You may be understating how much 15 orders of magnitude are.

The only truly exponential technological progress we’ve ever had, transistors, only scaled by ~5 orders of magnitude in feature size. Thermal engines went from maybe 0.1% to ~50%, less than 3 orders of magnitude, in about 200 years. There’s very fundamental physical laws that suggest that engines are done, and transistor scaling as we have known it for 30 years is also done. Perhaps very clever things might give us 5 more orders of magnitude? E.g. truly 3D integration somehow? Then we’re still 5 orders of magnitude off from our target. I can’t think of any technology that ever improved by more than 10^6, perhaps 10^9 if you count some derivative number (like “number of transistors on chip”, rather than actual size), and that’s from literally zero to today. Not from already-pretty-advanced to Death Star scale.

Another perspective is that, to get to those kinetic energies, we need accelerators as large as the solar system. Possibly the galaxy, I can’t quite remember. Will you concede that galaxy-wide objects are so far from current reality that there’s no point seriously talking about them?

Are you seriously insinuating that string physics are asking for this collider you alone entirely made up? As if people who actually do study string theory are too stupid to know primary school math and this criticism is somehow high-brow and novel?

Not to mention you entirely missed the point of what I said. There is research into the most niche, useless fields imaginable, because not every endeavor taken by every human being needs to be profitable or applicable. Sometimes people are just really good at making jigsaws or want to make a stinky chemical or get fascinated with properties of prime numbers.

And then, sometimes, those turn out to be the fundamental underpinnings of an entire generation of economic and military strategy. You can't often know what spurs what in that sense.

I didn’t make it up, it’s a well known talking point around string theory. I think it was first mentioned by a practicing string theorist. Of course it’s not a novel critique, but I’ve read about putting data centers in space on this website, so I think it’s worth trying to teach people how to do these sort of Fermi problems quickly.

I did indeed miss your point, it was well hidden under a lot of sarcasm. I think it is of course completely valid. People should be free to research what they want, and I’m sure string theory must be beautiful mathematics.

But if your goal is unifying QM and GR, and/or achieving a theory of everything (as is for most theoretical physicists), then me and a growing fraction of physicists think that it’s not a promising avenue. I’m not advocating for only working on “useful” things, because such a theory is not likely to yield much profit to anyone in the foreseeable future anyway. But if you state that a unifying theory is your goal and seek funding for that goal, then string theory should move to the backstage. The mathematics department would rightfully be happy to house you otherwise.