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Genetic Building Blocks Found In Meteorite
FiReaNGeL writes to tell us scientists have confirmed that the components of genetic material could have originated in a place other than Earth. A recently published report explains how uracil and xanthine, two basic biological compounds, were found within a meteorite that landed in Australia. From Imperial College London:
"They tested the meteorite material to determine whether the molecules came from the solar system or were a result of contamination when the meteorite landed on Earth. The analysis shows that the nucleobases contain a heavy form of carbon which could only have been formed in space. Materials formed on Earth consist of a lighter variety of carbon."
I think they mean the carbon 13 to carbon 12 ratio is not "earth normal".
IANAB (I am not a biologist), but I think that when scientists talk about "life coming from space" they mean "complex carbon compounds that could, given the circumstances, combine into self-replicating structures that would, some time later, become living organisms". In other words, the secret ingredient needed for life to appear on Earth.
But thinking "ZOMG there were living cells in the meteorite!" is just crossing the line.
a meteorite that landed in Australia...
landed you say? fascinating indeed.
Of course that would be silly. The living cells trapped inside the meteorite would have been baked into the material these researchers found. It's the light fluffy life forms on the exterior of the meteorite that would have been brushed off the surface of the meteorite on first contact with the atmosphere and drift gently down to the nutrient rich sea that covers most of our planet. There these hypothetic organisms would breed and diversify until they filled every sea, covered every continent and dwelled deep within the crust.
Eventually a form would evolve, such as a lichen or mold, that bred with colonies so small and potentially electrostatically charged by sunlight that they might rise to the highest reaches of the atmosphere - to be scooped up by passing meteors on their way to the unknown depths of space. Perhaps they might by a fluke of trajectory be thrown clear of the solar system altogether. Frozen in the cold of space these breeding colonies might last millions of years. The vast majority of these would wander 'twixt the stars eternally, finding no place they might rest or fall on a hostile environment and die. Given enough of them, though -- perhaps millions an hour for a billion years -- some few might land someplace they can start anew.
It's called panspermia
Help stamp out iliturcy.
the so called hostile temperatures on earth are nothing compared to the hostility of the environment in space.
massive radiation, shockwaves, coronal mass ejections, MASSIVE extremes of heat and cold, and very importantly, the tendency for water to remain in a vaporous or solid form rather than liquid because of the lack of pressure.
Not to say the first dna fragments, amino acids, or single celled life forms could not have come from space, but they had to develop on some body with enough gravity and atmospheric pressure to host some liquid water water.
This characteristic need for liquid water is too fundamental to have simply arisen after this life came to earth.
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Whole microbes surviving in an airless, nutrientless, radiation-saturated enviornment is not unprecedented. The Apollo 12 crew found scores of living streptococcus mitus doing just fine on the Surveyor probes on the moon, which had been there for three years. While its doubtful whole cells came here and populated the planet, it also seems unlikely that the Earth alone provided all the ingredients.