Path: ...!eternal-september.org!feeder3.eternal-september.org!fu-berlin.de!uni-berlin.de!news.dfncis.de!not-for-mail From: Mikko Newsgroups: sci.physics.research Subject: Re: Equivalence principle Date: 10 Jun 2024 11:46:37 GMT Lines: 19 Approved: hees@itp.uni-frankfurt.de (sci.physics.research) Message-ID: References: X-Trace: news.dfncis.de 5Ir8j8ScPsB6p104yw6bpA/U65eM6pPnzdAC6pTdmoLvcUPhud/TAqx9ijzY8ZD1Dv Cancel-Lock: sha1:9nDZqUkO1T8wyZjA2Q+bhnMaF6Y= sha256:CImJcfpZoYBRh8v/Z5OgGaP25TS4Sx9T4Cxwlv0Ny4Q= Bytes: 1481 On 2024-06-08 17:40:15 +0000, Luigi Fortunati said: > In the video https://www.youtube.com/watch?v=R3LjJeeae68 at minute 6:56 > it states that there is no measurement that can be made to distinguish > whether you’re being accelerated or whether you are sitting still on the > surface of a planet. > > So, I ask: what stops us from measuring the presence (or absence) of > tidal forces? If tidal forces are there, then we are stationary on the > surface of a planet, if they are not there, we are experiencing a > non-gravitational acceleration. Consider a situation where you are not sitting on a surface of a planet but acclerated by a real non-gravitational interaction; and this happens near a planet or a star: you can measure a tidal force (if your instruments are big and sensitive enough). -- Mikko