EARTH

NASA African view

Third farthest from the Sun is the strangest plant in the solar System (Earth). It’s an active world, combining many of the most exciting features we find on the other planets - volcanoes, erosion, hurricanes, an out sized moon - with features that are unique to the Earth alone: drifting continents, liquid water, and beings.

The ‘Blue Planet’ of the inner Solar System, the Earth’s color is due to it’s unique oceans of liquid water. Separating the two oceans, the Atlantic and the Pacific, are the twin contents of North and South America. If we could watch our active planet for millions of years, we would see the continents gradually drifting around the world.

NASA Full Moon

Our partner in space, the Moon, is as different from the Earth as we could imagine: the Moon is a dry, dead and air less world, unchanged for billions of years. The bright areas we see are the lunar highlands, pocked with ancient craters. The smooth dark plains consist of lava that welled up and solidified almost four billion years ago.

The lunar Alps are similar in height to there terrestrial namesake, but are in fact part of the rim of a huge ancient crater. Empty lava channels snake though the mountains and along the floor of a great rift, the Alpine Valley. Molten rock folded the low-lying region adjoining the mountains to form the dark dry plan, called Mare Frigoris, the Sea of Cold. Eralosthenes and Copermicus are the Moon’s two largest craters. The impact that produced the ninety kiometor wide (56 miles) Copernicus was among the most recent events the Moon has witnessed: even so, it took place 850 million years ago. The giant hole in the Moon is Mare Orientale, the result of a massive cosmic collision 3,800 million years ago. The impact basted out the circular basin and the surrounding mountain ridges in all some 900 kilometers across (558 miles) and threw out lumps of rock that created smaller craters as far as 2,000 kilometers (1,240 miles) from the crater it self.

While the Moon’s surface is typified by the Hadley Mountains; is barren and unchanging under a backless sky, the Earth is a dynamic world.

The Pacific island of Moorea is the tip of a giant volcano that has recently puched its way up from the ocean floor; the abrasive power of the rain is now wearing it down again. White clouds contrast with the blue sky as they condense over the mountains. Living plants grow up the slopes, while polyps form a mighty coral barrier that becalms the lagoon around the island.

Shimmering curtains of color-theaurora, or Northern Lights-are a familiar sight in regions near to the Earth’s poles. The aurora is the most picturesque manifestation of the Earth’s magnetic field. As electrically charged particles stream away from the Sun, our planet’s magnetism channels some of them towards the magnetic poles and the particles make atoms in the Earth’s upper atmosphere flow red and green.