Lunar Phases
Full Moon:
The Moon is said to be full when the Sun shines on it, lighting up the half that we can see. When the Moon is full, it is halfway through its monthly orbit of the Earth. This moon often appears a rich yellow when it is full and sits low in the sky. This colour is due to the fact that we look at it through the thicker, dustier part of the atmosphere that is close to the ground.
Waxing Crescent:
The black area is the night on the Moon, where the Sun is not shining. The brighter area is the day on the Moon, where the Sun is reflecting brightly off its surface. The line on the Moon between the night and the day is called ‘The Terminator’, like the movie of the same name. The bright area, just visible on the edge of the dark limb, is called ‘earthshine’. The Sun shines on the Earth and that light bounces off of the Earth’s oceans and lights up some of the darkness on the Moon.
First Quarter:
The Moon looks like this when it is one-quarter of the way around the Earth in its monthly orbit. We see a quarter of it lit up from our place on Earth, but half of the Moon is lit up by the Sun shining on the Moon’s surface. In the northern hemisphere the first quarter looks like a growing "D", while in the southern hemisphere it looks like a "C".
Last Quarter:
The Moon is three-quarters of the way around the Earth when it looks like this. In the northern hemisphere the last quarter looks like a "C", while in the southern hemisphere looks like a "D".
Waning Crescent:
The Moon has travelled almost all the way around Earth during the month when it looks like this. At this point, it is almost a New Moon. When it is a New Moon, we see no light shining on it at all. The Sun’s light is shining only on the far side of the Moon during a New Moon, so we cannot see the Moon at all from Earth.
Other Moons of our Solar System:
Saturn has many moons. Enceladus, one of Saturn’s moons, is one of the most beautiful moons in the Solar System. It has an ocean under its surface that is made of very, very cold water. Every now and then, this water explodes out of the southern half of this moon. The water shoots out of slits in its icy surface, and is shot hundreds of kilometres out into space. Hyperion, another one of Saturn’s moons, is very strange indeed. Most moons go around their planet in a nice, smooth path, but Hyperion tumbles around Saturn. Titan, Saturn’s largest moon, has an atmosphere made of methane and ethane.
Europa:
One of Jupiter’s moons, is an interesting ice moon. It has a smooth icy surface that is covered in lines. The surface is full of fractured ice sections and is very unusual. Under Europa's surface is a cold ocean. Sometime in the future, a spacecraft may land on this moon, drill a hole in the surface and put in a submarine to see if there is anything living within it. Io is another one of Jupiter’s moons. Some people think that it looks a bit like a pizza, but actually, the marks we see are caused by active volcanoes. Io's volcanoes can spray sulphur and sulphur dioxide hundreds of kilometres above its surface. What goes up then falls back down, creating huge circular red, yellow, white and black bruises on its surface. Callisto, another of Jupiter’s moons, is very beautiful. Callisto is one of four of Jupiter’s moons that we can see through a small telescope.It was first discovered by Galileo in 1610.
Phobos:
Phobos is the largest and closest of the two natural satellites of Mars. It is so close that it orbits Mars faster than Mars rotates. As a result, from the surface of Mars it appears to rise in the west, move across the sky in 4 hours 15 min or less, and set in the east, twice each Martian day. Phobos is named after the Greek god Phobos, a son of Ares (Mars) and Aphrodite (Venus) which was the personification of Horror.