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Quantum Coherence Found Fueling Photosynthesis
Gaygirlie writes "Ars Technica has posted an interesting article about new findings regarding quantum physics and photosynthesis. Their excerpt for the article: 'Physicists have found the strongest evidence yet of quantum effects fueling photosynthesis. Multiple experiments in recent years have suggested as much, but it has been hard to be sure. Quantum effects were clearly present in the light-harvesting antenna proteins of plant cells, but their precise role in processing incoming photons remained unclear.' Here's a little background info for those unaware of what coherence and quantum coherence are."
helped me, yet again, realize how little I understand quantum physics.
If quantum effects are real (as they demonstrably are), should it be a surprise that evolution made use of them?
I've seen some comments stating that 'meh photoelectric effect nothing new to see here'. While it is true that emission/absorption is subject to quantum mechanics, specifically the photo-electric effect being governed by the work function hf = phi - eV, with hf = hc/lambda, phi being the work-function of the material, and eV being the 'escape velocity' of the electrons; the point being that energy emitted/absorbed must satisfy the above relationship, otherwise the photo-electric effect does not work.
What I believe this study is saying is that 'antennae' structures can act as a single quantum mechanical unit (the coherence) so that the incoming insolar radiation has more paths for electron conduction, since the transfer of energy/conduction of electrons is limited to the quantization by the work function, i.e., charge quantization limits the specific wavelengths/frequencies/energies of incoming photons that the plant can use to harvest energy, so in effect the evolution of these 'antennae' structures over time allows for a coherent systems that can act as single particles, with the different permutations of antennas allowing for vastly more permutations of allowed incoming wavelengths to satisfy the Schrodinger eqn (probably not dirac since these are most likely not relativistic interactions, at least the effects are negligible).
I deal more with relativity and QED/QCD, but that's my interpretation of the article.
'We are trying to prove ourselves wrong as quickly as possible, because only in that way can we find progress.' RPF
Any evolved system will use all possible inputs to its fitness function, simply because there isn't any mechanism of focusing. Unlike human design, which is all about making known mechanisms work and all but those mechanism are ignored, and even actively avoided. When early researchers used solid-state electronics to make genetic algorithms, often the "solution" only worked on the specific hardware circuit it was learnt on (not supposedly identical copies), because it relied on otherwise-undefined race conditions in the silicon.
So don't be surprised if quantum effects are also used by your brain cells ... and by your anal sphincter.
What right do we have to alter what will happen to this planet millions of years from now?
Wrong question. We have no rights in this regard.
But we do have a duty towards self-preservation.
Linux, you magnificent bastard, I read the fucking manual!
The way people often describe quantum decoherence is that an "observation" occurs that "collapses the wave function" and causes a superposition to converge to a single classical state. But I really think that's a misleading explanation. For one thing, surely the same phenomena occurred long before there were any intelligent observers, and secondly, scientists have observed things in states of quantum superposition WITHOUT causing decoherence.
The way think of it (as a total amateur in the area) is that rather than the wave function representing probabilities of states, it represents the degrees to which something is in all of those states. An "observation" is just like many other interactions with the environment that change those probabilities (or degrees of state).
Then there's the question of why subatomic particles (and some larger things) can be in states of quantum superposition, while larger things cannot. Penrose had a suggestion here. It's gravity. The more massive you are, the less your superimposed states can diverge from one another. Even a planet is in a state of superposition, but all of those states overlap so much relative to the dimensions of the object that you cannot distinguish them.
A) The "what if" scenarios that have the Earth being destroyed, if we aren't off the Earth by then humankind is done.
The problem is that even if we have off-Earth colonies, humankind will still be in just as much danger as if we didn't. Consider the most likely scenarios:
1. Asteroid impact. Extensive damage to population and biosphere, but nothing that would render Earth less habitable than Mars. If we had the ability to colonise Mars, we'd certainly have the ability to build shelters on Earth. Result: no need to colonise Mars, just build greenhouses on Earth.
2. War, social unrest, mass insanity. Possible huge damage to Earth's population, depending on how crazy things get. However, space structures will be launched by nation-states and large commercial combines with ties to Earth and will therefore surely be part of the wider Sol system social fabric and will take part in the war. Possibly they'll be the first to be destroyed. For example, World War II began in the core European nations but quickly swept up all European colonies, and some of them such as North Africa and the Pacific became key battlegrounds. Also, the technologies which launched human spaceflight were the flip-side of Earth's worst weapons of mass destruction - the ICBM program. Result: little shelter from a war by extending human culture into space, and a lot of actual danger created by doing so.
3. Plague (including aliens and zombies). A fast spreading virus could conceivably take out most of the human population on-planet, but is unlikely to take out the biosphere or even all of the human population. Earth's survivors will still vastly outnumber any reasonably expected number of space colonists, and will still inherit a much more robust ecosystem than anything on Mars. Worse, any space colonisation program will involve constant resupply and then travel and trade between Earth and the colonies, which will be vectors for transmission of disease. Space colonies themselves will be tightly-packed and fragile, vastly more dangerous places in terms of plague. Result: no survival advantage in space colonies, in fact the colonies will probably die first.
4. Environmental collapse. We're certainly degrading Earth's environment, but space won't help us - all other planets are far worse environmentally than we could conceivably ever make Earth. All space colonies will need either constant resupply from Earth, or the environmental skills to be completely self-sustaining. And if we had those skills, we could just build greenhouses on Earth. Terraform Mars? Well, if we could terraform anywhere reliably, we could start doing it on Earth and fix all our environmental problems in one hit. Result: no environmental disadvantage to going into space, but no advantage either.
5. Ore depletion. Okay, so let's assume we fix the biosphere, but we're still running out of metals to make iPods. We can mine those in space, right? Well, yes and no. If we mine vast quantities of metal and introduce that into Earth's biosphere, that might mess up the biosphere (see 4). Moving asteroid-sized rocks around the system introduces huge military problems (see 2) as they'll be more dangerous than nukes. Space mining is also likely to be be more expensive than just recycling landfill, so where's the commercial advantage? Result: a commercial non-starter and a major military threat, best avoided really.
6. Supernova, red giant. The big one, a complete solar-system destroying event with no chance of sheltering in place. This is the only scenario where conceivably we could improve our chances by going into (interstellar) space. Problem is, to get out of range of Sol going boom we'd need to have either a generation ship going for several hundred years and having already solved the closed life support problem (see 1, 4), so this will be a long-term rather than short-term capability. Best estimates for Sol going boom are millions to billions of years, so again, this is not a pressing human need. Result: maybe worth look
You are not a brain: http://books.google.com/books?id=2oV61CeDx-YC