Zkribbler
Deity
I loved those helicopter-saucers in The Incredibles. I really wanted one until I realized that, while the hoverblade was rotating clockwise, Newton's 3rd Law would cause the cabin to rotate counter clockwise.
But life, it seems, is different. Indeed the internal compass that enables female robins to migrate in the winter relies on a curious capability that wouldn’t sound out of place in an X-Men line-up: magnetoreception. The theory goes that the eye of a robin contains a chemical that, when it absorbs light of the right energy, can shuffle its electrons around. This shuffling creates a system that exists, thanks to some quantum jiggery-pokery, in two forms at once – each of which leads to a different outcome in the reaction that follows. Which form predominates, and hence which outcome is more likely, is influenced by the angle of the Earth’s magnetic field, allowing the robin to detect if it is heading towards the equator or away from it.
Quantum mechanics is one of science’s most successful theories, superseding Sir Isaac Newton’s “classical” physics, the workaday version taught at school. The theory’s weirder predictions—spooky connections, tunnelling and the like—are not part of people’s everyday experience. They happen at a microscopic level and, it was thought, only under precisely controlled conditions. Experiments were done by the steadiest hands in the darkest labs at the lowest achievable temperatures.
But life is nothing like that. Plants and animals are warmed and lit by the sun, mostly, and tend to be squidgy, moving and watery. It had long been assumed that a living being is a poor laboratory in which to carry out quantum experiments. But in 2007 scientists who were trying to understand how plants gather the sun’s energy so efficiently stumbled across something strange: that energy was sloshing around in what are called quantum coherences. In effect, the energy is in multiple places at the same time and “finds” the most efficient route from where it is collected to where it is put to use.
This first credible example inspired other scientists to follow similarly bold avenues of enquiry. To grasp these new threads in quantum biology is to grasp a quantity of quantum theory; the coherence is just one of the complex phenomena that Jim Al-Khalili and Johnjoe McFadden set out to teach the reader. They succeed by using delightfully revealing analogies and similes, some borrowed from their prior work, that make slippery concepts sit still for study.
Well, I was impressed by the evidence of quantum processes showing up as part of chemical interactions and enabling those chemical processes to happen in an improved fashion. The authors also opened the door to wider work that should be done.
But in 2007 scientists who were trying to understand how plants gather the suns energy so efficiently stumbled across something strange: that energy was sloshing around in what are called quantum coherences.
What is the current consensus on that? Seminars I visited a couple of years (2013?) ago said that it was still very controversial if/how quantum coherence influences photosynthesis.
Does anybody have a rough idea of how quickly things like river meanders form? Is it a matter of decades, or centuries, or millennia? I can find plenty about how it happens but nothing that will give me a time-scale.
Does anybody have a rough idea of how quickly things like river meanders form? Is it a matter of decades, or centuries, or millennia? I can find plenty about how it happens but nothing that will give me a time-scale.
So this is probably stupid, but:
Does like the entire universe (or maybe rather the things in it) have a not-moving centre of mass?