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Can someone please prove to me (so that i can prove to others as well) that the earth goes around the sun. Do not be afraid to explain using mathematics, as i see that as the only way of undeniable proof.

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Can someone please prove to me (so that i can prove to others as well) that the earth goes around the sun. Do not be afraid to explain using mathematics, as i see that as the only way of undeniable proof.

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selfAdjoint

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The first person who had experimental evidence for this was the astronomer F.W. Bessel who in 1838 was able to measure the parallax of a nearby star. This showed that the earth was at a different place, relative to the star, in June than it was in January. And geometry showed that the two places were on opposite sides of the sun. More parallax measurements since his time have confirmed that the earth follows a closed path around the sun.

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Phobos

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Welcome to Physics Forums, rattis.

It certainly looks like it, doesn't it? But looks can be deceiving.

The "aberration of starlight" was the definitive proof of the heliocentric solar system.

http://www.encyclopedia.com/html/a1/aberstrlt.asp [Broken]

And then there's all the spacecraft we send around the solar system which (1) successfully reach their destinations based on a heliocentric model of the solar system and (2) take photographs showing the sun at the center.

If you accept the values for the mass of the Earth and Sun, then the laws of gravity & planetary motion show you that the orbit around the common center of mass is near the center of the sun, not the Earth.

There are other evidences too...

It certainly looks like it, doesn't it? But looks can be deceiving.

The "aberration of starlight" was the definitive proof of the heliocentric solar system.

http://www.encyclopedia.com/html/a1/aberstrlt.asp [Broken]

And then there's all the spacecraft we send around the solar system which (1) successfully reach their destinations based on a heliocentric model of the solar system and (2) take photographs showing the sun at the center.

If you accept the values for the mass of the Earth and Sun, then the laws of gravity & planetary motion show you that the orbit around the common center of mass is near the center of the sun, not the Earth.

There are other evidences too...

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Zero

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I thought the doctrine of Galilean relativity asserted that we couldn't know which orbited which. The maths is a lot easier in a heliocentric solar system, but that doesn't in itself entail that it is one. Surely all we know is that a heliocentric solar system is a very useful assumption? Or is this nonsense?

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Zero

Just because it is a useful assumption, that does not mean it is nonsense. If both views are assumptions, but one is more useful and practical, guess which one we should go with?Originally posted by Canute

I thought the doctrine of Galilean relativity asserted that we couldn't know which orbited which. The maths is a lot easier in a heliocentric solar system, but that doesn't in itself entail that it is one. Surely all we know is that a heliocentric solar system is a very useful assumption? Or is this nonsense?

Plus, of course, I'm not sure if Galilean relativity even applies?

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well yes, but i dont know if the spacecarft have every acctually gone into space or if it is just a con by government (worse case sinario).And then there's all the spacecraft we send around the solar system which (1) successfully reach their destinations based on a heliocentric model of the solar system and (2) take photographs showing the sun at the center.

Can i see some mathematical proof that the earth does infact go around the sun?. Like i say the only proof i have at the moment is that i can see the sun move around the earth everyday, but this is not the case as everyone says.

I am not an astronomer but mathematician, so im not sure if this whould be in the maths section

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Zero

You may as well give up, if you have to try to account for people who think the entire space program is a lie...Originally posted by rattis

well yes, but i dont know if the spacecarft have every acctually gone into space or if it is just a con by government (worse case sinario).And then there's all the spacecraft we send around the solar system which (1) successfully reach their destinations based on a heliocentric model of the solar system and (2) take photographs showing the sun at the center.

Can i see some mathematical proof that the earth does infact go around the sun?. Like i say the only proof i have at the moment is that i can see the sun move around the earth everyday, but this is not the case as everyone says.

I am not an astronomer but mathematician, so im not sure if this whould be in the maths section

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I didn't suggest that the assumption was nonsense. I was wondering if what I said was nonsense.Originally posted by Zero

Just because it is a useful assumption, that does not mean it is nonsense.

No argument - but it's not really relevant.but one is more useful and practical, guess which one we should go with?

No I'm not either, that's what I'm checking. But I can't immediately see why not, it's relative motion after all.Plus, of course, I'm not sure if Galilean relativity even applies? [/B]

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Phobos

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At the time of/preceding Galileo, you could model it (the motion of the planets, etc.) very well either way. But the aberration of starlight nailed the sun down in the center with the Earth going around it. (that required very precise telescope measurements...something not available at the time of Galileo)Originally posted by Canute

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Phobos

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Diehard skeptic, eh? Check the math on parallax & aberration of starlight. (Google search or wait for some helpful PF member to present it here.)Originally posted by rattis

well yes, but i dont know if the spacecarft have every acctually gone into space or if it is just a con by government (worse case sinario).

Can i see some mathematical proof that the earth does infact go around the sun?. Like i say the only proof i have at the moment is that i can see the sun move around the earth everyday, but this is not the case as everyone says.

I am not an astronomer but mathematician, so im not sure if this whould be in the maths section

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Thanks. Can you explain that aberration a bit?Originally posted by Phobos

At the time of/preceding Galileo, you could model it (the motion of the planets, etc.) very well either way. But the aberration of starlight nailed the sun down in the center with the Earth going around it. (that required very precise telescope measurements...something not available at the time of Galileo)

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Nereid

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If you want a mathematical proof, completely disconnected from any observation or experiment, then you'll be disappointed - without any observations at all, you can't even know of the existance of the Sun, Moon, or even the Earth!

If you distrust everything that you read, and need proof of your own, you can do the stellar aberration experiment yourself. You could buy the equipment, probably for less than the cost of an average US house, or make it all yourself, from scratch. You may find an interested physics teacher at a nearby high school, who would welcome the chance to have her class take part in some real, 'hands-on' physics, so you could have the benefit of a critical audience.

Canute (and rattis) -> A one page, mathematical introduction to stellar aberration.

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selfAdjoint

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How do you feel about the earth's rotation on its axis? Skeptical there too? Look up Foucalt's pendulum and coriolis force. If you can accept the earth's rotation then it affects you candidate idea that the stars go around the earth.

The point is that it's your responsibility, denying the common wisdom, to come up with a self consistent alternative. If you can't find one, that in itself is an argument for the orbiting earth.

Incidentally, parallax shows that the stars move relative to the earth in an annual cycle, and abberation shows that light moves relative to the earth in an annual cycle (90^{o} out of phase with the first one). If you assume the earth stationary, then these are two curious unexplained facts, but if you assume it orbits, then it is explained, the earth is moving relative to the stars and as it moves its speed causes the abberation of light. Even the phases are in sync.

The point is that it's your responsibility, denying the common wisdom, to come up with a self consistent alternative. If you can't find one, that in itself is an argument for the orbiting earth.

Incidentally, parallax shows that the stars move relative to the earth in an annual cycle, and abberation shows that light moves relative to the earth in an annual cycle (90

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Not at all. Spin is a different case. (BTW I'm not skeptical aboutOriginally posted by selfAdjoint

How do you feel about the earth's rotation on its axis? Skeptical there too?

the fact the the earth goes around the sun, just wondering about whether it is the only way of interpreting the facts. I understood that with enough Ptolemaic circles you could model a stationary earth).

That's the possibility I'm exploring.The point is that it's your responsibility, denying the common wisdom, to come up with a self consistent alternative. If you can't find one, that in itself is an argument for the orbiting earth.

Surely some fancy maths could sort that out, based on a stationary earth and an orbiting universe? I agree that it would a peverse way of looking at it, but it seems possible.Incidentally, parallax shows that the stars move relative to the earth in an annual cycle, and abberation shows that light moves relative to the earth in an annual cycle (90^{o}out of phase with the first one). If you assume the earth stationary, then these are two curious unexplained facts, but if you assume it orbits, then it is explained, the earth is moving relative to the stars and as it moves its speed causes the abberation of light. Even the phases are in sync. [/B]

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I'm not going to read the whole thread, so I apologise if someone has already properly answered this.Originally posted by rattis

Can someone please prove to me (so that i can prove to others as well) that the earth goes around the sun. Do not be afraid to explain using mathematics, as i see that as the only way of undeniable proof.

Rattis, the Earth and Sun both spin around the common centre of mass, called the barycentre, or baricentre. Exactly the same as if you hold hands with someone and both spin around each other, leaning out.

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Phobos

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Oops...aberration of light was the first major evidence and then stellar parallax nailed it down.Originally posted by Phobos

At the time of/preceding Galileo, you could model it (the motion of the planets, etc.) very well either way. But the aberration of starlight nailed the sun down in the center with the Earth going around it. (that required very precise telescope measurements...something not available at the time of Galileo)

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Phobos

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No. "The Onion" (source of that quote) is a website that makes up fictional/funny news stories.Originally posted by Canute

http://www.theonion.com/index.php?i=1 [Broken]

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LURCH

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According to relativity, there is no difference between an orbitting Earth in a stationary universe and a stationary Earth with the universe rotating around it; they are the exact same situation viewed from two different frames of refference.Originally posted by Canute

Surely some fancy maths could sort that out, based on a stationary earth and an orbiting universe? I agree that it would a peverse way of looking at it, but it seems possible.

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selfAdjoint

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Um, I don't think these accelerated (rotating) frames can be equated so simply via special relativity. And if you're thinking of the equivalence principle, remember that's only true in the limit; in extended frames tidal effects will easily detect which frame is moving. Note that Mercury, for example, revolves in the Schwartzschild geometry near the Sun, not the other way around.Originally posted by LURCH

According to relativity, there is no difference between an orbitting Earth in a stationary universe and a stationary Earth with the universe rotating around it; they are the exact same situation viewed from two different frames of refference.

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Nereid

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"The dipole signal seen by an observer moving with speed [tex]v[/tex] relative to the rest frame of the CMB is [tex]T_0 v/c[/tex], where [tex]T_0[/tex] is the absolute temperature of the CMB, and [tex]c[/tex] is the speed of light. Thus, additional sources of error that could affect the absolute calibration of the WMAP data include errors in the determination of WMAP’s velocity with respect to the solar system barycenter (the point of reference for the COBE dipole) and errors in the absolute temperature of the CMB. The velocity of WMAP is routinely measured with respect to geocentric inertial coordinates (GCI) with an accuracy of < 1 cm s^{-1}. The velocity of the Earth is determined from the JPL ephemeris with similar accuracy."

http://lambda.gsfc.nasa.gov/product/map/pub_papers/firstyear/syserr/wmap_syserr.pdf

Pity rattis, (s)he will have to build and launch a space probe like WMAP to convince him/herself that the Earth moves around the barycentre (so Jupiter's, Saturn's etc motion is included), as measured against the CMB.

Canute's model of the universe will have not only horribly complex orbits of the solar system planets (and asteroids, comets etc), but a very odd semi-annual ~2.73 K blackbody that goes round the Earth is just the same plane as the Sun does, but is clearly not connected to the Sun!

In principle, you could make observations of the CMB from the surface of the Earth, but ...

So, other indicators of semi-annual motion?

- pulsars (you have to know where you are wrt the barycentre to get the timing right - in fact, rattis could build a telescope, fit a webcam and good clock, and measure the Earth's motion quite accurately, all by looking at M1, the Crab pulsar!)

- (BTW, really good, coordinated observations by LBI radio telescopes will also show the ~200 million year motion of the solar system around Sag A*)

- doppler signals etc from the Voyagers and Pioneers (I think there's only one still broadcasting)

- fast binary timing (this is a variation on pulsars, but with quite different objects, and different physics)

- interstellar meteor streams (yes, we do have samples of particles from other stellar systems, burning up in the atmosphere every few seconds)

- doppler shifts in stars all around the celestial sphere, with a 6 months' period, and a magnitude which exactly matches a model of the Earth in orbit around the barycentre, in a plane pole at coordinates ([tex]\alpha, \delta[/tex]), ellipticity e, nodes at ...

http://lambda.gsfc.nasa.gov/product/map/pub_papers/firstyear/syserr/wmap_syserr.pdf

Pity rattis, (s)he will have to build and launch a space probe like WMAP to convince him/herself that the Earth moves around the barycentre (so Jupiter's, Saturn's etc motion is included), as measured against the CMB.

Canute's model of the universe will have not only horribly complex orbits of the solar system planets (and asteroids, comets etc), but a very odd semi-annual ~2.73 K blackbody that goes round the Earth is just the same plane as the Sun does, but is clearly not connected to the Sun!

In principle, you could make observations of the CMB from the surface of the Earth, but ...

So, other indicators of semi-annual motion?

- pulsars (you have to know where you are wrt the barycentre to get the timing right - in fact, rattis could build a telescope, fit a webcam and good clock, and measure the Earth's motion quite accurately, all by looking at M1, the Crab pulsar!)

- (BTW, really good, coordinated observations by LBI radio telescopes will also show the ~200 million year motion of the solar system around Sag A*)

- doppler signals etc from the Voyagers and Pioneers (I think there's only one still broadcasting)

- fast binary timing (this is a variation on pulsars, but with quite different objects, and different physics)

- interstellar meteor streams (yes, we do have samples of particles from other stellar systems, burning up in the atmosphere every few seconds)

- doppler shifts in stars all around the celestial sphere, with a 6 months' period, and a magnitude which exactly matches a model of the Earth in orbit around the barycentre, in a plane pole at coordinates ([tex]\alpha, \delta[/tex]), ellipticity e, nodes at ...

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Does this mean that orbital motion is not relative?

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I am sorry to be a sceptic, but generally until i have proof i do not believe.

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