# ­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:** 175
**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 10, 2024, 6:20pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3483 "2024-10-10T18:20:13Z")
> [@eburacum45](#): > > technically speaking, the mineral graphite counts as a fossil fuel if you burn it. Wood can be relatively green if produced and sourced correctly. Depends on the source of the carbon that was used to make the graphite; although there is natural graphite, virtually all of it used today is synthesized in electric arc furnaces. ---
**Author:** ![Ponderoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ponderoid/32/19221_2.png) [@Ponderoid](https://boards.straightdope.com/u/Ponderoid)\ **Post date:** [October 10, 2024, 7:12pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3484 "2024-10-10T19:12:54Z")
> [@eburacum45](#): > > Wood can be relatively green if produced and sourced correctly. Green wood doesn’t burn too well. ---
**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:** [October 10, 2024, 7:36pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3485 "2024-10-10T19:36:22Z")
> [@Lumpy](#): > > Depends on the source of the carbon that was used to make the graphite; although there is natural graphite, virtually all of it used today is synthesized in electric arc furnaces. That’s okay, so long as the electricity comes from renewables. Eventually, it will. Unless civilisation collapses, we might be able to keep our steam trains. ---
**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:** [October 10, 2024, 7:52pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3486 "2024-10-10T19:52:15Z")
Just put electric heaters in the locomotive boilers, and source the electricity from overhead lines. ---
**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:** [October 10, 2024, 7:59pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3487 "2024-10-10T19:59:01Z")
Like this Swiss loco? [![](https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/SBB_Ee_3-3_8521.png/320px-SBB_Ee_3-3_8521.png) ](https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/SBB_Ee_3-3_8521.png/320px-SBB_Ee_3-3_8521.png) ---
**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:** [October 10, 2024, 8:00pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3488 "2024-10-10T20:00:39Z")
Damnit. All of my worst ideas have already been tried! > **[Electric-steam locomotive](https://en.wikipedia.org/wiki/Electric-steam_locomotive)** > > An electric-steam locomotive is a steam locomotive that uses electricity to heat the water in the boiler to create steam instead of burning fuel in a firebox. This is a highly unusual type of locomotive that only makes economic sense under specific conditions. Normally, it would be much more efficient to build and use an electric locomotive. However, lack of time and resources (as during wartime), lack of coal or similar fuel, and the presence of relatively cheap and available electricity may Sw... ---
**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 11, 2024, 3:04am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3489 "2024-10-11T03:04:22Z")
> [@Dr.Strangelove](#): > > All of my worst ideas have already been tried! Turn in your Mad Scientist license. ---
**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 11, 2024, 12:11pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3490 "2024-10-11T12:11:56Z")
More Power! ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 11, 2024, 10:02pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3491 "2024-10-11T22:02:14Z")
> **[Solar Protons](https://xkcd.com/2997/)** > > If any of you want to meet some cool local oxygen atoms, I can introduce you! ---
**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:** [October 11, 2024, 10:27pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3492 "2024-10-11T22:27:36Z")
> [@Pleonast](#): > > Turn in your Mad Scientist license. Gimme a minute. I can come up with something worse. A decent steam locomotive needs something like 8 megawatts of thermal power to operate. Pu238 produces 500 W/kg. So we only need to dump 16 tons of plutonium in our boiler, which is actually less than a cubic meter–plenty of room. Divide it up into small pellets and just dump it in. It’ll run for decades without significant slowdown. You’d best keep the water topped off, though. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [October 11, 2024, 10:32pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3493 "2024-10-11T22:32:36Z")
At $4M/pound, that’s only $128 billion dollars worth of fuel. Such a deal. ---
**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 11, 2024, 10:47pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3494 "2024-10-11T22:47:30Z")
Anyone know the minimum-volume non-critical geometry of 16 tons of plutonium? Asking for a friend… A quick google shows others have thought about it. > **[Nuclear locomotive](https://locomotive.fandom.com/wiki/Nuclear_locomotive)** > > There were Multiple Proposals for trains that were Nuclear Powered. The Earliest Proposal was made by Dr Lyle Borst at the University of Utah, He suggested a 360 ton x-12 locomotive that carried a nuclear reactor fueled by Uranium-235. He went as far... ---
**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 12, 2024, 1:57am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3495 "2024-10-12T01:57:06Z")
I believe he was referring to Pu-23 **8** , like in radiothermal power from alpha decay rather than fission reactions. No pesky neutrons to deal with. ---
**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:** [October 12, 2024, 2:51am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3496 "2024-10-12T02:51:51Z")
I’m kinda confused, actually. Pu-238 is, as you say, mainly an alpha emitter, used in RTGs, which is why I thought of it. Few neutrons to speak of. And yet the wiki page and other sources say it has a critical mass. Ok, maybe the neutrons get going when it starts fissioning (say, using a neutron initiator). But other sources say that the neutron spectrum is wrong and hence it can’t go critical. At any rate, I’m sure there are many ways to avoid criticality problems. Just coat the pellets with boron nitride or something. ---
**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 12, 2024, 1:12pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3497 "2024-10-12T13:12:33Z")
> [@Dr.Strangelove](#): > > So we only need to dump 16 tons of plutonium… A better poet than me is needed for the Tennessee Ernie Ford adaptation. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [October 12, 2024, 4:51pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3498 "2024-10-12T16:51:01Z")
Saint Peter don’t you call, because I glow, I owe that glow to the company ore! ---
**Author:** ![Ponderoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ponderoid/32/19221_2.png) [@Ponderoid](https://boards.straightdope.com/u/Ponderoid)\ **Post date:** [October 12, 2024, 5:44pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3499 "2024-10-12T17:44:09Z")
You load sixteen tons, what do you get? A critical mass and a global threat. Saint Peter, don’t you call me, I ain’t ready yet; I’m buried knee-deep in the world’s regret. You dump sixteen tons and what do you see? The glow of the future, bright as can be. Saint Peter now listen, this isn’t a joke, I’m covered in dust and I’m starting to croak. If you see me coming, better step aside, A lot of men didn’t and a lot of men fried. I got one fist of iron, the other of steel, If the radiation don’t getcha then the lead shield will. You dump sixteen tons, what do you claim? A radioactive world with a new kind of fame. Saint Peter, hold off, keep the gate shut tight, I’m glowing too much to come into the light. ---
**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:** [October 12, 2024, 7:27pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3500 "2024-10-12T19:27:54Z")
Bravo! ---
**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 13, 2024, 8:47pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3501 "2024-10-13T20:47:38Z")
Absolutely fantastic. I am in awe. ---
**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:** [October 13, 2024, 8:58pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/3502 "2024-10-13T20:58:41Z")
Impressive. The sixteen tons was sheer dumb coincidence on my part. And props to **Chronos** for recognizing it. [Previous page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=174) [Next page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=176)