Mirror life
en.wikipedia.org
en.wikipedia.org
Does this have "great filter" implications? If it confers such a huge advantage for a prokaryote to have the opposite chirality, then it must be very unlikely for prokaryotes to evolve from scratch, as if it wasn't then something would have evolved to take advantage of this. It means that "the evolution of a simple prokaryote" has definitely only happened once.
edit: it might take some time though. Wood was indigestible for a long time, giving us coal deposits.
While it's true that a mirror cell wall would be a barrier to being broken down, there's nothing that would fundamentally stop the evolution of a suitable degradation machinery for it.
It may be the case that there is no easy jump for existing prokaryotes to handle mirror proteins. However in the 'worst case', predation would simply re-emerge from the original prokaryote via speciation ... but it may take a long time.
Interesting, this has been considered as a diet alternative but too expensive so far:
> L-Glucose was once proposed as a low-calorie sweetener and it is suitable for patients with diabetes mellitus, but it was never marketed due to excessive manufacturing costs. [1]
Through the Looking Glass, by Lewis Carroll
It would stand to reason then that some of these mirror good microbes would eventually evolve to become mirror bad microbes?
[1]: https://en.wikipedia.org/wiki/Chemical_chirality_in_popular_...
It's also a rather minor plot point in The Expanse series' 4th Novel, Cibola Burn. Some of the life on a new planet is bi-chiral, meaning it integrates both handednesses of proteins, amino acids, RNA bases and backbones, etc.
I'm not a microbiologist at all, but I don't think so. If big organisms can be mirrored, so will microbes. You need various good bacteria so already have to mirror those. If you've got the mirrored organisms with mirrored DNA and RNA, it's pretty certain virii and bacteria will form from it at some point.
On another note, it's a shame we don't have a 4th dimension that we can rotate ourselves through to mirror ourselves, that would be interesting!
This chiral world would give protection for all organisms to all the current pathogenic microbes. Many would have to evolve from scratch.
No. This is wrong on two fronts. First, there would be new diseases which are of the opposite chirality, obviously. There is no such thing as a real objective definition of 'disease'. There are only patterns which successfully reproduce themselves and those which do not. But whatever sort of environment constructed will essentially create its own diseases, which will infect and interfere with what we intend to create. Successful systems breed parasites. That's a truism in microbiology.
Secondly, a microbe-free world would kill us. There are more bacterial cells in our body than there are cells with our own DNA. Our understanding of the importance of our microbiology to our lives is pretty meager, but it's enough to know that 'clean room' living would be nightmarish in the best case, but more likely just lethal. And if your intent is to only allow in the 'good' bacteria and viruses and funguses... that line doesn't really exist. Biology is too messy to enable those sorts of distinctions, really.
Creating a 'mirror life' world might be pretty neat, but I don't think the benefit would be from eliminating microbial interference in our precious bodily fluids.
In fact even Atiyah touches on this idea (though without speculating that it might be a property of our universe). In Mind, Matter and Mathematics, he says:
"When I was a student in Cambridge our mathematical society invited a distinguished professor of philosophy, C.D. Broad, to give us an evening lecture. He chose to talk on a problem which had much exercised Kant, the difference between right-handed gloves and left-handed gloves. After the lecture, over dinner, I diffidently suggested to Broad that, since Kant’s time, we mathematicians had a much better understanding of “handedness”, or chirality as scientists call it. We could even envisage a universe in which a left-handed glove could wander around to distant regions and return to fit your right-hand. "
Incidentally the Mobius strip need not have a edge; you can leave out the boundary circle at the cost of having a non-compact space. This is exactly analogous to the difference between the closed and open intervals: [0, 1] vs (0, 1).
In fact the projective plane can be obtained by taking a disc and glueing its boundary to that of the Mobius strip, which makes the two boundaries "cancel".
It seems to me that the statement that Wu's experiment holds globally is equivalent to the statement that the universe has an orientation so I now tend to think the universe does not admit one of these orientation-reversing loops.
At first I was surprised that we could apparently draw a global conclusion based on local observations but I've mostly convinced myself now based on the following analogy (which I hope is not misleading).
Imagine we live in a two-dimensional universe and we want to know whether or not it is orientable. E.g., do we live on the surface of a torus or on the surface of a Klein bottle? We have defined a local orientation in the topologically-trivial patch where we live and so are used to speaking of "left-handed" and "right-handed" gloves. The question of whether these words are globally meaningful is exactly the question of whether our universe is orientable.
One day we learn about "colour" and are stunned to discover that all left-handed gloves are red and all right-handed gloves are blue. It seems very unlikely to us that red somehow transitions into blue as we traverse a loop and so we conclude we must live in an orientable universe.
Nice! I tried to play around with this. There's the https://en.wikipedia.org/wiki/Gold_universe where two inhabitants can honestly disagree about the direction of time. (And the interactions between the two are hilarious.) Can we have a version where one can go far away and come back time-reversed? Or is that excluded by CT=P symmetry breaking? It sounds like it, but it's confusing.
With regard to:
> Can we have a version where one can go far away and come back time-reversed? Or is that excluded by CT=P symmetry breaking?
I don't know. Having mulled these thoughts further after writing the above I'm now more cautious about guessing. Specifically it seems to me that electromagetic charge, weak isospin, isospin etc. are all only globally well-defined provided we have an orientation of spacetime. So it seems to me that if spacetime is not orientable then there's no guarantee that if we send an instance of Wu's experiment off in a spacecraft on a hypothetical orientation-reversing loop then the apparatus will arrive back at earth unchanged: perhaps its electrons are all now positrons etc.
My analogy with the coloured gloves does not permit such a phenomenon because colour is manifestly well-defined. I could make it more elaborate to account for this (e.g., replacing colour with a clockwise/anti-clockwise concept) but I no longer find it useful.
In summary: I revert to my original "no opinion" point of view.
An interesting consequence is that two particles may attract if brought together along one route, and repel if brought together along another.
Heart on the right side is called Dextrocardia in this universe, so I guess it would be called "Levocardia" in the chiral universe.