Ask a physicist anything. (4)

[Wiccan_Child]

But this is surely circular reasoning.

Heres a schematic of trigonometric star parallax:



At the bottom we see that the measurements assume that the Earth is orbiting the sun.

So they take a measurement to the target, and then six months later take another measurement ASSUMING the Earth is 186 million miles away on the other side of the sun.

So you're saying because we can measure the stars using a system that assumes the Earth orbits the sun, we can prove the Earth orbits the sun.

It's circular.

It's theoretical trig because one of the points is completely made up.


Doc.

I disagree.

First, it's not assumed, and it's certainly not 'made up': it's a known fact that's being exploited to calculate the distance to the stars. We can discuss other methods of demonstrating the heliocentric model, establish that the Earth is, in fact, orbiting the Sun, and thus come back to parallax.

Second, it's not circular: the sheer fact that the stars change relative position every six months in perfect accordance with a heliocentric model in a relativistic universe, demonstrates that the Earth is, in fact, moving round the Sun.

Think of it as a scientific experiment. If the Earth is going round the Sun, then parallax works. Parallax works. Thus, parallax constitutes evidence that the Earth is going round the sun.

What, in your opinion, is the alternative?
Do you at least agree that, if the Earth is going round the Sun, then would parallax work?

 

[Dr.Strangelove]

I disagree.

First, it's not assumed, and it's certainly not 'made up': it's a known fact that's being exploited to calculate the distance to the stars. We can discuss other methods of demonstrating the heliocentric model, establish that the Earth is, in fact, orbiting the Sun, and thus come back to parallax.

Well.....if we could have some non-theoretical methods that would be great.

Second, it's not circular: the sheer fact that the stars change relative position every six months in perfect accordance with a heliocentric model in a relativistic universe, demonstrates that the Earth is, in fact, moving round the Sun.

Think of it as a scientific experiment. If the Earth is going round the Sun, then parallax works. Parallax works. Thus, parallax constitutes evidence that the Earth is going round the sun.

What, in your opinion, is the alternative?
Do you at least agree that, if the Earth is going round the Sun, then would parallax work?

Sure it would work. But you can make up any theoretical point in a calculation and make it work. It doesnt prove the premise. The green section doesn't make sense.

Your premise is that the Earth orbits the sun. The calculations which show the Earth orbits the sun make the primary assumption that the Earth orbits the sun. You cant use an assumption to prove a premise. If you do......its circular.

Whats the alternative?

Uhm......you can only measure shorter distances, that can utilize the true baseline of the trigonometric calculation which is 8,000 miles, the distance from one side of the Earth to the other.

 

[Wiccan_Child]

Well.....if we could have some non-theoretical methods that would be great.

It should do, it's the foundation of all science. "Think up idea. Make prediction. Test prediction. Success = supporting evidence for idea. Failure = categoric disproof of idea".

Sure it would work. But you can make up any theoretical point in a calculation and make it work. It doesnt prove the premise. The green section doesn't make sense.

See above. We can postulate anything we wish.

Your premise is that the Earth orbits the sun. The calculations which show the Earth orbits the sun make the primary assumption that the Earth orbits the sun. You cant use an assumption to prove a premise. If you do......its circular.

Since we don't, it's not.

We start with a premise we want to test ("The Earth orbits the Sun").

We assume it's true, then make predictions ("If the premise is true, then we shold observe stellar parallax").

We go out and test that prediction ("Do the stars actually exhibit parallax over a 6-month period?").

Lo and behold, all the stars behave exactly as the heliocentric model predicts. Thus, the fact that stellar parallax is indeed observed constitutes evidence that the Earth is orbiting the Sun (after all, if it weren't, we wouldn't observe a 6-month relative shift in every single star's position).

Whats the alternative?

Uhm......you can only measure shorter distances, that can utilize the true baseline of the trigonometric calculation which is 8,000 miles, the distance from one side of the Earth to the other.

Sadly not. If the Earth is not orbiting the Sun, then stellar parallax must be caused by something else - that is, if it's not just an optical phenomenon, the stars must actually be moving about in just the right way (it's a pretty big coincidence that every star is moving in just the right way, but nevermind).

So, the stars are moving far more rapidly than we anticipated. If the stars are moving about like fat people on ice, then using the Earth's diameter as a baseline for parallax is utterly useless - we won't know if the relative change in position is due to their actual movement, or due to parallax.

 

[shernren]

So you're saying because we can measure the stars using a system that assumes the Earth orbits the sun, we can prove the Earth orbits the sun.

It's circular.

No, sir, the orbit of the Earth is actually elliptical. *heh*

All one has to do is to look up into the night sky (with a sufficiently advanced telescope, mind you - that's why this piece of evidence was not available to Galileo) and determine which of the following is more accurate:

If the distant stars do not move relative to the Earth (right side), then there should be no parallax. But in fact, not only is there parallax, but this parallax is in sync with the yearly cycle of the seasons, which suggests (by Occam's Razor) that both parallax and yearly seasons are caused by the same phenomenon, this phenomenon being the fact that (relative to the fixed stars) the Earth orbits the Sun rather than vice versa.

 

[Dr.Strangelove]

It should do, it's the foundation of all science. "Think up idea. Make prediction. Test prediction. Success = supporting evidence for idea. Failure = categoric disproof of idea".


See above. We can postulate anything we wish.


Since we don't, it's not.

We start with a premise we want to test ("The Earth orbits the Sun").

We assume it's true, then make predictions ("If the premise is true, then we shold observe stellar parallax").

We go out and test that prediction ("Do the stars actually exhibit parallax over a 6-month period?").

Lo and behold, all the stars behave exactly as the heliocentric model predicts. Thus, the fact that stellar parallax is indeed observed constitutes evidence that the Earth is orbiting the Sun (after all, if it weren't, we wouldn't observe a 6-month relative shift in every single star's position).

The stars also behave exactly as you would expect in a geocentric system. Without any assumptions having to be made. So that is evidence that the Earth doesnt move.

Sadly not. If the Earth is not orbiting the Sun, then stellar parallax must be caused by something else - that is, if it's not just an optical phenomenon, the stars must actually be moving about in just the right way (it's a pretty big coincidence that every star is moving in just the right way, but nevermind).

Stellar parallax is simply a phenomenon involving lights in the sky. It could be caused for any number of reasons including reflections off water crystals beyond the stars. Can you actually show me a real stellar parallax? Do you have a telescope photo or something?

So, the stars are moving far more rapidly than we anticipated. If the stars are moving about like fat people on ice, then using the Earth's diameter as a baseline for parallax is utterly useless - we won't know if the relative change in position is due to their actual movement, or due to parallax.

Again, we dont know how fast the stars are moving coz the method to measure their distances is faulty. it assumes a 186 million mile trigonometric baseline which is totally theoretical.

 

[Dr.Strangelove]

No, sir, the orbit of the Earth is actually elliptical. *heh*

All one has to do is to look up into the night sky (with a sufficiently advanced telescope, mind you - that's why this piece of evidence was not available to Galileo) and determine which of the following is more accurate:

If the distant stars do not move relative to the Earth (right side), then there should be no parallax. But in fact, not only is there parallax, but this parallax is in sync with the yearly cycle of the seasons, which suggests (by Occam's Razor) that both parallax and yearly seasons are caused by the same phenomenon, this phenomenon being the fact that (relative to the fixed stars) the Earth orbits the Sun rather than vice versa.

Who said that the stars dont move telative to the Earth in the geocentric system? Of course the entire universe revolves around the Earth every 24 hours just like we observe. And the North Star (Polaris) is the celestial North pole. Thats why it never moves.

 

[Wiccan_Child]

The stars also behave exactly as you would expect in a geocentric system. Without any assumptions having to be made. So that is evidence that the Earth doesnt move.

I disagree: in the geocentric model, we should not observe stellar parallax, since it is the periodic change in the stars relative position in a regular motion - not random flickering or atmospheric distortion.

But by all means, explain how a geocentric model can explain stellar parallax.

Stellar parallax is simply a phenomenon involving lights in the sky. It could be caused for any number of reasons including reflections off water crystals beyond the stars. Can you actually show me a real stellar parallax? Do you have a telescope photo or something?

There are a number of papers on the subject. To attribute something so mechanical and regular to "reflection off water crystals beyond the stars" - how would that even work?

Again, we dont know how fast the stars are moving coz the method to measure their distances is faulty. it assumes a 186 million mile trigonometric baseline which is totally theoretical.

On the contrary, the distance to the stars can be deduced by a variety of techniques. Stellar parallax is the most intuitively obvious, but it is not the only one: objects of known brightness, the various cephid variables, novae and supernovae, x-ray and gamma ray bursts, etc.

Further, if the Earth is not only not orbiting the Sun, but not rotating, then General Relativity gives us a minimum distance the stars can be: 0.00045 light years, or about 4 light hours away, and that's the maximum distance they can be when they're travelling at lightspeed.

Now I don't know about you, but something tells me the stars are a wee bit further away than that. If nothing else, all the stars would have to be on a shell that's closer than pluto.

 

[Dr.Strangelove]

I disagree: in the geocentric model, we should not observe stellar parallax, since it is the periodic change in the stars relative position in a regular motion - not random flickering or atmospheric distortion.

But by all means, explain how a geocentric model can explain stellar parallax.

We CANT measure stellar parallax because the stars are too far away to triangulate with the true baseline of 8,000 miles. What you're talking about is theoretical trigonometry. So stellar parallax is not evidence of anything. At best we can measure the distance of the moon and a few of the very close planets.

On the contrary, the distance to the stars can be deduced by a variety of techniques. Stellar parallax is the most intuitively obvious, but it is not the only one: objects of known brightness, the various cephid variables, novae and supernovae, x-ray and gamma ray bursts, etc.

Can you show how these techniques are evidential of Earth movement?

Do any of these techniques not assume that the Earth is orbiting the sun?

Further, if the Earth is not only not orbiting the Sun, but not rotating, then General Relativity gives us a minimum distance the stars can be: 0.00045 light years, or about 4 light hours away, and that's the maximum distance they can be when they're travelling at lightspeed.

Now I don't know about you, but something tells me the stars are a wee bit further away than that. If nothing else, all the stars would have to be on a shell that's closer than pluto.

The only way we know how far pluto is away from the Earth is by using the same faulty parallax measurements.

Moving on. Is there any non-theoretical evidence that the Earth is spinning on it's axis or orbiting the sun?

Doc.

 

[Wiccan_Child]

We CANT measure stellar parallax because the stars are too far away to triangulate with the true baseline of 8,000 miles. What you're talking about is theoretical trigonometry. So stellar parallax is not evidence of anything. At best we can measure the distance of the moon and a few of the very close planets.

Nonsense. If the Earth goes round the Sun, the baseline is sufficient to measure parallax. Thus, we can assume heliocentricity and see if parallax really does show itself: it does.

My question to you was, how does the geocentric model account for the observations attributed to parallax? We really do see the stars shift relative to each other in a 6-month cycle, exactly as predicted by heliocentrism.
Heliocentrism attributes this phenomenon to parallax.
How does geocentrism account for this phenomenon?

If the universe is geocentric, why do stars shift their relative position in a way that is exactly in accordance with parallax in heliocentrism? It's not just that the stars move, but that they move in precisely the right way.

Can you show how these techniques are evidential of Earth movement?

Do any of these techniques not assume that the Earth is orbiting the sun?

Yes: only parallax uses the Earth's orbit. The rest use stellar phenomena to calculate distance.

So, we can reliably know the distance to the stars.
So, we can compare the results yielded from testing parallax with the results yielded from every other method.
And they're in perfect match.

Thus, because stellar parallax yields results that are in accordance to all the other techniques used to measure distance, we have very strong evidence that the foundational premises of parallax are indeed true - this is the core of the scientific method, after all.

In other words, the results from using parallax fit what we know, greatly supporting the claim that parallax (and its foundational assumptions, including heliocentricity) are indeed correct.

The only way we know how far pluto is away from the Earth is by using the same faulty parallax measurements.

We know how far away Pluto is because we've sent probes up there to take a look. Moreover, even a geocentric parallax can verify the distance to Pluto - which is indeed what they do.

Moving on.

No no, let's stay.
Are you really saying that we don't know how far away Pluto is? Are you not denying that, in geocentrism, the stars must be at most 4 lighthours away, if not closer?

Is there any non-theoretical evidence that the Earth is spinning on it's axis or orbiting the sun?

Yes.

First, Foucault's Pendulum.

Second, the notion of a non-spinning Earth is nonsensicle. What, exactly, is fixed? If I pick up a hunk of earth and throw it, I thus apply a torque to the Earth and cause it to rotate.

Third, the stars would have to travel at superluminal speeds to orbit a non-rotating Earth once per day.

Fourth, Venus exhibits phases - it orbits the Sun, not the Earth. It follows that all the planets orbit the Sun, not epicycles among epicycles among epicycles of geocentric orbits. Thus, at best, you can subscribe to a Tychonic system, but see the seventh point for more on that.

Fifth, mechanics requires that two objects will orbit their barycentre - in the case of the Earth-Sun system, this barycentre is deep in the Sun. So the Sun moves very little, while the Earth spins around it like a ballerina. We can model these objects using iterative software - and orbits are decidedly heliocentric.

Sixth, a rotating Earth would cause a minute deviation of a free-falling object's path from the associated plumb line. That is, an object in free fall will appear to drift slightly Eastward as the Earth rotates beneath it.

Seventh, stellar aberration is the very real phenomenon whereby the moving Earth means telescopes have to be calibrated accordingly. It was the final proof the scientific community needed to discard the Tychonic model and fully adopt the heliocentric one.

Eighth, Foucault's Pendulum. I know I said it before, but it's kinda the definitive proof here:

YouTube - Foucault Pendulum Timelapse

 

[Nabobalis]

What about retrograde motion of planets seen from the earth?

Plus we have a Foucault's Pendulum in our building! I love it.

 

[Wiccan_Child]

What about retrograde motion of planets seen from the earth?

Epicycles! Epicycles upon epicycles!

Plus we have a Foucault's Pendulum in our building! I love it.

Lucky! We used to have one at the nanotech building on my old campus. I spent so long there I could tell the time by the pendulum

 

[Nabobalis]

Epicycles! Epicycles upon epicycles!


Lucky! We used to have one at the nanotech building on my old campus. I spent so long there I could tell the time by the pendulum

Well come here and you can stare at it all day long

 

[Wiccan_Child]

Well come here and you can stare at it all day long

Northampton is too far North to have anything of value, I'm sure

I went to Durham once, that was just frightening!

 

[Dr.Strangelove]

Nonsense. If the Earth goes round the Sun, the baseline is sufficient to measure parallax. Thus, we can assume heliocentricity and see if parallax really does show itself: it does.

Yeah IF the Earth goes round the sun then the baseline is sufficient. BUT that IF is an assumption. Therefore stellar parallax is theoretical.

My question to you was, how does the geocentric model account for the observations attributed to parallax? We really do see the stars shift relative to each other in a 6-month cycle, exactly as predicted by heliocentrism.
Heliocentrism attributes this phenomenon to parallax.
How does geocentrism account for this phenomenon?

Where is this phenomenon? Show me it please. Is there a photo or a printout of the actual observation?

If the universe is geocentric, why do stars shift their relative position in a way that is exactly in accordance with parallax in heliocentrism? It's not just that the stars move, but that they move in precisely the right way.

The stars move in precisely the right way as if we were living in a geocentric universe.

Yes: only parallax uses the Earth's orbit. The rest use stellar phenomena to calculate distance.

Can you show me though?

So, we can reliably know the distance to the stars.
So, we can compare the results yielded from testing parallax with the results yielded from every other method.
And they're in perfect match.

Thus, because stellar parallax yields results that are in accordance to all the other techniques used to measure distance, we have very strong evidence that the foundational premises of parallax are indeed true - this is the core of the scientific method, after all.

In other words, the results from using parallax fit what we know, greatly supporting the claim that parallax (and its foundational assumptions, including heliocentricity) are indeed correct.

But parallax is theoretical so it's not reliable. Is musings.

We know how far away Pluto is because we've sent probes up there to take a look. Moreover, even a geocentric parallax can verify the distance to Pluto - which is indeed what they do.

So how far is pluto away using geocentric parallax? Can you show me the calculations please?

No no, let's stay.
Are you really saying that we don't know how far away Pluto is? Are you not denying that, in geocentrism, the stars must be at most 4 lighthours away, if not closer?

If you say geocentric parallax can show us the distance to pluto then maybe we do know it's distance.

Yes.

First, Foucault's Pendulum.

The pendulum changing it's course is due to coreolis force correct?

Second, the notion of a non-spinning Earth is nonsensicle. What, exactly, is fixed? If I pick up a hunk of earth and throw it, I thus apply a torque to the Earth and cause it to rotate.

Huh?

Third, the stars would have to travel at superluminal speeds to orbit a non-rotating Earth once per day.

Assuming they are the distance that stellar parallax says they are. A parallax that relies on the assumption that the Earth orbits the sun. Not admissable in court I'm afraid.

Fourth, Venus exhibits phases - it orbits the Sun, not the Earth. It follows that all the planets orbit the Sun, not epicycles among epicycles among epicycles of geocentric orbits. Thus, at best, you can subscribe to a Tychonic system, but see the seventh point for more on that.

The Modified Tychonic model will do just fine yes.

Fifth, mechanics requires that two objects will orbit their barycentre - in the case of the Earth-Sun system, this barycentre is deep in the Sun. So the Sun moves very little, while the Earth spins around it like a ballerina. We can model these objects using iterative software - and orbits are decidedly heliocentric.

Do these 'mechanics' involve gravitational forces? Coz last I checked gravity doesn't describe how one mass orbits another mass. It's just a word that describes heavyness. Are you sure theres no theoretical science here?

Sixth, a rotating Earth would cause a minute deviation of a free-falling object's path from the associated plumb line. That is, an object in free fall will appear to drift slightly Eastward as the Earth rotates beneath it.

Are you talking about coreolis force?

Seventh, stellar aberration is the very real phenomenon whereby the moving Earth means telescopes have to be calibrated accordingly. It was the final proof the scientific community needed to discard the Tychonic model and fully adopt the heliocentric one.

Is it possible that parallax and aberration are not separate but a single phenomenon that is not due to the earth’s motion, but due to properties of space between a geocentric earth and distant stars?

Eighth, Foucault's Pendulum. I know I said it before, but it's kinda the definitive proof here:

So theres no way a pendulum can display that phenomenon in a geocentric universe?

 

[SithDoughnut]

The stars move in precisely the right way as if we were living in a geocentric universe.

The stars are moving at several times the speed of light?

 

[Dr.Strangelove]

The stars are moving at several times the speed of light?

Either that OR the stars are much closer to Earth than theoretical science says they are.

 

[mzungu]

Moving on. Is there any non-theoretical evidence that the Earth is spinning on it's axis or orbiting the sun?

Doc.

The Coriolis effect is proof that the Earth is spinning. These effects are easily observed both in meteorology, hydrodynamics, projectiles, etc.

As for the earth orbiting the sun? That is an easy one: If it was not so then the observed orbit of Mars would not be observed as retrograding at certain times of the year

 

[Tinker Grey]

Here's a question:

Moon's orbit planets. Asteroids, comets, and planets orbit stars. Stars orbit the black holes at the center of the galaxy. So, do galaxies orbit anything? Bigger galaxies? Super-massive black holes (though I imagine the necessary size for a black hole such that galaxies would orbit it would be beyond the theoretical limit)?

Second question: Do we know of celestial objects that are orphaned? By that I mean, do we know of, say, stars that are not part of a galaxy?

 

[mzungu]

Here's a question:

Moon's orbit planets. Asteroids, comets, and planets orbit stars. Stars orbit the black holes at the center of the galaxy. So, do galaxies orbit anything? Bigger galaxies? Super-massive black holes (though I imagine the necessary size for a black hole such that galaxies would orbit it would be beyond the theoretical limit)?

Second question: Do we know of celestial objects that are orphaned? By that I mean, do we know of, say, stars that are not part of a galaxy?

There are runaway stars that were flung from their orbit! Eventually they will be captured into new orbits, perhaps in another galaxy.

Hubble catches heavyweight runaway star speeding from 30 Doradus

11 May 2010

A heavy runaway star rushing away from a nearby stellar nursery at more than 400 000 kilometres per hour, a speed that would get you to the Moon and back in two hours. The runaway is the most extreme case of a very massive star that has been kicked out of its home by a group of even heftier siblings. Tantalising clues from three observatories, including the NASA/ESA Hubble Space Telescope’s newly installed Cosmic Origins Spectrograph (COS), and some old-fashioned detective work, suggest that the star may have travelled about 375 light-years from its suspected home, a giant star cluster called R136.

 

[pgp_protector]

Who said that the stars dont move telative to the Earth in the geocentric system? Of course the entire universe revolves around the Earth every 24 hours just like we observe. And the North Star (Polaris) is the celestial North pole. Thats why it never moves.

For the Love of God tell me this is a joke or poe.