1. I read somewhere about a year ago that we don't have to worry too much about the earth heating up so much that it becomes sterilized because the process occurs so slowly, we can use an asteroid and a zillion series of gravity assists to move the Earth (and Mars) into orbits more distant from the sun. As you may know, space craft get gravity assists all the time from planets, causing them to speed up or slow down, and the planet to do the opposite (much less noticably, because of the planet's enormous mass). A large asteroid--perhaps 50 miles across--could be put into an orbit that passes between the Earth, Jupiter, and Saturn periodically, stealing speed from the later two and giving it to earth through carefully crafted gravity assists. Quite clever. We'd need to move the Earth a lot, but we have a billion years to do it.
2. Regarding Martian and Earth life. Considering that thousands of tons of Mars have been blasted into space and landed on Earth, and hundreds of tons of Earth have been blasted into space and landed on Mars, over the last few billion years, for all we know, life may have originated on Mars and got transported here by a meteor impact. It is possible we are Martians and that when we visit Mars, we will find ancient, primitive cousins in some steam vent. It is also possible that life originated in Venus first, was sent to both the other two worlds by asteroidal impacts, and then was wiped out on Venus. We may never know, but finding life on Mars with substantial biochemical similarity would be indication something was transported somewhere, and Mars will have older rocks than the Earth, so it may tell us whether life originated there or not.
But we have to send people there to do this research; it'd take robots a hundred years.
-- RobS
]]>It seems that each of our cells, human cells, contain organelles called mitochondria. These things contain DNA and we all inherit our mitochondrial DNA from our mothers. This DNA does not take part in the sharing and shuffeling of genes during sexual reproduction, and we all seem to have, according to the sources I've read, the same mitochondrial DNA.
What makes this especially interesting, is that the structure and form of the mitocondria are almost indestinguishable from cyanobacteria. The thought is that some time in the development of higher life forms some strain of cyanobacteria were incorporated as essential organelles within each cell.
Would alternate developments be available on Mars?
I realize the life aspect of the original topic seems to have taken over, sorry if it's inappropriate.
Rex G. Carnes
]]>RobS
]]>So it may be that in the first billion years or so, Mars was close to freezing, but usually below. Volcanic activity was much greater than today, with millions of square kilometers being repaved by basalt flows. The flows brought heat to the surface as well as water. So water accumulated in the regolith partly as vapor perculating upward, partly as snow (it may have snowed; this would explain the few gullies that appear to come from meteorological sources) and when volcanic activity occurred in an area vast quantities of permafrost melted, oozed out their water, sometimes gushed out their water. Some of the Mariner Canyons were filled with lakes; the horizontal strata of lakebed deposits seem to be visible in some pictures. As Mars aged, the volcanic activity decreased, more and more water and air escaped into space, and the episodes of water flow and even precipitation grew less and less.
A billion years or so from now, when the sun is 40% brighter than today, Mars may have a brief renaissance, then the atmosphere leaks away at a faster rate and we have a "warm dry" Mars model instead!
-- RobS
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