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Earth now weighs six ronnagrams: New metric prefixes voted in

phys.org

41–50 of 215 posts

Re: Earth now weighs six ronnagrams: New metric prefixes voted in

#42

From https://en.wikipedia.org/wiki/Metric_system : “The SI has been adopted as the official system of weights and measures by all nations in the world except for Myanmar, Liberia, and the United States.”

I believe the US legally defines the US customary units by metric counterparts anyway. https://www.nist.gov/pml/owm/si-units-length

Still, I'm probably the 1% of 1% of Americans who uses Celsius in daily life, except where I cannot (my car won't let me do hybrid miles and Celsius, ugh).

Re: Earth now weighs six ronnagrams: New metric prefixes voted in

#43
post #31

From https://en.wikipedia.org/wiki/Metric_system : “The SI has been adopted as the official system of weights and measures by all nations in the world except for Myanmar, Liberia, and the United States.”

Weird: > https://usma.org/laws-and-bills/metric-conversion-act-of-197... > https://usma.org/laws-and-bills/executive-order-12770 The US government hasn't been great in converting US industry to metric. But ... it's a bit disingenuous to say we didn't even try .

I believe we have Ronald Reagan to thank for cancelling our efforts from the 70s.

Re: Earth now weighs six ronnagrams: New metric prefixes voted in

#45

The way I remember Earth's approximate mass is the fact it's 10 times Avogadro's number in kg. My physics teacher always had a great way of drilling in these tidbits.

Yes and the circumference of the earth is about 40 million meters. This is because a meter was originally supposed to be 1/10E6 the distance from the equator to the north pole through Paris.

Re: Earth now weighs six ronnagrams: New metric prefixes voted in

#46
post #34

Is anyone seriously using prefixes above Giga, besides for counting bytes or boasting numbers in popular science articles? In physics, in practice you either state the number in exponential notation and don't care abut it or for brevity introduce a more appropriate unit: barns (10⁻²⁸ m²) and electronvolts (10⁻¹⁹ J) in nuclear physics or solar mass (~10³⁰ kg) in astrophysics, etc.

> electronvolts (10⁻¹⁹ J) in nuclear physics

CERN is at TeV ranges so yes, even in different units we use high prefixes. Might not come up in your every day small talk but they are used.

Re: Earth now weighs six ronnagrams: New metric prefixes voted in

#48
post #44

I'm disappointed that hella has not become a prefix

I'll give the grad students at UC Davis props for trying: https://theaggie.org/2010/02/18/uc-davis-student-gives-hella....

My lab at the time slipped hella- into a few conference presentations here and there. We had to back our university. I always remember it getting a few chuckles.

Re: Earth now weighs six ronnagrams: New metric prefixes voted in

#49
Via https://www.nature.com/articles/d41586-022-03747-9, "Extreme numbers get new names":

The prefixes ronna and quetta represent 10^27 and 10^30, and ronto and quecto signify 10^−27 and 10^−30. Earth weighs around one ronnagram, and an electron’s mass is about one quectogram.

This is the first update to the prefix system since 1991, when the organization added zetta (10^21), zepto (10^−21), yotta (10^24) and yocto (10^−24).

Re: Earth now weighs six ronnagrams: New metric prefixes voted in

#50

A question... Why do humans (or at least engineers) work so well in 1,000? I mean. I use milli/micro/nano/pico as an electrical engineer every day, and it's so intuitive to me. But why three orders of magnitude? Why not two orders, or five?

I think it's because we can scan it easily. Groups of 4 or more can confuse the eye: when looking at 5 things, you sometimes have to take a moment to realize it's 5 not 4 (and, to a lesser extent, the same is true of 4).

groups of 3 have first, middle, last - crucially _one_ middle digit, not 2+, which makes for quick comprehension.

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