What are the phases of the Moon? - NASA
You can see the phases drawn in the image below. Just like the Earth, half of the Moon is lit by the Sun while the other half is in darkness. The phases we see result from the angle the Moon …
The Phases of the Moon - NASA
Return to the StarChild Main Page Go to Imagine the Universe! (A site for ages 14 and up.)
Why is the crescent moon sometimes lit on the bottom? - NASA
This diagram shows typical paths for the Moon during the year (and the resulting look of the waxing crescent Moon) for a specific latutude in the northern hemisphere. Notice that during …
What is the orbital period of the Moon? - NASA
The Moon takes 29.5 days to return to the same point on the celestial sphere as referenced to the Sun because of the motion of the Earth around the Sun; this is called a synodic month (lunar …
StarChild: Glossary - NASA
Satellites may be naturally occurring, such as the Moon, or they may be man-made, such as the Hubble Space Telescope and the Compton Gamma-Ray Observatory. SILICON A non …
StarChild: The Solar System - NASA
What is the solar system? It is our Sun and everything that travels around it. Our solar system is elliptical in shape. That means it is shaped like an egg. The Sun is in the center of the solar …
Who figured out the Earth is round? - NASA
As I recall, he based his idea on the fact that he showed the Moon must be round by observing the shape of the terminator (the line between the part of the Moon in light and the part of the …
If you are on the Moon, does the Earth move in the sky? - NASA
Our Moon spins on its axis so that as it orbits the Earth, it always presents the same face to the Earth. As a result, when viewed from the Moon, the Earth will always remain in about the …
What does it mean for Mercury to be in retrograde? - NASA
How the planet Mars would appear to have both prograde then retrograde then prograde motion is shown in the diagram below. Notice that it is all due to the fact that the Earth moves faster in …
Teachers' Center Activity: Sun Motion - NASA
Objectives: Identify the Sun as the source of Earth's light. Observe and describe changes in the Sun's altitude and position. Recognize that day and night are determined by our view of the Sun.