JCC Go science?

@DarthPhilosopher
Agreed, the thought experiment of the two little holes and the interference of the particles passing through is one of the best way to make the idea without cheating.

 

Isn't it literally an observational experiment? It's certainly more intuitive then the whole Cat in the Box or coin thing in my opinion...

 

When Feynman came out with it, it wasn't an actual experiment, in the sense that nobody had ever actually done anything similar back then.
I don't know about later.

The cat was not for explaining QM, but rather another thought experiment to make a case against a particular concept (the superposition of states before the measurement), AFAIR.

The spinning coin analogy... I don't know, the spinning coin still sounds BS to me. I believe it doesn't help at all.

 

Oh I thought the cat described the same concept - that we don't know which state the cat will end up in and therefore either both happen, or one just happens and we don't really know why.

 

@DarthPhilosopher
Well, with the cat Schroedinger wanted to bind a big-scale phenomenon to a quantum system, with the goal of somehow revealing an absurd consequence of the concept of superposition of quantum states. We might find it not too difficult to accept that a particle is in a superposition of states (let's say spin up and spin down), and it will collapse in one of the two when we make the measurement. The math works, and things look alright. However, when it comes to the cat, it's not easy for us to convince ourselves that a cat can be in a superposition of death and life, and it will "collapse" onto being dead or alive only when we measure. That's the point he wanted to make, very roughly.

 

Bear in mind that the 'other dimensions' are folded on themselves in M-Theory, meaning that they only 'exist' (for want of a better term) at the quantum level.
Many Worlds interpretation is, I fear, more of way to evade the Uncertainty Principle and dealing with the mechanism of the collapse of the wave function. Feynman's work - to my mind - indicates that such 'many worlds', even if the theory is correct, is again limited to the quantum realm, in which case we see the aggregate results.

The Copenhagen Interpretation can be summed up with "It works, who cares why?" - which is, by my definition, the mantra of an engineer, not a physicist. The only thing worse than that is belief in a Steady State universe.

In all seriousness, my expertise was electromagnetic fluid dynamics, with an emphasis on high magnetic fields, cryogenics, and complexity theory, for whatever that's worth. (It's also ancient history at this point, I haven't done anything relevant to physics in almost 20 years).

I get what Schroedinger was trying to say - that the claim that the act of 'observation' - itself a vague, non-scientific term - would collapse the wave function, otherwise the system would be in an indeterminate state - was absurd.
As far as the mysteries of physics go, though, I don't find it too interesting - to me, it seems obvious that it is a result of the interaction of a complex macroscopic system with the quantum level, rather than dragging other nonqualifiable concepts like 'consciousness' into the picture.

 

Shame. Theories tested outside of labs are equally valid, they just still require testing (not saying string theory has this)

Except you're complaining about a rationale of "it works, who cares why", and then comparing it to steady state universe, which doesn't work.

 

I thought that was only for some string theories? I thought M-theory involved at least some higher and larger dimensions (the 'bulk' for instance)?

 

Oh no, I dislike Steady State theory for a different reason which is that it's based almost solely on the idea that a physicist thought the theory of the Big Bang was 'too religious' (and coined the term 'Big Bang', BTW, as a term intended to mock the idea). It was an attempt to jam someone's personal philosophy into science, and to me it's little different that a creationist, other than a physicist really should've known better. It's a moot point, though, because the theory was completely discredited by the discovery of the cosmic background radiation in the early 60s, not that the original proponents haven't tried other, more bizarre models, in an attempt to salvage it.
A more apt analogous scientific approach to the Copenhagen Interpretation that I also find distasteful is the 'anthropic principle', which to me is just lazy at best, and at worst leads to absurd untestable conclusions such as "we're the only intelligent life in our galaxy". As Roger Penrose dryly remarked, "...it tends to be invoked by theorists whenever they do not have a good enough theory to explain the observed facts."

Admittedly not my area of expertise, but from my awareness the presence of other macroscopic spacial dimensions would change the laws of physics (for example one physicist in 1922 showed that electromagnetism only functions correctly in the standard 3+1 dimensional model). M-theory is a subset that specifically calls for a total of 11 dimensions, whereas as some string theories allow up to 26.
Doing a little research, it does look like one interpretation of M-theory - called the ADD model - has the 7 extra dimensions larger than the Planck scale, as a way to explain the extreme weakness of the gravitational force - only that force can access these extra dimensions. However, these additional dimensions are still incredibly small and would still not have any direct bearing on the macroscopic world.
What's more fun is that M-theory may suggest an additional temporal dimension, which is rife with its own issues.

 

The Copenhagen interpretation is not "it works, who cares why," it's an argument for the ontological realism of the probability waves. Which, I'll be honest, is way easier to swallow than a lot of the proposed alternatives regardless of how big or small you like your metaphysics.

 

Ideas are often developed around a sense of intuition that is then put to the test. The issue with steady state isn't the conception of it, it's the clinging to it beyond the point where it has failed testing.

And the anthropic principle is fairly valid in making sure that the "why"s being asked are actually valid. I don't see how that leads to "we're the only intelligent life in our galaxy" at all, since it states that we can only be in the position to observe things in an environment (universe down to planetary) that was suitable for intelligent life to develop. That doesn't lead to us being the only one, and I don't see how you're saying it leads to that conclusion. It's the same reason why the "Aren't we lucky we live on the Earth and not Venus" thing people will say is a non-starter. I do think there's a danger in presuming that there is no stochastic behavior, and presuming that there's an exact explanation for every value is going to overly constrain understanding if there's no basis for presuming that a process is that deterministic.

 

I criticize the motivation of idea to begin with, as it resulted from a philosophical distaste of the results based on scientific evidence. Quantum mechanics suffered from this in general for years among more orthodox physicists; one could also argue that Einstein's true revelation of relativity was simply accepting the results of experimentation as valid; prior physicists could've easily derived the same result but wasted years of time coming up with more elaborate theories to preserve the classical view of physics.
I will say that at least 'steady state' still tries to abide by scientific principles and wasn't as egregious as, say, Lysenkoism, where biology in the Soviet Union was crippled for decades by a quack who felt genetics and natural selection were too 'capitalistic' in nature.

Don't look at me, that's from a book called the Anthropic Cosomological Principle. I don't agree with the reasoning.
I suppose it's fine as a philosophical belief, albeit a boring one (a sort of secular agnosticism), but as a motivation for scientific research I find it detrimental.
Not that it really came up with my own work, mind you - I dealt with more mundane physics rather than highly theoretical material. It's not something that really came up in the study of magnetic fluids.

 

At the same time, mistaking something as deterministic is going to go down that same sort of wrong path of constantly trying to come up with more elaborate theories to maintain a deterministic system. And I think the core of the anthropic principle is that in any case where there's a range of values that would impact life, we can only observe values that would not prevent life from occurring. I think there's a difference between using it as a consideration to ask if there's sufficient reason to think that something is suitably deterministic or not. Which isn't to say it's not worth checking to see if something can be explained in a more deterministic fashion, just that it shouldn't be presumed to be deterministic when it can also be that some things are as we observe not because prior conditions dictated that, but that if stochastic processes had resulted in a different circumstance that we couldn't be present to observe.

 

Life on Venus?

"Venus Might Host Life, New Discovery Suggests."

https://www.scientificamerican.com/article/venus-might-host-life-new-discovery-suggests/

 

Seriously though, if this gets confirmed, it could be the most exciting scientific discovery of our time. I knew they were looking at the upper atmosphere again, because the conditions for life there are just right, but I had no idea until now that they were drawing any real conclusions so soon.

Temperatures and pressures in the upper atmosphere are about the same as Earth. Microbes exist in the upper atmosphere of Earth. We know that Venus likely had surface water billions of years ago, and so may have had the right conditions for life to evolve, only for a runaway greenhouse effect to destroy any life on the surface (where conditions are literally hellish), but for it to survive in the upper atmosphere.

 

Watching this but haven't dug into it much yet. It's usually a safe bet that it's something else we haven't figured out yet, and Venus is a particularly rough environment, so this would seem like it suggests (as my quick take) something in the high atmosphere where temperatures are much lower, if it is indeed life.

 

I am a natural sceptic. The whole point of this report is that life is the most likely source. It does not mean it is the only possible source, but I do think people need to get away from this idea that conditions are rough in the upper atmosphere. People need to read the article.

They are not hypothesising that temperatures and pressures in the upper atmosphere are possible balmy, this is well established fact.

 

That was indeed why I said this would suggest high atmosphere, because otherwise the planet is rough and hadn't yet gone to the Nature paper (that comment was being written at the same time your longer post was being written)

I would disagree that the whole point is that "life is the most likely source". As they said, "Even if confirmed, we emphasize that the detection of PH3 is not robust evidence for life, only for anomalous and unexplained chemistry."

 

These studies have been going on for years. I was aware of them some time back, because there's stuff in Venus's upper atmosphere that is difficult to explain. The article isn't saying that this is conclusive evidence, otherwise I'd be way more excited than this. The researchers are not going to go out on a limb and say 'this is probably life', because it is natural to be cautious and not invite ridicule. Some astrophysicists on Twitter however are less cautious in their speculation, because it isn't their research. But that doesn't mean they are clueless. That's why I posted Dr Katie Mack's comments. She says, 'It's unclear how else to produce it there.'

Phosphine can be produced abiotically; this is well known, but the conditions on Venus don't readily lend themselves to this. The CO2 in the atmosphere should be soaking up the phosphorus; but something is replenishing it. Bear in mind that there has been speculation about sources of olivine on Mars, but abiotic explanations there probably cover that. Here, the abiotic explanation is more open to challenge. Also, most studies on Mars regarding life are focussing more on the possibility of signs of ancient life. Mars is pretty inactive.

The studies inevitably looked at all possible abiotic causes of this gas on Venus. Any scientist worth their salt would do this. Ironically, none of them are as compelling as one may think. Once you consider the possibility of life however (natural scepticism aside), then it becomes a plausible explanation.

 

I don't think it's accurate to say that the field itself is really having that sort of speculation (I think it's even a stretch on that tweet to read it that way, honestly). This absolutely raises questions and is worth follow-up, but I don't think that equates to the most likely answer being life, as such. The likelihood of unknown phenomena is also something that has to be taken into consideration, particularly as there's a lot left to learn as it relates even to Venus. To use a more historic example from outside the solar system, pulsars were distinctly lacking in an actual explanation when they were discovered, and so in a sense the only explanation anyone had on hand was 'aliens', but I don't think anyone believed that meant that was the most likely outcome, just that there was a wide range of unknown possibilities.

So here I think the most likely explanation is "things we don't know about". Not that life isn't implausible, but that our understanding being complete is more likely. Worth investigating, but framing this as "life is the most likely source" is really not what the paper is doing. It establishes it as not having a known cause, but that isn't the same thing as life being the most likely source at all.

 

I just asked a friend who works in the field of astrochemistry. She is also prudent and she wouldn't say that it's an ultimate proof that there is life on Venus. But there are no known non-biological mechanisms through which a similar amount of phosphine can be produced.
Now it remains to understand how plausible it is to conclude that there are microorganisms on Venus, compared to the existence of non-biological mechanisms producing phosphine. For people in the field, both possibilities are probably extremely exciting, whereas of course for the general public only the existence of aliens sounds cool.

 

"There are no known non-biological mechanisms through which a similar amount of phosphine can be produced."

Which the article states, and that's my point. Of all known explanations, life is the most plausible. That's why a number of astrophysicists and astrochemists have added their voice to the reactions coming out of this publication.

Further research is needed. Lots of it. Clearly, we cannot begin to dismiss the possibility that an unknown chemical process is at work here. It should not come as a surprise to anyone that there is a natural scepticism around this; after all, such a discovery would be unprecedented if confirmed. We are right to be cautious. However, as things stand, this is an extraordinary discovery, whatever the explanation.

 

Yeah, as I was saying, this would also be cool, but the excitement would probably be mostly limited to the chemists community, more or less like with the pulsars common people would have probably liked it more if the explanation were aliens, even though how pulsars work is cool as well.

 

Amazingly, Carl Sagan had predicted the possibility of life on Venus way back in the late 60s...