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xkcd: What If? #120 - Alternate Universe What Ifs
Posted: Sun Nov 23, 2014 6:40 pm
by 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:
xkcd: What If? #121 - Frozen Rivers
Posted: Mon Dec 15, 2014 5:12 am
by bystander
Frozen Rivers
- What would happen all of the rivers in the US were instantly frozen in the middle of the summer? — Zoe Cutler
xkcd: What If? #122 - Lava Lamp
Posted: Fri Dec 26, 2014 5:31 pm
by 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)
xkcd: What If? #123 - Fairy Demographics
Posted: Wed Jan 07, 2015 7:47 pm
by 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
xkcd: What If? #124 - Lunar Swimming
Posted: Mon Jan 12, 2015 5:42 pm
by 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
xkcd: What If? #125 - Bowling Ball
Posted: Wed Jan 21, 2015 5:23 pm
by 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
xkcd: What If? #126 - Stairs
Posted: Tue Feb 03, 2015 4:56 pm
by 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
xkcd: What If? #127 - Tug of War
Posted: Tue Feb 03, 2015 5:25 pm
by 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
xkcd: What If? #128 - Zippo Phone
Posted: Sat Feb 07, 2015 7:55 pm
by 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
Re: xkcd: What If? #128 - Zippo Phone
Posted: Sat Feb 07, 2015 8:02 pm
by Chris Peterson
bystander wrote: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 = mc
2
Doing something useful with that energy, of course, is an entirely different matter.
Re: xkcd: What If? #128
Posted: Sat Feb 07, 2015 9:27 pm
by geckzilla
He seems to be restricting the use of the word "energy" to caloric energy but didn't bother mentioning it.
Re: xkcd: What If? #128
Posted: Sat Feb 07, 2015 9:49 pm
by Chris Peterson
geckzilla wrote: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.
Re: xkcd: What If? #128
Posted: Sat Feb 07, 2015 10:36 pm
by 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.
xkcd: What If? #129 - Black Hole Moon
Posted: Fri Feb 13, 2015 4:53 pm
by 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
Re: xkcd: What If? #129
Posted: Fri Feb 13, 2015 10:23 pm
by 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.
xkcd: What If? #130 - Snow Removal
Posted: Sat Feb 21, 2015 7:11 am
by 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
Re: xkcd: What If?
Posted: Tue Feb 24, 2015 6:00 pm
by 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 ?
Re: xkcd: What If?
Posted: Tue Feb 24, 2015 6:30 pm
by bystander
Re: xkcd: What If?
Posted: Tue Feb 24, 2015 7:05 pm
by geckzilla
THX1138 wrote: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.
xkcd: What If? #131 - Microwaves
Posted: Mon Mar 23, 2015 6:11 pm
by 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
xkcd: What If? #132 - Hotter than Average
Posted: Mon Mar 23, 2015 6:17 pm
by 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
xkcd: What If? #133 - Flagpole
Posted: Mon Mar 23, 2015 6:22 pm
by 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
xkcd: What If? #134 - Space Burial
Posted: Fri Apr 03, 2015 3:14 pm
by 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
xkcd: What If? #135 - Digging Downward
Posted: Mon Apr 06, 2015 3:33 pm
by 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
xkcd: What If? #136 - Spiders vs. the Sun
Posted: Tue Apr 21, 2015 6:45 am
by 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