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Re: Gravity and pi



Samuel Held wrote:

Paul,
I have never used the much higher (and smaller) prefixes like
yotta/yocta and never will. In high energy nuclear, we do use energy
(usually GeV) for everything, since c=1 in these natural units. For
cross-sections, we do use barns but usually millibarns (maybe even
smaller depending on the process). However, for time units we use fm/c
(or just fermi's since c=1), which makes the numbers much more managable
and let's you see how far the particle travels. I like it a lot.
Everything is for laziness, oops, I mean convenience. 8-)

Sam Held

-----Original Message-----
From: Paul Johnson [mailto:PJohnson@CCCCD.EDU]
Sent: Friday, November 13, 1998 10:44 AM
To: PHYS-L@LISTS.NAU.EDU
Subject: Re: Gravity and pi

Sam

Keeping track of positive and negative exponents is sure easier than
keeping track of those latest stupid prefixes the guys in the
smoke-filled room added to the metric system -- yotta/yocto,
zetta/zepto, etc. Have you ever seen any of those used to designate
very large or very small values?

Things were better back when I was just a tad undergraduate. My
department chair (Swerwood Githens) told us that nuclear types had
their own names for very small values of area and time. Neutron cross
sections were measured in BARNS (10*-24 sq cm) and very short
radioactive halflives were measured in JIFFYS (10*-24 sec).

Only astronomers are smart enough not to fall for all this prefix
crap. Parsecs are perfectly good distance units.

poj


Sam

Are you trying to tell me that nuclear types are as smart as
astronomers?

poj