I agree with everything Stross said here, but I don't think he characterized the speed-of-light verification mechanism well. He proposed it in his novel "Neptu

I agree with everything Stross said here, but I don't think he characterized the speed-of-light verification mechanism well. He proposed it in his novel "Neptune's Brood" in 2013 and it is described in some more detail here: https://web.archive.org/web/20210514225451/http://www.antipope.org/charlie/blog-static/2014/09/crib-sheet-neptunes-brood.html https://web.archive.org/web/20210514225451/http://www.antipo... (original at http://www.antipope.org/charlie/blog-static/2014/09/crib-sheet-neptunes-brood.html http://www.antipope.org/charlie/blog-static/2014/09/crib-she... but the site is dying) I think it merits some formal consideration, a scifi novel isn't a whitepaper, but I think the concept has promise. You can't cheat the speed of light without finding a few jupiters worth of exotic matter.