Aamuyöstä kun ei uni tullut simmuun, niin mietin tarvitaanko niitä G: palleroita ja löysin tämän
"You also ask about the absence of "force" in GTR, aside from that we think of GTR as defining the geodesics of spacetime and therefore inertial motions, i.e. that it is a kind of "application note" for when to apply Newton's first law and what "force" one needs to deviate from geodesic motion. I know nothing of physics beyond GTR, but it is worth saying that many physical theories can be formulated in both "force mediators on empty flat background" terms as well as in geometric terms. The four-potential AA in electromagnetism defines the gauge covariant derivative and the notion of parallel transport through electromagnetic configuration space. So "force" and "geometry" can be complementary and not contradictory. Having said this, I have never really understood the need to make gravity of exactly the same character as the other forces simply because it's not "choosy" - it affects things equally independent of composition, or at least seems to in the continuum limit. It's quite possible that, at the Planck scale, this is no longer true."
enkä tullut ns. hullua hurskaammaksi.