The Sun and Earth

Why Earth goes around the Sun

The Sun has about 330,000 times more mass than Earth. So it bends the net much more deeply. Earth tries to keep going straight, but the curved path keeps turning it toward the Sun. As a result, it goes around the Sun once a year.

Why?Earth travels about 30 km every second. Any slower, and it would fall toward the Sun. Much faster, and it would escape the curve and fly away. Its speed is just right for going around in a circle.

Learn moreThe net picture has a weak spot. A ball rolls down a rubber sheet because of Earth’s gravity, so we are using gravity to explain gravity. In reality, time bends along with space. Chapter 3 shows how time bends.

Clock we are watching

A clock on Earth’s orbit (because of the Sun)

How much slower

About 0.3 s slower per year

Clock rate

0.9999999901

seconds this clock ticks while a clock far away in empty space ticks one second · calculated with the formulas of relativity