Entry tags:
today I learned...
TIL #1:
Somebody linked to this question on Stack Overflow about some unexpected results when doing math on dates in Java. The problem, according to Jon Skeet, is that the date being used in the calculation is near midnight on December 31, 1927 in the Shanghai time zone -- when Shanghai moved its clocks by 5 minutes and 52 seconds. So the time in question existed twice, and Java chose the one that the programmer wasn't expecting.
That answers the programming question, but my question from that was: why in the world would somebody move clocks by 5 minutes and 52 seconds? I understand shifts of an hour (that happens all the time), and there are timezones out there that have 30-minute offsets and even one with a 15-minute offset, so that wouldn't have much surprised me either. But 5:52???
So I asked Google, which led me to a question on History Stack Exchange about this, where an answer explained that 1927 was not a good year for political stability in Shanghai, and one of the side-effects was a change in who had control over the central astronomical institution, with the result that the reference point moved east from Beijing to Nanjing. Greenwich was apparently not yet a thing as far as they were concerned.
A comment on the answer, from Taiwan, casts doubt on whether there was a time shift at all -- but, if not, doesn't explain where Java got the idea. Curious.
TIL #2:
A few days ago on Mi Yodeya somebody asked if, during the Exodus, the commandment to place the blood on the doorposts and lintel was just on one door or all of them. (Is it like mezuzot, which are on every door, or like the chanukiyah, which we place next to one door only?) My first thought was that there might have only been one door in ancient Egyptian slave housing. Last night I learned a little about ancient architecture and then wrote an answer about the four-room house, which appears to have had one outside door. I argued that we're given the reason for the commandment: it's to mark which houses are to be passed over. To me, that says blood on exterior doors, of which there was one.
Not TIL #3:
Today on Mi Yodeya somebody asked how many people the Pesach offering would feed. The torah says to use a lamb or kid, that it all has to be eaten that night, and that if you don't have enough people to do that, get together with your neighbors. So how big a group are we talking about? One can find plenty of information (not always in agreement, mind) about the weights of modern livestock animals, but animal husbandry has worked its magic over the centuries -- heck, even within my lifetime we've seen "standard" chickens for food get a lot bigger. So knowing how much a yearling lamb weighs today doesn't necessarily tell us what it might have weighed in ancient Egypt or in the time of the first or second temple, when this was done.
I considered asking on History SE, but I haven't yet. Anybody happen to know?
Somebody linked to this question on Stack Overflow about some unexpected results when doing math on dates in Java. The problem, according to Jon Skeet, is that the date being used in the calculation is near midnight on December 31, 1927 in the Shanghai time zone -- when Shanghai moved its clocks by 5 minutes and 52 seconds. So the time in question existed twice, and Java chose the one that the programmer wasn't expecting.
That answers the programming question, but my question from that was: why in the world would somebody move clocks by 5 minutes and 52 seconds? I understand shifts of an hour (that happens all the time), and there are timezones out there that have 30-minute offsets and even one with a 15-minute offset, so that wouldn't have much surprised me either. But 5:52???
So I asked Google, which led me to a question on History Stack Exchange about this, where an answer explained that 1927 was not a good year for political stability in Shanghai, and one of the side-effects was a change in who had control over the central astronomical institution, with the result that the reference point moved east from Beijing to Nanjing. Greenwich was apparently not yet a thing as far as they were concerned.
A comment on the answer, from Taiwan, casts doubt on whether there was a time shift at all -- but, if not, doesn't explain where Java got the idea. Curious.
TIL #2:
A few days ago on Mi Yodeya somebody asked if, during the Exodus, the commandment to place the blood on the doorposts and lintel was just on one door or all of them. (Is it like mezuzot, which are on every door, or like the chanukiyah, which we place next to one door only?) My first thought was that there might have only been one door in ancient Egyptian slave housing. Last night I learned a little about ancient architecture and then wrote an answer about the four-room house, which appears to have had one outside door. I argued that we're given the reason for the commandment: it's to mark which houses are to be passed over. To me, that says blood on exterior doors, of which there was one.
Not TIL #3:
Today on Mi Yodeya somebody asked how many people the Pesach offering would feed. The torah says to use a lamb or kid, that it all has to be eaten that night, and that if you don't have enough people to do that, get together with your neighbors. So how big a group are we talking about? One can find plenty of information (not always in agreement, mind) about the weights of modern livestock animals, but animal husbandry has worked its magic over the centuries -- heck, even within my lifetime we've seen "standard" chickens for food get a lot bigger. So knowing how much a yearling lamb weighs today doesn't necessarily tell us what it might have weighed in ancient Egypt or in the time of the first or second temple, when this was done.
I considered asking on History SE, but I haven't yet. Anybody happen to know?
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