# ­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:** 305
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 7, 2026, 12:17pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6083 "2026-07-07T12:17:00Z")
Note that the deepest holes drilled by mankind are only a kilometre or so deeper below sea level than the bottom of the Marianas Trench, so we haven’t got that far into the Earth yet, ---
**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 7, 2026, 1:14pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6084 "2026-07-07T13:14:05Z")
> [@eburacum45](#): > > so we haven’t got that far into the Earth yet Hence the lack of balrogs. ---
**Author:** ![Mollie\_Magill](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mollie_magill/32/20882_2.png) [@Mollie\_Magill](https://boards.straightdope.com/u/Mollie_Magill)\ **Post date:** [July 7, 2026, 1:39pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6085 "2026-07-07T13:39:18Z")
I hope you like Balrogs, because that’s how you get Balrogs. ---
**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:** [July 7, 2026, 1:54pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6086 "2026-07-07T13:54:37Z")
I also note that the two deepest boreholes are very close to the same depth; based on the limitations of drilling technology perhaps? Which makes me wonder: if the mechanical challenges of drilling can be handwaved away for purposes of discussion, what would the deepest hole be that steel pipe could keep open? ---
**Author:** ![Frodo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frodo/32/302_2.png) [@Frodo](https://boards.straightdope.com/u/Frodo)\ **Post date:** [July 7, 2026, 1:59pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6087 "2026-07-07T13:59:36Z")
Complete WAG, but I think it would be determined by the fusion point of steel (when it gets too hot and it bends) and/or the tensile strength of steel (when the pressure gets too high and it buckles), probably a combination of both. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 7, 2026, 2:04pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6088 "2026-07-07T14:04:13Z")
If they started drilling at the bottom of the Marianas trench, (a cold location [~4 celsius] where steel doesn’t buckle because of heat), how deep do you think they could drill before the heat and pressure became too much? I’d guess at much more than an extra kilometre, but I really don’t know if that is correct or not. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [July 7, 2026, 4:43pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6089 "2026-07-07T16:43:01Z")
My guess would be that the cooling effect of the overlying water would not extend very deep, maybe a few hundred feet at most? After that, the temperature would be the same as anywhere else at that depth in the crust. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 7, 2026, 5:28pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6090 "2026-07-07T17:28:57Z")
Yes, the crust is a very good insulator. I wonder if there is any way to test this theory out; oceanic crust is completely different to continental crust, so anything might happen. The heat in the lower crust and mantle has to go somewhere, but it doesn’t seem to make much impression on abyssal temperatures. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [July 7, 2026, 7:20pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6091 "2026-07-07T19:20:12Z")
The sand may be annoying, but rainbows would be cool: [![](https://img.youtube.com/vi/BO8rOs05v48/maxresdefault.jpg "What would a rainbow be like on Tatooine?") ](https://www.youtube.com/watch?v=BO8rOs05v48) Brian ---
**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 7, 2026, 7:30pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6092 "2026-07-07T19:30:10Z")
Of course, that also relies on it actually, you know, raining on Tatooine. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 7, 2026, 7:32pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6093 "2026-07-07T19:32:13Z")
You can also get multiple rainbows by reflecting sunlight on a lake. > **[Reflection Rainbows, Eilean Donan Castle, Scotland](https://www.atoptics.org.uk/rainbows/bowim19.htm)** > > Rainbows take many forms. Multiple bows, bows that cross, red bows, twinned bows, coloured fringes, dark bands, spokes and more. Find out about them here. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 7, 2026, 7:39pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6094 "2026-07-07T19:39:26Z")
Incidentally, circumbinary planets are in so-called _p-type orbits_, whereas planets that orbit only one star in a binary pair are in _s-type orbits_, so ‘the other kind’ of planet could be called ‘s-type’ planets if we really need a name for them. [![](https://www.orionsarm.com/im_store/med_ps.png) ](https://www.orionsarm.com/im_store/med_ps.png) [https://en.wikipedia.org/wiki/Habitability\_of\_binary\_star\_systems#Non-circumbinary\_planet\_(S-Type)](https://en.wikipedia.org/wiki/Habitability_of_binary_star_systems#Non-circumbinary_planet_(S-Type)) ---
**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:** [July 7, 2026, 7:47pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6095 "2026-07-07T19:47:18Z")
I’ve been down Mponeng Mine. ---
**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:** [July 7, 2026, 8:03pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6096 "2026-07-07T20:03:08Z")
VERY improbable, but could the right combination of masses and orbital parameters for a binary star system have a planet with a chaotic orbit without either being ejected or crashing into either star? ---
**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 7, 2026, 8:05pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6097 "2026-07-07T20:05:37Z")
I mean, for any given configuration and any given desired lifespan, there’s going to be a nonzero probability of a planet lasting that long. But if we’re looking at timescales of billions of years, that probability is going to be really, really low. ---
**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:** [July 7, 2026, 8:07pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6098 "2026-07-07T20:07:09Z")
> [@Pardel-Lux](#): > > The only freshwater seals in the world will become seawater seals again. Not the only ones. There are two species in Karelia, [one in Russia](https://en.wikipedia.org/wiki/Ladoga_ringed_seal) and [one in Finland](https://en.wikipedia.org/wiki/Saimaa_ringed_seal). And [a subspecies of a seagoing one](https://en.wikipedia.org/wiki/Ungava_seal) in Canada. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [July 7, 2026, 8:33pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6099 "2026-07-07T20:33:35Z")
The Russians lied to me when I was there? Inconceivable! TIL. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [July 8, 2026, 1:25pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6100 "2026-07-08T13:25:13Z")
> [@Lumpy](#): > > VERY improbable, but could the right combination of masses and orbital parameters for a binary star system have a planet with a chaotic orbit without either being ejected or crashing into either star? I’ve been thinking about this one. There are quite a few ‘chaotic orbit’ situations in astronomy; the Sun follows a somewhat chaotic orbit around the galaxy, because the matter (and dark matter) in the Milky Way is not distributed evenly. Similarly the stars inside a globular cluster all follow chaotic orbits around their mutual centre of gravity - they are far enough apart so that they rarely collide (but this does happen, on a timescale of millions of years, and the collision creates a new single, bright star called a ‘blue straggler’). Most of the time the stars in a globular cluster are relatively safe and ‘stable’. I think that even the objects in our own Oort cloud follow somewhat chaotic orbits, but rarely encounter each other. So I think some binary stars might be distantly accompanied by a little cloud of planets in orbits that are chaotic, but not particularly dangerous. Especially some bright stars; for instance Albireo A and Albireo B are separated by more than the distance between Earth and Pluto, in eccentric orbits around each other. Any S-type planets orbiting these stars could be frequently perturbed by their eccentric movement, making the climate on those planets unpredictable. ---
**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:** [July 8, 2026, 1:51pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6101 "2026-07-08T13:51:07Z")
ISTM the relevant measure of time for the survival of perturbed orbits is not years or even millions of years. It’s number of orbits. e.g. the Sun takes ~240M years to make one orbit around the galaxy. If it takes 10,000 orbits before the chaotic perturbations build to “eject from galaxy” magnitude, well, then for all practical purposes the orbit is stable since the time required to eject exceeds the life of the star and perhaps the whole galaxy. OTOH, the Earth has completed 10,000 orbits of the sun just since shortly before the last ice age ended. Any chaos in our orbit that manifested in a mere 10K orbits would have killed us, and perhaps the whole biosphere long ago. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 8, 2026, 11:51pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/6102 "2026-07-08T23:51:16Z")
> **[Airport Meeting](https://xkcd.com/3269/)** [![](https://imgs.xkcd.com/comics/airport_meeting.png) ](https://imgs.xkcd.com/comics/airport_meeting.png) “Although it was a setback for physics, I’m glad the particle naming rights issue led to the cancelation of Pizza Hut’s Superconducting Super Collider in the early 90s, so the Double Stuffed Extra Cheese Topping Quark ended up just being named ‘top quark.’” [Previous page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=304) [Next page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=306)