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https://xkcd.com/2897

Alt text:

When Pope Gregory XIII briefly shortened the light-year in 1582, it led to navigational chaos and the loss of several Papal starships.

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[-] Sibbo@sopuli.xyz 71 points 8 months ago

Why not redefine lightyears to include a leap year every four years. Except when the number ends on 00, but only if it is not divisible by 400. Physics would be so much easier!

[-] Kecessa@sh.itjust.works 12 points 8 months ago* (last edited 8 months ago)

Well it's in fact easy to calculate...

To make it easier to visualize we'll start with year 400. From year 400 to year 799 you've got a leap year every 4 years except for years 500, 600, 700 and including year 400, so that's 25 leap years for the first century and 24 for the others.

So you've got 25 + (3x24) = 97 leap years

And 75 + (3 x 76) = 303 non leap years

(97 x 366) + (303 x 365) = 146097 days every 400 years which means a year is 365.2425 days long on average.

365.2425 x 24 = 8765.82 hours on average

8765.82 x 60 x 60 = 31 556 952 seconds per year on average

31 556 952 x 299 792 458 (speed of light per second) = a light year is 9460536207068016 meters long or 9460536207068.016 km long when adjusted to take leap years into consideration.

[-] Sibbo@sopuli.xyz 5 points 8 months ago

Okay, but now whenever you state one light year, it's just a normal year. When you state four, it is three normal ones and one leap year. So four times one light year would not equal four light years.

[-] Kecessa@sh.itjust.works 8 points 8 months ago* (last edited 8 months ago)

You asked for a lightyear adjusted based on leap years, I provided the number. It's a bit more than 365 light days and a bit less than 366 light days, it's closer to the real distance covered by light during the time the earth goes around the sun.

Edit: Don't know why anyone would downvote me for providing what OP asked for in the first place, especially when their reply didn't really make sense in the context...

[-] LSNLDN@slrpnk.net 62 points 8 months ago

Alt text lol

[-] randomaccount43543@lemmy.world 34 points 8 months ago
[-] youngalfred@lemm.ee 69 points 8 months ago

there's never been a "Papal starship"^[citation ^needed]

[-] nickhammes@lemmy.world 23 points 8 months ago

There hasn't been a Papal starship yet. I'm pretty sure he could Christen one, or delegate that authority to the bishop of the moon, an actual thing that technically exists.

[-] Kusimulkku@lemm.ee 11 points 8 months ago

Clearly they don't know about Hyperion books

[-] Frozengyro@lemmy.world 3 points 8 months ago

That was my first thought

[-] someguy3@lemmy.ca 27 points 8 months ago* (last edited 8 months ago)

Hmmm now that I think about this a light year would be (should be) based on an average year, not what we observe in any given year.

365.2425 days. Different searches give different results but that's what I'm going with.

[-] callyral@pawb.social 12 points 8 months ago* (last edited 8 months ago)

idk, it feels more intuitive for it to be based on the mode (most common) year length (365) instead of the average year length (365.2425).

[-] MBM@lemmings.world 27 points 8 months ago

The boring answer is that in physics a year is just defined as the time it takes for the Earth to orbit the sun, they don't care about calendars and leap years

[-] EtzBetz@feddit.de 4 points 8 months ago* (last edited 8 months ago)

I would've said 365.25 days?

[-] KISSmyOS@feddit.de 10 points 8 months ago

No, years divisible by 100 aren't leap years, except if they're also divisible by 400.

[-] datelmd5sum@lemmy.world 4 points 8 months ago

what is this, some sort of FizzBuzz calendar?

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[-] fahfahfahfah@lemmy.billiam.net 6 points 8 months ago

Interestingly, Wikipedia says they actually did base it on 365.25 instead of the actual 365.2425, so you’re technically right.

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[-] someguy3@lemmy.ca 5 points 8 months ago* (last edited 8 months ago)

They skip leap years every now and then. And then skip the skip. Etc. The rotation of the earth around the sun and the spin of the earth on its axis simply don't line up into a nice number.

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[-] psud@lemmy.world 3 points 8 months ago* (last edited 8 months ago)

You'd be imprecise for civil timekeeping, but spot on for astronomy

The civil rule is it's a leap year if the year is divisible by 4, unless it is also divisible by 100 unless it is also divisible by 400

We saw the rules play out in 2000 (at least those of us over 23 saw it) which is a year divisible by 100 and by 400 so it was a leap year

Yours (and astronomy's) is Julian style "if it's divisible by 4"

I prefer the newer calendars, where there is no good mental calculation for leap years - it's a leap year when the computer says it's a leap year

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[-] psud@lemmy.world 3 points 8 months ago

I would think that the best time period to use for a light year is whatever year definition has been used to date

Now let's work on the best second to use for the light second

[-] MidRomney@lemmy.world 13 points 8 months ago

Just wondering, but do people actually find xkcd funny? Are these comics supposed to be funny?

[-] Opafi@feddit.de 101 points 8 months ago

do people actually find xkcd funny?

Yes. And I should know, I'm a people.

[-] jballs@sh.itjust.works 13 points 8 months ago

I'm a people.

Citation needed

[-] noughtnaut@lemmy.world 5 points 8 months ago

I don't have an exact reference for you, but it sounds like a quote from Hawkeye (Alan Alda) from MASH.

[-] jballs@sh.itjust.works 2 points 8 months ago

Haha I wasn't looking for a quote, I was just making the "citation needed" joke that XKCD throws into a lot of stuff.

[-] wrath_of_grunge@kbin.social 80 points 8 months ago

absolutely.

not every joke is going to land with everyone. sometimes they're not even jokes, just pointing out absurdities.

if they don't land with you, i wouldn't stress it. sometimes the humor is extremely nerdy. it's like the Far Side or Monty Python. it's not everyone's cup of tea, and that's OK.

[-] brbposting@sh.itjust.works 3 points 8 months ago

Wholesome reply 🥰

[-] GlitterInfection@lemmy.world 36 points 8 months ago

It falls often into sensible chuckle territory rather than stand-up comic material kind of funny.

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[-] NeatNit@discuss.tchncs.de 23 points 8 months ago

They're hit or miss. This one is mildly amusing to me. It's been going strong 3 comics a week for how many years now? Not all of them are good of course, some I consider just bad but I think most weeks have at least one good one.

[-] Firefly7 23 points 8 months ago

This one made me laugh. Most I just find to be novel, silly, or interesting, but a fair few are pretty funny to me.

[-] umbraroze@kbin.social 15 points 8 months ago

It's a comic published multiple times a week. Common social etiquette is that if you find it funny (which is known to happen), you give it a grin or a mild chuckle or whatever, and then move on with your morning and, by extension, the rest of your life.

[-] psud@lemmy.world 2 points 8 months ago

I would argue that nearly no one finds this one funny but many found this one funny

The OP comic is less accessible than the empiricism one, so the target audience is smaller, some of the smaller audience comics required one knew Firefly, open source memes, and Corey Doctorow. When you're in the target group the comics are especially hilarious

Some have fallen flat for me until I looked up XKCD explained, since I have very low knowledge of pop culture. I wouldn't say those aren't funny, I say I don't get them

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this post was submitted on 22 Feb 2024
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