# ­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:** 115
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 15, 2023, 3:12am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2283 "2023-07-15T03:12:27Z")
> **[Fireflies](https://xkcd.com/2802/)** > > I feel bad for Earth 2 and their shadowflies. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 18, 2023, 5:21am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2284 "2023-07-18T05:21:28Z")
> **[Geohydrotypography](https://xkcd.com/2803/)** > > The Atlantic is expanding at about 10 ppm (points per month). ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [July 19, 2023, 3:32am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2285 "2023-07-19T03:32:11Z")
> [@Chronos](#): > > I feel like he’d already done the Down one before… this one? > **[Sky](https://xkcd.com/1115/)** > > I dropped a bird and I didn't hear it hit bottom. ---
**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:** [July 19, 2023, 1:39pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2286 "2023-07-19T13:39:52Z")
No, the one I’m thinking of was at an angle, and I think the reference frame was specified as being off Earth. I think it was one panel of a 16-panel collection of mini-strips. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 19, 2023, 8:42pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2287 "2023-07-19T20:42:34Z")
> **[Marshmallow](https://xkcd.com/2804/)** > > The increasing number of graham crackers and chocolate bars in orbit has created a growing risk of Kessler s'mores. ---
**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:** [July 19, 2023, 8:46pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2288 "2023-07-19T20:46:59Z")
So how long does it take to perfectly toast a marshmallow this way? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [July 19, 2023, 9:43pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2289 "2023-07-19T21:43:37Z")
I think it’s in the ballpark of several seconds. Not too different than putting it in the hottest part of a campfire. The heat flux from LEO is on the order of 1000 kW/m^2. A 4-cm marshmallow has a cross-sectional area of about 0.0016 m^2, which makes the total heating about 1.6 kW. That’s high, but not crazy-high. Similar to taking a hairdryer directly to the marshmallow. It’s a lot of heat, but it doesn’t vaporize the thing instantly. It’ll take several seconds to brown the surface and heat the inside. The heat flux from further out than LEO can get much higher. Perhaps 2500 kW/m^2 from the moon, and \>10 MW/m^2 from interplanetary transfers. It would take under a second to cook the marshmallow in that case. ---
**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:** [July 19, 2023, 9:52pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2290 "2023-07-19T21:52:43Z")
Videos of re-entry show the capsules surrounded by what appears to be orangeish flames (they’re not literally flames, not being the result of something combining with oxygen, but close enough). Orangeish flames are also what a campfire produces, and color indicates temperature. So yeah, it’d be the same ballpark. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 22, 2023, 2:03am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2291 "2023-07-22T02:03:09Z")
> **[Global Atmospheric Circulation](https://xkcd.com/2805/)** > > Refs generally say that you can exercise enough altitude control to avoid the ground, but if you start strategically choosing air layers to steer yourself, that's traveling. ---
**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:** [July 22, 2023, 1:25pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2292 "2023-07-22T13:25:46Z")
I’m really curious about the 1500 years figure… It’s not just the time it takes to make a single circumnavigation, because at any reasonable windspeed, he’ll make several of those per year. But nor does it seem to be the time, allowing for random perturbations, that it would take him to pass close by the net again (“close by” meaning “close enough to be able to toss the ball in”), because 1500 years is long enough that he could have diffused to anywhere in the hemisphere, or probably even anywhere on Earth, and at several circumnavigations per year, a ball-toss-width band will cover only a small fraction of the hemisphere. ---
**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:** [July 23, 2023, 9:33pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2293 "2023-07-23T21:33:15Z")
Yeah, I don’t get it either. ---
**Author:** ![Civil\_Guy](https://avatars.discourse-cdn.com/v4/letter/c/d78d45/32.png) [@Civil\_Guy](https://boards.straightdope.com/u/Civil_Guy)\ **Post date:** [July 25, 2023, 12:58am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2294 "2023-07-25T00:58:06Z")
That’s why they have a shot clock, isn’t it? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [July 25, 2023, 1:03am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2295 "2023-07-25T01:03:47Z")
Yikes. I went to the usual explainxkcd.com, but they’ve been hacked or maybe just vandalized, and the main page is has some horrific medical images on it. Hopefully that gets fixed soon. I’d been thinking that maybe there’s some 1500-year atmospheric cycle, but couldn’t find anything. I searched for “cycle”, “recurrence time”, and a few other things. While there are some multi-year cycles, none were close to 1500 years. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 25, 2023, 3:57pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2296 "2023-07-25T15:57:38Z")
> **[Anti-Vaxxers](https://xkcd.com/2806/)** > > The vaccine stuff seems pretty simple. But if you take a closer look at the data, it's still simple, but bigger. And slightly blurry. Might need reading glasses. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 27, 2023, 11:54pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2297 "2023-07-27T23:54:38Z")
> **[Bad Map Projection: ABS(Longitude)](https://xkcd.com/2807/)** > > Positive vibes/longitudes only ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [July 28, 2023, 12:01am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2298 "2023-07-28T00:01:20Z")
Looks like land overrides ocean. I.e., a union operation with respect to the landmasses. But why should ocean get the shaft? I say the map should be the union of the water, not land. ---
**Author:** ![ENugent](https://avatars.discourse-cdn.com/v4/letter/e/4af34b/32.png) [@ENugent](https://boards.straightdope.com/u/ENugent)\ **Post date:** [July 28, 2023, 12:21am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2299 "2023-07-28T00:21:14Z")
But the ocean gets the whole back side! ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 30, 2023, 12:41am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2300 "2023-07-30T00:41:58Z")
> **[Daytime Firefly](https://xkcd.com/2808/)** > > Mr. Jones, watch out for Ms. Lenhart! She's from genus Photuris! ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [August 1, 2023, 2:43am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2301 "2023-08-01T02:43:13Z")
> **[Moon](https://xkcd.com/2809/)** > > I mean, it's pretty, but it doesn't really affect us beyond that. Except that half the nights aren't really dark, and once or twice a day it makes the oceans flood the coasts. ---
**Author:** ![Mr.E](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.e/32/8932_2.png) [@Mr.E](https://boards.straightdope.com/u/Mr.E)\ **Post date:** [August 1, 2023, 9:38pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/2302 "2023-08-01T21:38:11Z")
I’ve heard astronomers point out that it’s probably pretty unusual for an earth-sized rocky world to have a moon this size, and that the tidal effects it has on our oceans may have been key to the development of life in tidal pools. Interestingly enough, things that seem immutable like the being moon the right distance to allow for total solar eclipses that reveal the Sun’s corona, and Saturn’s rings, and Jupiter’s big red spot, are actually all temporary. The Red Spot may be gone in another 100 years, Saturn’s rings in 100 million years, and after 620 million years every eclipse on Earth will be an annular eclipse. [Previous page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=114) [Next page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=116)