4 ms·

I wish it had been defined in relation to the speed of light in a vacuum. 299,792,458 metres per second. Set it at 300,000,000 meters per second and derive the

I wish it had been defined in relation to the speed of light in a vacuum. 299,792,458 metres per second. Set it at 300,000,000 meters per second and derive the length of the meter from that.

reaperman 3y ago
> I wish it had been defined Wish what had been defined? the second?
- ryanmcdonough 3y ago
  > and derive the length of the meter from that. I would assume they meant meter since they wrote that.
- irrational 3y ago
  The meter. The distance light travels in a second in a vacuum is fixed. Divide that distance by 300,000,000. That is the length of 1 meter.
  - reaperman 3y ago
    So the current definition is: > The meter (m) is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299,792,458 when expressed in the unit m s−1, where the second is defined in terms of ∆νCs.[0] Your proposed change is keeping this the exact same but changing 299,792,458 to 300,000,000? You said: “I wish it had been defined in relation to the speed of light in a vacuum.” I believe it is already, as written above. 0: https://www.nist.gov/pml/owm/si-units-length#:~:text=The%20meter%20(m)%20is%20defined,terms%20of%20∆νCs https://www.nist.gov/pml/owm/si-units-length#:~:text=The%20m....
    - tialaramex 3y ago
      If you prefer for some universal constants to be round numbers you can choose a Natural Units systems according to your preference. For example in some of these systems c = 1, which turns Einstein's famous equation into just E = m. Convenient.
IvyMike 3y ago
Interesting. The meter was defined in 1791. James Bradley got the speed of light correct to about 1% in 1728, and I think that value stood in 1791. That value was less accurate than either the 10000km pole-to-equator or 1-second-pendulum, as measurable in 1791. And until special relativity, the idea of speed of light being constant wasn't really firmly established. Ultimately, I think in 1791 I think using the speed-of-light as the basis wasn't really practical. P.S. Not really necessary but in writing this comment, I read these documents, each of which taught me something new: https://interestingengineering.com/science/a-brief-history-of-the-speed-of-light https://interestingengineering.com/science/a-brief-history-o... https://spie.org/publications/tt82_25_speed_of_light https://spie.org/publications/tt82_25_speed_of_light https://en.wikipedia.org/wiki/Luminiferous_aether https://en.wikipedia.org/wiki/Luminiferous_aether

I wish it had been defined in relation to the speed of light in a vacuum. 299,792,458 metres per second. Set it at 300,000,000 meters per second and derive the length of the meter from that.

reaperman 3y ago

> I wish it had been defined Wish what had been defined? the second?

ryanmcdonough 3y ago
> and derive the length of the meter from that. I would assume they meant meter since they wrote that.
irrational 3y ago
The meter. The distance light travels in a second in a vacuum is fixed. Divide that distance by 300,000,000. That is the length of 1 meter.
- reaperman 3y ago
  So the current definition is: > The meter (m) is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299,792,458 when expressed in the unit m s−1, where the second is defined in terms of ∆νCs.[0] Your proposed change is keeping this the exact same but changing 299,792,458 to 300,000,000? You said: “I wish it had been defined in relation to the speed of light in a vacuum.” I believe it is already, as written above. 0: https://www.nist.gov/pml/owm/si-units-length#:~:text=The%20meter%20(m)%20is%20defined,terms%20of%20∆νCs https://www.nist.gov/pml/owm/si-units-length#:~:text=The%20m....
  - tialaramex 3y ago
    If you prefer for some universal constants to be round numbers you can choose a Natural Units systems according to your preference. For example in some of these systems c = 1, which turns Einstein's famous equation into just E = m. Convenient.

IvyMike 3y ago

Interesting. The meter was defined in 1791. James Bradley got the speed of light correct to about 1% in 1728, and I think that value stood in 1791. That value was less accurate than either the 10000km pole-to-equator or 1-second-pendulum, as measurable in 1791. And until special relativity, the idea of speed of light being constant wasn't really firmly established. Ultimately, I think in 1791 I think using the speed-of-light as the basis wasn't really practical. P.S. Not really necessary but in writing this comment, I read these documents, each of which taught me something new: https://interestingengineering.com/science/a-brief-history-of-the-speed-of-light https://interestingengineering.com/science/a-brief-history-o... https://spie.org/publications/tt82_25_speed_of_light https://spie.org/publications/tt82_25_speed_of_light https://en.wikipedia.org/wiki/Luminiferous_aether https://en.wikipedia.org/wiki/Luminiferous_aether