Here's a breakdown:
* Perihelion: This is the point in Earth's orbit where it is closest to the Sun. It occurs around January 3rd and the average distance is about 91.4 million miles (147.1 million kilometers).
* Aphelion: This is the point in Earth's orbit where it is farthest from the Sun. It occurs around July 4th and the average distance is about 94.5 million miles (152.1 million kilometers).
Why is the orbit elliptical?
The shape of Earth's orbit is determined by the balance of gravity and inertia.
* Gravity: The Sun's gravity pulls Earth towards it.
* Inertia: Earth's inertia, a property of matter that resists changes in motion, causes it to continue moving forward in a straight line.
The combination of these forces creates a slightly elliptical path rather than a perfect circle.
How do we know the exact distance?
We know the exact distance between the Earth and the Sun at different points in the orbit thanks to:
* Astronomical observations: By observing the angle of the Sun in the sky at different times of the year, astronomers can calculate the distance.
* Radar measurements: By bouncing radar signals off of Venus and other planets, we can accurately determine their distances and then use those measurements to calculate Earth's distance from the Sun.
Important Note: The distances mentioned are averages, and the actual distance can vary slightly from year to year due to gravitational influence from other planets.
