Saturday, December 1, 2018

Birds Use Quantum Physics to Navigate

It is difficult for me to accept and believe that at some levels physics is a list of possibilities AND that particles can be at two places at once or even not "decide" where they are until they are observed. So in a very real way we can make our own reality. 

Spooky action at a distance is what Einstein called it. But apparently this is what mathematics and physics tells us. What is more interesting to me though is not the insights humans gain from supercollider experiments but the apparent fact that birds, who by most standards, weren't considered to be the Einsteins of the animal world, use quantum physics/biology to navigate. And that would mean that a bird's perception of and experience of reality is EXTREMELY different from our own.

As little as a decade ago, scientists were sure that the chemistry of life and the weird chemistry of the quantum world were completely separate things. Quantum effects were usually observed only on the nanometer scale, surrounded by hard vacuum, ultra-low temperatures, and a tightly controlled laboratory environment. Biology, however, is a macroscopic world that is warm, messy, and anything but controlled. It seemed elementary that a quantum phenomenon such as 'coherence', in which the wave patterns of every part of a system stay in step, wouldn't last a microsecond in the tumultuous realm of the cell. It would be simply unthinkable.

Or so we thought…

Recent years have seen scientists finding coherent quantum processes all across the natural world. And it’s not just in some exotic halobacteria or flying marsupial, it turns out quantum biology is pretty much ubiquitous. In fact, it appears to be a central part in the most important chemical reactions on Earth: photosynthesis and cellular respiration.

Niels Bohr, one of the founders of the field, said of quantum mechanics, “If you're not astonished by it, then you haven't understood it.” And he was absolutely right. One of the most beautiful uses of quantum effects in nature is with the migratory compass of the European robin. 

This bird migrates from Scandinavia down to the Mediterranean every autumn, and like a lot of other marine animals and even insects, they navigate by sensing the Earth's magnetic field. But the Earth's magnetic field is very, very weak; it's 100 times weaker than a fridge magnet. And yet it somehow affects the chemistry within a living organism. A built-in compass! But how does it manage this? Well, in the case of the robin at least, with quantum entanglement. This is the term for when two particles are far apart, and yet somehow remain connected (and we have no good explanation for why—even Einstein called it “spooky action at a distance”). 

Somehow though, inside the robin's retina is a protein called cryptochrome, which is light-sensitive. And within cryptochrome are a pair of electrons which are quantum-entangled. These electrons are far enough apart that the difference between the weak magnetic field interactions on each one is actually detectable, which allows the bird to sense whether it is flying towards or away from the equator. Now, just for reference, if coherence is a “delicate” process, entanglement may as well be neurosurgery with a chainsaw.

The theory goes that electrons in the receptor cells of birds’ eyes can change their spin, and therefore their state of entanglement with other electrons, based on the Earth’s gravitational field. And depending on which way they’re flying in relation to this field, the electrons will either absorb energy from the Sun or release it back into the optic nerve.

This is amazing, not only because it’s a quantum phenomenon taking place inside the cells of a living creature, but also because it may mean that birds can SEE quantum entanglement - something our best scientists can barely visualise.

This also means that they may be able to see with their own eyes whether they’re going west or north, sort of like an inbuilt, Google Glass-style compass. And that. is. mind-blowing

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