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The Exploding Whale (1970)

posted Wednesday, 12 November 2014

The blast blasted blubber beyond all believable bounds…. The humor of the entire situation suddenly gave way to a run for survival as huge chunks of whale blubber fell everywhere. Pieces of meat passed high over our heads while others were falling at our feet…. A parked car over a quarter of a mile away was the target of one large chunk. The passenger compartment was literally smashed…. Everyone at the scene was covered with small particles of dead whale.

For the latest exploding whale news visit theexplodingwhale.com. For more exploding whale videos visit expwhale’s YouTube channel.

physics.info/news/?p=655

Columbus and crew see America for the first time (1492)

posted Sunday, 12 October 2014

Crossing the Atlantic Ocean took 40 days. Sailor Rodrigo de Triana, who was stationed in the crow’s nest for the night watch, was the first member of Columbus’ crew to sight what is now known as the Bahamas. Columbus explored the Caribbean for 3 months before heading for the Azores.

physics.info/news/?p=4413

Time zones adopted in the US (1883)

posted Saturday, 11 October 2014

The first five standardized time zones of the US and Canada went into effect on this day in 1883. The agreement reached by the General Time Convention (later known as the American Railway Association) was designed to simplify railway scheduling.

physics.info/news/?p=522

AAAS founded (1848)

posted Saturday, 20 September 2014

The American Association for the Advancement of Science (a.k.a. the "Triple A-S") was established on this day in 1848.

AAAS Logo

physics.info/news/?p=4398

Columbus begins transatlantic voyage to America (1492)

posted Saturday, 6 September 2014

Calm winds kept him within sight of the Canaries for 2 days. They would not sight land again until 12 October 1492, 40 days after leaving port.

physics.info/news/?p=4392

Columbus sets sail on first voyage to America (1492)

posted Sunday, 3 August 2014

Christopher Columbus and crew departed Palos de la Frontera, Spain on 3 August 1492. America was first sighted 12 October 1492. He returned to his home port on 15 March 1493. The journey lasted a total of 224 days (or 7 months and 12 days).

physics.info/news/?p=4374

Leap Second Day

posted Saturday, 30 June 2012

Today is longer than yesterday and tomorrow by one second.

The hyperfine transition is the basis of International Atomic Time (TAI). By definition, the outermost electron in an ordinary cesium 133 atom cycles through this transition 9,192,631,770 times in one second.

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International Atomic Time (abbreviated TAI after the French Temps Atomique International) began at midnight GMT on the first day of 1958 and has continued advancing forward at the rate of one second every 9,192,631,770 periods of the hyperfine transition in 133Cs. TAI is maintained by the Bureau International des Poids et Mesures (BIPM) in Paris, which periodically averages the time kept by various atomic clocks around the world. The BIPM then disseminates correction factors needed to synchronize these clocks with the master clock in the Observatoire de Paris.

Coordinated Universal Time (abbreviated UTC) is the basis of legal time throughout the world. All local civil times differ from UTC by either a whole number of hours or an odd number of half hours, but never by any other amount. One second of Coordinated Universal Time is the same as one second of International Atomic Time, but UTC and TAI are slightly out of step. TAI marches forward uniformly, while UTC is adjusted from time to time to keep it synchronized with the earth’s rotation.

The earth is not an effective timekeeper. For most of the last two hundred years the mean solar day has been slightly longer than the 86,400 s currently defined by the International System. Universal Time UT, or more specifically UT1, is in effect the mean solar time. It is continuous (i.e. there are no leap seconds) but has a variable rate because of the Earth’s non-uniform rotation period. It is needed for computing the sidereal time, an essential part of pointing a telescope at a celestial source.

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When UT1 lags too far behind UTC, a leap second is inserted at the end of the day before January 1 or July 1 as appropriate. When this happens, 23:59:59 is followed by the unusual time of 23:59:60 before turning over to 00:00:00 and starting the next day. In the unlikely event that UT1 were to lead UTC (that is, if the earth’s rate of rotation were to increase) the provision exists for the insertion of a negative leap second. Were this to ever occur, 23:59:58 of one day would be followed by 00:00:00 of the next, skipping 23:59:59 altogether. In any case the absolute difference between UTC and UT1 must never exceed 0.9 s.

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Leap Seconds and Cumulative Adjustments to UTC
year month offset   year month offset   year month offset
1971   n/a*   1986   23   2001   32
1972 July 11   1987   23   2002   32
1973 January 12   1988 January 24   2003   32
1974 January 13   1989   24   2004   32
1975 January 14   1990 January 25   2005   32
1976 January 15   1991 January 26   2006 January 33
1977 January 16   1992 July 27   2007   33
1978 January 17   1993 July 28   2008   33
1979 January 18   1994 July 29   2009 January 34
1980 January 19   1995   29   2010   34
1981 July 20   1996 January 30   2011   34
1982 July 21   1997 July 31   2012 July 35
1983 July 22   1998   31   2013   ?
1984   22   1999 January 32   2014   ?
1985 July 23   2000   32   2015   ?
Adjustments from 1961 to 1971 follow a different, more complicated protocol and were omitted

Are leap seconds even necessary?

  • In seven or eight centuries the difference between TAI and UT1 will be about an hour.
  • By the year 5000, day and night will have reversed; that is, 12 noon will occur in the middle of the night and 12 midnight will synch up with the midday sun.

What would be so wrong with that? Does it really matter what number we assign to a position of the sun in the sky?

In 1582 Pope Gregory XIII managed to extract ten days from the calendar. On 4 October 1582 the Catholic world went to sleep. When they woke up it was 15 October 1582. By 1752 the protestant nation of England and her American colonies also accepted the change. (They needed to add 11 days to catch up.) In 1873 Japan made the switch. (They needed 12 days.) Then Russia in 1917 and China in 1949. (13 days.) The Greek Orthodox Church is possibly the only European agency that has not accepted this change (although the nation of Greece made the switch in 1923).

I think the big thing is that everyone agrees what time (or day) it is. Not that the time is any particular number. Time is a social construct, remember.

physics.info/news/?p=3661

Wordbook

posted Thursday, 23 September 2010

Wordbook says …

Hi, Glenn!

Wordbook appears to be configured and working just fine.

I Disagree. Wordbook does not appear to be posting anything to Facebook anymore … or is something else going on?

physics.info/news/?p=2603

Science caught in the Web 2010-02-13

posted Saturday, 13 February 2010

physics.info/news/?p=1073

Science caught in the Web 2010-02-06

posted Saturday, 6 February 2010

physics.info/news/?p=973