Tag: xkcd


By Phil Plait | August 25, 2012 7:00 am

I have a very odd coincidence to report.

I like getting fun questions from folks, the kind that take a little bit of math and physics to explain, but wind up taking you to fun places. A common question like that is, "What would happen if everyone in China jumped all at once?" Would it throw the Earth out of orbit? Would it cause an earthquake? Would it do anything?

The answer is, essentially, no. I tackled this a few years back; there was this announcement by a group that wanted to get 600 million people to all jump at once so that the Earth would be pushed farther from the Sun and global warming would be solved.

Um, yeah. They called it World Jump Day, and I made quick work of it. Nothing at all would happen, for lots of reasons. Still, it’s fun to think about, right? And it turns out World Jump Day was something of a prank anyway.

And that’s where the coincidence I mentioned comes in. I recently happened to see a video done by vsauce asking this very question. He handles it really well in an entertaining video:

My opinion: science is always better when Felicia Day makes a cameo! And, of course, vsauce is right.

So anyway, I liked the video, and made a note to myself to write it up on the blog here. And then, literally the next day, what happens? My pal Randall Munroe (of xkcd fame) goes and writes about this very topic for his "what if?" series!

Although, to be fair, Randall takes it in a slightly different direction. Still. Weird.

Of course, coincidences happen all the time. It’s a big world out there, with lots of things going on. There’s bound to be the seemingly-spooky overlap or two between ’em.

And as a final note, if you want to read more about the gnarly math of millions of people jumping, Dot Physics has you covered.

CATEGORIZED UNDER: Cool stuff, Debunking, Geekery, Humor, Science

xkcd asks, "what if…?"

By Phil Plait | July 12, 2012 9:57 am

If you read this blog, then you probably already know about xkcd, the web comic by the geektastic Randall Munroe. What you may not know is that Randall really is just that smart, with a keen interest in physics and math. He likes thinking about big-picture stuff, including taking what might seem like silly ideas and running with them to see where they lead.

So I’m really excited to see he’s started a blog called "what if?" He takes crazy questions from readers and answers them, following the logic wherever it may lead.

The inaugural post asked, what if you threw a baseball at very nearly the speed of light? I have seriously thought about this as well, and while I found myself smiling at Randall’s explanation – his thinking followed mine very closely – he took a turn I hadn’t thought about: atoms in the air undergoing nuclear fusion with the baseball. Huh.

The second post, which just went up, is about how well you’d score if you answered SAT questions randomly, and somehow due to Randall’s machinations all the US Presidents and 75% of the the cast of Firefly get electrocuted by lightning.


As usual, this is clever, funny, odd, and just plain cool. You’ll feel smarter – you’ll be smarter – after reading it.

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CATEGORIZED UNDER: Cool stuff, Geekery, Humor, Science

xkcd is the very model of a modern major science grad

By Phil Plait | May 7, 2012 9:00 am

Hmmmm… the astronomer in today’s xkcd comic looks familiar, even as a stick figure.

At least he didn’t draw me as a zombie. But I’m no Feynman.

And hey, together with SMBC I think this makes me king of the four-letter comics. I mean, um. Well.

[N.B. And yes, it really is me, I got word from The Man himself. Funny how a minimalist drawing with some context invokes recognition; I’ve been getting notes from people all morning.]



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CATEGORIZED UNDER: Astronomy, Cool stuff, Geekery, Humor

Randall Munrion

By Phil Plait | February 22, 2012 10:26 am

I’m not sure why so many people think I don’t read xkcd, but a metric buttload of people sent me a link to today’s comic [marginally NSFW]. I thank all of you who did, but take note: given that I am a vastly huge geek, and xkcd is the most popular geek comic in the observable Universe, rest assured I read it.

I have something to add, but go read the comic first. Go.

Back now? OK, so now that you’ve seen it, I have to note we used to make a similar joke when I was in grad school. When my roommate Erik and I ran a night sky lab, he would show students the constellations (they had to learn a handful of them and a few stars for a quiz). In the winter, when it came time to point out Orion, he’d show them Betelgeuse, Rigel, the belt… and then when he pointed out the "dagger", he’d quip, "… and if you want to call that a dagger, be my guest. But I think we all know better."

Or is it SMBC? We need a quattuorlitteras acronymically-known web comic stats-off.

CATEGORIZED UNDER: Astronomy, Geekery, Humor
MORE ABOUT: Orion, SMBC, xkcd

xkcd on neutrinos

By Phil Plait | September 23, 2011 7:51 am

I have a hard time thinking that my readers need to be reminded to read the web comic xkcd, but just in case, Randall Munroe chimes in on the faster-than-light neutrino controversy. Go read the comic now, since I spoil it below…

In fact, I agree with his idea, and said as much on Google+ yesterday:

So yeah, I’m skeptical. The fact that you’re reading this on a computer shows we understand a lot of physics pretty well, so the best thing to do here is to calm down and see what comes out of this. But I’d bet against it.

… and I’d win that bet either way. If I’m right, I make money. If I’m wrong, warp speed! Woohoo!

Scientist Brian Cox has an interview online where he describes why this is important, too.

We should have more news about all this soon, since the scientists involved are giving a talk in Zurich, and I’ll write up a review once I understand what’s what.

CATEGORIZED UNDER: Geekery, Humor, Science
MORE ABOUT: Randall Munroe, xkcd

xkcd and other-world walkers

By Phil Plait | May 5, 2011 11:00 am

Like a bazillion other geeks, I’m a big fan of Randall Munroe’s web comic xkcd. It’s funny and wonderful, but sometimes it’s his particular way of expressing his view that’s simply astonishing.

As poignant as that is, you really need to go to his page and mouse over the comic to read the text that pops up. It reminded me strongly of my own sentiments in an OpEd I wrote for the New York Post a couple of years ago. Especially this part:

For all of history, the Moon was a metaphor for an unreachable place, beyond our grasp. But in 1969 NASA looked to this unachievable destination and made it achievable. It was an event so singular that every accomplishment ever since has been compared to it. It was NASA’s shining hour.

But I’ve met many Apollo astronauts, and — no offense to them — they’re old. The last man to walk on the Moon is 75. How old will he be when the next human leaves a footprint on the lunar surface?

It’s a question I’d like the answer to very soon.

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CATEGORIZED UNDER: NASA, Piece of mind, Space
MORE ABOUT: Randall Munroe, xkcd

xkcd radiates

By Phil Plait | March 21, 2011 7:09 am

Randall Munroe, who draws the geekerrific xkcd webcomic, has created a really good chart showing relative radiation doses absorbed by humans doing various activities.

I’ve put a piece of it here, the section with the lowest doses. I like this! A lot of folks don’t understand what radiation is — light is radiation, for example — or that just by existing on the surface of our planet you absorb a certain amount all the time: from the ground, from space, from things you eat. Wikipedia actually has an excellent rundown of what radiation is, and the critical distinction between ionizing and non-ionizing radiation (there’s also electromagnetic versus subatomic particle radiation, but that’s less of a concern here).

In the chart, Russel deals with doses from ionizing radiation. This is the kind that can cause damage… but only in sufficiently high doses. For example, bananas are a natural source of gamma rays due to the decay of an isotope of potassium (40K). It’s a pretty weak source — a few years back I had access to a gamma-ray detector and we could barely detect a banana’s emission — and it doesn’t affect you in any real way. Potassium iodide is a common salt that’s also a gamma-ray emitter, but again you’d need a lot of it for it to be dangerous… and if you ate that much you’d have worse issues!

The average amount of radiation you absorb in a year is about 3 – 4 milliSieverts, depending on where you live. At higher elevations — like, say, Boulder, where I live — cosmic radiation puts you on the higher end of that scale. I’ll note that cancer risk is not really higher living up here than at sea level (lung cancer rates are lower than average here, probably due to the healthy lifestyles most people follow in Boulder, but skin cancer rates are slightly higher than average, probably due to a combination of people being outside more than average together with the thinner air blocking less UV).

In general, you can actually absorb a much higher than usual radiation dose (up to a point, of course) without ill effects, since your body can heal some amount of damage (just like it heals from a cut). Too many such doses too close together, or too big a dose all at once, can do too much tissue damage and be fatal (I guess, again, like a cut). For example, I like to point out that the Apollo astronauts got roughly a year’s worth of radiation absorption in their tissue while voyaging to the Moon and back, but didn’t suffer any ill effects.

Obviously, this is a complicated issue, but the xkcd chart looks like a pretty good way to eyeball where things fall on a scale of "nothing to worry about" to "AIEEEEPANICPANICPANIC".

CATEGORIZED UNDER: Cool stuff, Geekery

xkcd nails nonsense

By Phil Plait | October 20, 2010 2:00 pm

xkcd_altmoneyThe brilliant web comic xkcd is usually right, but he’s never been righter than in this destruction of alt-med nonsense.

Of course, some will argue that these things do make lots of money, but then those people probably didn’t read the text that pops up when you hover your mouse over the comic…

… or they aren’t used to making reality-based arguments anyway. I’m no fortune teller, but I predict this comic will get sent far and wide for years to come. Especially when someone gets that email from their Great Aunt about that one person who predicted that one thing happening because of that other thing they did.

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Not-So-Happy Valentine's Day. Love, xkcd

By Phil Plait | February 14, 2010 10:29 am

xkcd_valentineHmmm, not all VDs are happy: this strip from xkcd is a little bit of a downer, but I have a hard time disagreeing with his message. Hover your mouse over the strip to see what he means.

This particular strip reminds me of Robert Sheckley’s "The Language of Love". I have to say, I’m rather fond of his writing.


xkcd has the Spirit

By Phil Plait | January 29, 2010 9:27 am

xkcd_spiritToday’s xkcd comic takes a somewhat different stance on the plight of Spirit than I did.

Still, it’s funny how we anthropomorphize objects, especially when they are vaguely human or animal looking. Especially if they’re cute. And Spirit is very cute.

Who’s a good rover? Hmmm? You are! You’re a good rover!

MORE ABOUT: Spirit, xkcd

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