Book 1, Question 82
Why Do We Orbit the Sun Instead of Falling In?
The Sun's gravity pulls on Earth like an invisible tug, so why do we not fall straight in? Because Earth is also zooming sideways through space. Falling toward the Sun while moving sideways makes a curved path called an orbit, and the balance of gravity and sideways motion keeps Earth on a steady path year after year. Without that sideways speed, gravity would pull you straight in. Swing a ball on a string in a circle to feel how the pull of the string is like gravity.
From the book
Page from A Million Whys Book 1
More fun facts
- Earth is always falling toward the Sun because of the Sun's huge gravity. It just keeps missing.
- Earth zooms around the Sun at about 67,000 miles per hour, moving almost completely sideways.
- That sideways speed is what keeps Earth from plunging into the Sun.
- The Sun's gravity is also what keeps Earth from flying off out of the solar system.
- Objects with more mass, like stars and planets, pull with more gravity.
- It takes 55 times more energy to send a spacecraft to the Sun than to Mars, because the spacecraft has to cancel out Earth's sideways speed.
- The Sun holds 99.8 percent of the mass in our solar system.
Questions kids ask
How fast does Earth move around the Sun?
About 67,000 miles per hour.
Is it easy to fly to the Sun?
No. It takes 55 times more energy than going to Mars, because you must cancel Earth's sideways speed.