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Martian Rock Found In Morocco
daeley writes "The BBC is reporting that a rock found in 2001 in Morocco is originally from Mars, similar in composition to the 1977 Antartica find. 'The meteorite would have been blasted off the Red Planet by an impact and may hold clues to Mars' watery past... scientists say the fragments are magmatic rocks. Magmatism is the main process by which water moves from the core of planets to their surface.'"
I ask one question, could this rock not have come from the same source as the billions of rocks that litter the martian surface? I.E. somewhere other than Mars.
Two reasons for suspecting they originated on Mars:
Martian meteorites come in a range of ages - some as young as a billion years old. By comparison, most meteorites hang out around the 4.6 billion years old mark - the point when small planetary bodies were forming in the Solar System.
For rocks to be much younger than 4.6 billion they have to come from a body that was evolving - that was hot, partially molten and volcanically active. Such a body would have to be big - a planet. Mars is the most obvious candidate, it shows clear signs of tectonism until relatively recently - new rock was being formed on Mars within the last billion years.
The second reason for suspecting these are Martian rocks is so clever it borders on magical. Some meteorites have been analysed in the lab. They contain vesicles - tiny bubbles of gas trapped in the molten rock. When the rock cooled and froze, the gas was trapped.
When these bubbles are cracked open, the gas inside can be analysed. The ratios of the inert gases (gases such as neon, argon and krypton) precisely match the ratios in the Martian atmosphere measured by American and Soviet probes.
I've no idea if the Egyptian dog-killer has been analysed though.
Best wishes,
Mike.
AFAIK, the parent is wrong.
RS
Shoes for Industry. Shoes for the Dead.
What's next? Are we now going to find out that the rocks being analyzed by Spirit are actually from earth?
It is easier for Mars debri to transfer to Earth than the other way around because of the stronger gravity on Earth. I read somewhere that Earth's gravity is on the borderline of being too strong to allow rocks to escape via meteor impact. One might say that some impacts are much stronger than others so that fast ones might still do it. However, past a certain impact energy, ejected material vaporizes such that there are no projectiles left.
In other words, too slow and rocks cannot reach escape velocity. Too fast and rocks vaporize from the heat of the impact. The middle "just right" window may not exist, or barely exist on Earth, but is relatively wide on Mars because of lower gravity.
Thus, if there are Earth rocks on Mars, there will be far far fewer compared to the other way around.
Table-ized A.I.
Yes, all terrestrial planets in the solar system (excpet Venus, which appears to undergo periodic resurfacing, erasing old impact craters) show evidence of a period of extremely heavy bombardment in their early histories, about 3 billion years ago. This is why the lunar highlands are so much more heavily cratered than the mare (lava floodplains formed sometime after the heavy bombardment period). If you've got pictures of the moon handy, the "dark side" is primarily the heavily cratered highlands, while the side that faces us has more mare.
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD