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Comment by hn_throwaway_99 | Hacker News Reader

> A second paper, published simultaneously in Nature Communications and led by Professor Oppenheim's former Ph.D. students, looks at some of the consequences of the theory, and proposes an experiment to test it: to measure a mass very precisely to see if its weight appears to fluctuate over time.

Definitely don't know enough to comment about the overall proposal, but given how many grand physics theories over the past couple decades have been untestable, it's really nice to see the proponents proposing a test.

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Love that there is a test.

Some of the theories like gravity waves and Higgs boson took almost half a century to be confirmed by experimentation.

The hard part about this is building tools that can precisely measure mass fluctuations with extremely low error bars at picosecond timescales.

Because we need to both validate the theory and that the device is correctly measuring.

So much of science became only possible because of better instruments. Be it microscopes to see the tiniest phenomena or telescopes to observe the furthest phenomena.

I’m not a physicist much less an astrophysicist and so take what I’m about to say with a hefty grain of salt. But I wonder if this new approach can also explain observations of distant galaxies. Distant galaxies either redshift because they’re moving away faster over time due to dark energy or redshift because their mass is changing. Can this new theory help explain why older galaxies might lose increasing mass over time?

>redshift because their mass is changing.

Why would that cause red shift?

Losing energy shifts the frequency of your emissions towards red.

Basically, cooling down is the same thing as moving farther away from an inertial reference point.

Are you thinking of thermal radiation? And what does losing mass have to do with cooling down?

We observe redshift in the spectrum. Hydrogen emits radiation in very specific frequencies, which are redshifted. This cannot be explained by losing mass, heat or energy.

I thougt the red shift is due to Doppler effect and the universe expansion (planets are running away from any observer in the universe)

> So much of science became only possible because of better instruments.

I would argue a stronger claim: experimental confirmation of theories and better measurements must always bootstrap each other. The history of temperature has many examples [1].

[1] https://psychology.okstate.edu/faculty/jgrice/psyc4333/Therm...

Surely someone has at some point come up with a theory that was testable with then-current equipment.

Yeah, since untestable proposals for this kind of theory are basically the norm, the fact that they have a proposed test made me think it was worth sharing.

> it's really nice to see the proponents proposing a test.

Is it feasible though? I wonder whether that test is not just outside of what can be technically realized today, but Heisenberg's uncertainty principle gets in the way.

Well,... measuring gravity waves was outside of the technically realisable for a long time, but a couple of decades of trial and refinement and it got realised.

It's good that it's testable. This is one of those ideas which either wins a Nobel Prize or is totally bogus. So what does it take to test it?

Bogus usually implies something meant as a fake or counterfeit, I think a better way to describe it would be "incorrect", I don't think these scientists are trying to fake anything.

Untestable theories are not theories - I mean, for what purpose and why care?

Path finding

The other big theories aren't completely untestable, the issue is basically that the models have a lot of parameters which can often be tuned in a way that leaves a possibility for the general theory to still work, and testing them to the point that any corrections seem too unreasonable is even more difficult and expensive.

Not reflecting to this particular theory, but in general history is full of theories which were not testable at their birth, but both engineering and the evolution of the theory eventually found a way to do so, even if it took a century.

Black holes, Higgs bozon and neutrinos are a few popular examples.

Some theories are only untestable for practical reasons, like needing a particle accelerator the size of the solar system. That doesn't make them unscientific or "not theories". That is not the kind of falsifiability that Karl Popper had in mind.

Yes, it does. The word "theory" has a specific meaning. What this article is about is really a hypothesis, not a theory. I saw no evidence or data to back up what they think might be happening, thus not a theory.

"In scientific reasoning, a hypothesis is constructed before any applicable research has been done. A theory, on the other hand, is supported by evidence: it's a principle formed as an attempt to explain things that have already been substantiated by data."

Most people in this thread, as well as the writers of the article seem to be confused about the meaning of the word theory.

Maybe that should give you a hint that professional working scientists don't care much for definitions from wordbooks.

Besides, I was commenting on the topic of falsifiability. To be a scientific hypothesis or theory it must be falsifiable - in principle, not practically. At least that's my claim in the context of Popper. Evidence didn't even enter the discussion.

Do you have any examples? I‘d to read up!

This guy is exploring ultra large colliders:

https://arxiv.org/abs/2106.02048

> The CCM will be an important stepping stone toward an ultimate Planck- scale collider, with a centre-of-mass energy of ∼10^16 TeV, that would require a minimum size equal to a tenth of the distance from Earth to Sun.

Yeah they are, they just cannot be verified - or cannot be verified yet.

The higgs boson theory was theorised in 1964 and it was untestable at the time, but that theory got the funding together to create one of the largest and most expensive scientific instruments built to prove the theory.

Nuclear fusion was theorised in 1915, again untestable at the time, and look how far we've come.

The above comment is an anti-science comment if I've ever seen one.

Usually when people say something is untestable they don't mean like the Higgs Boson. It was testable, they just needed the proper tools. This was always known and was being actively worked towards. An untestable theory is one that cannot be tested regardless of the tools due to the nature of the theory. Multiverse is an example of an untestable theory. There is no way we know of to actually prove or disprove it. And its fair to question their legitimacy as theories. As testing a hypothesis is the core action of the scientific method, it logically follows that anything untestable is fundamentally not science and therefore not a theory.

Isn't the term for this "unfalsifiable"?

A theory can be untestable but also falsifiable. For example, while the multiverse theory/interpretation may be untestable, it could be immediately falsified if QM were falsified.

Popper's falsifiability criterion was more aimed at theories like Marxism, where it seemed that within the theory there was always something available to account for an exception or challenge.

In this case I think multiverse is both. Testability and falsifiability are closely related. But its possible to make a testable statement that can't be falsified in most examples I can think of the test can't be exhaustive.

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