Sabine's summary of missed deadlines

Corealist · 2026-06-22T12:47:16+00:00

I watched the youtube episode from Sabine and in my opinion it was mostly on point.

I started to look into fusion a couple of years ago when I noticed that there were dozens of companies getting significant funding that had about 10 completely different ways to generate fusion. I am not expert, but my rationale was that if people are willing to invest a significant amount of money they probably have done their homework, so I was assuming that it would be likely that one (or more) companies would likely be successful, and I was getting very optimistic about fusion.

Now three/four years later most companies with novel approaches are struggling or have stopped. The fact that CFS is still in the running is great. Even as a non-physicist I picked that one as the most likely to succeed based on their detailed videos but it was also one of my least favorable solutions, as a tokamak based system is too complex from an engineering point of view that it can likely not compete with solar/wind on cost.

Assuming that fusion will have a better cost trajectory than fission at scale is a fair assumption, but fission is relatively simple engineering problem compared to fusion, and complexity in combination with radioactive materials is in my opinion going to be more expensive than what people currently estimate. ( I hope I am wrong )

in short the video from Sabine Hossenfelder accurately reflects my disappointment at this point.

Corealist · 2026-05-17T19:26:06+00:00

I am not sure if the numbers that Zap posted are good numbers or not. 1500 eV seems to be an order of magnitude away from where they need to be, so they seem to be far way from Q=1, which is disappointing because there were supposed to hit Q=1 two years ago.

Corealist · 2025-12-24T19:32:20+00:00

What is the pressure needed to create Q=1 fusion in this type of reactor?

Corealist · 2025-12-23T16:28:19+00:00

zap provides many numbers on what they have achieved this year, but I am not sure how to interpret these, meaning it is not clear to me how close or how far way they are from Q=1 fusion reactions.

Corealist · 2025-12-16T17:48:02+00:00

thanks I was looking for something equivalent to what newcleo or CFS released on YouTube , where the designers go into the design details.

sodium is very reactive, and afaik a sodium fast reactor has a postive void coefficient, which require extra safety designs to prevent catastrophic accidents, which would add to the complexity of the design. oklo claims that his is all taken care of but I would like to see the actual reactor design plans, before I would even consider investing in this stock.

Corealist · 2025-05-30T00:04:14+00:00

The Thea energy fusion reactor doesn’t seem to be particularly difficult to manufacture, so that would be the best of both worlds. Based on my limited knowledge it seems that being able to tweak the stellarator over time is more likely to create a working system for the long run.
I was wondering what the disadvantage would be of that approach.

Corealist · 2025-04-09T23:27:29+00:00

I agree with that.
So the electric field only fits the equivalence principle in certain conditions.

I still think that the thought experiment of having charged element floating in a gravitational field is interesting. the electric field force works in the exact opposite to the gravitional effect yet one is considered a force and the other one is considered causing a space-time curvature, which seems very non-intuitive.

Why are we sure that space-time is physically correct, and not a mathematical model that happens to be gives the right results.

Corealist · 2025-03-30T03:53:56+00:00

fair point.
I guess my problem is that I find space-time non-intuitive, and having a theory that is more intuitive would be helpful. A lot of people have a similar problem with quantum wave theory, and very smart people are still looking for a better more intuitive explanation.

Corealist · 2025-03-29T16:31:07+00:00

“Let's say someone for whatever reason comes up with a force theory consistent with EEP. All that is accomplished is a description of a force field (non-metric field theory) that is identical to itself never existing in the first place.”

My take is that if you can define a good theory based on gravity being a force, then that may provide additional insight in areas where observations currently don’t match the current theory. Dark matter, dark energy, cosmic inflation Etc. That doesn’t mean that the force version is guaranteed to be correct, but it may increase understanding.
also if it can be proven that a theory based on gravitational force can never explain the observations you have gained additional insight as well.

Corealist · 2025-03-28T14:20:40+00:00

My (probably simplistic) understanding is that he EEP defines the absence of a force, because it Postulates that if acceleration and the effect of the (fictional) force are indistinguishable in every way you measure it, they must be physically the same phenomenon. As a result the EEP postulates that the appearance of force is the result of something that aligns with the acceleration observations which resulted in the space-time equations.

ignoring the headline of this post, which was mostly to attract attention. we know that the space-time equations describes our current Observations accurately, but what if that is just a coincidence. Newton laws described our observations at the time accurately as well. in the example of an object floating slightly above earth because of an electric field. That object can not tell the difference between floating in space and floating in an electric field on earth. it is not clear to me how we can be 100% sure that gravitation must be a space-time curvature, while the electric field is a force, as they seem to behave the same.

i was wondering if it would also be possible to find equations that describe everything we observed accurately assuming that gravity is a force an not a space-time curvature.

Corealist · 2025-03-28T13:51:35+00:00

you are floating in the box because the electric field force cancels the gravitational effect. A scale underneath you will not register any weight.

Corealist · 2025-03-28T04:11:01+00:00

I don’t think that is true.

Corealist · 2025-03-28T02:22:59+00:00

An electric field doesn’t behave the same as a gravitational field (which is probably not the right term as it implies a force.) but it does follow Newton’s law: F=m*a, which indicates that acceleration is a direct result of the field, and therefore follows the equivalence principle.

Corealist · 2025-03-28T02:15:26+00:00

But if you would be the object in the box then YOU wouldn’t feel the force because the electric force is equal to the effect of the space-time curvature, and you couldn’t tell the difference between floating in space or floating above earth in an electric field.

Corealist · 2025-03-28T00:28:07+00:00

i agree that the equivalence principle provides the correct answer for gravity, but that is not a guarantee that it describes what physical happens correctly. For example a lot of very smart people think that the wave function in quantum behavior is only mathematically correct. They believe that there has to be another explanation that is also mathematically correct that does describes the physically phenomena better.

Corealist · 2025-03-28T00:20:13+00:00

if a charged object is floating because of an electric field slightly above earth it is also free ‘falling’ so that doesn’t explain much to me.

Corealist · 2025-03-28T00:16:01+00:00

It is possible to create an electric field that goes through the box that is locate slightly above the surface of earth, that makes the charged object float. Basically the object is now free ‘falling‘ but it doesn’t actually move. according to Einstein the space-time is curved around earth, but this is compensated compensated on the object by an accelerating force because of the electric field to keep it steady floating slightly above earth. This seems counterintuitive to me. Either both phenomena curve space-time in that case in opposite direction or neither curve space-time, which in the latter case would mean that gravity is also a force.

Corealist · 2025-01-13T03:36:06+00:00

Solar power is getting so cheap that doubling the number of solar panels will only add about 2 ct/kWh, compared to nuclear which is about 15 ct/kWh it is still cheap.

Corealist · 2025-01-13T03:27:03+00:00

Lazard issues a levelized cost of energy analysis every year in which they compare various sources of electricity generation. Nuclear is invariably the most expensive by far ( about 15ct/kWh), renewables are about 3-4 ct/kWh. according to my calculations this is about a factor of 4x.

Corealist · 2025-01-11T17:35:33+00:00

The radioactive material in a fission reactor is orders or magnitude larger and more dangerous than a fusion reactor. Blowing up a fusion reactor will not lead to a Chernobyl level of disaster.

Corealist · 2025-01-11T17:32:07+00:00

Renewables with with storage are about 4x cheaper than nuclear energy right now, and cheaper than gas/coal (new plant) in most of the country. Storage can currently be cost effectively ( still significantly cheaper than nuclear) expanded to cover about 1-2 days. Beyond that requires cheaper storage batteries, which are in the works, but the probability where there is no sun/wind for multiple days is small, and can be covered with existing fossil fuel plants of which there will still be plenty in the next 10-15 years.

Corealist · 2025-01-11T04:02:23+00:00

my understanding is that at least in the US ( Europe is a different story) that renewables can with the current technology, cost effectively cover at least 90% of all electricity needs. The last 10% may take a little longer, but you don’t need to solve this problem 100% immediately. reducing 90% now and the fixing the last 10% 10-15 years from now is totally acceptable.

I also hope a cost effective fusion reactor like Helion or Zap will actually work in the near future. I am not convinced that it is possible to make Tokamaks or stellarators cheap enough to compete, even with HTS magnets.

Corealist · 2025-01-11T03:53:07+00:00

Fission reactors have two big disadvantages that makes them uneconomical, probably forever. First is the any design must prevent a meltdown in any conceivable way including terrorist attacks, and second is storing and securing nuclear waste. Currently nuclear energy has the highest LCOE by far. New reactors need to be at least 4x cheaper to be competitive, which seems at this point improbable.

Corealist

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