Aim your laser pointer at the moon!

October 1, 2012 10:58 AM

If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color? No? *sigh* Well, what if we tried more power? Keep asking that question and you get an astonishing result.
posted by exphysicist345 (42 comments total)

"The answer to your question is: nothing much happens. Now let's take the principle in question to its theoretical extreme until it explodes!"

See also: Mythbusters.
posted by Holy Zarquon's Singing Fish at 11:04 AM on October 1, 2012 [9 favorites]

So you're telling me the Chairface depiction was unrealistic?
posted by Durn Bronzefist at 11:08 AM on October 1, 2012 [9 favorites]

Well, yeah, how would a guy with a chair for a face even breathe?
posted by Ghostride The Whip at 11:09 AM on October 1, 2012 [7 favorites]

But just try waving it at an airplane in a friendly manner, and suddenly it's a bad thing...
posted by Old'n'Busted at 11:10 AM on October 1, 2012 [1 favorite]

The Boeing YAL-1 was a megawatt-class chemical oxygen iodine laser mounted in a 747. It was an infrared laser, so it wasn’t directly visible, but we can imagine building a visible-light laser with similar power.

No need to imagine.
posted by DU at 11:10 AM on October 1, 2012 [4 favorites]

"America can, should, must and will blow up the moon!"

"And we'll be doing it during a full moon so we make sure we get it all."
posted by inturnaround at 11:18 AM on October 1, 2012 [8 favorites]

What if we all jump at the same time? Can we make it cold enough to snow in San Francisco this Christmas? TIA.
posted by 2bucksplus at 11:20 AM on October 1, 2012

Well first, we'd have to get everybody over to one side of the moon (so they could all point to it at the same time,) and we all know that if they were to all simultaneously jump, it'd throw the earth's orbit out of whack.
posted by nushustu at 11:21 AM on October 1, 2012

Who defaced the moon best?
posted by painquale at 11:21 AM on October 1, 2012 [3 favorites]

Oh dammit and just when I was going to make a YOU GUYS SOCK joke.
posted by shakespeherian at 11:26 AM on October 1, 2012

Here's a great interview with Randall Munroe about how the What If series got started.
posted by villanelles at dawn at 11:28 AM on October 1, 2012

2bucksplus, I can't tell from your comment, but did you see the previous answer -- 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?

It's fairly comprehensive.
posted by jhc at 11:29 AM on October 1, 2012 [4 favorites]

I wonder if alt.blow.up.the.moon is taken yet...
posted by Argyle at 11:33 AM on October 1, 2012 [1 favorite]

The Moon? Feh.

The Moon Is A Propaganda Hoax
posted by the man of twists and turns at 11:35 AM on October 1, 2012 [4 favorites]

Randall Munroe is the smartest person on the Internet. I don't know why I find that unsettling.
posted by dgaicun at 11:36 AM on October 1, 2012 [1 favorite]

By the way, does anybody know of any easy-view version of that monster click and drag comic from a few weeks ago?
posted by dgaicun at 11:42 AM on October 1, 2012

Several were suggested in the relevant thread.
posted by zamboni at 11:45 AM on October 1, 2012

Forget the entire rest of the article, this part blew my mind...

The typical red laser pointer is about 5 milliwatts, and a good one has a tight enough beam to actually hit the Moon—though it’d be spread out over a large fraction of the surface when it got there.
posted by Busmick at 11:47 AM on October 1, 2012 [1 favorite]

And THIS sort of discussion is exactly why I have fond memories of AP Physics in High School. Our teacher, Mr. Gibbs, basically sat around with us and asked us what we'd like to talk about. We got some pretty wild ideas, and then we tried to work through the math.
posted by thanotopsis at 11:52 AM on October 1, 2012 [2 favorites]

Laser ablative propulsion, baby! Use LAP to get off the ground and past the Van Allen belts, and then nuclear pulse propulsion to move around the solar system. Put a city on Mars in 5 days.

That's where I wish my NASA tax dollars were a'goin'.
posted by BeeDo at 11:53 AM on October 1, 2012 [1 favorite]

I almost wrote "Van Halen" belts, because the "newer post" was smiling at me.
posted by BeeDo at 11:55 AM on October 1, 2012 [4 favorites]

It's taken 37 years, but we now have a barely-plausible rejoinder Asimov's critique of Space: 1999.
posted by googly at 11:58 AM on October 1, 2012

I rather liked his answer to what would happen if the continents were rotated 90 degrees. He answered it two ways -- the first, assuming that the continents had always been that way, and the second, assuming a sudden magic cataclysmic shift.

The first premise, he did a really good analysis of where different air and sea currents would be, and did a good job of mapping all that out on a hypothetic new planetary configuration, and came out with a pretty good explanation of "so Ireland would be kind of like how Borneo is now...."

In the second, though, he just got delightfully silly and speculated that it would lead to a sudden chaotic episode of Prairie Home Companion in which Garrison Keillor got eaten by alligators and fire ants.
posted by EmpressCallipygos at 12:05 PM on October 1, 2012 [4 favorites]

"You did it, Zorglub! It's magnificent! You carried it off...but there's just...uh...one little problem..."
posted by Smart Dalek at 12:16 PM on October 1, 2012 [1 favorite]

Several were suggested in the relevant thread.

I should've known there would've been a FPP.

It's too bad that Allie Brosh went all Syd Barrett, since she was the only contender to Munroe's stick figural Internet hegemony.
posted by dgaicun at 12:22 PM on October 1, 2012 [2 favorites]

It’s an ultraviolet laser with an output of 500 terawatts. However, it only fires in single pulses lasting a few nanoseconds, so the total energy delivered is about equivalent to a quarter-cup of gasoline.

There's something that's just darling about this. Something along the lines of using a Bagger 288 to dig holes for planting trees, or programming a Terminator humanoid killbot to fetch you tea.
posted by Apocryphon at 12:23 PM on October 1, 2012

Several years ago I was asked to consider what it would take to sequentially bounce lasers off of the Lunar Laser Ranging experiment retro-reflectors- to music. We had access to some 5 watt argon lasers so all the spec work was done with those in mind. It wasn't even close- not even if we used telescopes to pick up the return beams. We could very possibly detect light coming back but nothing that would make for the oohs and aahs the sponsor wanted. Fun idea though.
posted by Phyllis Harmonic at 12:23 PM on October 1, 2012

Randall Munroe is the smartest person on the Internet. I don't know why I find that unsettling.

Cecil Adams would like to have a word with you.
posted by Apocryphon at 12:26 PM on October 1, 2012 [3 favorites]

Well, yeah, how would a guy with a chair for a face even breathe?


He didn't actually have a chair for a face. His face was just locked in a horrible chair expression.
posted by TheWhiteSkull at 12:28 PM on October 1, 2012 [3 favorites]

My favourite bit is in A Mole of Moles:

I can pick up a mole (animal) and throw it.[Citation needed] Anything I can throw weighs one pound. One pound is one kilogram. The number 602,214,129,000,000,000,000,000 looks about twice as long as a trillion, which means it’s about a trillion trillion. I happen to remember that a trillion trillion kilograms is how much a planet weighs.

posted by Gordafarin at 12:29 PM on October 1, 2012

… if anyone asks, I did not tell you it was ok to do math like this.
posted by Holy Zarquon's Singing Fish at 12:31 PM on October 1, 2012 [5 favorites]

At the risk of self-linking ... a little conceptual art piece I did 11 years ago: Paint the Moon.

It got a fair amount of attention at the time.
posted by Shadan7 at 12:32 PM on October 1, 2012 [1 favorite]

I wonder if alt.blow.up.the.moon is taken yet...

'alt.blow.up.the.moon.pyew.pyew.pyew' might still be available.
posted by aught at 12:40 PM on October 1, 2012 [3 favorites]

Thank goodness that this research did not emerge until after the passing of Alexander Abian.
posted by delfin at 12:43 PM on October 1, 2012 [1 favorite]

At any given instant, an average of half the people on Earth cannot see the moon. So it's impossible for everyone to do it simultaneously.
posted by Chocolate Pickle at 1:05 PM on October 1, 2012

He addresses that in the article.
posted by LobsterMitten at 1:11 PM on October 1, 2012 [3 favorites]

And thanks for posting this - I'm enjoying this new series of his. Any word on whether he is going to be phasing out the comics in favor of focusing on these longer written pieces? Or is it just a side project?
posted by LobsterMitten at 1:13 PM on October 1, 2012

So for the last five years all the liberals and the hippies and the nattering nabobs of normalcy have been coming up to Giblets and going "Was the war a mistake Giblets?" and "Are we losing the war Giblets?" and "Oh look at all the dead people Giblets, maybe we should stop the war." And the correct answers to these questions have been "Shut up," "Shut up you traitor," and "We'd be winning already if you'd just shut up." But Giblets is a patient Giblets and is willing to entertain even the most tedious requests of his dullest subjects, especially if it gets him published columns in Slate and The New York Times. So was Giblets really wrong? Was the war a mistake? Were we right to blow up the moon?
posted by Sebmojo at 1:17 PM on October 1, 2012 [2 favorites]

At any given instant, an average of half the people on Earth cannot see the moon. So it's impossible for everyone to do it simultaneously.


Not only does he address this, he cites the results of his previous work demonstrating that it would be a bad idea to invite everyone on the planet to bring their laser pointers to Rhode Island so we could all shine them all together.
posted by straight at 1:19 PM on October 1, 2012

A 1-watt laser is an extremely dangerous thing. It’s not just powerful enough to blind you—it’s capable of burning skin and setting things on fire. Obviously, they’re not legal for consumer purchase in the US.

Just kidding! You can pick one up for $300.
posted by mecran01 at 2:33 PM on October 1, 2012 [3 favorites]

If every person on Earth aimed a laser pointer at the Moon at the same time...

No doubt some idiot would turn it around and blind the other kid.
posted by BlueHorse at 7:32 PM on October 1, 2012

Many problems; one solution.
posted by kagredon at 8:55 AM on October 2, 2012