Talk:Terrestrial Time

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level of clarity[edit]

i find this article incredibly difficult to understand. should it be rewritten in a less technical fashion? —Preceding unsigned comment added by Richar4034 (talkcontribs) 23:53, 21 January 2007

It's a very technical subject. The detail and precise terminology does have to be there. I oppose a wholesale rewrite, but if a less technical explanation (which would inevitably be less complete) can be added then that would be a good thing. I'm not sure how to go about that though: I find the article very clear. What do you suggest? Perhaps if you ask about particular points of confusion here then this would point to ways to explain it better. 81.168.80.170 20:23, 14 February 2007 (UTC)

Yes, but I'm inclined to agree that there is room for improvement. The initial paragraph really only says that Terrestial Time takes relativistic effects into account. Most people will have some concept of what SR and GR are all about, even if terms like proper time, and perhaps even time dilation will be unfamiliar. Another issue is that many readers will be familiar with special relativity, as it really does not require advanced mathematics, but general relativity will be more mysterious. Or will it? Greg Woodhouse 21:07, 19 March 2007 (UTC)

TT is a coordinate time, not a proper time[edit]

IAU Resolution B1.9 (2000) as seen at http://syrte.obspm.fr/IAU_resolutions/Resol-UAI.htm reiterates the content of IAU Resolution A4 (1991) wherein TT is defined as a coordinate time, not a proper time. This distinction was further explicated by Gerard Petit at IAU Joint Discussion 16 (2006, Prague) as cataloged at http://adsabs.harvard.edu/abs/2006IAUJD..16E..21P (the actual presentation is at http://syrte.obspm.fr/iauJD16/petit.pdf ). To wit, TT is defined as a linear transformation of TCG. TCG is a coordinate time, therefore TT is a coordinate time. At the sub-nanosecond level this distinction is important. Steven L Allen 19:18, 1 July 2007 (UTC)

Need to update TT − UTC[edit]

Even though the date of the last leap second was updated, the value of TT-UTC was not; should be updated to 66.184 s. User:Arnold Rots —Preceding unsigned comment added by 133.40.12.59 (talk) 03:05, 5 October 2009 (UTC)

Are you confusing this article with another? This article does not mention leap seconds or TT−UTC, although maybe it should. It does mention TT−UT1, which is not the same thing. — Joe Kress (talk) 00:48, 6 October 2009 (UTC)

Relativistic relationship[edit]

A lot has been written about the General Relativistic effect of altitude here, but nothing on the different rotation speeds at different latitudes.

I infer from the article that TT is defined for someone who is at sea level and who is not moving along with the rotating surface of the earth. Is that inference correct? Whether it's correct or not, I think the article should spell it out. Rwflammang (talk) 21:52, 29 November 2012 (UTC)