xkcd: What If?

[bystander]

Answering your hypothetical questions with physics, every Tuesday.

From the creators of:


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Relativistic Baseball

• What would happen if you tried to hit a baseball pitched at 90% the speed of light? — Ellen McManis

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SAT Guessing

• What if everyone who took the SAT guessed on every multiple-choice question?
  How many perfect scores would there be? — Rob Balder

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Yoda

• How much Force power can Yoda output? — Ryan Finnie

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A Mole of Moles

• What would happen if you were to gather a mole (unit of measurement) of moles (the small furry critter) in one place? — Sean Rice

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Robot Apocalypse

• What if there was a robot apocalypse? How long would humanity last? — Rob Lombino

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Glass Half Empty

• What if a glass of water was, all of a sudden, literally half empty? — Vittorio Iacovella

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Everybody Out

• Is there enough energy to move the entire current human population off-planet? — Adam

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Everybody Jump

• What would happen if everyone on earth stood as close to each other as they could and jumped,
  everyone landing on the ground at the same instant? — Thomas Bennett (and many others)

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Soul Mates

• What if everyone actually had only one soul mate, a random person somewhere in the world? — Benjamin Staffin

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Cassini

• What would the world be like if the land masses were spread out the same way as now -
  only rotated by an angle of 90 degrees? — Socke

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Droppings

• If you went outside and lay down on your back with your mouth open,
  how long would you have to wait until a bird pooped in it? — Adrienne Olson

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Raindrop

• What if a rainstorm dropped all of its water in a single giant drop? — Michael McNeill

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Laser Pointer

• If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color? — Peter Lipowicz

[BMAONE23]

Raindrop

• What if a rainstorm dropped all of its water in a single giant drop? — Michael McNeill

That would cause a localized flood of biblical proportions

[bystander]

Short Answer Section

In today’s article, I give short answers to several reader questions.

• How long would the Sun last if a giant water hose were focused upon it? My sixth grade brother, Adam, asked me this. — Austin Dickey
  
  What if you shined a flashlight (or a laser) into a sphere made of one-way mirror glass? — Chase Montgomery
  
  If Michael Phelps could hold his breath indefinitely, how long would it take for him to reach the lowest point in the ocean and back if he swam straight down and then straight back up? — Jimmy Morey
  
  In the first Superman movie, Superman flies around Earth so fast that it begins turning in the opposite direction. This somehow turns back time [... ] How much energy would someone flying around the Earth have to exert in order to reverse the Earth's rotation? — Aidan Blake
  
  How fast would you have to go in your car to run a red light claiming that it appeared green to you due to the Doppler Effect? — Yitzi Turniansky
  
  What would happen if you opened a portal between Boston (sea level) and Mexico City (elev. 8000+ feet)? — Jake G.
  
  When my wife and I started dating she invited me over for dinner at one time. Her kitchen had something called Bauhaus chairs, which are full of holes, approx 5-6 millimeters in diameter in both back and seat. During this lovely dinner I was forced to liberate a small portion of wind and was relieved that I managed to do so very discretely. Only to find that the chair I sat on converted the successful silence into a perfect, and loud, flute note. We were both (luckily) amazed and surprised and I have often wondered what the odds are for something like that happening. We kept the chairs for five years but despite laborious attempts it couldn't be reproduced. — R. D.

[owlice]

This ... isn’t actually a question.
i don't know how all these words got on my screen.

But thank you for sharing!

lol!!!

[owlice]

I managed to do so very discretely.

What, pray tell, might have been the other choices?

[geckzilla]

Let it rip and hope she laughs?

[Moonlady]

Funny page!

I had not a long time ago a big virus party going on on my pc which caused some problems I could not solve alone, I called
a friend who is doing his dissertation as computer engineer and he showed me xkcd.com site, especially this sheet:

xkcd.com 627

...my solution was: ask Paolo! Mille grazie Paolo

...he brought his own notebook and could use google and follow the instructions to solve the problem

[bystander]

Mariana Trench Explosion

• What if you exploded a nuclear bomb (say, the Tsar Bomba) at the bottom of the Marianas Trench? — Evin Sellin

[bystander]

Today's topic: Lightning

• How dangerous is it, really, to be in a pool during a thunderstorm? — Jay Gengelbach
  
  What would happen if you were taking a shower when you were struck by lightning?
  Or standing under a waterfall? — same3chords
  
  What would happen if you were in a boat or a plane that got hit by lightning? Or a submarine? — SoobNauce
  
  What if you were changing the light at the top of a radio tower and lightning struck? Or what if you were doing a backflip?
  Or standing in a graphite field? Or looking straight up at the bolt? — Danny Wedul
  
  What would happen if lightning struck a bullet in midair? — Timothy Campbell
  
  What if you were flashing your BIOS during a thunderstorm and you got hit by lightning? — njsg

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Green Cows

• If cows could photosynthesize, how much less food would they need? — Anonymous

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BB Gun

• In Armageddon, a NASA guy comments that a plan to shoot a laser at the asteroid is like “shooting a b.b. gun at a freight train.”
  What would it take to stop an out-of-control freight train using only b.b. guns? — Charles James O'Keefe

[emc]

BB Gun

• In Armageddon, a NASA guy comments that a plan to shoot a laser at the asteroid is like “shooting a b.b. gun at a freight train.”
  What would it take to stop an out-of-control freight train using only b.b. guns? — Charles James O'Keefe

Take an amount of BB guns to equal the weight of the train and melt them down into a large block then place the block on the track moving from the opposite direction toward the train at the same speed.