6 ms·

The experiments are now so sensitive that if an electron were the size of Earth, they could detect a bump on the North Pole the height of a single sugar molecul

The experiments are now so sensitive that if an electron were the size of Earth, they could detect a bump on the North Pole the height of a single sugar molecule. This new bound is sensitive to energies above roughly 10^13 electron-volts — more than an order of magnitude beyond what the LHC can currently test. Wow.

JumpCrisscross 4y ago
It reminds me of Aristotelian physics’ perfect ætherial heavenly bodies. Ironinic they were on the terrestrial sphere in the end.
wkat4242 4y ago
Yeah how do they manage to get that kind of accuracy. Mind boggling.
- moron4hire 4y ago
  That's precision, not accuracy.
  - lifeisstillgood 4y ago
    hang on - what? Yes it is precise ... to 17 decimal places or whatever. But it is also I believe accurate? I mean are they wrong and the electron is as bumpy as my chin on a weekend?
    - delecti 4y ago
      It's not that the experiment is not accurate, "accuracy" is simply not the aspect of the measurement being discussed. The sentence "That's precision, not accuracy." should be read to mean "we are discussing precision, we are not discussing accuracy" rather than "it's precise, but inaccurate".
      - Wowfunhappy 4y ago
        But I feel like in this context, we're discussing both.
        Mezzie 4y ago
        Precision and accuracy are slightly different mathematical concepts, as demonstrated by this image [0]: [0]: https://wp.stolaf.edu/it/files/2017/06/precsionvsaccuracy_crashcourse-579x600.png https://wp.stolaf.edu/it/files/2017/06/precsionvsaccuracy_cr...
        rektide 4y ago
        To be honest accuracy Vs precision has always kind of makes sense to be but also not. If something is extremely accurate, it will also be extremely precise by necessity, it seems like? The difference between low precision but high & low accuracies is that points are closer to center. If you keep getting closer to center, more accurate, don't you necessarily get more precise too? Precise has always felt like a shitty alternate of accuracy. It's accuracy but with drift, accuracy to not the right place. But if you're accurate, you're both. Am I missing something? And, here specifically, if this is a case of very high precision but lower accuracy, can someone explain what the drift from center is about? Isn't a radius a radius? Where is the drift off center in these measures?
        alexpetralia 4y ago
        I wrote about precision here if you are interested. You first need precision before you can start even talking about accuracy (otherwise there is no "center"). https://alexpetralia.com/2023/01/31/what-does-it-mean-for-data-to-be-precise-part-4/ https://alexpetralia.com/2023/01/31/what-does-it-mean-for-da...
        hansvm 4y ago
        Something is accurate in this sense if the "true" value (ignoring any philosophical implications thereof) is contained in the error bounds of the measurement. What you're noting is that a high accuracy measurement will, upon application of statistics, allow you to derive a new measure which is both high-accuracy and high-precision, regardless of the low precision of any inputs. Not all things being described with accuracy and precision are the result of processing large amounts of data though.
  - klausnrooster 4y ago
    My (mis-?) understanding of the Central Limit Theorem is that the average of >30 measurements increases the accuracy. https://en.wikipedia.org/wiki/Central_limit_theorem https://en.wikipedia.org/wiki/Central_limit_theorem
    - moron4hire 4y ago
      No, that's increasing the precision, not accuracy. Many imprecise measurements can be averaged to a more precise measurement. Say we had a perfect ruler to measure the length of something. It's absolutely precise and accurate. All measurements from it return the exact, same value, and preternaturally we know it's the "correct" value. Now say some bandit comes in while we're not looking and adds a small chunck of diamond to the end of the ruler without telling us. Our ruler is still precise, but no longer accurate. If we take many measurements with it, they always come back with the same value. Averaging those values does not improve the accuracy at all. Alternatively, say the bandit starts randomly changing the temperature of the room we are in. Thermal expansion is constantly changing the length of the ruler. The average length of the ruler is still the same, so it's still accurate, but it's no longer precise. We could average the measurements we take with it and get a more precise measurement. What the central limit theorem says is that the averages of our measurements will be normally distributed, even if the change in temperature is not.
      - kelseyfrog 4y ago
        This really doesn't make much sense in the context of the measurement which is bounding the value(0) with 90% confidence[1]. 1. https://arxiv.org/pdf/2212.11841.pdf https://arxiv.org/pdf/2212.11841.pdf
        random314 4y ago
        I think op is talking about bias vs variance. In some cases we have a bias variance trade off.
        kelseyfrog 4y ago
  - wkat4242 4y ago
    What's the point in measuring it with high precision if it's not accurate?
    - ilyt 4y ago
      Sometimes you're interested in delta of change, not absolute value itself. So absolute accuracy might be "wrong" but as long as it is consistently wrong (within duration of measurements you need to make) it doesn't matter all that much.
    - moron4hire 4y ago
      My understanding is that a highly spherical electron implies the electron has no sub component parts. Knowing the exact radius of the electron doesn't change that, it's knowing there is no variance in the radius that is important. And again, I was only commenting on what was being commented on here. I don't know if the experiment was also highly accurate. But people here were commenting on the precision and calling it accuracy.
    - MattPalmer1086 4y ago
      Precision is about how tightly clustered your measurements are. Accuracy is about how well those measurements reflect reality. If you are just trying to see how smooth a ball is by measuring the diameter many times at different points, then a high precision can tell you that, even if the actual diameter is different to your measurement. You don't care about the actual diameter, you care about the variation in it.
- deleted 4y ago
  [deleted]
- rightbyte 4y ago
  Statistics, right? It is not "one" measurement?
gattr 4y ago
Average Earth diameter = 2·6371 km ([1]). Size of glucose molecule ≈ 9 Å ([2]). Ratio = 7.06·10¹⁷. [1] https://en.wikipedia.org/wiki/Earth_radius https://en.wikipedia.org/wiki/Earth_radius [2] https://sphweb.bumc.bu.edu/otlt/mph-modules/ph/ph709_basiccellbiology/ph709_basiccellbiology8.html https://sphweb.bumc.bu.edu/otlt/mph-modules/ph/ph709_basicce...
- deleted 4y ago
  [deleted]
- deleted 4y ago
  [deleted]
- comboy 4y ago
  electron size: 10^-14 planck length: 10^-35 10^-14 * 10^17 = 10^-31 (in case somebody wondered just as I did)
  - fractalb 4y ago
    > 10^-14 * 10^17 = 10^-31 It’s actually 10^3
  - 1024core 4y ago
    Typo: you forgot the "-" before the 17 in 10^17
  - AnimalMuppet 4y ago
    10^-14 / 10^17. Or 10^-14 * 10^-17. Minor nit to an interesting parent.
  - A_D_E_P_T 4y ago
    Not even close. The diameter of the electron is under 10^-18 meters -- that's a sort of experimental upper bound derived from collision experiments -- but it may well be much smaller than that. Some estimates for the diameter of the electron approach the Planck length -- and some, which are no less credible, are well under the Planck length, e.g. at 10^-80m. In physics, the electron is usually described as a point with no size at all. Thus, for practical intents and purposes, it exists but is infinitely small. (Which sort of reflects the notion that human physics is an idealization of the natural world.) The Planck length isn't a hard physical limit for size. It's where direct measurement starts running into insurmountable barriers.
lagadu 4y ago
I struggle with understanding that size comparison, given that the size of the electron is unknown: we only have a maximum size that's based on the accuracy of the measurements, no lower bound.
- scotty79 4y ago
  I think it's supposed to relate the variation of the shape of electric field around electron not the size of the electron which is a pointlike particle.
ralferoo 4y ago
The next sentence after the first part you quoted: "The latest results are in: The electron is rounder than that." Which would be great if the Earth was actually perfectly round, but we've known for over three centuries that it's not. I'm sure the science the article is reporting on is fine, but it definitely sounds like the author of the article is out of their depth.
- LadyCailin 4y ago
  That’s not what it’s saying. It’s saying, if you blew up the electron to the size of the earth, and sprinkled a sugar grain on it, then the electron is rounder than that.
  - School-Cotton 4y ago
    Not a sugar grain, a sugar molecule.
- kevin_thibedeau 4y ago
  Definitely should have used spherical cows.
- WJW 4y ago
  I know you're getting at the whole "oblate spheroid" shape thing, but I'm pretty sure people have known it wasn't perfectly round for way longer than that. You only need to look out a window to see hills and mountains after all (unless you live in the Netherlands ofc). Fun fact: the actual shape of the Earth is neither a sphere nor an ellipsoid but a "geoid", literally something "shaped like the earth".
- butterNaN 4y ago
  It's trying to put a size comparison so that our human minds can picture the scale. Earth is just a placeholder in this example. The author is inviting you to picture the the size of the planet. They could've just written the sizes in terms of 10^x , however that is not as human-friendly to envison. There is no need to be unkind towards the author here, maybe your point is that they could have done a better job at presenting the scale for the reader? How would you write it?
dclowd9901 4y ago
I can’t even fathom how such a thing can possibly exist

JumpCrisscross 4y ago

It reminds me of Aristotelian physics’ perfect ætherial heavenly bodies. Ironinic they were on the terrestrial sphere in the end.

wkat4242 4y ago

Yeah how do they manage to get that kind of accuracy. Mind boggling.

moron4hire 4y ago
That's precision, not accuracy.
- lifeisstillgood 4y ago
  hang on - what? Yes it is precise ... to 17 decimal places or whatever. But it is also I believe accurate? I mean are they wrong and the electron is as bumpy as my chin on a weekend?
  - delecti 4y ago
    It's not that the experiment is not accurate, "accuracy" is simply not the aspect of the measurement being discussed. The sentence "That's precision, not accuracy." should be read to mean "we are discussing precision, we are not discussing accuracy" rather than "it's precise, but inaccurate".
    - Wowfunhappy 4y ago
      But I feel like in this context, we're discussing both.
      - Mezzie 4y ago
        Precision and accuracy are slightly different mathematical concepts, as demonstrated by this image [0]: [0]: https://wp.stolaf.edu/it/files/2017/06/precsionvsaccuracy_crashcourse-579x600.png https://wp.stolaf.edu/it/files/2017/06/precsionvsaccuracy_cr...
        rektide 4y ago
        To be honest accuracy Vs precision has always kind of makes sense to be but also not. If something is extremely accurate, it will also be extremely precise by necessity, it seems like? The difference between low precision but high & low accuracies is that points are closer to center. If you keep getting closer to center, more accurate, don't you necessarily get more precise too? Precise has always felt like a shitty alternate of accuracy. It's accuracy but with drift, accuracy to not the right place. But if you're accurate, you're both. Am I missing something? And, here specifically, if this is a case of very high precision but lower accuracy, can someone explain what the drift from center is about? Isn't a radius a radius? Where is the drift off center in these measures?
        alexpetralia 4y ago
        I wrote about precision here if you are interested. You first need precision before you can start even talking about accuracy (otherwise there is no "center"). https://alexpetralia.com/2023/01/31/what-does-it-mean-for-data-to-be-precise-part-4/ https://alexpetralia.com/2023/01/31/what-does-it-mean-for-da...
        hansvm 4y ago
        Something is accurate in this sense if the "true" value (ignoring any philosophical implications thereof) is contained in the error bounds of the measurement. What you're noting is that a high accuracy measurement will, upon application of statistics, allow you to derive a new measure which is both high-accuracy and high-precision, regardless of the low precision of any inputs. Not all things being described with accuracy and precision are the result of processing large amounts of data though.
- klausnrooster 4y ago
  My (mis-?) understanding of the Central Limit Theorem is that the average of >30 measurements increases the accuracy. https://en.wikipedia.org/wiki/Central_limit_theorem https://en.wikipedia.org/wiki/Central_limit_theorem
  - moron4hire 4y ago
    No, that's increasing the precision, not accuracy. Many imprecise measurements can be averaged to a more precise measurement. Say we had a perfect ruler to measure the length of something. It's absolutely precise and accurate. All measurements from it return the exact, same value, and preternaturally we know it's the "correct" value. Now say some bandit comes in while we're not looking and adds a small chunck of diamond to the end of the ruler without telling us. Our ruler is still precise, but no longer accurate. If we take many measurements with it, they always come back with the same value. Averaging those values does not improve the accuracy at all. Alternatively, say the bandit starts randomly changing the temperature of the room we are in. Thermal expansion is constantly changing the length of the ruler. The average length of the ruler is still the same, so it's still accurate, but it's no longer precise. We could average the measurements we take with it and get a more precise measurement. What the central limit theorem says is that the averages of our measurements will be normally distributed, even if the change in temperature is not.
    - kelseyfrog 4y ago
      This really doesn't make much sense in the context of the measurement which is bounding the value(0) with 90% confidence[1]. 1. https://arxiv.org/pdf/2212.11841.pdf https://arxiv.org/pdf/2212.11841.pdf
      - random314 4y ago
        I think op is talking about bias vs variance. In some cases we have a bias variance trade off.
        kelseyfrog 4y ago
- wkat4242 4y ago
  What's the point in measuring it with high precision if it's not accurate?
  - ilyt 4y ago
    Sometimes you're interested in delta of change, not absolute value itself. So absolute accuracy might be "wrong" but as long as it is consistently wrong (within duration of measurements you need to make) it doesn't matter all that much.
  - moron4hire 4y ago
    My understanding is that a highly spherical electron implies the electron has no sub component parts. Knowing the exact radius of the electron doesn't change that, it's knowing there is no variance in the radius that is important. And again, I was only commenting on what was being commented on here. I don't know if the experiment was also highly accurate. But people here were commenting on the precision and calling it accuracy.
  - MattPalmer1086 4y ago
    Precision is about how tightly clustered your measurements are. Accuracy is about how well those measurements reflect reality. If you are just trying to see how smooth a ball is by measuring the diameter many times at different points, then a high precision can tell you that, even if the actual diameter is different to your measurement. You don't care about the actual diameter, you care about the variation in it.
deleted 4y ago
[deleted]
rightbyte 4y ago
Statistics, right? It is not "one" measurement?

gattr 4y ago

Average Earth diameter = 2·6371 km ([1]). Size of glucose molecule ≈ 9 Å ([2]). Ratio = 7.06·10¹⁷. [1] https://en.wikipedia.org/wiki/Earth_radius https://en.wikipedia.org/wiki/Earth_radius [2] https://sphweb.bumc.bu.edu/otlt/mph-modules/ph/ph709_basiccellbiology/ph709_basiccellbiology8.html https://sphweb.bumc.bu.edu/otlt/mph-modules/ph/ph709_basicce...

deleted 4y ago
[deleted]
deleted 4y ago
[deleted]
comboy 4y ago
electron size: 10^-14 planck length: 10^-35 10^-14 * 10^17 = 10^-31 (in case somebody wondered just as I did)
- fractalb 4y ago
  > 10^-14 * 10^17 = 10^-31 It’s actually 10^3
- 1024core 4y ago
  Typo: you forgot the "-" before the 17 in 10^17
- AnimalMuppet 4y ago
  10^-14 / 10^17. Or 10^-14 * 10^-17. Minor nit to an interesting parent.
- A_D_E_P_T 4y ago
  Not even close. The diameter of the electron is under 10^-18 meters -- that's a sort of experimental upper bound derived from collision experiments -- but it may well be much smaller than that. Some estimates for the diameter of the electron approach the Planck length -- and some, which are no less credible, are well under the Planck length, e.g. at 10^-80m. In physics, the electron is usually described as a point with no size at all. Thus, for practical intents and purposes, it exists but is infinitely small. (Which sort of reflects the notion that human physics is an idealization of the natural world.) The Planck length isn't a hard physical limit for size. It's where direct measurement starts running into insurmountable barriers.

lagadu 4y ago

I struggle with understanding that size comparison, given that the size of the electron is unknown: we only have a maximum size that's based on the accuracy of the measurements, no lower bound.

scotty79 4y ago
I think it's supposed to relate the variation of the shape of electric field around electron not the size of the electron which is a pointlike particle.

ralferoo 4y ago

The next sentence after the first part you quoted: "The latest results are in: The electron is rounder than that." Which would be great if the Earth was actually perfectly round, but we've known for over three centuries that it's not. I'm sure the science the article is reporting on is fine, but it definitely sounds like the author of the article is out of their depth.

LadyCailin 4y ago
That’s not what it’s saying. It’s saying, if you blew up the electron to the size of the earth, and sprinkled a sugar grain on it, then the electron is rounder than that.
- School-Cotton 4y ago
  Not a sugar grain, a sugar molecule.
kevin_thibedeau 4y ago
Definitely should have used spherical cows.
WJW 4y ago
I know you're getting at the whole "oblate spheroid" shape thing, but I'm pretty sure people have known it wasn't perfectly round for way longer than that. You only need to look out a window to see hills and mountains after all (unless you live in the Netherlands ofc). Fun fact: the actual shape of the Earth is neither a sphere nor an ellipsoid but a "geoid", literally something "shaped like the earth".
butterNaN 4y ago
It's trying to put a size comparison so that our human minds can picture the scale. Earth is just a placeholder in this example. The author is inviting you to picture the the size of the planet. They could've just written the sizes in terms of 10^x , however that is not as human-friendly to envison. There is no need to be unkind towards the author here, maybe your point is that they could have done a better job at presenting the scale for the reader? How would you write it?

dclowd9901 4y ago

I can’t even fathom how such a thing can possibly exist