1
$\begingroup$

I am learning Astronomy. I videos or lessons I look at are already biased over heliocentric math to explain the parallax concept. I am looking for an intuition to get myself a deeper understanding of what we are part of the universe. I am not looking for math but if there is anyway I can understand that we revolve around the Sun without understanding the complex math behind it? I was told that unless I account for math & parallax, it was impossible to prove that we are revolving around the Sun. Is that true? What if our parallax calculations & newton laws related to our solar system are wrong?

$\endgroup$
3
  • $\begingroup$ The proof is not in the math, the proof is in all experimental evidence confirming the mathematical calculations based on the physical theory. So there is no bias towards the heliocentric model. Every experiment and measurement is confirming the theory and there are none that indicate something else. $\endgroup$
    – Javatasse
    Aug 30 '18 at 15:14
  • $\begingroup$ We use extremely distant stars as a reference, what we consider as "stationary". Then we can determine how the Earth moves with respect to the Sun. $\endgroup$ Aug 30 '18 at 15:17
  • $\begingroup$ i.chzbgr.com/full/3121925/hB5B398F7 ;) $\endgroup$
    – safesphere
    Aug 30 '18 at 16:00
1
$\begingroup$

Here are three things to consider:

(1) Telescopic observations of Venus show that it exhibits phases just like the Moon-- first seen by Galileo in 1610.

(2) Careful observations of starlight show the light is 'shifted' in the same way as raindrops that fall straight down when you stand still but appear to fall toward you at an angle when you walk through the rain. This is called stellar aberration-- first seen in 1725.

(3) Finally, there is stellar parallax, with the first observations in the 1830s.

All of these are straight-forward predictions of the heliocentric model, and all of them are observationally confirmed. A geocentric model could possibly account for #2 (am I correct here? maybe not), but not #1 and #3.

$\endgroup$
2
  • $\begingroup$ Can you explain how the geocentric theory contradicts above statements too. Thanks $\endgroup$
    – plotop
    Aug 31 '18 at 8:16
  • 1
    $\begingroup$ In the geocentric model, Venus is always positioned between the Earth and Sun and is constrained to never be far from the Sun. Therefore, the model predicts it will exhibit only crescent and new phases, and will never exhibit gibbous, quarter, or full phases. (And yet it does.) Because the Earth is immobile in the geocentric model, we observe the stars always from the same vantage point. Thus, the model predicts we will never see stellar parallax. (And yet we do.) $\endgroup$ Aug 31 '18 at 20:51
1
$\begingroup$

First, suppose that the earth is spherical but not rotating on its axis once per day or orbiting around the sun once per year.

That is the view held by the ancient Greeks for several hundred years BCE forward. It was codified by Ptolemy in his Almagest. It was a complex clockwork where the domes carrying the sun and stars rotated around the world in amazingly precise ways. You don't want to think about planets, but they followed a system of cycles within cycles.

It wasn't until Copernicus a few hundred years ago basically said "Wouldn't it really simplify things a lot if the sun stood still, and the earth both rotated and orbited?" Things would look the same, but see how much simpler the explanation is?

Then of course Galileo said "I like that" and Newton proved how it all made sense with the simple fact that things fall on earth.

Of course, these guys ran up against the people in funny hats, but that's how it goes...

$\endgroup$
0
$\begingroup$

The fact that we see parallax in the distant stars (i.e. that the stars appear to shift by tiny amounts as the Earth moves) is just one of many pieces of experimental evidence that point to the Earth revolving around the Sun. There are many others, like:

  • the existence of phases of Venus besides "crescent"
  • the fact that we have put vehicles on other planets like the Mars rovers using the heliocentric model
  • distance and velocity measurements made by bouncing radar pulses off of planets
  • Newtonian gravity being tested in the laboratory and correctly explaining behaviors in other star systems

and the fact that they all agree that the Earth revolves around the Sun is why it's a widely-accepted fact. In science, we arrive at the truth by seeing if our explanations for the natural world are consistent with the experiments we do to test them, and if the predictions they make turn out to be accurate. In the case of the heliocentric model, it has satisfied every rigorous test that we put it through* and has predicted the behavior of objects in the Solar System well enough for us to conduct numerous planetary missions, sending scores of probes to orbit or land on the surface of most of the larger astronomical bodies in the Solar System.

*There are numerous YouTube videos out there that claim to debunk the heliocentric model. However, invariably they run into one or more of the following problems: their methodology is not rigorous (i.e. they don't account for sources of uncertainty or bias in their experimental setup), their conclusions aren't supported by the data they take, or they aren't clear enough about their methods for others to repeat and verify their experiment. These problems are why you won't see experiments like this published in peer-reviewed scientific journals (who take the methodology of collecting data and the interpretation of that data very seriously, and tend to reject papers that are not sufficiently rigorous, well-reasoned, and transparent, regardless of the pedigree of their authorship), and they are also often highlighted in the numerous other YouTube channels that have arisen to debunk such claims.

$\endgroup$
1
  • $\begingroup$ Lets not get into FE vs GE discussion. I am not interested with that. I want to know more about understanding heliocentric conclusions. Can you elaborate on Venus besides crescent. What experiments did prove Newtonian gravity? Thanks $\endgroup$
    – plotop
    Aug 31 '18 at 8:33
0
$\begingroup$

Here is the simplest I can think of as an answer. as the earth orbits the sun, there is a spot on the earth each night that, at midnight, is pointing directly away from the sun.

Now imagine that an observer at that spot notes the positions of the stars in the midnight sky, every night for a year. S/he then compares those observations and discovers that different constellations are visible at different times of the year, and that this pattern repeats itself year after year.

This would not happen if the sun were orbiting the earth. in that case, the constellations would not shift around in the sky with the passing of the seasons.

$\endgroup$
4
  • 1
    $\begingroup$ It would happen if the constellations were orbiting the earth, though, and if one assumes that the sun orbits the earth, there doesn't seem to be any reason why that wouldn't also be possible (indeed, this is what most early geocentric models did: the stars were points of light affixed on a rotating "celestial sphere"). $\endgroup$ Aug 30 '18 at 18:54
  • $\begingroup$ in that case there would be no parallax shift in their positions. so if you "really" want an airtight case you'd have to measure that as well. However, OP's question (as I interpreted it) deals just with sun vs. earth orbit. $\endgroup$ Aug 30 '18 at 21:12
  • $\begingroup$ Indeed, stellar parallax is the ultimate downfall of the celestial sphere, but that's very different (and much more difficult to measure) than your original evidence. And even then, a sufficiently complex geocentric theory could include stellar parallax (i.e. the stars all rotate around the Earth, not quite fixed in a celestial sphere; the stars are allowed to shift very slightly in their moorings, like docked ships, and due to some celestial force, they move back and forth with a period of a year, where the amplitude varies from star to star, just like the amplitude of waves in a harbor). $\endgroup$ Aug 30 '18 at 21:19
  • $\begingroup$ this is why all the data must be brought to bear during a discussion of geocentrism with an ardent supporter of same: parallax, procession of the constellations, and the slant-line adjustment of stellar light (stellar aberrations). Then you artfully slit their throat with Occam's razor and hope for the best... $\endgroup$ Aug 30 '18 at 21:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.