Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Tue, 18 Jan 2005 15:52:23 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m23.mx.aol.com ([64.12.137.4] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 612066 for lml@lancaironline.net; Tue, 18 Jan 2005 15:45:41 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.4; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m23.mx.aol.com (mail_out_v37_r3.8.) id q.12d.54055ae5 (2519) for ; Tue, 18 Jan 2005 15:44:56 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <12d.54055ae5.2f1ecf47@aol.com> X-Original-Date: Tue, 18 Jan 2005 15:44:55 EST Subject: Re: [LML] Units - Schumnits X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1106081095" X-Mailer: 9.0 Security Edition for Windows sub 5000 -------------------------------1106081095 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Ask an engineer what time it is and he (or she) will tell you how a watch i= s=20 made. Ask a person who has mastered the art of assembly language computer=20 programming what time it is and you will get the exact time in binary, thus= =20 every bit usable. =20 METER =20 An international standard unit of length, approximately equivalent to 39.37=20= =20 inches. It was redefined in 1983 as the distance traveled by light in a vacu= um=20 in 1/299,792,458 of a second (.0000000033356409519815204957557671447492 of=20= a=20 second). Now there's some accuracy. =20 But, in 1960, the length was determined by using a definition based upon a =20 wavelength of krypton-86 radiation, thanks to Superman. =20 Earlier, the French thought it should equal 10-7 or one ten-millionth of th= e=20 length of the meridian through Paris from pole to the equator. This was=20 later shown to be at least .2 mm in error. Ahhhh, "Le plume de ma tante" an= d=20 other French lessons. =20 KILOMETER or KLICK =20 1000 METERs all over the world. Don't ask about the Ole R=F8mer mile=20 (Scandinavia) or what the Danes and Germans did with Kms 2 centuries ago. =20 =20 STATUTE MILE =20 Queen Elizabeth I of England redefined the mile from 5000 feet to 8 furlong= s=20 (5280 feet) by statute in 1593 and, currently, a foot is the imperial foot=20 now defined to be exactly 0.3048 meters. Don't ask any more about the basi= s=20 for feet or iambic pentameters. =20 The Roman mile was 1000 double 2.4 foot (whose foot?) paces - apparently =20 made while wearing armor and represents the distance between milestones to =20= Rome.=20 Better yet, a league is the distance a horse or man could walk in 1 hour=20 (however that hour was then measured) - usually about 3 miles.=20 =20 KNOT =3D Nautical Miles per Hour =20 The nautical mile was historically defined as a minute of arc along a great= =20 circle of the Earth. It can therefore be measured on a meridan as change of= =20 latitude on a nautical chart. Slight variations in national definitions wer= e=20 settled in 1929, when the IEHC in Monaco adopted a definition of 1 nm =3D 1= 852=20 meters. The US adopted it in 1954. The Royal Hydrographic Office of the UK=20 converted in 1970. I don't know about other places like France, Australia o= r=20 Utah. =20 A nautical league is about 3 nm - not measured by how long you've been=20 walking on water. =20 SECOND =20 A fundamental unit of the hour frequently referenced herein. The time =20 needed for a cesium-133 atom to perform 9,192,631,770 complete oscillations= . Just=20 ask any artificial-star GPS satellite user, "How important is that amount o= f=20 accuracy?" =20 Hmmmmm, a second used to be 1/86400 of a mean solar day until 1960. Becaus= e=20 of variances, in 1967 atomic clocks were shown to be more accurate and the=20 Cesium clock, in its ground state at 0 degrees Kelvin, was affirmed in 1997= . =20 SUMMARY =20 Let's see, 200 Kts =3D 230.156 mph =3D 102.8888888888888889 Benz (meters/sec= ) - =20 Use _http://www.onlineconversion.com/_ (http://www.onlineconversion.com/)=20 =20 Hey, these and millions of other units of measurement have changed over tim= e=20 - currently we rely on the speed of light in a vacuum and the twittering of=20= =20 a specific Cesium atom to keep us honest. =20 How about this report to ATC: "N1234 is now 15 DME on the RFD 180 radial."=20= =20 How far laterally? That depended on the altitude.=20 =20 When observing closing aircraft, there are only 2 distances that matter: No=20= =20 problem and Yikes! =20 =20 Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Fair and Balanced Opinions at No Charge! There is an oxymoron in that, somewhere... -------------------------------1106081095 Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable
Ask an engineer what time it is and he (or she) will tell you how=20= a=20 watch is made.  Ask a person who has mastered the art of assembly langu= age=20 computer programming what time it is and you will get the exact time in bina= ry,=20 thus every bit usable.
 
METER
 
An international standard unit of length, approximately equivalent to 3= 9.37=20 inches. It was redefined in 1983 as the distance traveled by light in a vacu= um=20 in 1/299,792,458 of a second (.0000000033356409519815204957557671447492 of a= =20 second).  Now there's some accuracy.
 
But, in 1960, the length was determined by using a definition based upo= n a=20 wavelength of krypton-86 radiation, thanks to Superman.
 
Earlier, the French thought it should equal 10-7 or one= =20 ten-millionth of the length of the meridian through Paris from pole to the=20 equator.  This was later shown to be at least .2 mm in error. Ahhhh, "L= e=20 plume de ma tante" and other French lessons.
 
KILOMETER or KLICK
 
1000 METERs all over the world.  Don't ask about the Ole R= =F8mer=20 mile (Scandinavia) or what the Danes and Germans did with Kms 2 centuries=20 ago.  
 
STATUTE MILE
 
Queen Elizabeth I of England redefined the mile from 5000 feet to=20= 8=20 furlongs (5280 feet) by statute in 1593 and, currently, a foot is the=20 imperial foot now defined to be exactly 0.3048 meters.  Don't ask=20= any=20 more about the basis for feet or iambic pentameters.
 
The Roman mile was 1000 double 2.4 foot (whose foot?) paces - apparentl= y=20 made while wearing armor and represents the distance between milestones to=20 Rome.  Better yet, a league is the distance a horse or man could walk i= n 1=20 hour (however that hour was then measured) - usually about 3 miles. 
 
KNOT =3D Nautical Miles per Hour
 
The nautical mile was historically defined as a minute of arc alon= g=20 a great circle of the Earth. It can therefore be measured on=20 a meridan as change of latitude on a nautical chart. Slight variations=20= in=20 national definitions were settled in 1929, when the IEHC in Monaco adop= ted=20 a definition of 1 nm =3D 1852 meters. The US adopted it in 1954. The Ro= yal=20 Hydrographic Office of the UK converted in 1970. I don't know about oth= er=20 places like France, Australia or Utah.
 
A nautical league is about 3 nm - not measured by how long you've=20 been walking on water.
 
SECOND
 
A fundamental unit of the hour frequently referenced herein.  The=20= time=20 needed for a cesium-133 atom to perform 9,192,631,770 complete=20 oscillations.  Just ask any artificial-star GPS satellite user, "How=20 important is that amount of accuracy?"
 
Hmmmmm, a second used to be 1/86400 of a mean solar day until 1960.&nbs= p;=20 Because of variances, in 1967 atomic clocks were shown to be more accurate a= nd=20 the Cesium clock, in its ground state at 0 degrees Kelvin, was affirmed in=20 1997.
 
SUMMARY
 
Let's see, 200 Kts =3D 230.156 mph =3D 102.8888888888888889 Benz (meter= s/sec) -=20 Use http://www.onlineconversion.com/
 
Hey, these and millions of other units of measurement have changed over= =20 time - currently we rely on the speed of light in a vacuum and the twitterin= g of=20 a specific Cesium atom to keep us honest.
 
How about this report to ATC: "N1234 is now 15 DME on the RFD = ;180=20 radial."  How far laterally? That depended on the altitude. 
 
When observing closing aircraft, there are only 2 distances that matter= : No=20 problem and Yikes!
 
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Fai= r=20 and Balanced Opinions at No Charge!
There is an oxymoron in that,=20 somewhere...

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