Grav­ity keeps your feet on the ground yet no such ‘force’ ac­tu­ally ex­ists

Sky at Night Magazine - - MYSTERIOUS GRAVITY -

Although New­ton imag­ined the force of grav­ity be­tween the Sun and Earth as like a piece of in­vis­i­ble elas­tic con­nect­ing the bod­ies, Ein­stein dis­cov­ered the truth is dif­fer­ent. A mass like the Sun warps space-time around it, cre­at­ing a val­ley. We can’t see the val­ley be­cause space-time is a four-di­men­sional thing and we are three-di­men­sional be­ings. But Earth cir­cles around the val­ley like a ball around a roulette wheel. It ex­pe­ri­ences no ‘force’ but trav­els along the short­est path through warped space-time. Sim­i­larly, there is a ten­dency for you to fall to the bot­tom of the val­ley of space-time around Earth. The sur­face ob­structs, how­ever. In push­ing back, it cre­ates the ‘feel’ of grav­ity.>

Large masses like the Sun warp space-time, cre­at­ing a ‘val­ley’; Earth is fall­ing through this val­ley

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