Why Can You Sometimes See the Dark Part of a Crescent Moon?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why can you sometimes see the dark part of a crescent Moon?

The Big Idea

You can sometimes see the dark part of a crescent Moon because of Earthshine! Sunlight bounces off Earth onto the Moon's night side, gently lighting the rest of the disk like a ghostly glow. Earth is a night-light for the Moon!

Sunlight Hits Earth

Step one: Earth reflects sunlight. Earth's clouds, oceans, and ice bounce a lot of sunlight back into space. Seen from the Moon, Earth looks like a big bright ball.

Light Bounces Back

Step two: light bounces to the Moon. Some of Earth's reflected light travels across space to the Moon. It lands on the part of the Moon that the Sun isn't lighting.

A Ghostly Glow

Step three: the dark side glows. That light is dim, so you notice it best next to a thin crescent. It looks like a ghostly, grey ball held in the crescent's arms.

A Closer Look

Let's take a closer look! The Sun shines on Earth. Earth bounces some light to the Moon. That light touches the Moon's night side. And it glows softly, just enough to see.

Quick Facts

Quick facts! Another name for Earthshine is the old Moon in the new Moon's arms. Earthshine is easiest to see a few days after new Moon. Leonardo da Vinci explained Earthshine over 500 years ago. Moon watch with a grown-up, and never look at the Sun.

Think Like a Scientist

Now, think like a scientist! A few evenings after new Moon, find a thin crescent just after sunset. Go out with a grown-up. Can you spot the faint grey glow on the dark part? Share what you discover with a grown-up.

Outro

Earth can be a night-light for the Moon. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!