Even for general relativity, it is not clear whether this statement is true, see
> https://en.wikipedia.org/wiki/General_relativity_priority_di...
According to this Wikipedia article, David Hilbert came up with a different derivation of general relativity at about the same time as Albert Einstein.
As compared to SR as Einstein originally developed it, yes. But note that modern usage of SR often makes use of the same differential geometry tools that were developed for GR--because those tools turn out to be useful even in flat spacetime.
> But once SR was clear it was "just" an extension to the same ideas.
Again, if that were the case one would not have expected it to take ten years to get to GR. Yes, Einstein had to learn about Riemannian geometry from Grossmann, but that didn't take him anywhere close to the ten years to do. He spent most of that ten years struggling with the physical concepts involved, not learning the math.
> The leap here was the original idea that gave rise to SR. The rest could have been worked out by most physicist of the time.
This is strongly contradicted by the fact that there were many other physicists working on a relativistic theory of gravity at the time--and they all got it wrong. Only Einstein, and Hilbert (who was a mathematician, not a physicist) after getting key input from Einstein, got it right.
The necessary transformations for special relativity (Lorentz transformations) were already developed by Hendrik Lorentz and Henri Poincaré. Einstein's central contribution for special relativity was to reinterpret these equations in a novel way.
But he did that only after having Einstein visit him for several weeks in the summer of 1915 and having long discussions with Einstein about the latter's ongoing efforts to discover a general theory of relativity. AFAIK Hilbert himself acknowledged that his final effort was only possible because of all the work that Einstein had already done.
Once you start trying to measure the speed of light compared to your own speed it becomes quite obvious that there’s a problem with not being able to measure anything but c regardless of the movement of source and receiver.
All other observations likely would have taken decades to stumble upon as well. I see no argument still why any other scientist would have made the relativity leap (which to be clear isn’t directly a requirement for deriving E=mC^2).
This seems like a hyperbole to make a point about how smart Einstein was.
From what I've seen in past discussions like this, including one on HN [0], is that it would've been delayed by 1-5 years. And it wasn't just the Mercury's orbit. There were fundamental questions about electormagnetism that had unclear answers with the predominant theory of aether.
> The new feature of it was the realization of the fact that the bearing of the Lorentz transformation transcended its connection with Maxwell's equations and was concerned with the nature of space and time in general. A further new result was that the "Lorentz invariance" is a general condition for any physical theory.
This seems like a massive leap even given what Lorentz and Poincaré were coming up with, which is all at that point trying to understand what the math leads to and no real intuition on what that means in reality. Einstein on the other hand came up with something that had almost no mathematical underpinning (his first paper had no derivation). The final conclusion of the author in that comment, that this insight was only a year away, is thus completely unfounded in my opinion.
In that thread itself someone quotes Feynman concluding the same. I’ll listen to Kip Thorne, Feynman and my own intuition for now until someone gives a fairly thorough reasoning for their skepticism then.
I would also make a point of not quoting Einstein himself on such nuanced takes. He spent basically 30 years just commenting on his own theory and its motivations every single day. One would assume he would have decided to be more modest on some of those occasions in a mere whim or to placate that particular audience.
Great spoilers for the book Project Hail Mary below so stop reading if you’ve not finished it (and why havent you?): it was such a brilliant idea in that book to suggest that the space faring alien race never figured out relativity still and could still head out to a nearby star and only then discover there’s a massive discrepancy in their calculations. To use such an obscure observation that relativity is not obvious at all as a plot point needs a lot of kudos to the author.