Stephanie LaRose (03/10/04)
It is strange to me to think of a planet without plate tectonics. They still have mantle and crust, so I see no reason why it shouldn't break (as the Red Sea is doing now) and start to create plates. Maybe it is simply cooler because it is smaller and farther from the sun, so the currents in the mantle are not as active as ours. There is the question of recent volcanism, and if not, my hypothesis could be correct, because it seems that mantle plumes (which also form volcanoes) will start rifting.
It is amazing how enormous the geologic features are on Mars because of the lack of plate tectonics. Olympus Mons is absolutely enormous and it must be because of a continual supply of magma from the core. If true, this could help us to better understand the idea of hotspots, which is the most well-known explanation for the Hawaiian Islands, but has recently come under fire by those who say that hot spots are not stationary. Looking at other planets definitely helps one to understand our own. This is especially true in the fact that the Moon, Mercury, and Mars all show signs from the beginning of our solar system; things that have now disappeared from our planet due to its plate tectonics.
There is the question of water on Mars that has recently been confirmed by the two rovers on the surface now. It has always been speculated that this was the case. The question is how much and for how long. The younger craters show an interesting pattern of eject, which almost looks as if it mixed with water as it was ejected, creating lobe-like features around the crater.
When Sojourner ventured to Mars, it found that there was a wide range of silica content, including silica contents that make the rock more andesitic than basaltic. The reading does not go into detail as to how this might have happened, only to say that it may not have formed from partial melting. From Geo 22, I learned that andesite was formed due to the wet partial melting of basalt at a subduction zone. I would like to know more about what the scientists think. Some do say that there might have been plate tectonics early in Mars's history.
All of this work is being done by various rovers and orbiters that we send out to Mars. I know that it would be an amazing thing to have humans on Mars, but as an article that we read earlier in the semester pointed out, we would mostly be humans sending out rovers of our own, only based on Mars as opposed to Earth. But of course, as with the Moon missions, it would be great to bring back rocks from Mars to study here. I am still undecided as to whether or not it is better to have humans on Mars versus rovers.
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At "Bliny Night" I listened to Alexander Basilevsky talk about the Soviet missions to the moon. He listed over 20 missions, saying if they were a failure or not and if they were rovers or orbiters. There were a lot of successful missions by them! As he put it, there were about two successful missions for every one crash. I was very surprised by this, having thought before there were fewer missions that actually were launched and that more of them had been failures.
Basilevsky also talked about why the Lunokhod ended up dying after 11 months. He basically said the same thing our reading did. There was a shadow in the way of the driver, so they ended up inside a small crater. After reaching a 20 degree tilt, it stopped. When they opened the solar collectors, they got dust on them from hitting the side of the crater. They did not care about the slight loss of power. When they closed them up for the night, the dust was pushed onto the radiator and overheated it. It was nice to hear the story first-hand though.