Why Don’t We Feel the Earth Move?
Showing only ideas leading to #5814.
See chronicle·See most recent related ideasThe Earth is a planet. It spins once a day and goes around the Sun once a year, as the other planets do. Mars moves on an ellipse, a stretched circle, with the Sun at one of the ellipse’s two foci, so that the line from the Sun to the planet sweeps out equal areas in equal times, and the other planets, I expect, move the same way.
If the Earth circled the Sun, we would see the stars from different places over the year, so they would seem to shift back and forth. They don’t.
The stars are so far away that, next to their distance, the Earth’s orbit is like a point. Their shift is far too small to see.
Even my instruments, precise to a minute of arc, show no shift of the stars. So they would have to be at least 700 times farther from the Sun than Saturn is, leaving an absurd empty gap in between.
The parallax is there, only tiny. Over the year, 61 Cygni moves back and forth by 0.31 seconds of arc either way against two fainter stars beside it, just as it should if the Earth circles the Sun. The stars are simply that far away: 61 Cygni is about 660,000 times farther from us than the Sun.