Wednesday is Doomsday

[It Aint Necessarily So]

Relax. Nothing bad is expected for Wednesday.

What's being called Doomsday is the day of the week that an algorithm for determining the day given the date points to. This year, 2018, it is a Wednesday. April 4, June 6, August 8, October 10 and December 12 (4/4, 6/6, 8/8, 10/10 and 12/12) all fall on Wednesdays this year. Lat year, they were all Tuesdays. Now you know that Halloween will be on a Wednesday this year, since if 10/10 is a Wednesday, so is 10/31 three weeks later.

How about the odd numbered months in between? 5/9, 9/5, 7/11 and 11/7 are all Doomsdays as well. The mnemonic for this is "Working 9 to 5 at the 7-Eleven."

February and March are handled by recognizing that March 0th (sic) is also a Doomsday. March 0th is the day before March 1st, which is February 28th in common years, and February 29th in leap years. So, St. Patrick's Day, March 17, will fall on the same day of the week as March 3rd two weeks earlier, which falls 3 days after March 0th. If March 0 is a Wednesday, March 3rd and hence March 17th are Saturdays.

And Valentine's Day, February 14th, is two weeks before February 28th, the other name for March 0th, and hence will fall on a Wednesday.

That leaves only January, which can be handled by memorizing that January 3rd is a Doomsday in common years like this one (if you didn't already know it, you could count back two days to figure out that today, New Years Day, is a Monday), and January 4th in leap years.

This link and this one can help you generalize the method to other years even if they fall in other centuries. The method gets pretty complex when generalized to this degree, but is pretty simple for use in any current calendar year.

 

[Shadow Wolf]

Nerd!

 

[Brickjectivity]

Relax. Nothing bad is expected for Wednesday.

What's being called Doomsday is the day of the week that an algorithm for determining the day given the date points to. This year, 2018, it is a Wednesday. April 4, June 6, August 8, October 10 and December 12 (4/4, 6/6, 8/8, 10/10 and 12/12) all fall on Wednesdays this year. Lat year, they were all Tuesdays. Now you know that Halloween will be on a Wednesday this year, since if 10/10 is a Wednesday, so is 10/31 three weeks later.

How about the odd numbered months in between? 5/9, 9/5, 7/11 and 11/7 are all Doomsdays as well. The mnemonic for this is "Working 9 to 5 at the 7-Eleven."

February and March are handled by recognizing that March 0th (sic) is also a Doomsday. March 0th is the day before March 1st, which is February 28th in common years, and February 29th in leap years. So, St. Patrick's Day, March 17, will fall on the same day of the week as March 3rd two weeks earlier, which falls 3 days after March 0th. If March 0 is a Wednesday, March 3rd and hence March 17th are Saturdays.

And Valentine's Day, February 14th, is two weeks before February 28th, the other name for March 0th, and hence will fall on a Wednesday.

That leaves only January, which can be handled by memorizing that January 3rd is a Doomsday in common years like this one (if you didn't already know it, you could count back two days to figure out that today, New Years Day, is a Monday), and January 4th in leap years.

This link and this one can help you generalize the method to other years even if they fall in other centuries. The method gets pretty complex when generalized to this degree, but is pretty simple for use in any current calendar year.

What if I know the calendar date and the position of the Earth around the Sun on some particular day, but from that what if I want to find out days when the Earth was last in the same position? Obviously its going to vary because February Doomsdays shift the Calender about while the Earth travels smoothly in its continuum but not precisely 365 days per lap.

 

[beenherebeforeagain]

more help is at Perpetual calendar - Wikipedia, which also links to doomsdays...

 

[sun rise]

Oh goodie. Now I can have a new depth to my utterances when I get in a Chicken Little mood and starting chanting "Doom. We're all doomed". Now I can add "today (or better a future date) is doomsday".

 

[It Aint Necessarily So]

What if I know the calendar date and the position of the Earth around the Sun on some particular day, but from that what if I want to find out days when the Earth was last in the same position? Obviously its going to vary because February Doomsdays shift the Calender about while the Earth travels smoothly in its continuum but not precisely 365 days per lap.

This is the problem that calendar makers struggle with. The tropical year - solstice to solstice - is about 365.2422 days long.

But calendar years are 365 or 366 days.

If you want to discuss returning to the same place in the orbit, we need to consider sidereal years, which are reckoned not by the solstices and equinoxes, but by the position of the fixed background stars.

background stars

These are about 365.2564 days. These two differ by about 20 minutes and 24.5 seconds, or 20.41 minutes/0.0141 days - about 1/25,800th of a year - the tropical year being shorter.

The reason is because the earth precesses like a top, making one full 360 degree rotation about every 25,800 years.

I believe that the arrows in each of these pictures is reversed. The earth both rotates on its axis and revolves around the sun counterclockwise as judged from above the north pole, and precesses in a clockwise direction from the same vantage point.

So, when the earth returns a year later to the precise place in it's orbit where one of its poles pointed precisely at the up-and-down line that bisects the sun last year, it is no longer pointing perfectly.

It's a tricky subject.

And yes, @Shadow Wolf I cannot deny your claim except to say that for me what characterizes the nerd is liking only such things, and being socially awkward.

Speaking of which, don't forget that tonight is the first of two full moons this month, that February will have none, and that March will also have two full moons - a relatively rare situation. This is the schedule:

2018 Jan 01 20:26 Mon (Central Standard Time)
2018 Jan 31 07:28 Wed
2018 Mar 01 18:52 Thu
2018 Mar 31 06:38 Sat

 

[shunyadragon]

Relax. Nothing bad is expected for Wednesday.

What's being called Doomsday is the day of the week that an algorithm for determining the day given the date points to. This year, 2018, it is a Wednesday. April 4, June 6, August 8, October 10 and December 12 (4/4, 6/6, 8/8, 10/10 and 12/12) all fall on Wednesdays this year. Lat year, they were all Tuesdays. Now you know that Halloween will be on a Wednesday this year, since if 10/10 is a Wednesday, so is 10/31 three weeks later.

How about the odd numbered months in between? 5/9, 9/5, 7/11 and 11/7 are all Doomsdays as well. The mnemonic for this is "Working 9 to 5 at the 7-Eleven."

February and March are handled by recognizing that March 0th (sic) is also a Doomsday. March 0th is the day before March 1st, which is February 28th in common years, and February 29th in leap years. So, St. Patrick's Day, March 17, will fall on the same day of the week as March 3rd two weeks earlier, which falls 3 days after March 0th. If March 0 is a Wednesday, March 3rd and hence March 17th are Saturdays.

And Valentine's Day, February 14th, is two weeks before February 28th, the other name for March 0th, and hence will fall on a Wednesday.

That leaves only January, which can be handled by memorizing that January 3rd is a Doomsday in common years like this one (if you didn't already know it, you could count back two days to figure out that today, New Years Day, is a Monday), and January 4th in leap years.

This link and this one can help you generalize the method to other years even if they fall in other centuries. The method gets pretty complex when generalized to this degree, but is pretty simple for use in any current calendar year.

Doom, doom, doom, . . . doom d' dumb, dumb d'doom, dumb, dumb, dumb, and ah . . . dumb.