The Earth,The Moon and The Sun

he Earth is certainly the most familiar planet, though it has only been a few hundred years since we fully realized it was a planet. We begin our study of objects in the Solar System with the Earth because it is interesting in its own right, and it provides a test of many observing techniques that we wish to use for other objects in the Solar System.

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The Earth is, at least by human standards, a beautiful planet, as the following images indicate.

Apollo 11 shot of Earth (Ref)	Galileo shot of the Earth and Moon	Galileo image of S. America (Ref)

Here is an interactive viewer that displays either a map of the Earth showing the day and night regions at this moment, or a view of the Earth from the Sun, the Moon, the night side of the Earth, above any location on the planet specified by latitude, longitude and altitude, from a satellite in Earth orbit, or above various cities around the globe (Credit: John Walker). Here is the NASA Earth from Space image gallery, where you can find many images of the Earth taken from space.