The Moon – What are Those Dark Regions on the Moon

The Moon is an object that every telescope can see with great detail, making it a favorite target for many astronomers. I thought it would be an idea if Sydney StarGazers allocated a series of posts looking at the Moon and getting to know a little more about it.

When looking at the Moon, the first thing you notice is all the craters marking the Moon. These are the results of surface  impacts which have scarred the Moon over thousands of years. On the side of the Moon facing the Earth , there are over 300,000 craters which are larger than 1km in size. Of these, 234 of them are more than  100 km in width.

(Click to Enlarge)

The other thing you notice is what appears to be dark regions on the Moon’s surface. These dark regions make up 16% of the surface of the Moon and are called the lunar maria. Most of these large dark regions were formed about 3 billion years ago when there was volcanic activity on the Moon. The lava flowed into low lying plains and cooled to form a basalt plain.

The reason that the lunar maria are darker than the rest of the moon is due to the basalt being less reflective and therefore darker to our eyes than the rest of the Moon.

It is interesting to find out that most of these dark regions are on the side of the Moon which is facing the Earth. Scientists have still not worked out why this is the case.

~ by sydneystargazers on March 7, 2010.

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