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So, if I understand this response correctly,
"billionths of a micro-gauss" is more understandable then teslas. What
planet is this guy from?
Euric
----- Original Message -----
Sent: Tuesday, 2004-04-27 12:13
Subject: [USMA:29641] Fwd: Gravity Probe
B article
Here is the reply I received from the NASA official responsible
for the internet information on the Gravity Probe B. Some of you expressed an
interest in seeing his answer to my message.
Begin forwarded
message:
From:
"Koczor, Ron"
<[EMAIL PROTECTED]>
Date:
2004 April 27 8:20:31 AM EDT
To: 'Bill Hooper'
<[EMAIL PROTECTED]>
Subject:
RE: Gravity Probe B article
Thanks for
your note, Bill. All of our writers use the measurements that
they get
from their interviews as most are not scientists themselves. We do
try to
relate what we consider unfamiliar metric units with more
easily
recognized English units when we feel it is
appropriate.
Remember that we are not writing scientific journal
papers here. We are
trying to communicate to non-scientists and we do so
in a manner that we
feel is most understandable.
Eventually my
successors will not have to worry about ye Olde English units!
But for
now, we feel that we must be communicators.
Best
wishes,
Ron
-----Original Message-----
From: Bill
Hooper [mailto:[EMAIL PROTECTED]
Sent: Monday, April 26, 2004
8:41 PM
To: Koczor, Ron
Cc: USMA
Subject: Gravity Probe B
article
Ron Koczor:
I read with interest the article about the
gravity Probe B on the
following web
page:
http://science.nasa.gov/headlines/y2004/26apr_gpbtech.htm?list533332
I
understand from that page that you are the responsible NASA official
for
this article.
It was a fascinating story about an experiment that I
had been
following for some time. It was marred, however, by the awkward
use of
a mish-mash of measurements, some in the SI metric system, some
in
older versions of metric system and even some in Ye Olde English
mixture.
I would be interested to know how much of the complex
mix of units was
a result of the scientists and engineers who actually
use those
measurements and how much was the result of the reporting and
editing
of the information for this article.
Of particular
concern was the use of the unit "micro-gauss". The SI
unit of magnetic
field is the tesla. A gauss corresponds to
one-ten-thousandth of a
tesla.* In SI, the field of "3 micro-gauss"
could have been given as 0.3
nanotesla. The use of an SI prefix (like
micro) with a non-SI unit (like
"gauss") is odd (although not entirely
unheard of) but the use of a
hyphen between them is something which
definitely is not done in SI
metric and which I have never seen it done
by anyone else in any other
system of units.
There really was no need to use all those Olde
English measures. Most
of the people who are sufficiently interested in
reading this type of
article would be reasonably familiar with the SI
metric system which is
used so extensively in science. The reference to
400 miles could have
been 650 kilometres, the 1.5 inches could have been
38 millimetres, the
12 feet could have been 3.6 metres and the 400
gallons could have been
1500 L (or 1.5 cubic metres). Few readers would
have any trouble
understanding those measures and many would prefer
them.
It is curious to note that when a good SI unit, the nanometre,
was
used, it was "explained" by telling that it is one-millionth of a
millimetre. The author apparently knew that the reader would understand
how big a millimetre was so it could be used to explain the nanometre.
So why did the author have to give the diameters of those spheres in
inches; if the reader understands millimetres in the other case, surely
he or she would understand 39 millimetres in this case.
There was
very little other information reported in SI metric.
Temperatures in
kelvins and the SI related degrees Celsius were the
only other metric
uses. I would have thought NASA reports on scientific
work would have
been reported using the units that are almost
universally used by
scientists; SI metric. I am disappointed to find
that this is not
so.
Sincerely,
Dr. William Hooper
Prof. of Physics
(ret.)
University of Virginia's College at Wise
* I recognize that
the magnetic field measured in CGS units of gauss
and the magnetic field
measured in the SI units of tesla, are not the
same thing. Therefore,
the tesla cannot strictly speaking be said to
"equal" a number of gauss.
The problem here is a bit more fundamental;
namely, why are NASA
scientists still using the definitions of
quantities (as well as the
units) of the old CGS system instead of
using SI and the definitions of
quantities inherent in that
system.
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