AHC: Nuclear Fission by 1920

Well at first we are looking at pushing back the discovery of radiation to the 1870s, being almost hand in hand with X-Rays. Then you have to get atomic theory down pat by 1890s. Beyond that I am not too sure
 
That's certainly true (though given the electron's OTL discovery in 1897, it's a very small stretch so far). Also necessary to understand, as I see it:

1) Mass Energy Equivalence, or E=mc^2; FWIG, there was work on this OTL as early as 1881, so I think it's doable
2) Neutrons; not really sure on this one, only that it can really only be discovered by work in radiation
 
First, let me explain that nuclear fission does not equate many of the assumptions you're making. Neutrons need not be involved and neither do radioactive elements. Rutherford split gold atoms with naturally occurring alpha particles in 1917 for example.

You're confusing nuclear fission with a nuclear fission chain reaction because, like too many people, you assume the word fission only means "Bombs!!!" and "Reactors!!!" Einstein's mass-energy equivalence equation has nothing to do with the discovery of fission either. All it does is suggest that fission chain reactions may be self-sustainable in certain situations, something which is needed for "Bombs!!!" and "Reactors!!!" but not something which is needed for fission.

Second, the answer to this one is the same as the answer you already received concerning "steampunk fission" during your previous thread on earlier technologies. By moving forward the "discovery" of fission from 1938 to 1920, you're basically looking dialing forward a huge number of scientific theories, discoveries, and technical achievements by the same period of time. Let's look at the "discovery" of fission itself in 1938 first.

Hahn and Strassmann weren't the first to split an atom, either deliberately or inadvertently. They were simply the first to prove they'd split an atom to the satisfaction of the scientific community and that proof was possible to Meitner's incredibly painstaking chemical work. Prior to 1938, Fermi had announced his observation of fission in 1934, but few accepted his proofs, and Rutherford had actually split atoms in 1917, but unwittingly as part of another experiment.

Looking at just the theory side of things, among other things you'll need an earlier discovery of subatomic particles. Not because neutrons are needed for fission chain reactions, but so that the Rutherford/Bohr planetary/nucleus atomic model can be developed from the earlier indivisible and "plum pudding" models. The discovery of electrons sparked, no pun intended, that shift in thinking so anything that speeds along work with electrons can help.

While work with what we now call cathode ray tubes began as early as the 1870s and the electrons making up cathode rays were proven to consist of tiny particles as opposed to atoms or molecules, Millikan didn't perform his flawed oil drop experiment until 1909.

An earlier understanding of radioactivity would be required too. Becquerel's discovery of spontaneous emission, that fluorescent materials didn't need outside energy sources, didn't occur until 1896 when Becquerel was duplicating Roentgen's work with, you guessed it, cathode ray tubes.

Historically, I feel the discovery of fission occurred pretty much as quickly as it could have. While it seems incredible to our post-Cold War, science harnessed for military purposes, mindset, even WW1 didn't advance or slow things appreciably. Rutherford performed many of his experiments during the war with neither hindrance in the form of rationing or help in the form of government wartime research monies.

Of course, funding the early physicists and providing them with more resources could have goosed things along. Such a directed effort however presumes a known and specific goal, as when you research Electricity because it's required to research Atomic Theory so you can build the Manhattan Project and nuke your opponents in a game of Civilization.

Sadly, reality is not a computer game. ;)

Across the board scientific philanthropy may work in a small way. Imagine that Carnegie doesn't fund libraries and other civic improvements or that Nobel doesn't set up those idiotic prizes in his will. Instead, they and men like them fund general research efforts perhaps along the lines of the MacArthur Fellows Program's "genius" grants. Even then, lab work will outrun theory, as it did in the OTL, and the discovery of fission will not come much sooner. Rutherford split atoms in 1917, but he lacked the theory to even guess at what was occurring let alone look for the proofs.
 
Well Don, you've given me a lot to think about; and you may well be right that the harnessing of nuclear energy happened as soon as it plausibly could. Still...

You're confusing nuclear fission with a nuclear fission chain reaction because, like too many people, you assume the word fission only means "Bombs!!!" and "Reactors!!!"

Sorry, my bad :eek: -- if it helps, I am looking for enough of an understanding a fission chain reaction by 1920 that a model reactor by 1925.

While work with what we now call cathode ray tubes began as early as the 1870s and the electrons making up cathode rays were proven to consist of tiny particles as opposed to atoms or molecules, Millikan didn't perform his flawed oil drop experiment until 1909.

An earlier understanding of radioactivity would be required too. Becquerel's discovery of spontaneous emission, that fluorescent materials didn't need outside energy sources, didn't occur until 1896 when Becquerel was duplicating Roentgen's work with, you guessed it, cathode ray tubes.

Radiation, I thought as much; I was thinking Becquerel's "accident" with uranium salt could plausibly have happened earlier...

First, let me explain that nuclear fission does not equate many of the assumptions you're making. Neutrons need not be involved and neither do radioactive elements... Rutherford split atoms in 1917, but he lacked the theory to even guess at what was occurring let alone look for the proofs.

Did not know this -- but it could be the key to what I'm going for :eek: What would Rutherford have needed to be able to know what he was looking for that came later?
 
Sorry, my bad...


It's not "bad" to make those assumptions. They're in general use for a reason! :)

Radiation, I thought as much; I was thinking Becquerel's "accident" with uranium salt could plausibly have happened earlier...
Becquerel's happy accident in 1896 occurred when he was investigating Roentgen's reports of 1895. You can't get much faster than that.

Following the chain one step backwards, Roentgen's discovery of x-rays only occurred because he had access to both better cathode ray tubes and a higher frequency power source for them. He needed both the tubes and a very specialized transformer and the fairly recent advent of electrical "grid" infrastructure.

Stepping back again, Crooke wasn't able to successfully and regularly hand build cathode ray tubes until the late 1870s until a fellow researcher hand built a high quality mercury vacuum pump. When powering his tubes, Crooke had to produce his own electricity because there was no "grid" to plug into.

Anyone wanting to further investigate Crooke's findings or simply play around with cathode ray tubes then had to either build their own tubes and vacuum pump or find someone who would build the same for them. You just didn't open a catalog and order what you needed. After making those tubes, they usually then had to make their own electricity.

Beginning to see all the strands involved?

Did not know this -- but it could be the key to what I'm going for :eek: What would Rutherford have needed to be able to know what he was looking for?
You're putting the cart before the horse again. Let me explain.

With the discovery of electrons, the best guess regarding subatomic structure was Thomson's "plum pudding" model. In it negatively charged electrons swam around in a "pudding" of some ill-defined positively charged substance. Thomson and everyone else knew there had to be a positive charge in play within the atom to balance out the electron's negative charges, but no one knew what form that positive charge took. Was it a field? Vorticies? A cloud? A particle? Particles? No one knew.

The experiment in which Rutherford split atoms provided proof that the positive charge was located at the center of the atom leading to the his planetary atomic model. Bohr later elaborated on that model thanks to of early quantum dynamics and produced the Bohr nucleus model.

So, Rutherford "discovered" that atoms has nuclei but he wasn't looking for nuclei. He was just throwing stuff at atoms and watching what came out as a way of determining just what the hell was going on inside atoms.

Now follow me closely ...

  • Fission involves splitting atomic nuclei ...
  • ... and Rutherford split atomic nuclei, but ...
  • ... Rutherford didn't know atomic nuclei existed until he split one ...
  • ... how could he have known about nuclei or fission before he found nuclei by inadvertently achieving fission?


The theory just isn't there. When he began bombarding atoms with particle streams, Rutherford didn't already have the Bohr Model in hand complete with a knowledge about electron orbits, protons, and neutrons. Instead, it was the data that Rutherford collected which led to the development of the Bohr Model and the discovery of electron orbits, protons, neutrons, and all the rest.

Rutherford cannot exploit the fact of fission when he doesn't know what is going on. We cannot put the cart before the horse.
 
OK, when is the earliest that a pump like that could have been developed? How much earlier can the development of cathode ray tubes occur?
 
Becquerel's happy accident in 1896 occurred when he was investigating Roentgen's reports of 1895. You can't get much faster than that.

Sure you can. Have someone be investigating flourescent minerals for some totally different reason and stumble across it. It's not too implausible for it to gain interest as a curiosity, much like (say) electricity a hundred years earlier, and have people start doing Curie-like chemical analyses to it, even if they won't have all the equipment the Curies did. The key problem there is the invention of the dry process which allowed Bequerel to put a uranium salt sample next to a *ready to develop* glass plate and have it actually do something--that couldn't happen with the wet processes, since it wouldn't be ready to develop, and the radiation would just go through without doing anything.
 
OK, when is the earliest that a pump like that could have been developed?


It's not just the pump.

How much earlier can the development of cathode ray tubes occur?

Look at it this way. The Crookes or cathode ray tube is a type of electric light bulb.

While Edison did not invent the electric light, he "merely" invented a cheap, easily produced version, how much earlier can you push back electric lighting? How many other advances are involved?
 
The key problem there is the invention of the dry process which allowed Bequerel to put a uranium salt sample next to a *ready to develop* glass plate and have it actually do something--that couldn't happen with the wet processes, since it wouldn't be ready to develop, and the radiation would just go through without doing anything.

Well, AIUI, the dry process was in very common use by 1870 (essentially invented 1850), so no problem in that.

But I'm still going to wait on DL's response before I say anything certain...

Don Lardo said:
You're putting the cart before the horse again. Let me explain.

<snip>

Point very well taken.
 
Sure you can.

No you can't.

As soon as some form of photography is developed - and I've argued on this board that photography could have been plausibly achieved by medieval alchemists - you can observe the effect but you won't know it's radiation.

In a time line with earlier photography, someone can easily recreate Bequerel's happy accident. However, absent Crooke's developments, the subsequent realization that "something" is streaming through those tubes, Roentgen's observation that that "something" also streamed beyond the tube though his hand and made images on a photographic plate, Bequerel isn't going to realize that the same "something" or a similar "something" also streamed out of his uranium salts and into his dry plates.

Hell, Bequerel didn't even mention the word radiation in his announcement. Years before Bequerel's discovery Hertz had theorized that electromagnetic radiation was at work in cathode ray tubes but confirmation had to wait until 1897 when Thomson actually measured the particles involved.

Given earlier photography, someone could have easily stumbled across the effect Bequerel noted. However, that effect would have been called 'salt shadows" or some sort. It most certainly not would have been called "radiation" and no one seeing it would have clapped a hand to their forehead, shrieked "EUREKA!", and immediately began babbling about subatomic particles, fission, and all the rest.

There are just too many other discoveries, experiments, and advances that also need to occur first.
 
Given earlier photography, someone could have easily stumbled across the effect Bequerel noted. However, that effect would have been called 'salt shadows" or some sort. It most certainly not would have been called "radiation" and no one seeing it would have clapped a hand to their forehead, shrieked "EUREKA!", and immediately began babbling about subatomic particles, fission, and all the rest.

Duh, of course they wouldn't know it was radiation or call it that. But they would know something funny was going on, and probably experiment with other materials (mainly various uranium compounds) to see about it. This, despite your claims, WOULD have an effect on nuclear chemistry and nuclear physics--eventually. It would certainly have an effect on chemistry immediately if people start experimenting like the Curies (as I said) and discover radium and the other rarer radioactive compounds, and it would probably have an effect on physics as people struggled to explain what was going on. The initial guess would probably be some kind of invisible, highly penetrating rays--like x rays or gamma rays. Not too wrong, either. But it IS going to spur interest and experimentation--just not what happened IOTL, and in a different order.
 
But they would know something funny was going on...


So what? They knew something funny was going with pottery glazes for thousands of years but that didn't spark empirical chemical research beyond Try this and see what works level of alchemy.

They knew lots of funny things were going on in a myriad of fields for thousands of years but, again, empirical research into all those funny bits is a fairly recent development.

Here's what you're failing to comprehend...

... have an effect on nuclear chemistry and nuclear physics ...

... an effect on chemistry...

...start experimenting...
... you're presuming things like "chemistry", "physics", "experiments", and many, many other things that didn't even begin to exist until roughly the 18th Century.

You need a scientific worldview for these things to exist. Prior to that it's all just mumbo-jumbo and mysticism.

But it IS going to spur interest and experimentation--just not what happened IOTL, and in a different order.
Interest, yes. But it won't spur anything resembling actual reproducible scientific experimentation until the paradigm shift I mentioned occurs.
 
Don Lardo said:
However, absent Crooke's developments, the subsequent realization that "something" is streaming through those tubes, Roentgen's observation that that "something" also streamed beyond the tube though his hand and made images on a photographic plate, Bequerel isn't going to realize that the same "something" or a similar "something" also streamed out of his uranium salts and into his dry plates.

Well, if the "accident" happens around or after 1876, that just leaves out Roentegen's discovery; even there, wasn't Ivan Pulyui making some headway in X-Rays around this time as well?
 
Well, if the "accident" happens around or after 1876, that just leaves out Roentegen's discovery; even there, wasn't Ivan Pulyui making some headway in X-Rays around this time as well?


That could happen and Hertz was publishing his theory about electromagnetic radiation. So we have a theory and an observed effect which may be related to it. Now what?

Thomson "proved" Hertz' ideas in 1897 when he was able to measure the weight of the particles in a cathode ray tube's stream. What physical tools did he use to do that? What tool did he have in 1897 that weren't available in 1876? What advances would need to be made earlier for those 1897 tools to be available twenty years earlier?

Moving on, Thomson's discovery of the electron pointed the way to subatomic particles and Millikan measured the charge of an electron in 1909. Again, what physical tools did Millikan have that Thomson didn't? Or that someone in 1876 didn't? Again, what advances are necessary for those tools to be available earlier.

Now ask yourself the same questions about theories and tools for Rutherford's experiments, Chadwick's experiments, and up through Hahn's, Strassmann's, and Meitner's experiments.

There's a lot of stuff that has to happen. You can't simply pick one item, craft one POD, and presume everything will then happen earlier. All this stuff isn't sitting on some shelf waiting to be put together in certain ways. These men were working on the bleeding edge of both theory and technology and they routinely made what we would consider basic lab equipment.

Look at Crooke again because he was experimenting during the 1870s around the date you're interested in. Crooke needed a vacuum pump which no one had ever seen before, a pump which was made specifically for him so he could create higher vacuums than anyone before him. Crooke also used voltages which, for the period, were incredibly high, something around 6000 volts IIRC. Again, he needed to build a transformer to provide that voltage while also producing his own electricity.
 
That could happen and Hertz was publishing his theory about electromagnetic radiation. So we have a theory and an observed effect which may be related to it. Now what?

Thomson "proved" Hertz' ideas in 1897 when he was able to measure the weight of the particles in a cathode ray tube's stream. What physical tools did he use to do that? What tool did he have in 1897 that weren't available in 1876? What advances would need to be made earlier for those 1897 tools to be available twenty years earlier?

Moving on, Thomson's discovery of the electron pointed the way to subatomic particles and Millikan measured the charge of an electron in 1909. Again, what physical tools did Millikan have that Thomson didn't? Or that someone in 1876 didn't? Again, what advances are necessary for those tools to be available earlier.

Now ask yourself the same questions about theories and tools for Rutherford's experiments, Chadwick's experiments, and up through Hahn's, Strassmann's, and Meitner's experiments.

Those are very good questions; I certainly do not know the answers...
 
Those are very good questions; I certainly do not know the answers...


What I'm trying, and failing, to point out is that any PODs which lead to fission in the 1920s are going to be either "deep" or "wrenching". So deep and wrenching that they'll have effects far beyond simply allowing someone to observe nuclear fission and prove that it occurred.

We'd need many advances in theory and many more in technology. The technological bits alone will have huge effects.
 
Oh I don't doubt that -- I'm quite sure even the smallest necessary PoDs are going to give technology as a whole an enormous bump by the 20th Century...
 
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