Earth reached perihelion, its closest approach to the Sun for the year, on January 3rd, 2024. As our planet travels along its elliptical orbit around the Sun, perihelion marks the point where Earth passes about 91 million miles from the Sun’s fiery surface. This annual event holds no immediate danger for life on Earth, but does subtly impact our planet’s climate and seasons.
What Is Perihelion?
Perihelion is an astronomical event that occurs once per Earth year in early January. It marks the moment when Earth reaches the closest point to the Sun along its orbital path.
At perihelion on January 3rd, 2024, Earth passed within 91,346,984 miles of the Sun. Compare this to the farthest point in Earth’s orbit, aphelion, which will next occur on July 6th, 2024 at a distance of 94,510,889 miles.
| Event | Date in 2024 | Distance from Sun |
|---|---|---|
| Perihelion | January 3 | 91,346,984 miles |
| Aphelion | July 6 | 94,510,889 miles |
While a difference of around 3 million miles may seem insignificant on a cosmic scale, it has subtle but noticeable effects on Earth’s climate. Seasons in the northern hemisphere tend to be slightly warmer when Earth is near perihelion during our winter. Meanwhile, seasons in the southern hemisphere experience slightly cooler temperatures when Earth is farthest at aphelion in their winter.
Why Does Perihelion Occur?
The reason Earth goes through perihelion and aphelion is because its orbit around the Sun is not perfectly circular – it has an elliptical or oval shape.
Earth’s varying distance from the Sun is caused by the complex gravitational forces exerted in the Solar System. The combined gravitational pulls of the Sun, other planets like Jupiter and Saturn, and even the Moon all interact to stretch Earth’s orbit into its oval path.
Perihelion Has No Major Impacts on Earth
While perihelion brings Earth millions of miles closer to the Sun’s intense heat and radiation, you likely didn’t notice any drastic changes from the event. Our planet receives only about 6% more solar energy at perihelion compared to aphelion. This subtle difference gets smoothed out by Earth’s tilt on its axis and oceans storing heat over long periods.
Some scientists hypothesize that seasonal differences between the two hemispheres may become more extreme over thousands of years if perihelion occurs during different seasons. But for now and the foreseeable future, perihelion has no major or hazardous impacts on Earth’s climate, weather, seasons or life.
When to See the Sun at Its Biggest and Brightest
Around the time of perihelion in early January each year, the Sun also appears slightly larger and brighter than average in our sky. This happens because Earth’s elliptical orbit brings us several million miles closer to the Sun.
To see the Sun at its biggest and brightest for 2024, look to the southeast skies shortly before local noontime in the week surrounding January 3rd. Use proper eye protection like eclipse glasses – never look directly at the Sun with unprotected eyes due to risk of eye damage.
While the Sun looks biggest at perihelion, later in the year around June 20th it actually reaches its highest point and longest period above the horizon. This marks the summer solstice in the northern hemisphere.
Earth’s Changing Orbit Over Thousands of Years
While perihelion and Earth’s orbit show exceptional stability year after year, scientists have found that subtle shifts do occur over a scale of tens of thousands of years.
Analysis of ancient solar eclipses recorded in historical texts reveal a phenomenon called orbital forcing. Essentially as the gravity of other Solar System bodies exert small tugs on Earth, its orbit shifts between more circular and more elliptical shapes on a 100,000 year cycle.
In addition, Earth’s axis wobbles similar to a spinning top over about a 26,000 year cycle. This means the seasons when perihelion occurs also shift over millennia. Orbital forcing is one of many hypotheses about what drives ice age cycles on Earth.
Conclusion
In our lifetimes, the annual event of perihelion holds no major significance beyond showing off principles of orbital mechanics. But over the course of human history, periodic shifts in Earth’s orbit have likely played a role in climatic changes.
As our planet passed perihelion for 2024 on January 3rd, we can reflect on how small variations in Earth’s path around the Sun impact everything from seasons to ancient ice ages. Paying attention to subtle astronomical phenomena ultimately gives us perspective on just how finely tuned our Solar System is to support life.
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.
