Re: Year 2000 Issue

["Otto G. Raabe" <ograabe@ucdavis.edu>]

NO. IT IS THE TROPICAL YEAR THAT IS DECREAING BY 0.53 SECONDS PER CENTURY,
NOT THE DAY! Please re-read my posting.

At 10:52 AM 6/16/97 -0500, you wrote:
>Dear Otto,                                              June 13, 1997
>
>        If we assume from your note that the day is slowing up by 0.530
>secs per century, I estimate that our ancestors a million years ago had a
>day shorter than ours by 5,300 secs, or 1.47 hours, that is, 22.53 hours.
>
>        The burning question is, what was the length of the day say 50
>million years ago, still just a blink in geologic time, at a time when the
>mammals were starting to proliferate? Or 100 million years ago during the
>age of the dinasours. Seems that there wouldn't be time to get a good
>night's sleep.
>
>        Probably some geologic colleague already knows the answer to this
>and can enlighten us.
>
>                                Mike Quastel MD PhD
>                                Head, Inst of Nuclear Medicine
>                                Soroka Medical Center
>                                Ben Gurion University of the Negev
>                                POB 151, Beer Sheva, Israel 84101
>                                Fax +972-7-6400765
>                                Email: maay100@bgumail.bgu.ac.il
>
>>Leap years are necessary because of the time required for the earth to move
>>around the sun with respect to their relative positions. The tropical year,
>>which keeps the seasons in their right places, is defined by the time for
>>two consecutive returns of the sun to the vernal equinox (at the earth's
>>equator). That is 365 days, 5 hours, 48 minutes, and 46 seconds in 1990
>>(1997 World Almanac). It is decreasing by about 0.530 seconds per century.
>>Hence, the tropical year is now about 365.2422 days. With the leap year
>>system, there is an extra 3 days every 10,000 years. That's about an extra
>>26 seconds per year. We could approximately correct by not allowing years
>>divisible by 4,000 to be leap years. Luckily, we have astrophysicists and
>>atomic clocks to help keep us on time.
>>
>>Although 1900 was not a leap year, the last year of the 20th century, the
>>year 2000, will be a leap year. There will be a February 29,2000.
>>
>>I hope this is all there is on this issue.
>>
>>Best regards,
>>
>>Otto
>>                *****************************************************
>>                Prof. Otto G. Raabe, Ph.D., CHP
>>                Institute of Toxicology & Environmental Health (ITEH)
>>                     (Street address: Old Davis Road)
>>                University of California, Davis, CA 95616
>>                Phone: 916-752-7754     FAX: 916-758-6140
>>                E-Mail: ograabe@ucdavis.edu
>>                ******************************************************
>
>
>