Eclipses and the phases of the Moon

Why solar and lunar eclipses occurIf you have ever seen a solar or lunar eclipse, you may have asked this question:

Why do eclipses occur?

Ancient people certainly asked the question and invented many contradictory answers, usually involving supernatural powers. To answer the question using physics, you need to know the relative positions of the Sun, the Moon, and the Earth, as well as the fact that light travels in straight lines. Read the text aloud
Eclipses occur when one celestial body blocks the light coming from another body. In other words, one of them is casting a shadow! When the Moon lines up between the Sun and the Earth, the Moon casts a shadow onto the Earth, blocking the Sun for a small region on the Earth. This creates a solar eclipse in which some or all of the Sun appears to vanish. When the Earth lies between the Sun and the Moon, the Earth’s shadow—which is larger than the Moon’s shadow—engulfs the Moon, blocking sunlight from reaching the Moon. This creates a lunar eclipse in which the Moon appears to vanish. Solar and lunar eclipses do not occur very often because the plane of the Moon’s orbit around the Earth is inclined a little bit relative to the plane of the Earth’s orbit around the Sun. Read the text aloud Show Do solar eclipses have a season?
Have you ever wondered whether Earth’s shadow creates the crescent Moon? How does that explain the full Moon? Why is the dividing line between light and dark straight instead of curved in a half Moon? Why does the Moon go through these phases? The answer is that a shadow does create the observed phases of the Moon, except that the shadow is not the shadow of Earth but the shadow of the Moon itself. Read the text aloud
Why the Moon has phasesSunlight travels in straight lines toward the Moon, which illuminates the side of the Moon facing the Sun. The Moon orbits around the Earth, which causes the illuminated side of the Moon to change its orientation relative to the Earth. Sometimes, we can see the fully illuminated side of the Moon, which is called a “full Moon.” Other times, the illuminated side is facing completely away from the Earth, which is called a “new Moon.” In between are the other phases of the Moon: crescent, quarter, and gibbous. Read the text aloud
Are lunar or solar eclipses more visible on Earth? Show

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