Is there a logical proof to the Heliocentrism?

Question

Is there a logical proof to the Heliocentrism? I don't mean to a science-proof like telescope and sateline pictures, etc...

Thank you,

Answer 1

The logical proof for the geocentric system was: "Hey. Look outside. Does it look like we're moving? If I let go this apple, does it fly off sideways or does it simply fall at my feet? Wake up! Earth is not moving!"

And as long as it could not be shown that Earth really moved, there was not other "logical" proof. It is what is known as "common sense".

The earliest known proof that Earth really moves is called "aberration of light". But before we get there, we had to find out that light does not get somehwere instantaneously. Light takes time to get somewhere (also not clear with "common sense").

It has been known since the late 16th century, that the speed of light is not infinite. Light took more time to cover longer distances than short distances.

Predictions of phenomena involving Jupiter's satellites had to be corrected for the distance from Jupiter to Earth. When Jupiter was on the other side of the sun (not exactly in conunction, when it is lost in the glare, but a month before or after), the events were always late on the calculated predictions.
When Jupiter was at its closest to Earth, the events were earlier than predicted.

This showed that Jupiter was in orbit around the Sun. It did not prove that Earth was in orbit around the Sun. Maybe Jupiter (and other planets) were going around the Sun, and the Sun was in orbit around a fixed Earth.

It was clear that the difference in distance (the diameter of the Earth's orbit around the Sun OR of the Sun's orbit around Earth) corresponded to 1000 seconds in light-distance. Because the distance itself was not known with great accuracy at the time, meant that astronomers only had a rough idea of the speed of light.

But (this is the important part): they knew that it was fixed and not infinite.

In 1725, James Bradley (Astronomer Royal in UK) noticed a yearly cycle of change in the apparent position of fixed stars. He had hoped that he had discovered parallax (giving a way to measure distances to stars) but he found that all stars were affected.

Finally, astronomers understood that it was the light "coming down" from above, that appeared to be shifted in one direction as Earth moved in that direction.

Same as rain falling when there is no wind; it falls vertically. However, if you travel through such rain in a fast car, the rain will appear to come from in front, instead of appearing vertical. Stop the car, the rain is vertical again. Drive off in another direction and the rain appears slanted from that new direction.

So, as Earth moves around the Sun, the light appears to "fall" from a slight angle. You have to tilt the telescope (really!) by a little more than 20" -- that is, 1/180 of a degree -- in the direction that the Earth moves. For a small amateur telescope, you can't tell. But for the major telescopes (like at Greenwich in England), one could tell the difference. Even back in the mid 1700s.

In fact, it had been reported earlier (Flamsteed 1689) but no one wanted to believe the explanation at the time.

The angle is small because (as we now know), Earth speed of 29.8 km/s is very small compared to the speed of light 300,000 km/s.

Of course, before accepting this explanation, astronomers checked everything else (including the accuracy of all the telescopes involved in the tests).

So, aberration of light shows that the Earth is moving through space and that its direction changes constantly, so that it follows a circle (almost) that is repeated every year.

The speed is known (roughly) from the amount of tilt and the direction is known by the direction of the tilt. Astronomers could tell that the circle (actually, they already knew it was an ellipse, not a circle) was centred on the Sun.

Conclusion, the Earth is in orbit around the Sun.

We already knew that Jupiter was in orbit around the Sun (from the correction that had to be made to its satellite events) and Kepler's calculations showed that planetary positions were much easier to predict if they were considered in orbit around the Sun.

Newton had already given us his theory of gravity (1687). Knowing our speed around the Sun and the (approximate) size of our orbit, astronomers were able to calculate the mass of the Sun. It was... ahem... astronomical.

It then became clear that a "puny" planet like Earth could not hold, in its gravitational grasp, a Sun that was more than 330,000 times more massive.

The Sun was far more massive than anything else in the solar system. Logically (based on the theory of gravitation), the largest mass of a system must be closer to the barycentre of the system.

(We now know that the Sun contains over 90% of the entire mass of the whole solar system).

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PS: At the time of Galileo's trial (well before Newton's theory), the Church's position, that the Earth, not the Sun, was at the centre, was based on the logical fact that the Sun, being made of fire, had to be very light while Earth was known to be very heavy. It was logical that the heavier of the two body be the centre.

That is why one had to wait for the determination of the Sun's mass (using Newton's theory) for the shift in logical conclusion.

Answer 2

I guess the closest thing to a "logical proof" would be Occam's Razor, which says you ought not to arbitrarily add unnecessary details to an explanation, when a simpler explanation will suffice.

Ptolemy came up with a geocentric system that included lots of complex, seemingly arbitrary details that were necessary in order to explain the observed weirdly looping motions of Mars and other planets.

Copernicus showed that, if you imagine the sun at the center instead of the earth, all the complexity disappears. Suddenly the looping orbit of Mars becomes a natural consequence of both Earth and Mars orbiting the sun. None of Ptolemy's "epicycles" and other weird details were necessary any longer.

This simplification was a powerful logical argument in favor of heliocentrism. It did not PROVE that heliocentrism was true--after all, Ptolemy's complex theory still "worked"--but simpler is generally viewed as better.

Since the time of Copernicus, there have been additional observations that support heliocentrism--such as the aberration of starlight--and additional supporting theories, such as Newton's theory of gravity. These make it increasingly difficult to devise a logical system in which the earth is the center of the solar system.

Answer 3

The direct observational proof is indisputable, but the logical proof is that everything in the universe is gravitationally affected by everything else.

This means that objects in fairly close proximity will orbit their center of gravity.

Since the sun is 333,000 times the mass of the Earth, and 1000 times the mass of all the planets together, it is totally illogical that any of the planets could be the center of the system, with the gigantic sun making an orbit around it.

In fact, the whole system inlcuding the sun orbits the point of center of gravity of the system. However, the sun is so large that that point is inside the sun, causing the sun to execute a tiny orbital circle.

So effectively the sun has to be at the center of the system, simply because of its sheer size. Anything else would make gravitational nonsense.

Answer 4

No, there is no "logic-only" proof. There is not even a science proof.

The equations of motion for the solar system bodies are well understood. Modern ephemeris use general relativity as well as Newtonian physics. The positions, masses and velocities of the major planets are known with high accuracy. For the asteroids, the masses are less accurate, but still good enough.

But my main point is, the equations work for any "center". You could arrange the equations to use Pluto as the center, if you want. They will be a bit complex, but you could do it. The simplest (shortest) form of the equations is when you use the solar system barycenter as the center. That's the center of gravity of the solar system, adjusted for relativistic effects. The barycenter is close to the center of the Sun, but is often a bit outside it. The Sun orbits the barycenter, just like the planets.

Answer 5

Since will get lot of answers and this will go on and on, the lets see what we got?, dozens of footage from space station show us; none of them have continuity, looks like 20 or more min footage is 6 or more 3min footage they put all together in a 20 to 25 min footage. Why? they do not complete the orbit, they cut when sun's comming up, they don't let camera's lens open for 24h just for watching Earth spinning. Then we'll get the answer at once.

Answer 6

How is it illogical to incorporate the findings of science? The sizes of the sun and planets have been calculated fairly exactly. Keplers laws and Newton's theory of gravitation works for the sun at the center. They would not work for the earth at the center. This should mean something to even the most average student.

Answer 7

The question of Heliocentrism is a question of nature. As such it cannot be addressed without empiricism, i.e. actually looking at nature.

Perhaps you should sit down and have a nice chat with Aristotle, who, as brilliant as he might have been, decided that it was not necessary to observe nature in order to discuss it, and as a result turned out to be wrong about absolutely everything.

Answer 8

As it is already known as fact, heliocentrism doesn't need proof.
We (and 7 other major planets) orbit the Sun...along with countless millions of other obects.

End of story.

Answer 9

The path Mars follows in the night sky. Its "sometimes retrograde" motion is best explained by having both Earth and Mars moving around the sun, with Earth moving faster than Mars.

Answer 10

there is no such thing as a purely logical proof of a fact of nature. perhaps though, you might be interested in the arguments of copernicus, kepler or galileo, which were made when physical evidence was still rather scarce.

vv raymond's answer is awesome :)