xkcd: What If?

[bystander]

Alternate Universe What Ifs

• Dispatches from a horrifying alternate universe
  
  This week: Excerpts from What If articles written in a world which, thankfully, is not the one we live in:

[bystander]

Frozen Rivers

• What would happen all of the rivers in the US were instantly frozen in the middle of the summer? — Zoe Cutler

[bystander]

Lava Lamp

• What if I made a lava lamp out of real lava? What could I use as a clear medium?
  How close could I stand to watch it? — Kathy Johnstone, 6th Grade Teacher (via a student)

[bystander]

Fairy Demographics

• How many fairies would fly around, if each fairy is born from the first laugh of a child
  and fairies were immortal? — Mira Kühn, Germany

[bystander]

Lunar Swimming

• What if there was a lake on the Moon? What would it be like to swim in it? Presuming
  that it is sheltered in a regular atmosphere, in some giant dome or something. — Kim Holder

[bystander]

Bowling Ball

• You are in a boat directly over the Mariana Trench. If you drop a 7kg
  bowling ball over the side, how long would it take to hit the bottom? — Doug Carter

[bystander]

Stairs

• If you made an elevator that would go to space (like the one you mentioned in the
  billion-story building) and built a staircase up (assuming regulated air pressure)
  about how long would it take to climb to the top? — Ethan Annas

[bystander]

Tug of War

• Would it be possible for two teams in a tug-o-war to overcome the ultimate tensile strength
  of an iron rod and pull it apart? How big would the teams have to be? — Markus Andersen

[bystander]

Zippo Phone

• What in my pocket actually contains more energy, my Zippo or my smartphone? What would be the
  best way of getting the energy from one to the other? And since I am already feeling like Bilbo in this
  one, is there anything else in my pocket that would have unexpected amounts of stored energy? — Ian Cummings

[Chris Peterson]

Zippo Phone

• What in my pocket actually contains more energy, my Zippo or my smartphone? What would be the
  best way of getting the energy from one to the other? And since I am already feeling like Bilbo in this
  one, is there anything else in my pocket that would have unexpected amounts of stored energy? — Ian Cummings

Usually he gets these things right, but not this time. Your phone contains quite a bit more energy than your lighter, unless it's a very massive lighter and an incredibly tiny phone.

E = mc²

Doing something useful with that energy, of course, is an entirely different matter.

[geckzilla]

He seems to be restricting the use of the word "energy" to caloric energy but didn't bother mentioning it.

[Chris Peterson]

He seems to be restricting the use of the word "energy" to caloric energy but didn't bother mentioning it.

Which is a little surprising, because he would usually consider all options with a question like this.

[geckzilla]

There are a lot of pedants following his every comic and what-if. I'd be surprised if someone hasn't messaged him about it but you could be the first if you sent him an email.

[bystander]

Black Hole Moon

• What would happen if the Moon were replaced with an equivalently-massed black hole?
  If it's possible, what would a lunar ("holar"?) eclipse look like? — Matt

[emc]

I think it would be sad if the moon were to become a black hole. I think our howling would certainly no longer be heard... and things would generally get very quiet... at least from a human perspective.

[bystander]

Snow Removal

• I've long thought about putting a flamethrower on the front of a car to melt
  snow and ice before you drive across it. Now I've realized that a flamethrower
  is impractical, but what about a high-powered microwave emitter? — Matt Van Opens

[THX1138]

In order for earths moon to hold an atmosphere it would need a much greater magnetic field
Seems to me the simplest way, the cheapest way and the fastest way to accomplish this could be treating the moon as if it were an electric motor.
Set up some nuclear power plants and run an electrical grid across the surface to create an artificial magnetic field
What if ?

[bystander]

What if ?

xkcd: What If? Submit a Question

[geckzilla]

In order for earths moon to hold an atmosphere it would need a much greater magnetic field
Seems to me the simplest way, the cheapest way and the fastest way to accomplish this could be treating the moon as if it were an electric motor.
Set up some nuclear power plants and run an electrical grid across the surface to create an artificial magnetic field
What if ?

I think you need a much higher gravity to keep the atmosphere concentrated at the surface, too.

[bystander]

Microwaves

• I have had a particular problem for as long as I can remember. Any time I attempt to heat left
  over Chinese food in a microwave, it fails to heat completely through somewhere. Usually the
  center but not always and usually rice, but often it will be a small section of meat. It's baffling
  and has made me automatically adjust heating times to over 2 minutes. In most cases this tends
  to heat the bowl or plate more than the food. So I suppose the question is what is the optimal
  time to heat left over Chinese food in the microwave, how about an 800 watt microwave? — James

[bystander]

Hotter than Average

• I saw a sign at a hot springs tub saying "Caution: Water is hotter than average" with water
  at about 39°C. Although they were presumably trying to say "hotter than the average
  swimming pool," this got me wondering: What is the average temperature of all water
  on the Earth’s surface, and how does that temperature compare to 39°C? — Graham Ward

[bystander]

Flagpole

• So, you're falling from a height above the tallest building in your town, and you don't have
  a parachute. But wait! Partway down the side of that skyscraper there's a flagpole sticking
  out, sans flag! You angle your descent and grab the pole just long enough to swing around
  so that when you let go you're now heading back up toward the sky. As gravity slows you
  and brings you to a halt, you reach the top of the skyscraper, where you reach out and
  pull yourself to safety. What's the likelihood this could happen? — Rex Ungericht

[bystander]

Space Burial

• I've often joked I'd like to have my remains put into orbit. Not in a "scatter my ashes" sense,
  but, like, "throw my naked corpse out the airlock" sense. Honestly, my main motivation is to
  baffle someone in the distant future, but it's an interesting scientific question: what would
  happen to my body in orbit over the course of years, decades or centuries? — Tim in Fremont

[bystander]

Digging Downward

• What would happen if I dug straight down, at a speed of 1 foot per second?
  What would kill me first? — Jack Kaunis

[bystander]

Spiders vs. the Sun

• Which has a greater gravitational pull on me: the Sun, or spiders?
  Granted, the Sun is much bigger, but it is also much further away,
  and as I learned in high school physics, the gravitational force is
  proportional to the square of the distance. — Marina Fleming