Why does sometimes the moon looks red?
What makes the eclipsed moon turn red? The answer lies inside Earth’s shadow: Our planet casts a long shadow. It starts on the ground–Step outside at night. You’re in Earth’s shadow. Think about it!–and it stretches almost a million miles into space, far enough to reach the moon. Suppose you had a personal spaceship. Here’s your mission: Tonight, at midnight, blast off and fly down the middle of Earth’s shadow. Keep going until you’re about 200,000 miles above Earth, almost to the moon. Now turn around and look down. The view from your cockpit window is Earth’s nightside, the dark half of our planet opposite the sun. But it’s not completely dark! All around Earth’s limb, the atmosphere glows red. What you’re seeing is every sunrise and sunset on Earth–all at once. This ring of light shines into Earth’s shadow, breaking the utter darkness you might expect to find there. Turn off the cockpit lights. There’s a lovely red glow. That same red light plays across the moon when it’s inside
