Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Testing quantised inertia on Proxima Centauri

academic.oup.com

Post reply on HN
Print view View original

11–20 of 41 posts

Re: Testing quantised inertia on Proxima Centauri

#11

Post by btilly »

myrmidon wrote: post #7

Not a physicist, but I never heard of this before and looks quite interesting at first glance. Google indicates that mainstream physics regards it sceptically ("pseudoscience"), but it was difficult for me to find out why . I found a single paper containing criticism from an actual physicist ("A sceptical analysis of quantized inertia" by Michele Renda: https://academic.oup.com/mnras/article/489/1/881/5545603 ), but…

My first criticism is this. The scale on which quantization works is the https://en.wikipedia.org/wiki/Planck_constant. We should not expect quantization to be a visible effect at the scale of stars.

And if quantization was a visible effect at the scale of stars, it should be very visible in our own solar system. But no, our solar system operates classically to a crazy number of decimal places, and the deviations follow general relativity - with no evidence of quantization.

Re: Testing quantised inertia on Proxima Centauri

#12

Post by btilly »

basil-rash wrote: post #10
ilove_banh_mi wrote: post #4

Earlier quoted context omitted.

I'm not aware of any match between GR theory and observations when it comes to galaxy rotation curves. The wikipedia entry provides a decent description of the issue. https://en.wikipedia.org/wiki/Galaxy_rotation_curve

> The discrepancy between the two curves can be accounted for by adding a dark matter halo surrounding the galaxy. Funny. “This discrepancy can be accounted for by accounting for the discrepancy using the number fudging we developed specifically to account for the discrepancy.” Discrepancy’s been accounted for, boss!

I don't know why this got downvoted.

The top theory is exactly that - most of the mass in a galaxy is in the form of dark matter of some kind that can't fit our current theories of physics. The second top theory is that gravity behaves differently at long distances than at short distances. The third theory that is proposed every so often is general relativity, but those who know it best universally agree that it is too small an effect by several orders of magnitude. Every other theory that I've encountered is generally labeled a crank theory.

The reality is that we don't actually know what's going on with the galaxy curves. But we do know that it involves physics that we do not yet understand. And the leading two theories involve weird fudge factors.

Re: Testing quantised inertia on Proxima Centauri

#13

Post by andrewflnr »

ilove_banh_mi wrote: post #4
andrewflnr wrote: post #2

So, not a physicist, but the claims in the PDF about how GR has "never predicted a single galaxy rotation curve" are overblown, right? Aren't there a handful of galaxies where the rotation curve lines up pretty close with the predictions from the visible mass? Any new physics has to explain those, too. Anyway, I think I can see why QI is so appealing. The paper contains a very short and sweet explanation.

I'm not aware of any match between GR theory and observations when it comes to galaxy rotation curves. The wikipedia entry provides a decent description of the issue. https://en.wikipedia.org/wiki/Galaxy_rotation_curve

For instance: https://en.wikipedia.org/wiki/NGC_1277 Citation trail leads to https://www.aanda.org/articles/aa/full_html/2023/07/aa46291-... I vaguely recall there being a few more such instances, but can't find them with a casual googling. The paper is from 2023. Perhaps the Galaxy Rotation Curve wiki article is out of date.

Re: Testing quantised inertia on Proxima Centauri

#15

Post by andrewflnr »

btilly wrote: post #12
basil-rash wrote: post #10

Earlier quoted context omitted.

> The discrepancy between the two curves can be accounted for by adding a dark matter halo surrounding the galaxy. Funny. “This discrepancy can be accounted for by accounting for the discrepancy using the number fudging we developed specifically to account for the discrepancy.” Discrepancy’s been accounted for, boss!

I don't know why this got downvoted. The top theory is exactly that - most of the mass in a galaxy is in the form of dark matter of some kind that can't fit our current theories of physics. The second top theory is that gravity behaves differently at long distances than at short distances. The third theory that is proposed every so often is general relativity, but those who know it best universally agree that it is t…

Because it's a conspiratorial mindset that willfully ignores the long list of other evidence for dark matter in favor of mocking physicists who are doing their best to make sense of confusing observations. That's exactly the kind of thing that downvotes are meant for.

Re: Testing quantised inertia on Proxima Centauri

#16

Post by yongjik »

I'm not a physicist, but a massive Wikipedia article on Alpha Centauri says nothing about the system not being gravitationally bound, and at least one scholarly article says they are gravitationally bound:

https://www.aanda.org/articles/aa/abs/2017/02/aa29930-16/aa2...

> ... the question as to whether they actually form a single gravitationally bound triple system has been open since the discovery of Proxima one century ago. Owing to HARPS high-precision absolute radial velocity measurements and the recent revision of the parameters of the α Cen pair, we show that Proxima and α Cen are gravitationally bound with a high degree of confidence. The orbital period of Proxima is ≈ 550 000 yr.

Re: Testing quantised inertia on Proxima Centauri

#17

Post by btilly »

andrewflnr wrote: post #15
btilly wrote: post #12

Earlier quoted context omitted.

I don't know why this got downvoted. The top theory is exactly that - most of the mass in a galaxy is in the form of dark matter of some kind that can't fit our current theories of physics. The second top theory is that gravity behaves differently at long distances than at short distances. The third theory that is proposed every so often is general relativity, but those who know it best universally agree that it is t…

Because it's a conspiratorial mindset that willfully ignores the long list of other evidence for dark matter in favor of mocking physicists who are doing their best to make sense of confusing observations. That's exactly the kind of thing that downvotes are meant for.

I see zero evidence for any of that.

Science has a long history of proposals based on various fudge factors. Some of those fudge factors disappear when we get better measurements. Some require learning more about the system. For example Newton's theory of sound was consistently wrong until Laplace figured out how adiabatic heating changed things. Some require learning more about the physics. For example Einstein got rid of the need for a fudge factor for figuring out Mercury's orbit. Some require proposing new physics.

When dark matter is called a fudge factor, that is absolutely technically correct. It *IS* a fudge factor. It is a fudge factor that explains a whole lot of stuff, at the cost of requiring something new whose nature we have no real clue about. This isn't conspiracy theory. This is how science works. It is how science is supposed to work.

It's current status is much like that of the neutrino when it was first proposed. A particle we can't think of a way to detect in any way other than the fact that it is required for conservation laws to work out. As it happens, we did eventually figure out how to detect it. But only through discovering then-unknown physics (chain reactions), and building detectors which required a budget that was unthinkable for physics back when the neutrino was proposed in 1930.

Re: Testing quantised inertia on Proxima Centauri

#18

Post by andrewflnr »

btilly wrote: post #17
andrewflnr wrote: post #15

Earlier quoted context omitted.

Because it's a conspiratorial mindset that willfully ignores the long list of other evidence for dark matter in favor of mocking physicists who are doing their best to make sense of confusing observations. That's exactly the kind of thing that downvotes are meant for.

I see zero evidence for any of that. Science has a long history of proposals based on various fudge factors. Some of those fudge factors disappear when we get better measurements. Some require learning more about the system. For example Newton's theory of sound was consistently wrong until Laplace figured out how adiabatic heating changed things. Some require learning more about the physics. For example Einstein got…

If you don't see the mocking tone of the comment we're talking about, and you don't see the conspiratorial tone of the anti-dark-matter crowd in general, then yeah, you won't see why they're worthy of downvotes. But then we live in different worlds, so I guess there's not much to discuss.

Re: Testing quantised inertia on Proxima Centauri

#19

Post by delichon »

> All three stars are co-moving with similar chemistry, which implies they are bound ...

I am not an orbital mechanic, but the word "chemistry" is jarring to me here. Is it just a strained metaphor or is there some sense it which it fits? Maybe the romantic chemistry of mutually attracting bodies?

Re: Testing quantised inertia on Proxima Centauri

#20

Post by lopuhin »

delichon wrote: post #19

> All three stars are co-moving with similar chemistry, which implies they are bound ... I am not an orbital mechanic, but the word "chemistry" is jarring to me here. Is it just a strained metaphor or is there some sense it which it fits? Maybe the romantic chemistry of mutually attracting bodies?

I think they mean "chemical composition", e.g. how much hydrogen / helium / other elements there are in the star, deduced from their spectra
Post reply on HN