# ­xkcd thread **URL:** \ **Category:** Cafe Society\ **Tags:** comic-strips\ **Created:** [May 28, 2020, 12:57am UTC](https://boards.straightdope.com/t/xkcd-thread/854574 "2020-05-28T00:57:03Z")\ **Posts on this page:** 20\ **Page:** 256
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 22, 2025, 1:16pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5103 "2025-10-22T13:16:07Z")
If you have a snowmobile you don’t need a paved road. OTOH, pretty soon at the North pole you’ll be needing a boat, not a snowmobile. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 23, 2025, 1:44am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5104 "2025-10-23T01:44:11Z")
> **[Shielding Chart](https://xkcd.com/3158/)** [![](https://imgs.xkcd.com/comics/shielding_chart.png) ](https://imgs.xkcd.com/comics/shielding_chart.png) “Sharks can occasionally travel short distances through air when pursuing prey, but their attenuation coefficient is pretty high.” ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [October 23, 2025, 2:56am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5105 "2025-10-23T02:56:55Z")
I take it that blue means effective, yellow means ineffective and green partially effective. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [October 23, 2025, 3:10am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5106 "2025-10-23T03:10:55Z")
> [@Lumpy](#): > > blue Blue? I only see gray and yellow. ---
**Author:** ![Kron](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kron/32/12444_2.png) [@Kron](https://boards.straightdope.com/u/Kron)\ **Post date:** [October 23, 2025, 3:30am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5107 "2025-10-23T03:30:53Z")
Gray, yellow, and grayish-yellow. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [October 23, 2025, 3:32am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5108 "2025-10-23T03:32:20Z")
I see gray (effective), yellow (not effective), and a light greenish-gray for the partially effective. And this chart brings me back to my nuclear power school days where we studied shielding and tenth-thicknesses for gammas, neutrons, alpha particles, beta particles, etc. But not sharks. 😉 ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 23, 2025, 7:54am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5109 "2025-10-23T07:54:17Z")
> [@Pleonast](#): > > Blue? I only see gray and yellow. I see the same as you, but this might be something like the infamous dress. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [October 23, 2025, 9:52am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5110 "2025-10-23T09:52:39Z")
I see a pale Goldenrod, Mishka and Kidnapper, personally. But it depends on your monitor. ---
**Author:** ![Q.Q.Switcheroo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/q.q.switcheroo/32/5713_2.png) [@Q.Q.Switcheroo](https://boards.straightdope.com/u/Q.Q.Switcheroo)\ **Post date:** [October 23, 2025, 10:57am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5111 "2025-10-23T10:57:09Z")
While oven mitts may not provide much protection against sharks, “boop”ing can be surprisingly effective: [https://amp.charlotteobserver.com/news/local/article231162853.html](https://amp.charlotteobserver.com/news/local/article231162853.html) > Florida Museum’s International Shark Attack File says it’s the [tip of the nose that makes the best target,](https://www.floridamuseum.ufl.edu/shark-attacks/reduce-risk/divers/) but warns that one’s aim must be good, considering “the mouth is close to the nose.” ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [October 23, 2025, 12:11pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5112 "2025-10-23T12:11:48Z")
Sage advice. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 23, 2025, 4:38pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5113 "2025-10-23T16:38:49Z")
Perhaps we can say it’s handy advice? ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [October 23, 2025, 7:26pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5114 "2025-10-23T19:26:08Z")
It does give, “Draw back a bloody stump,” a vivid mental image. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 24, 2025, 12:58am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5115 "2025-10-24T00:58:31Z")
The very first square is wrong, or at least misleading. Air is inconveniently effective at shielding gamma rays, at least at full atmospheric thickness. Gamma ray astronomy must be done entirely by satellites. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [October 24, 2025, 8:47pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5116 "2025-10-24T20:47:58Z")
> [@Chronos](#): > > Air is inconveniently effective at shielding gamma rays, at least at full atmospheric thickness. It wasn’t claiming that much thickness in the slightest. Nothing misleading about it. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 24, 2025, 9:02pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5117 "2025-10-24T21:02:23Z")
> **[Continents](https://xkcd.com/3159/)** [![](https://imgs.xkcd.com/comics/continents.png) ](https://imgs.xkcd.com/comics/continents.png) “The inflection point was probably in late 1966 or 1967, so when Neil Armstrong flew to space on Gemini 8, plate tectonics was not widely accepted, but when he landed on the Moon three years later it was the mainstream consensus.” ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 28, 2025, 1:06am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5118 "2025-10-28T01:06:52Z")
> **[Document Forgery](https://xkcd.com/3160/)** [![](https://imgs.xkcd.com/comics/document_forgery.png) ](https://imgs.xkcd.com/comics/document_forgery.png) “It comes with a certificate of authenticity, which comes with a certificate of authenticity, which comes with a…” ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 28, 2025, 9:35pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5119 "2025-10-28T21:35:08Z")
But if you’ve earned it, is it still a forgery? ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 30, 2025, 1:02am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5120 "2025-10-30T01:02:51Z")
> **[Airspeed](https://xkcd.com/3161/)** [![](https://imgs.xkcd.com/comics/airspeed.png) ](https://imgs.xkcd.com/comics/airspeed.png) “Carefully maneuvering the balloon down a mineshaft in an effort to break the OTHER altitude record” I’m no expert, but I don’t think 2 mph is anywhere near the record. Maybe if they launched during a hurricane… ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [October 30, 2025, 1:16am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5121 "2025-10-30T01:16:24Z")
Wouldn’t that be groundspeed, as the airspeed of an unpowered lighter than air craft tends to zero? Or is that the point? ---
**Author:** ![Q.Q.Switcheroo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/q.q.switcheroo/32/5713_2.png) [@Q.Q.Switcheroo](https://boards.straightdope.com/u/Q.Q.Switcheroo)\ **Post date:** [October 30, 2025, 1:17am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/5122 "2025-10-30T01:17:51Z")
The alt-text brings to mind Bob and Ray’s “World Champion Low Jumper” routine. [Previous page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=255) [Next page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=257)