Re: The real problem with leap seconds

2006-01-11 Thread Michael Deckers
On 2006-01-10, Mark Calabretta wrote: I can't let this one pass - UTC is continuous and monotonic. In fact, ignoring differences in origin, UTC = TAI. Surprised? If so then you're confusing a quantity with its representation (though in good company in doing so). I do not

Re: The real problem with leap seconds

2006-01-11 Thread David Malone
[A lot of discussion on this list seem to revolve around people understanding terms in different ways. In an impractical example of that spirit...] I do not understand. As a function of TAI, UTC is neither continuous nor monotone increasing in the mathematical sense. To say if TAI is a

Re: The real problem with leap seconds

2006-01-11 Thread Daniel R. Tobias
On 11 Jan 2006 at 0:08, Tim Shepard wrote: If humans spread out to other places besides the earth, an earth-centric time scale might begin to seem somewhat quaint. Distributing leap second information to a Mars colony seems kind of silly. As I recall, the NASA Mars missions are using

Re: The real problem with leap seconds

2006-01-11 Thread Steve Allen
On Wed 2006-01-11T09:01:07 -0500, Daniel R. Tobias hath writ: If, however, this Martian second is actually defined as a particular multiple of the SI second, then the use of leap seconds on Mars would ultimately be necessary to account for any future changes in the length of the Martian day.

War of the Worlds

2006-01-11 Thread Rob Seaman
I see Steve Allen has already supplied a thorough answer. Interested individuals might also scrounge through the list archives (http:// rom.usno.navy.mil/archives/leapsecs.html) since the topic has come up before. In fact, Demetrios Matsakis speculated on solar system wide timescales even

Re: The real problem with leap seconds

2006-01-11 Thread Michael Deckers
On 2006-01-11, David Malone wrote: [A lot of discussion on this list seem to revolve around people understanding terms in different ways. In an impractical example of that spirit...] Anyway: excuse me for repeating some basics of classical mechanics; but I believe it to be

Re: The real problem with leap seconds

2006-01-11 Thread Mark Calabretta
On Wed 2006/01/11 10:47:25 -, Michael Deckers wrote in a message to: LEAPSECS@ROM.USNO.NAVY.MIL At some instant when TAI took a value in the positive leap second between 2006-01-01 + 00 h + 00 min + 32 s and 2006-01-01 + 00 h + 00 min + 33 s (the exact instant is not clear from

Re: The real problem with leap seconds

2006-01-11 Thread M. Warner Losh
In message: [EMAIL PROTECTED] Mark Calabretta [EMAIL PROTECTED] writes: : On Wed 2006/01/11 10:47:25 -, Michael Deckers wrote : in a message to: LEAPSECS@ROM.USNO.NAVY.MIL : :At some instant when TAI took a value in the positive leap second between :2006-01-01 + 00 h + 00

Re: War of the Worlds

2006-01-11 Thread John Cowan
Rob Seaman scripsit: I don't have an envelope large enough, but there are various issues to consider. The Hurtling Moons of Barsoom are much smaller than our own and should have a negligible tidal breaking effect. (See http:// www.freemars.org/mars/marssys.html, for instance, for their

Re: The real problem with leap seconds

2006-01-11 Thread Mark Calabretta
On Wed 2006/01/11 20:58:25 PDT, M. Warner Losh wrote in a message to: [EMAIL PROTECTED] and copied to: LEAPSECS@ROM.USNO.NAVY.MIL : 60.999... 32.999... 32 :2006/01/01 00:00:00 2006/01/01 00:00:3333 :2006/01/01

Monsters from the id

2006-01-11 Thread Rob Seaman
What now, Dr. Moebius?                      Prepare your minds for a new scale...                    of physical scientific values, gentlemen.Mark Calabretta takes the lazy man's way out and appeals to facts: Here in a topology-free way is what the axis labels of my graph looklike during

Re: War of the Worlds

2006-01-11 Thread Neal McBurnett
I referenced this page, but missed the most interesting part of it: http://www.exo.net/~pauld/physics/tides/tidalevolution.htm The height of a tidal bulge on a planet is proportional to the inverse cube of the distance between the planet and the object causing the tidal bulge. The torque

Re: War of the Worlds

2006-01-11 Thread John Cowan
Neal McBurnett scripsit: I wouldn't be too quick to dismiss tidal braking from Phobos. It's awfully close to Mars, and tidal braking is as you say an inverse-cube effect. The formula (kai Wikipedia) is (2GMmr)/R^3, where M and m are the masses, r is the radius of the primary, and R is