Weather

The Earth is at its furthest from the Sun on Thursday

Earth reaches aphelion, or the furthest point from the Sun on Thursday, July 6.

Posted 2023-07-05T23:27:47+00:00 - Updated 2023-07-05T23:27:47+00:00

This image from NASA schematically illustrates the elliptical nature of our orbit about the sun (and the moon's orbit around the Earth), showing the points of aphelion and perihelion. Note that the eccentricity of the orbit is exaggerated somewhat in order to highlight the concept.

Tony Rice

, NASA Ambassador

The Earth's orbit around the Sun isn't quite circular. Earth is at its closest (perihelion) in January furthest (aphelion) on July.

With recent temperatures soaring into the mid 90s, you'd expect the opposite would be true during these hot summer days, but Earth reaches aphelion about 30 minutes before sunset Thursday July 6, 2023. We'll be 3.1 million miles closer on January 2, 2024.

The Sun is about 2% smaller in the sky and about 7% less sunlight reaches Earth around aphelion but seasonal weather patterns are shaped much more by the distribution of the contents and the Earth's tilt than its proximity to the Sun

Earth's eliptical orbit brings it closer to the Sun during winter in the northern hemisphere. Images: NASA Solar Dynamic Observatory

There is a lot more land in the northern hemisphere than the southern hemisphere. During northern summer, the Sun climbs higher in the sky and shines on all that land much longer, raising temperatures.

Earth-Sun distance as a unit of measure

Space is so big that kilometers and miles get unwieldy very quickly. Astronomers use the average Earth-Sun distance over the year to define the astronomical unit (AU). 92,955,807.3 miles or 149,597,870.7 km is 1 AU. We'll be 1.01668 AU at tomorrows aphelion and 0.98330 AU at perihelion in January.

An old astronomer's trick to remembering the difference between perihelion and aphelion the that the words "away" and "aphelion" both begin with the letter "A".