the first day of the year, Earth has attained its closest approach to the Sun for 2024. This regular event is the result of our planet’s oval-shaped path around the main source of light and life in our solar system. Perihelion provides a chance to reflect on Earth’s cosmic motions governed by gravity and illuminated by sunlight.
Although perihelion only slightly affects seasonal contrasts, it holds significance in the history of studying Earth and its celestial dynamics. Ancient cultures observed the cyclical relationship between the Sun and seasons long before science charted the planet’s exact orbit.
As Earth orbits through another revolution, perihelion reminds us of the planet’s astronomical realities: the tilt that gives rhythm to the year, the elliptical path that shapes the seasons, and the centripetal force that holds worlds in delicate balance. Our planet follows its prescribed course around the Sun, turning through the cosmos as it has for billions of years past and countless more to come.
To err is human, but AI does it too. Whilst factual data is used in the production of these articles, the content is written entirely by AI. Double check any facts you intend to rely on with another source.
