I feel like I’m back on USENET!
I believe you will find that the current time standard is no longer the earth's rotation but rather "atomic time" Which, if I remember correctly, is corrected back to a "celestial" time.dagosa, my apologies, I didn’t go back far enough. It looked to me like you were trying to defend that statement and I was confused. By your earlier posts, I knew you to be smarter than that. I remember many years ago, there was a physics professor that posted here a lot.
cont
He was quite intelligent, but one day he made a little slip of the tongue, and then tried to defend it, knowing he was wrong. He left after that and never came back. I really enjoyed his posts while he was here though.
Keith…no problem. Have done it myself, more then a couple of times. Easy when a discussion is this long. That’s considerate of you to check.
"I believe you will find that the current time standard …"
What is “the current time standard”? Are you referring to UTC, UTC1, “GMT,” or Eastern Standard Time?
"… is corrected back to a “celestial’ time” …"
There is no such thing as a “celestial time”. That is an object of your own concoction.
There was at one time an ephemeris time, but that was phased out in the 1960s.
There is a terrestrial time, which as of 2011.12.01 was in advance of UTC1 by 66.5706 seconds.
The US Naval Observatory reports it here => http://maia.usno.navy.mil/ser7/deltat.data
Yeah, I need to get a life, because some j–k on this board told me so.
The concept of time as divided into measurable increments is irrelevant to celestial bodies…or even the planet itself. Time is continuous, not incremental. We’ve chosen to reference it to the revolution of the earth as related to the sun, and divisions of that, and as related to the changing of the seasons, for obvious reasons, and divisions of that, but that just makes things able to be tracked and used as references.
Celestial time would create a relationshin between our earth and other celestial bodies. We could say “it’s summer on Venus”, or “a Martian day is 24 hours and 39 minutes long”, but we’d just be quantifying relationships. Is a martian day 25.625 hours long, or is it 24 hours long, with each hour being 60.027 minutes?
Think of the different calendars that have been used. According to the Mayan calendar, we should all be dead. And we start our years at teh birth of Christ. As if there were no years before that.
If you fly, you’re using Zulu time, Grenwhich Mean Time. GMT. Wne my son calls me, he’s using Zulu time, yet in a land that does not. Administrative personnel in his batallion use “local time” (Afghan time).
As you can probably tell, I have too much time on my hands today.
In the spirit of too much time on my hands and getting way off the subject, the earth does NOT rotate once on its axis every 24 hours. It actually takes less than 24 hours to rotate one complete revolution. It takes about 23 hours, 56.06 minutes to make one complete revolution. The earth makes 366.26 complete revolutions in one trip around the sun, not 365.26 as most people believe.
cont.
Think about it. As the earth rotates, it is also traveling a great arc around the sun. So it has to rotate just under 361° in order for a point on earth to face the sun again. So 24 hours is actually about 361° of earth rotation, not 360°
You are, of course, correct. And thus we have “leap year” to compensate.
And, if you really want to go nuts (as I am), the sun actually wobbles on its axis. And the earth’s rotational speed is slowing down due to the moon’s pull.
The leap year only compensates for the .26 day. You are right about the earths rotational speed slowing down. It is believed that at the dawning of the age of life on earth, the earth rotated on its axis about every 18 modern hours.
The whitworth system continuer past the MG TC series in American cars in strange places into the 60s usually in things that were bolted to the body like license plate brackets and tail lights. or brackets that held jacks.
"Frankly I can’t understand why someone would chose to have water freeze at 32º and boil at 212º while most of the rest of the world has water freeze at zero and boil at 100º "
Fahrenheit wanted 180º between freezing and boiling (212-32=180) with 100º as the core temperature of the human body (missed it by 1.4º).
"Fahrenheit wanted 180º between freezing and boiling (212-32=180) with 100º as the core temperature of the human body (missed it by 1.4º)"
Why 180º? Why not a nice round, fat number like 200º? Then water would boil at 200º, freeze at 0º, and (clinical) body temperature would be 100º. How perfectly mathematically symmetrical.
Clinical body temperature in Celsius is 37ºC. How ignoble. 37 has no factors. It is not a number easily remembered (unless you are an RN). Celsius (is that an actual name?) at least could have adjusted his scale to make body temperature 40º, with boiling/freezing remaining at 100º/0º. It would not have taken that much additional effort.
The only dimensionless physical constant that I know of is the fine structure constant α, 1/137 (why is it always given as a reciprocal?) And of course the actual number is not the reciprocal of 137 (that would be nice but still annoying) but the reciprocal of 137.035999074 … Is God playing a joke?
R.P. Feynman had a hypothesis that coupled α with π and e
http://www.maths.qmul.ac.uk/~jgg/page5.html
but that could just be Feynmen being Feynman.
When I did computer programming for the physics department eons ago as an undergraduate, we had clever (or so we thought) means of generating mathematical constants on the fly. For example, if we wanted π, we programmed 4 * arc tan(1). But the fine structure constant was never expressible in terms of other constants like electron mass or Planck’s constant. One had to plug the d__n 1/137 into the expression. (Well yes, one could write α as e²/ħc if e is expressed in cgs units, but still …)
I would say more but I hear the service trays tinkling in the hall, so I guess they are bringing breakfast around. I don’t want to miss that.
“Why 180º? Why not a nice round, fat number like 200º? Then water would boil at 200º, freeze at 0º, and (clinical) body temperature would be 100º. How perfectly mathematically symmetrical.”
Because 180 degrees is half a circle. Circles. Perhaps you’ve heard of them. They’re going to be a thing.
“Why 180º? Why not a nice round, fat number like 200º? Then water would boil at 200º, freeze at 0º, and (clinical) body temperature would be 100º. How perfectly mathematically symmetrical.”
And because then body temperature would be 74 degrees, not 100 degrees. Body temperature is not halfway between the freezing and boiling points of water. Really disappointing.
“Clinical body temperature in Celsius is 37ºC. How ignoble. 37 has no factors. It is not a number easily remembered (unless you are an RN). Celsius (is that an actual name?) at least could have adjusted his scale to make body temperature 40º, with boiling/freezing remaining at 100º/0º. It would not have taken that much additional effort.”
Why would an RN be especially good at remembering the number 37? Why would anyone need to remember it? Why not just mark all the thermometers? Or put up signs if the number is so hard to remember?
“The only dimensionless physical constant that I know of is the fine structure constant α”
That just speaks to your laziness. We expect better from the Dean of Computer Science at Carnegie Mellon University.
By the way, 37 has FOUR integer factors.
I have no basis in fact for this and it has been a loooong time since I was in school, but I seem to recall a teacher that said the Fahrenheit scale was based on 200 degrees between the boiling point and freezing point, but of blood, not water. However, it turned out that blood did not freeze at 0°F or boil at 200°F as believed at the time.
Make that 100°F for the boiling of blood. Apparently people though that our natural body temp was close to the boiling point of blood because if you got hot, you could “feel” your blood boil.
Wow. Did you go to school in the Bible?
The zero is the freezing(? or maybe something else) of a particular mixture of water and salt, the 32 is freezing of regular water, and 212 is 180 more degrees, half a circle, vide supra, for the boiling point of water.
Not long after. lol. I just vaguely remember the story but I have never seen any documentation that would back that up.
The biggest screwup ever recorded was a mistake made by an Air Ranada refuelling employee, who put in liters instead of Imperial gallons (1gallon=4.5 liters) shortly after Canada changed over to the metric system. The big 767 Boeing ran out of fuel over Manitoba on its way West. There was a small WW II training airstrip at a small town called Gimli. The pilot managed to glide the plane in with only a broken nose wheel upon landing.
Gimli is now on the map because of the “Gimli Glider”!