[HN Gopher] Nuclear spectroscopy breakthrough could rewrite fund...
___________________________________________________________________
Nuclear spectroscopy breakthrough could rewrite fundamental
constants of nature
Author : geox
Score : 64 points
Date : 2024-07-02 18:52 UTC (4 hours ago)
(HTM) web link (newsroom.ucla.edu)
(TXT) w3m dump (newsroom.ucla.edu)
| Animats wrote:
| Rewriting the fine structure constant sounds dangerous.
| mass_and_energy wrote:
| I'm listening?
| dekhn wrote:
| It's generally considered unlikely that the FSC or the
| gravitational constant has varied through time or space.
| Animats wrote:
| "Nuclear spectroscopy breakthrough could rewrite fundamental
| constants of nature". That's UCLA's PR department in action.
| westurner wrote:
| > _When trapped in a transparent, flourine-rich crystal,
| scientists can use a laser to excite the nucleus of a thorium-229
| atom._
|
| > [...] _This accomplishment means that measurements of time,
| gravity and other fields that are currently performed using
| atomic electrons can be made with orders of magnitude higher
| accuracy_
| quercusa wrote:
| I want to know how they trap the scientists in that crystal.
| dmvdoug wrote:
| First encase them in carbonite so they're not so wiggly.
| pdonis wrote:
| "Rewrite" is a misstatement; what is actually meant is "measure
| with greater accuracy".
| karmakaze wrote:
| Abbreviated from "Rewrite least significant digits of ..." /s
| pdonis wrote:
| Maybe so, but the abbreviation significantly changes how the
| average person is going to interpret what is being done.
| nayuki wrote:
| Interestingly:
|
| > One isotope, 229Th, has a nuclear isomer (or metastable state)
| with a remarkably low excitation energy, recently measured to be
| 8.35574 eV. It has been proposed to perform laser spectroscopy of
| the 229Th nucleus and use the low-energy transition for the
| development of a nuclear clock of extremely high accuracy.
|
| -- https://en.wikipedia.org/wiki/Isotopes_of_thorium
|
| See also: https://en.wikipedia.org/wiki/Nuclear_clock
| staunton wrote:
| Storage and cooling of thorium ions has also been achieved
| already. It's only a matter of time before a clock is built
| using such an ion-trap setup (and a matter of significantly
| more time until auch a clock can be used in real-world
| applications). The article is talking about avoiding this but I
| believe the first thorium clock will likely be an ion trap.
|
| A nice website collecting information about this is
| https://thoriumclock.eu
| MostlyStable wrote:
| What are the practical considerations of being able to measure
| time/gravity/etc more accurately?
|
| Will this make GPS cheaper/more accurate? Will this allow better
| astronomical observations?
|
| Note that I'm certainly not against blue-sky science where we
| don't immediately know of any practical uses. As the end of the
| article specifies, pure research often ends up paying dividends
| down the line.
|
| But I'm curious if there _are_ any more immediate applications.
| JumpCrisscross wrote:
| > _What are the practical considerations of being able to
| measure time /gravity/etc more accurately?_
|
| Likely nothing in the near term. Calibrating constants lets us
| project the limits of reality further and more confidently. The
| practical implications of that are in letting crazy shit get
| greenlit, _e.g._ the Manhattan project from nuclear physics or
| the light bulb from quantum mechanics.
| dotnet00 wrote:
| I think currently most of these things are dominated by other
| sources of noise such that a more precise clock isn't that big
| of an improvement, but the article claims these kinds of clocks
| could also be smaller than an atomic one, which may make them
| worth using. Could be useful for things like submarine
| navigation via gravitational mapping or other applications
| where size and lifetime/maintenance requirements might favor
| this design over a standard atomic clock.
| ProjectArcturis wrote:
| Adding more decimal points to various physical constants. Any
| everyday applications are far away.
| staunton wrote:
| Do you like having precise GPS? That requires using atomic
| clocks and the general theory of relativity.
| chrz wrote:
| We do but with breakthroughs in science, the future uses
| are impossible to see now, sometimes they lead to
| incredible things. When Maxwell confirmed that light is
| also electromagnetic force with much more than just visible
| light in it, then all the atom discoveries and after that
| all the texhnologies like computer and what not, or making
| laser led to compact disc drives for example. I think
| precise nuclear measurments might help someday
| discover/confirm something new in physics
| fsh wrote:
| The atomic clocks used in GPS are many orders of magnitude
| worse than state-of-the-art, and are not a significant
| limitation for the accuracy of the system.
| sandworm101 wrote:
| >> we don't immediately know of any practical uses.
|
| A nuclear clock may be accurate enough that speed could be
| measured by time dilation alone. More accurate clocks could
| mean better calibration and more precise tools that contribute
| to all manner of communication techs.
| eep_social wrote:
| TFA mentions scaling atomic clocks down from room sized, which
| they already are according to google's AI, but maybe the
| engineering tradeoffs to do so could be improved.
| gh02t wrote:
| Yeah, tiny atomic clocks/frequency references the size of a
| matchbox are something you can just buy for a couple thousand
| dollars. Mostly useful for stuff like cellular base stations,
| seismic measurements, and a bunch of military applications.
|
| * https://www.microchip.com/en-us/product/MAC-SA53#purchase-
| fr...
| perihelions wrote:
| Here's the open-access arXiv preprint:
|
| https://arxiv.org/abs/2404.12311 ( _" Laser excitation of the
| 229Th nuclear isomeric transition in a solid-state host"_)
|
| Here's an HN thread with 215 additional comments, from two months
| ago:
|
| https://news.ycombinator.com/item?id=40194636 ( _" Atomic nucleus
| excited with laser: A breakthrough after decades (tuwien.at)"_)
|
| (Both threads are about an optical coupling to 229Th nuclear
| transitions; also, the top comment of that thread links to the
| paper underpinning this thread).
| swayvil wrote:
| Would it be upsetting if we sent a probe a lightyear away and
| found that some constant, I dunno, Planck's constant or whatever,
| had changed?
| mr_mitm wrote:
| Not sure if upsetting is the right word, but people are looking
| for things like that. It would be a remarkable discovery for
| sure. There are markers in the spectra of distant stars that
| could give us a hint, so sending probes is not necessarily a
| requirement. So far, potential variances have been constrained
| to a very high degree.
| datameta wrote:
| Excuse me, to a very high degree? Can you elaborate?
| Modified3019 wrote:
| To put another way, the amount of change in plank's
| constant that could potentially happen is highly limited
| (based on our current methods of measuring and inferring),
| and only getting more limited as we improve accuracy.
| staunton wrote:
| Not OP, but this is talking about bounds on how different
| such constants can be across time and space. For example,
| wikipedia.org/wiki/Time-variation_of_fundamental_constants
| Gibbon1 wrote:
| Stuff I've read is spectroscopy can detect molecules from
| billions of light years away. And if something like Planck's
| constant varied with time or distance the spectral properties
| of those would change radically.
| setopt wrote:
| Very. One consequence is that, for example, momentum might not
| be conserved, since according to Noether's theorem momentum
| conservation is directly linked to the translation invariance
| of fundamental physical laws. One consequence of that in turn
| would be that Newton's 3rd law, "every action has an opposite
| and equal reaction", would not always hold since it's
| equivalent to momentum conservation.
| slashdave wrote:
| I love how university PR departments exaggerate the importance of
| research to almost a comical degree
| asdff wrote:
| They have to. Its written for lay people where most else they
| read is also exaggerated marketing versus boring truths. People
| in the field just read the underlying paper and have the
| experience to put the results of it into proper context.
| alan-hn wrote:
| We read the underlying paper while crying because we know one
| of our family members will come up to us talking about the
| incredible new world changing discovery
| j-wags wrote:
| I don't disagree with what you meant here, but this sentence
| threw my mind through a loop. It shows how "have to" is a
| real weak point in how we communicate and think.
|
| Maybe we should rank our "have to"s on a scale from 1 to 5,
| where for example:
|
| - "objects in motion have to (1) remain in motion unless
| acted upon by an external force"
|
| - "humans have to (2) eat food to stay alive"
|
| - "developed countries have to (3) maintain a scientifically
| literate populace"
|
| - "university PR people have to (4) write like that to pay
| for food and shelter"
|
| - "university PR people have to (5) write like that to afford
| a new sports car"
|
| I think you meant something like the example for (4), but
| reasonable people might see it more like (5), and in both
| cases it's at odds with the more fundamental "have to" (3)
| for society.
| throwanem wrote:
| This constitutes a loose extensional definition of a
| spectrum between the positive (1) and the normative (5), or
| between "is" and "ought".
|
| In the original example, it _is_ that university research
| PR has to be written this way to provide the grant
| substantiation its existence subserves, but arguably
| _ought_ to be that the PR piece could just describe the
| research properly and without all the exaggeration.
|
| To be clear, I would have no quibble with such an argument
| and also do not care how anyone else feels about it. The
| point is to help demonstrate that "ought" is the domain of
| that which is always arguable and which must always be
| argued. "Is," like the gravity which holds us to the bosom
| of this planet, _is._
| gaganyaan wrote:
| Reminds me of https://en.m.wikipedia.org/wiki/E-Prime
|
| Maybe we could invent some new verbs to delineate between
| the scenarios.
| 1vuio0pswjnm7 wrote:
| Unlike so-called "tech" companies who are very careful to avoid
| hyperbole and exaggeration.
___________________________________________________________________
(page generated 2024-07-02 23:00 UTC)