Why Are Planet Orbits Ovals, Not Perfect Circles?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why are planet orbits ovals, not perfect circles?

The Big Idea

Planet orbits are ovals because of how the Sun's pull and a planet's sideways speed work together! Together they shape the path into a slightly stretched circle called an ellipse. Earth's orbit is almost round, but Mercury's is clearly oval. A perfect circle is actually very rare.

The Sun Pulls

Step one: the Sun pulls on every planet. Gravity tugs a planet toward the Sun, which stops it from flying away into space. It is like a ball on a stretchy string.

The Planet Moves Sideways

Step two: the planet is also moving sideways. Because of its sideways speed, a planet doesn't fall straight into the Sun. It keeps curving around instead. Pull and speed play tug-of-war.

An Oval Path

Step three: pull and speed make an ellipse. Depending on the speed, the path stretches into an oval. The Sun sits a little off-center in every planet's oval. Mercury's oval is the most stretched.

A Closer Look

Let's take a closer look! An ellipse is a stretched circle. The Sun sits a little off-center. The planet swings closer, then farther. Earth's path is only slightly stretched.

Quick Facts

Quick facts! An ellipse is a stretched circle. The Sun sits off-center in each oval. Earth's orbit is almost round. Mercury's orbit is clearly oval.

Think Like a Scientist

Now, think like a scientist! With a grown-up, press two pins into cardboard. Loop string around the pins. Trace an oval with a pencil, keeping the string tight. Move the pins closer together. What changes?

Outro

Planets travel in ovals, because gravity and speed shape their path. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!