3 ms·

More Falsehoods Programmers Believe About Time (2012)

17 points by tie-in 2y ago

BeefySwain 2y ago
I really wish that these lists included explanations for why they are incorrect, or at least links to resources accordingly.
_xivi 2y ago
Related: Falsehoods Programmers believe about Time - https://news.ycombinator.com/item?id=4128208 https://news.ycombinator.com/item?id=4128208 - Jun 2012 (213 comments) Falsehoods Programmers Believe About Time (2012) - https://news.ycombinator.com/item?id=12675527 https://news.ycombinator.com/item?id=12675527 - Oct 2016 (154 comments) Falsehoods programmers believe about time - https://news.ycombinator.com/item?id=32548085 https://news.ycombinator.com/item?id=32548085 - Aug 2022 (204 comments) Falsehoods programmers believe about time and time zones - https://news.ycombinator.com/item?id=11515125 https://news.ycombinator.com/item?id=11515125 - Apr 2016 (80 comments)
PaulStatezny 2y ago
The article doesn't contain explanations, so I dug into a few especially surprising ones: --- > 7. Months have either 28, 29, 30, or 31 days. Great Britain skipped from Sept 2, 1752 straight to Sept 14 when they switched from the Julian to the Gregorian calendar. Google "English calendar riots". --- > 15. Unix time is the number of seconds since Jan 1st 1970. When flipping over to the next second, Unix time "rewinds" back a second (i.e. repeats the last one) for leap seconds. [1] --- > 73. Time passes at the same speed on top of a mountain and at the bottom of a valley. This is from "time dilation", related to Einstein's General Relativity. In short, gravity warps spacetime. Say you use a stopwatch to measure 1 Earth rotation (a "day"). For each extra km of altitude, the stopwatch will tell you it took ~10 extra nanoseconds to complete the trip around the Earth. [2] --- [1] https://en.wikipedia.org/wiki/Unix_time#Leap_seconds https://en.wikipedia.org/wiki/Unix_time#Leap_seconds [2] https://en.wikipedia.org/wiki/Time_dilation#Time_dilation_caused_by_gravity_or_acceleration https://en.wikipedia.org/wiki/Time_dilation#Time_dilation_ca...
deleted 2y ago
[deleted]
jbandela1 2y ago
All models are wrong. Some are useful. Determine what level of the model is useful for what you want to do.

17 points by tie-in 2y ago

I really wish that these lists included explanations for why they are incorrect, or at least links to resources accordingly.

_xivi 2y ago

Related: Falsehoods Programmers believe about Time - https://news.ycombinator.com/item?id=4128208 https://news.ycombinator.com/item?id=4128208 - Jun 2012 (213 comments) Falsehoods Programmers Believe About Time (2012) - https://news.ycombinator.com/item?id=12675527 https://news.ycombinator.com/item?id=12675527 - Oct 2016 (154 comments) Falsehoods programmers believe about time - https://news.ycombinator.com/item?id=32548085 https://news.ycombinator.com/item?id=32548085 - Aug 2022 (204 comments) Falsehoods programmers believe about time and time zones - https://news.ycombinator.com/item?id=11515125 https://news.ycombinator.com/item?id=11515125 - Apr 2016 (80 comments)

PaulStatezny 2y ago

The article doesn't contain explanations, so I dug into a few especially surprising ones: --- > 7. Months have either 28, 29, 30, or 31 days. Great Britain skipped from Sept 2, 1752 straight to Sept 14 when they switched from the Julian to the Gregorian calendar. Google "English calendar riots". --- > 15. Unix time is the number of seconds since Jan 1st 1970. When flipping over to the next second, Unix time "rewinds" back a second (i.e. repeats the last one) for leap seconds. [1] --- > 73. Time passes at the same speed on top of a mountain and at the bottom of a valley. This is from "time dilation", related to Einstein's General Relativity. In short, gravity warps spacetime. Say you use a stopwatch to measure 1 Earth rotation (a "day"). For each extra km of altitude, the stopwatch will tell you it took ~10 extra nanoseconds to complete the trip around the Earth. [2] --- [1] https://en.wikipedia.org/wiki/Unix_time#Leap_seconds https://en.wikipedia.org/wiki/Unix_time#Leap_seconds [2] https://en.wikipedia.org/wiki/Time_dilation#Time_dilation_caused_by_gravity_or_acceleration https://en.wikipedia.org/wiki/Time_dilation#Time_dilation_ca...

deleted 2y ago

[deleted]

jbandela1 2y ago

All models are wrong. Some are useful. Determine what level of the model is useful for what you want to do.