The Earth’s orbit around the Sun is a bit asymmetric. The average distance from the Sun is about 93 million miles. But over the course of the year, the distance varies by about three percent in each direction. This slight variation is known as the “eccentricity” of the orbit. The orbits of all the planets are eccentric, but by different amounts. Venus’s orbit is the least eccentric – less than one percent. Mercury’s is the most eccentric – about 20 percent. In fact, it is almost impossible for one body to have a perfectly circular orbit around another. Earth and the other planets in the solar system, for example, are pushed and pulled by the gravity of all the other planets. And collisions with other bodies have also distorted their orbits. As the Earth’s distance from the Sun changes, so does the amount of energy we receive from the Sun. At the closest, in January, we get about six percent more total energy than we get right now. Surprisingly, however, there is little effect on Earth’s climate. The atmosphere and oceans store heat and distribute it around the planet. This is why we can have really hot days during the summer here in the northern hemisphere, even though the Sun is three million miles further away than it is during the dead of winter. Screenplay: Damond Benningfield
