We Need Some Space – Why Our Planet Feels Warmer On The Aphelion When We Are Farthest Away From The Sun

Friday, 06 July 2018 - 12:38PM
Space
Solar System
Earth
Friday, 06 July 2018 - 12:38PM
We Need Some Space – Why Our Planet Feels Warmer On The Aphelion When We Are Farthest Away From The Sun
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Pixabay Composite
Today marks Earth's aphelion, the point in its orbit when we are farthest from the Sun! If you want to be exact, aphelion occurred at 12:46 PM EDT, when the Earth was exactly 94,507,803 miles from our star.

Despite the many, many erroneous maps of the solar system shown to children (which generally illustrate circular orbits for each planet), Earth's orbit is actually an ellipse. This means that our distance from the Sun waxes and wanes throughout the year.

The aphelion is not to be confused with the summer solstice (the longest day of the year), which happened on June 26th. It isn't the apogee, either – that's the point in the Moon's orbit that takes it furthest from Earth.

It might seem confusing that Earth's aphelion happens during the middle of summer when the planet is technically farthest from the warmth of the Sun. Despite the increased distance, the Earth shouldn't be any cooler today: although we're receiving about 7% less sunlight overall, Earth is generally 4 degrees warmer on its aphelion than its perihelion (the point when it closest to the Sun).

This is mostly because landmasses in the Northern Hemisphere are better at absorbing heat than the Southern Hemisphere's oceans. In addition, the change in distance isn't actually that dramatic in the grand scheme of things – the aphelion is "only" about a million miles greater than the average distance between the Earth and Sun, which is roughly 93 million miles.

And just to appease middle school science teachers everywhere, the Earth's distance from the Sun doesn't cause the seasons: its tilt does that. The Earth's angle of rotation is about 23.5 degrees off the orbital plane, meaning that – as it travels around the Sun – the part of it that faces the Sun (and receives the strongest, most direct sunlight) is skewed toward the Northern or Southern hemisphere, which explains why the summer solstice for the North is the winter solstice in the South.

So, you're welcome: We have officially made you the smartest person at happy hour tonight. You're on your own next weekend – and may the odds be ever in your favor.

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