Welcome again to JJNN for Monday October 27th, 2008. Today we will be talking about water on the moon.
More than likely, almost as long as humans have looked up towards the moon they have wanted to try to visit it. Even Jules Verne wrote about the idea of going to the moon in his book From The Earth To The Moon. Of course that dream of visiting the moon went unaccomplished until July 20th 1969. That was a monumental day in scientific history. The only problem with going to the moon is the fact that the environment there is just not hospitable for human life. Humans need a lot of things to survive. Everything from just the right type of atmosphere to drinkable water.
There are some people that say if water (in the form of ice) is found on the moon than something can be done to make the atmosphere and make the moon habitable. The only problem with this is the fact that if there is any ice on the surface of the moon and it gets hit by sun it will go though a process known as ablation. That means the solid water will go straight to water vapor without going though the intermediate liquid step. That means as soon as there is ice on the surface it will not be there any more as soon as the sun hits it.
It sounds like there just won't be any ice on the surface, right? Well, technically, there is still hope. Scientists just have to find a place in which the sun never shines. I know that sounds like the old "Stick it where the sun don't shine!" and I guess it is close. It is more like "probe were the sun don't shine." I guess that is actually worse.
Luckily enough there are places where the sun's rays don't reach. The most promising of these places is known as the Shackleton crater. The Shackleton crater is one that lays on the south pole of the moon. The lip of the crater shields the inside from sunlight so that it is in almost constant shadow. If there is hope for ice on the moon that crater is the place to find it.
So, what if there were ice in the crater? How much ice would there be? Well the crater has a diameter of 19 km (about 12 mi) and a depth of about 2 km (just over 1 mile). If we assume that the crater is shaped like a tube (in other words no sloping sides) and was completely filled with ice it would be: pi*(19/2)^2 * 2 (this is the area of the circle at the top times the depth of the crater). This would be 567 cubic Km (or about 2625 cubic miles). If that were all water how much would it be? It turns out to be just under the amount of water in lake superior. That is a lot of water. My calculations are actually an overestimate because I am not taking into account the sloping crater walls and the fact that the crater would not be totally full of water, but it is still a whole later of water.
Last year Japan sent it's satellite named Kaguya in the direction of that crater. Kaguya is in orbit 100 km (about 62 miles) over the surface of the moon. It has a resolution of about 10 m (32 feet) per pixel. That is good resolution for a satellite of its type. You can see Kaguya below.
So, what do you think that Kaguya found in the crater? As it turns out, absolutely nothing. I guess that is an understatement because Kaguya found a lot of dirt. But, Kaguya did not find what it was looking for, ice. It is really too bad that water was not found, but there is always hope for ice in other areas of the moon. The Kaguya team is planing on going on to the north pole of the moon soon.
Any way, it is now time for the word of the day. Today's word is 月(つき). It is pronounced tsuki and means moon. The Japanese have a rabbit in the moon instead of a man in the moon.
That's it for today. See you next time at JJNN.