If you are familiar with Newton's bucket, you may skip to 6:10. Until recently, I had not realized the flash of genius of Dennis Sciama who linked inertia and gravity in a Machain way already in 1953. Fay's paper: https://relativemotionorg.files.wordpress.com/2024/01/on_sciama_1953.pdf Sciamas paper: https://academic.oup.com/mnras/article/113/1/34/2602000 See also: https://www.amazon.com/Einsteins-Lost-Key-Overlooked-Century/dp/1519473435/ Thanks to Jonathan Fay for pointing my attention to it: http://www.jonathanfay.com/ Mind also my backup channel: https://odysee.com/@TheMachian:c My books: www.amazon.com/Alexander-Unzicker/e/B00DQCRYYY/