As far as i know earth’s orbis is stable.
If i understand it correctly it means that small perturbations in earth’s position or mass won’t change its orbit (like a spring effect that goes back to its rest state unless you break it), but if i simply balance out sun’s newtonian gravity vs the centrifugal force any little change would modify earth’s orbital speed and distance from the sun, so there’s something i’m missing, otherwise anytime a meteor hits or we send stuff to space we would be changing earth’s orbit.
So, IF my initial statement is correct, earth’s orbit doesn’t change for small perturbation, how do we know so? Secondly how big a perturbation would you need to change earth’s orbit?
On the other hand, if earth’s orbit changes with any minumum change, how big of a change in orbit would be needed for us to sebsibly perceive it?
Thanks
In: 4
It’s not “stable” in the sense of springing back to the way it was after any little bump.
It *is* “stable” in the sense that any small change to an elliptical (oval-shaped) orbit is still an elliptical orbit. Inward-spiraling orbits are not a thing in the vacuum of space, and it would take the mother of all bumps to shift us onto a hyperbolic (escaping from the solar system) orbit.
Changes in Earth’s orbit over time *are* perceptible. For example, if we define “winter” astronomically as “the duration between the December solstice and the March equinox”, winter lasted 128,157 minutes in 1972 but only 128,134 minutes in 2022. That’s a 23-minute difference! (Caused mainly by gravitational interactions with the Moon and other planets.)
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