How do we know that the earth orbits the sun?

Answer 1

We don't 'know'. It's not proven, and we won't have the ability to prove that it's right or wrong
until our technology grows a lot farther than what we have now.

The theory that Earth orbits the sun is only the best explanation we have for everything we
see happening in the sky. Also, effects that the theory predicts are found just as predicted,
and things we do based on that theory ... such as the way we choose to launch and navigate
our space probes ... work !

But it's still "just a theory". And if you come up with a description that fits our observations
better and makes more accurate predictions, then this theory will be discarded, and yours
will be adopted. That's how Science works.

Answer 2

We don't 'know'. It's not proven, and we won't have the ability to prove that it's right or wrong
until our technology grows a lot farther than what we have now.

The theory that Earth orbits the sun is only the best explanation we have for everything we
see happening in the sky. Also, effects that the theory predicts are found just as predicted,
and things we do based on that theory ... such as the way we choose to launch and navigate
our space probes ... work !

But it's still "just a theory". And if you come up with a description that fits our observations
better and makes more accurate predictions, then this theory will be discarded, and yours
will be adopted. That's how Science works.


The simplest way to know this (which is how the ancient Greeks figured this out, 2300 years ago) is to observe that any particular star rises four minutes earlier each day. Our "day" is calculated as the time from noon to noon, and is 24 hours long. The fact that the stars rise four minutes earlier each night tells us that it really only takes 23 hours 56 minutes for the Earth to spin exactly once; the additional 4 minutes in each "day" is how much longer the Earth takes to spin so that the same spot on Earth is pointing at the Sun each day. If the Earth weren't moving around the Sun, the stars would rise at the same time every evening.

So, the math works out.

And more recently, we've been able to launch satellites into space, and this allows us to calculate quite precisely how fast the Earth is moving around the Sun - and even, how fast the Sun is moving as it orbits the center of the Milky Way galaxy.

Answer 3

For all practical purposes, the distant stars are "fixed" in their locations; they do not move relative to each other. So as the days go by, look out and see what stars are visible at sunset each night for a year.

You will see that the stars rise four minutes earlier every evening, and a constellation that rises at sunset today will be 15 degrees above the horizon a month from now. Over the course of one year, the stars will have made one circuit of the night sky.

Answer 4

The simplest way to know this (which is how the ancient Greeks figured this out, 2300 years ago) is to observe that any particular star rises four minutes earlier each day. Our "day" is calculated as the time from noon to noon, and is 24 hours long. The fact that the stars rise four minutes earlier each night tells us that it really only takes 23 hours 56 minutes for the Earth to spin exactly once; the additional 4 minutes in each "day" is how much longer the Earth takes to spin so that the same spot on Earth is pointing at the Sun each day. If the Earth weren't moving around the Sun, the stars would rise at the same time every evening.

So, the math works out.

And more recently, we've been able to launch satellites into space, and this allows us to calculate quite precisely how fast the Earth is moving around the Sun - and even, how fast the Sun is moving as it orbits the center of the Milky Way galaxy.

Answer 5

Photo evidence from the Hubble Telescope (and various rockets). Before, that periodicity measurements were used (e.g. seasons,, as one example, as well as the precession of the planets)>