It may sound strange to hear during the heat of the summer, but Earth is farthest from the Sun for the entire year right now. Our planet is receiving almost seven percent less energy from the Sun than it did when it was closest to the Sun, in January.

The average distance to the Sun is 93 million miles. But the distance varies by about one and a half million miles in either direction – a result of the eccentricity of Earth’s orbit. It defines how lopsided the orbit is. And it varies over cycles of hundreds of thousands of years.

The change is caused by the gravitational pull of the other planets. The biggest impact comes from Venus and Jupiter. Venus passes closer to us than any other planet. And Jupiter is the solar system’s heaviest planet. So even though it’s a long way off, it has a big influence on Earth’s orbit.

Today, the eccentricity is less than two percent, so Earth’s orbit is almost circular. And it’s getting even more circular. When the eccentricity is lowest, the distance to the Sun will vary by only about 300,000 miles.

After that, the orbit will get much more eccentric. It’ll peak at almost six percent. That may not sound like a lot, but it’s enough to change the amount of sunlight Earth receives over the course of a year by 23 percent. That difference will have a major impact on Earth’s climate – thanks to the influence of the other worlds of the solar system.

Script by Damond Benningfield