Posted on Feb 29, 2020
APOD: 2020 February 29 - Julius Caesar and Leap Days
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Good morning, Rallypoint. Today's Astronomy Picture of the Day (APOD) is titled "Julius Caesar and Leap Days." Sosigenes of Alexandria was a Greek astronomer from Ptolemaic Egypt who, according to Roman historian Pliny the Elder, was consulted by Julius Caesar for the design of the Julian calendar (i.e. add a day every four years to account for the 365.24219 days it took for Earth to complete one solar orbit). In 1582 Pope Gregory XIII provided the further fine-tuning that leap days should not occur in years ending in 00, unless divisible by 400. This Gregorian Calendar system is the one in wide use today. We'll need to adjust things a bit further in ~4 million years or so. By then, tidal forces of the Earth-Moon system will have slowed the Earth enough to make leap days unnecessary. But until then...
APOD: 2020 February 29 - Julius Caesar and Leap Days
Posted from apod.nasa.gov
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Posted 5 y ago
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I have read a couple things today and read this one with interest- great history on Leap Year. Good morning Maj William W. 'Bill' Price
LTC Stephen F. SP5 Mark Kuzinski COL Mikel J. Burroughs SMSgt Lawrence McCarter Maj William W. 'Bill' Price SPC Margaret HigginsMaj Bill Smith, Ph.D. SGT Steve McFarlandLTC (Join to see) PO3Craig Phillips Lt Col Charlie Brown SSG Michael Noll PO1 H Gene Lawrence TSgt Joe C. Lt Col John (Jack) Christensen Sgt (Join to see)SFC Joe S. Davis Jr., MSM, DSL SSG Donald H "Don" Bates Cpl (Join to see)PVT Mark Zehner
LTC Stephen F. SP5 Mark Kuzinski COL Mikel J. Burroughs SMSgt Lawrence McCarter Maj William W. 'Bill' Price SPC Margaret HigginsMaj Bill Smith, Ph.D. SGT Steve McFarlandLTC (Join to see) PO3Craig Phillips Lt Col Charlie Brown SSG Michael Noll PO1 H Gene Lawrence TSgt Joe C. Lt Col John (Jack) Christensen Sgt (Join to see)SFC Joe S. Davis Jr., MSM, DSL SSG Donald H "Don" Bates Cpl (Join to see)PVT Mark Zehner
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MSgt Paul Connors SGT John Melvin LTC Tom McNew LTC Stephen C. SSG Michael Noll SGT Steve McFarland LTC Stephen F. Lt Col John (Jack) Christensen 1SG Steven Imerman Cpl (Join to see) Sgt Kelli Mays MSgt Robert "Rock" Aldi PO3 Lynn Spalding LTC (Join to see) SSG Gordon Holmes SMSgt Lawrence McCarterSGT Mark Anderson SP5 Jeannie Carle 1SG (Join to see)
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Julius Caesar ("Besame Mucho" by the Beatles)
Imagine an ancient Roman night club full of Julius Caesars listening to a song about Julius Caesar. (original remake of the instrumental)
Thank you, my friend Maj William W. 'Bill' Price for posting the NASA Astronomy Picture of the Day (APOD) for February 29, 2020 entitled "Julius Caesar and Leap Days."
The obverse and revers of an ancient Roman silver coin is interesting for NASA to post IMHO.
Images:
1. Julius Caesar AV Aureus. 46BC, issue of Aulus Hirtius
2. Julius Caesar AV Aureus. Rome, 44 BC. Diademed bust of Venus right, with bare
3. Julius Caesar denarius. COS TERT DICT ITER, head of Ceres
4. Julius Caesar, AR Denarius, 44 BC, Rome, left L. Aemelius Buca as Republican Moneyer; CAESAR-DICT PER_PETVO; Laureate head of Julius Caesar right
"Explanation: In 46 BC Julius Caesar reformed the calendar system. Based on advice by astronomer Sosigenes of Alexandria, the Julian calendar included one leap day every four years to account for the fact that an Earth year is slightly more than 365 days long. In modern terms, the time it takes for the planet to orbit the Sun once is 365.24219 mean solar days. So if calendar years contained exactly 365 days they would drift from the Earth's year by about 1 day every 4 years and eventually July (named for Julius Caesar himself) would occur during the northern hemisphere winter. By adopting a leap year with an extra day every four years, the Julian calendar year would drift much less. In 1582 Pope Gregory XIII provided the further fine-tuning that leap days should not occur in years ending in 00, unless divisible by 400. This Gregorian Calendar system is the one in wide use today. Of course, tidal friction in the Earth-Moon system slows Earth's rotation and gradually lengthens the day by about 1.4 milliseconds per century. That means that leap days like today will not be necessary ... about 4 million years from now."
Julius Caesar ("Besame Mucho" by the Beatles)
https://www.youtube.com/watch?v=nPYuxReh7fM
Thank you, my friend Maj Marty Hogan for mentioning me.
FYI COL Mikel J. Burroughs Col Carl Whicker SMSgt Lawrence McCarter Lt Col Charlie Brown Lt Col John (Jack) Christensen Maj Bill Smith, Ph.D. Maj Kim Patterson SPC Chris Bayner-Cwik SPC Chris Bayner-Cwik SP5 Mark Kuzinski CMSgt (Join to see) PO1 H Gene Lawrence SPC Margaret Higgins SP5 Jeannie Carle TSgt David L. TSgt Joe C.
The obverse and revers of an ancient Roman silver coin is interesting for NASA to post IMHO.
Images:
1. Julius Caesar AV Aureus. 46BC, issue of Aulus Hirtius
2. Julius Caesar AV Aureus. Rome, 44 BC. Diademed bust of Venus right, with bare
3. Julius Caesar denarius. COS TERT DICT ITER, head of Ceres
4. Julius Caesar, AR Denarius, 44 BC, Rome, left L. Aemelius Buca as Republican Moneyer; CAESAR-DICT PER_PETVO; Laureate head of Julius Caesar right
"Explanation: In 46 BC Julius Caesar reformed the calendar system. Based on advice by astronomer Sosigenes of Alexandria, the Julian calendar included one leap day every four years to account for the fact that an Earth year is slightly more than 365 days long. In modern terms, the time it takes for the planet to orbit the Sun once is 365.24219 mean solar days. So if calendar years contained exactly 365 days they would drift from the Earth's year by about 1 day every 4 years and eventually July (named for Julius Caesar himself) would occur during the northern hemisphere winter. By adopting a leap year with an extra day every four years, the Julian calendar year would drift much less. In 1582 Pope Gregory XIII provided the further fine-tuning that leap days should not occur in years ending in 00, unless divisible by 400. This Gregorian Calendar system is the one in wide use today. Of course, tidal friction in the Earth-Moon system slows Earth's rotation and gradually lengthens the day by about 1.4 milliseconds per century. That means that leap days like today will not be necessary ... about 4 million years from now."
Julius Caesar ("Besame Mucho" by the Beatles)
https://www.youtube.com/watch?v=nPYuxReh7fM
Thank you, my friend Maj Marty Hogan for mentioning me.
FYI COL Mikel J. Burroughs Col Carl Whicker SMSgt Lawrence McCarter Lt Col Charlie Brown Lt Col John (Jack) Christensen Maj Bill Smith, Ph.D. Maj Kim Patterson SPC Chris Bayner-Cwik SPC Chris Bayner-Cwik SP5 Mark Kuzinski CMSgt (Join to see) PO1 H Gene Lawrence SPC Margaret Higgins SP5 Jeannie Carle TSgt David L. TSgt Joe C.
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