Posted on 03/20/2004 7:38:37 PM PST by Leroy S. Mort
Without the Moon, there would have been no life on Earth.
Four billion years ago, when life began, the Moon orbited much closer to us than it does now, causing massive tides to ebb and flow every few hours. These tides caused dramatic fluctuations in salinity around coastlines which could have driven the evolution of early DNA-like biomolecules.
This hypothesis, which is the work of Richard Lathe, a molecular biologist at Pieta Research in Edinburgh, UK, also suggests that life could not have begun on Mars.
According to one theory for the origin of life, self-replicating molecules such as DNA or RNA emerged when small precursor molecules in the primordial "soup" polymerised into long strands. These strands served as templates for more precursor molecules to attach along the templates, creating double-stranded polymers similar to DNA.
But the whole theory fails without some way of breaking apart the double strands to keep the process going, says Lathe. It would take some external force to dissociate the two strands, he says.
Doubling up
As an analogy, he points to PCR, the technique used to amplify DNA in the lab. DNA is cycled between two temperatures in the presence of appropriate enzymes.
At the lower temperature of about 50 ýC, single DNA strands act as templates for synthesising complementary strands. At the higher temperature of about 100 ýC, the double strands break apart, doubling the number of molecules. Lower the temperature, and the synthesis starts again. Using this process, a single DNA molecule can be converted into a trillion identical copies in just 40 cycles.
Lathe believes that thanks to the Moon, something similar happened during Earth's early years. Most researchers agree that the Moon formed five billion years ago from debris blasted off Earth in a giant impact.
A billion years later when life is thought to have arisen, the Moon was still much closer to us than it is now. That, plus the Earth's much more rapid rotation, led to tidal cycles every two to six hours, with tides extending several hundred kilometres inland, says Lathe. Coastal areas therefore saw dramatic cyclical changes in salinity, and Lathe believes this led to repeated association and dissociation of double-stranded molecules similar to DNA.
When the massive tides rolled in, the salt concentration was very low. Double-stranded DNA breaks apart under such conditions because electrically charged phosphate groups on each strand repel each other.
But when the tides went out, precursor molecules and precipitated salt would have been present in high concentrations. This would have encouraged double-stranded molecules to form, since high salt concentrations neutralise DNA's phosphate charges, allowing strands to stick together.
Unrelenting cycles
These unrelenting saline cycles would have amplified molecules such as DNA in a process similar to PCR, says Lathe. "The tidal force is absolutely important, because it provides the energy for association and dissociation [of polymers]."
Many researchers do not believe DNA and RNA were the first replicating molecules. Graham Cairns-Smith of the University of Glasgow, UK, thinks much simpler "genetic" material formed first, from the crystallisation of clay minerals.
But he says Lathe's idea deserves attention. "Whatever the replicating entities were that started the evolutionary process, it would be significant that they lived in an environment in which the conditions were changing."
If the theory is right, life could not have evolved on Mars, says Lathe. Phobos, the larger of Mars's two Moons, is so small that the tidal forces it generates are just one per cent of those generated by our Moon. "Even if there was water on Mars, life could not have evolved there because these polymers could not have replicated," he says.
Please describe the difference between "abiogenesis" and "spontaneous generation."
the idea that maggots spontaneously appeared in rotting meat.
That is NOT the limit of his research, nor his finding.
It'll be a scientific "fact" by tomorrow. Just like all the other speculation masquerading as scientific "facts" that the evolution religion is pushing down our throats.
Pasteur showed that fully-formed microbes did not appear spontaneously. He, however, did not say that life from non-life was impossible. There is a difference, and you being the educated man we know you to be are sure to understand the difference.
The whole theory fails since there is no proven way to generate the oligomers(polymers are information-free) to even start the process. They've been pounding clay for several years to get peptides with no real success. They've "cheated" by taking a known protein and breaking it into two pieces. Then showing that the two pieces join back together, not much of a synthesis in my opinion.
Lotta information on this. Even creationists should be able to understand it. Help is only a Google away:
Spontaneous Generation.
I don't like it. No wonder things are all messed up. Can't you fancy-pants pointy-headed intellectuals do something about all this bobbing and weaving around? It's bad for the digestion.
"Ladies and Gentlemen; Welcome to the Cosmic Roller-Coaster; in the lounge tonight we have for your entertainment Medved the Magnificent, the 'Clown Prince of Astrophysics,' who has come straight here from his previous engagement as a mens-room attendant at the Taj Mahal...... let's all give it up for the Tedster, and his famous sidekick, Splifford the ASCII bat............."
Hehehe! Lats add another wrench into the equation. :-)
The reason the Moon keeps one face to the Earth (its rotation on its axis matches the period of its orbit) is it is tidally locked to the Earth. This tidal locking will eventually cause the Earth and Moon to keep one face to each other.
Here is a more in depth explanation. The total angular momentum of the earth moon system, which is spin angular momentum plus orbital angular momentum, is constant. (The Sun plays a small part as well, which will be ignored for this discussion.) Friction of the oceans caused by tides is causing the Earth to slow down a tiny bit each year. This is approximately two milliseconds per century, and amazingly this causes the moon to recede by about 4 centimeters per year. As the Earth slows down, the Moon must recede (this is an increase in orbital momentum) to keep the total angular momentum a constant. In other words as the spin angular momentum of the earth decreases, the lunar orbital angular momentum must increase. Here is an interesting side note: the velocity of the moon will slow down as the orbit increases.
Another example of tidal locking is the orbit period and rotation of the planet Mercury. What is interesting about this one is that instead of a 1:1 synchronization where Mercury would keep one face to the Sun at all times, it is actually in a 2/3:1 synchronization. This is due to the High eccentricity of its orbit.
There also can be more than one body "locked" to each other. Lets take a look at the moon Io. Io is very nearly the same size as the Earth’s moon. It is approximately 1.04 times the size of the moon. There is a resonance between Io, Ganymede, and Europa. Io completes four revolutions for every one of Ganymede and two of Europa. This is due to a Laplace Resonance phenomenon. A Laplace Resonance is when more than two bodies are forced into a minimum energy configuration.
There is also the thought that Venus and the Earth are also tidally "locked" as well.
Anything that persists in nature is likely to contain information such as ice cores and tree rings. It should be no surprise that self-replicating polymers also carry information.
One of these days you'll admit that the Fermi Paradox keeps looking better and better.
Or one could just as easily say that our place in the Universe was engineered so that life could evolve here. But that would raise the question of where the Engineer came from, and why did He do it.
This has nothing to do with the Fermi Paradox at all. My objection to the Fermi Paradox is with the distances involved and our understanding of special and general relativity. This has everything to do with the Drake equation however.
let's call that a foot every ten years or a mile every five thousand years. So 5 billion years would would be 100,000 5,000 years or 100,000 miles. That would put the moon 140,000 away 5 billion years ago. Hmmm, assuming constant drift then in another 5 billion years the moon is 340,000 miles away not the 480,000 miles you state. hmmmm, well maybe the drift is more like 2 miles every 5,000 years then the moon would only be 40,000 miles distant 5 billion years ago and the tital effect would be awesome, mind blowing to think of the moon orbiting that close! What a mess that would create!
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