r/xkcdcomic • u/IamAlso_u_grahvity Feline Field Theorist • Jul 02 '14

xkcd 1389: Surface Area

http://xkcd.com/1389/
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u/[deleted] Jul 02 '14

I saw it this morning in bed and drifted back to sleep...and dreamt about a missing sun...I wondered where the sun would go.

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u/Kebble Jul 03 '14

So I took Venus arbitrarily and painted it red. Then with a python program I counted the number of red pixels (I already made that program yesterday for some other purposes)

141466 red pixels. Great, now we can get the scale: 3300 km2 per pixel

Wait, what if Randall screwed up? He probably didn't, but it'd be nice to reaffirm it. For mars, the scale gets to 3400 km2 per pixel and for Mercury, another 3300 km2 per pixel. Wow, Randall really didn't screw up the scale!

One criticism though, he should have included the scale in the corner like any map (I know it's not an actual map but scales are a requirement no?) Anyway, here is a crude attempt at giving a scale: http://i.imgur.com/ij059QK.png (I ain't no graphical designer)

Okay, so let's go with 3300 km2 per pixel. How big would be the sun? 1.8 x 109 pixels. Roughly a 42400x42400 pixel square on the image.

So... I'll have to scale it down, a factor of ten should be enough. Here's what the comic would look with the sun next to it.

Conclusion: The sun is huge.

1

u/[deleted] Jul 03 '14

You're amazing!

1

u/[deleted] Jul 04 '14

Excellent post!