"The length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second, where the second is defined by a hyperfine transition frequency of caesium."
This is the actual definition, but it's also pretty weird.
this post was submitted on 19 May 2025
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And here I thought it was that sick of metal in the wall in France when it is 21 degrees C
They redefined it a few years ago to base all units on some objectively measurable natural constant. Because that stick of metal might still decay or warp or something and you don't always want to travel to France when you want to know the length of a meter. Much easier to measure the atoms and light you have on hand.
Updating the kilogram standard took them forever because you need really reliable force measurement instruments and very precise calibration
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Found the vampire.
Hey, just because I am Australian doesn't mean I am a crime of nature. That is just our animals.
Australia, where even the animals are criminals.
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Depends on the meter, dude. There are thermo-meters, speedo-meters, baro-meter...
You win.
Take a really long rope and put one end on either pole of the Earth, and the other end on the equator. Use the shortest path, and make sure the rope is tight. No squiggles allowed! Chop that rope into exactly 10 000 000 equal parts. One of them is as long as a meter. Now you just need to find the right one.
Edit: more zeros.
A bit more than 90 centimetres, a bit less than 110. Somewhere in that ballpark.
Okay, so, right, okay. Um. In German schools (and probably some other countries...?), many many years ago (possibly still today? or maybe it's all digital now? what am I saying, this is German schools), the blackboard in every classroom was a large, green, rectangular middle part and two square "wings", one on each side (as wings are wont to be...). They can swing in and out, providing extra room for writing on the outer side of the wings. Also for extracurricular shenanigans such as writing "[name] + [name] = SEX" in the middle, swinging the wings closed to hide the writing and then breaking out into hysterics when the teacher opens the blackboard to reveal your incredibly highbrow joke.
This type of blackboard is quintessential to my recollections about and concept of school.
Why am I going into such unnecessary detail about this? I have ADHD and possibly autism, I need you to understand what I'm saying and I can't find any sources of this existing in the English speaking world and I can't find an English word for those "wings" either. I can barely find a German one ("Tafelflügel"? I don't think it's ever come up before in my life).
So here's a picture:
The width/height of the "wings" and the height of the middle part, that's a metre. Thank you for coming to my TED talk.
Does the metallic edge count as part of the meter too or just the green surface? What if it's so hot the wings expand?
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5 letters
‘a meter’
5 = 6 = 1m
The distance light travels when it goes one meter.
About ten minutes, wait, what was the question?
Just about half as twice as much.
The overall length of an M16A4
I didn't even know what a M16A4 is. Some US unit, right?
Yes, with the official M16A4 unit being defined as 1/100th the length between the goal lines of an American Football field.
It is a very US unit, yes.
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About twice as long as half of its length
Only weird answers?
The truth itself is weird: The meter is defined as the distance that light travels in a vacuum in 1/299,792,458 seconds.
Powers of ten my ass
The problem is that the meter is originally defined in terms of the size of the earth, which is in no way related to the speed of light.
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A bit shorter than a (parking) meter.
3 1/3 Subway sandwiches
About 4 stacked house cats, or a bit longer than a 3-year-old.
The square root of a square meter
take a meter stick, now cut it in half. glue it back together. a meter is probably a little bit longer than this since you lost some material cutting.
About a yard
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