Academy of Sciences of Heroesland

But even approximately, it's only 300000 - 299792 = 208 km/s less. Compared to 300000, that's very little. I think it's not much more than the measurement error. I don't even remember how they measured it. They probably used some kind of water, split a beam into two parts, and sent one along the flow and the other against it, or something like that...