this post was submitted on 06 Feb 2025
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xkcd

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It was great until my thumb slipped and I accidentally launched my telescope into the air at Mach 8.

https://explainxkcd.com/3047/

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[–] moistclump 7 points 6 days ago (3 children)

Stupid question… are these RPMs true??

[–] [email protected] 20 points 6 days ago* (last edited 6 days ago) (2 children)

Everything in XKCD is based on truth. That's what makes it so funny... to geeks, at least.

Edit: God damn it, he put 72 instead of 78 RPM. I guess he does make mistakes after all...

[–] sanguinepar 16 points 6 days ago (1 children)

He also put 33 instead of 33 and ⅓. Get the pitchforks!

[–] [email protected] 9 points 6 days ago (1 children)

Just a random thought, I always knew that 33 multiplied by 3 is 99 and 33 1/3 multiplied by 3 is 100, but I never considered that 33 is 99% of 33 1/3.

[–] sanguinepar 2 points 5 days ago
[–] [email protected] 7 points 6 days ago (1 children)
[–] [email protected] 4 points 6 days ago

I mean, technically, the record will play just fine. Everything will be slightly slower and lower pitched, but it'll work. Think doom metal meets 1930s jazz.

[–] felbane 2 points 5 days ago* (last edited 5 days ago) (2 children)

Maybe I'm dense but shouldn't the clock be:

  • H: 0.01667
  • M: 1
  • S: 60

Yep, I'm a dumb, realized after a cup of coffee. Confirmed by the reply below.

I think I'm just going to go back to bed and skip today

[–] [email protected] 7 points 5 days ago

Yes, you're dense lol. The speeds are correct: the second hand that does one full Revolution Per Minute, the minute hand does one full Revolution Per Hour and the hour hand does one Revolution Per 12 Hours.

[–] [email protected] 3 points 5 days ago

Oh my god I'm full of caffeine and still wondered this same thing. In my defense it's Friday afternoon and I'm tired.

[–] KingRandomGuy 1 points 5 days ago

The sidereal telescope mount one seems to be right (approx 1 rotation per day).