reason for proving the galaxy is heliocentric

[blackhole123]

Today in Earth Science me leaned about how our universe is heliocentric (duh) but still he had to teach it. He gave us a list of reasons why we know that the galaxy is not geocentric. One of the reasons he gave us was that the heliocentric model was a lot simpler than the geocentric model and simpler is usually right. Why? just because something is simple doesnt make it correct. I just thought that this was really dumb reasoning. Can anyone explain why if something is simpler it is more likely to be right?

[Sisyphus]

The galaxy is not heliocentric. You mean the solar system, consisting of Earth, the Sun, the Moon, the other planets, etc.

 

The heliocentric model is, in fact, much simpler, but that's not the reason we know it's right. More careful observations of celestial bodies confirmed this, but the way in which that was done is not really the point of your question, I think.

 

Even if we didn't know that one was right (which we do), we would still favor the more simple one as more probable. For example, all of our measurements, all space probes, all the data we have ever gathered indicates the solar system is arranged in a certain way. However, such results could also be the result of an extremely sophisticated alien race, which has surrounded our planet in a vast holographic projection in order to make us believe these things. They could have intercepted our probes, hacked into their computers, and transmitted back false data to support their illusion. They could even take astronauts into their own separate virtual realities, so they would think they were travelling in space when they were really in some alien laboratory. We can't say for sure either way, and so we assume the simpler explanation is correct until we find something which contradicts it, because it's usually been our experience that it is.

[blackhole123]

Thanks, yeah sorry about putting galaxy. Guess i should pay more attention

[s pepperchin]

I could define all the math involved in the motion of planets with any point as the center. but the heliocentric math is easier than the rest.

[aguy2]

The heliocentric model is' date=' in fact, much simpler, but that's not the reason we know it's right. More careful observations of celestial bodies confirmed this, but the way in which that was done is not really the point of your question, I think.

 

Even if we didn't know that one was right (which we do), we would still favor the more simple one as more probable. For example, all of our measurements, all space probes, all the data we have ever gathered indicates the solar system is arranged in a certain way.

[/quote']

All of the visual representations I have seen of the structure of the solar system represents Sol as being stationary, with the orbits of the planets, et al depicted as ellipses. What I have been looking for, without success, is a visual depiction of the planetary orbits in relation to Sol's galactic orbital motion. Am I right in assuming that the planetary orbital paths will take the form of waves? Could anyone help me out?

aguy2

[Prime-Evil]

The center of our solar system is somewhat arbitrary. Is it the center of mass of the sun or the center of mass of the solar system? What matter is included in the solar system, and what matter is part of our galaxy but not part of our solar system? What about energy? What energy is considered part of our solar system and what energy is not?

 

Sometimes simpler is more likely to be correct.

Sometimed simpler is just simpler.

 

In this case I think simpler is just simpler.

[Prime-Evil]

Regarding the more general question of why simpler is more likely to be correct in matters which are not arbitrary, like boundaries of systems.

 

In a situation where it is known that there is one solution but it has not been determined what the solution is because there are some unknowns, it can be stated that the simplest individual solution is more likely to be correct than any other individual solution, though perhaps not more likely than the combined probability of the other possible solutions combined. To prove this it is sufficient to prove that a simpler solution is usually more likely than a more complex one. I do not have a proof for this, but it is a good theorem. I believe it has to do with the fact that something is more likely to fail if it is more complex. That is, the probablity of something not being true is more likely because in a more complex system has more things that might not be true, and so the product of all of these things being true is more likely to be a smaller number. Of course this theorem also depends on the definition of simpler. This is an interesting concept for anyone involved with specialized disciplines such as Systems Analysis or Probability, but eventually bumps into Logic, or even more generally Philosophy. Very good question.

 

All generalizations fail, but are still useful.

[deltanova]

its called ockham's razor,

 

http://en.wikipedia.org/wiki/Occam's_Razor :

"Occam's razor states that the explanation of any phenomenon should make as few assumptions as possible, eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory."

 

"entities should not be multiplied beyond necessity."

 

i guess entites when the heliocentric vs geocentric models are compared they include calculations, poltemy's model had far more mathematics and geometry to it than the heliocentric model. as s pepperchin has explained already. it would be interesting to see a "dumbed down" explanation of the maths.

[s pepperchin]

I have been working on an example for using different reference frames.

 

Say we have a star located at (0,0) in reference frame A and it is orbited by two planets M and N. The position vectors for the two planets are:

 

[math]\overrightarrow{r}_M=<a Cos(\omega_M t),b Sin(\omega_M t)>[/math]

[math]\overrightarrow{r}_N=<c Cos(\omega_N t),d Sin(\omega_N t)>[/math]

 

where [math]\omega_M[/math] and [math]\omega_N[/math] are the angular velocities of the planets and the values of a,b,c and d are the semimajor and semiminor axis of the orbits. This means that the three objects have the position vectors:

 

[math]\overrightarrow{r}_S=<0,0>[/math]

[math]\overrightarrow{r}_M=<a Cos(\omega_M t),b Sin(\omega_M t)>[/math]

[math]\overrightarrow{r}_N=<c Cos(\omega_N t),d Sin(\omega_N t)>[/math]

 

I decide that I am going to use a new reference frame B which has planet M at the center. I will start by adding a vector to the orbit of planet M such that the position of planet M is always <0,0>.

 

[math]\overrightarrow{r'}_M[/math]=[math]<a Cos(\omega_M t),b Sin(\omega_M t)>[/math]+[math]<-a Cos(\omega_M t),-b Sin(\omega_M t)>[/math]

 

when I combine these vectors into one vector I get:

 

[math]\overrightarrow{r'}_M[/math]=[math]<a Cos(\omega_M t)-a Cos(\omega_M t),b Sin(\omega_M t)-b Sin(\omega_M t)>[/math]

 

or

 

[math]\overrightarrow{r'}_M[/math]=[math]<0,0>[/math]

 

now to determine the position vectors of the other objects I just add the same vector to their position vectors as well.

 

[math]\overrightarrow{r'}_S[/math]=[math]<0,0>+<-a Cos(\omega_M t),-b Sin(\omega_M t)>[/math]

 

[math]\overrightarrow{r'}_S[/math]=[math]<0-a Cos(\omega_M t),0-b Sin(\omega_M t)>[/math]

 

[math]\overrightarrow{r'}_S[/math]=[math]<-a Cos(\omega_M t),-b Sin(\omega_M t)>[/math]

 

 

[math]\overrightarrow{r'}_N=[/math][math]<c Cos(\omega_N t)-a Cos(\omega_M t),d Sin(\omega_N t)>[/math]+[math]<-a Cos(\omega_M t),-b Sin(\omega_M t)-b Sin(\omega_M t)>[/math]

 

So now in reference frame B the position vectors are:

 

[math]\overrightarrow{r'}_S[/math]=[math]<-a Cos(\omega_M t),-b Sin(\omega_M t)>[/math]

 

[math]\overrightarrow{r'}_M[/math]=[math]<0,0>[/math]

 

[math]\overrightarrow{r'}_N=[/math][math]<c Cos(\omega_N t)-a Cos(\omega_M t),d Sin(\omega_N t)>[/math]+[math]<-a Cos(\omega_M t),-b Sin(\omega_M t)-b Sin(\omega_M t)>[/math]

 

as you can see they are both correct and all physics works in both frames the math is just easier in frame A.

[ecoli]

your math is pretty intense for me, pepperchin. But, we may be talking about the same thing....

 

 

A geocentric model doesn't account for the movements of the planets very well. When the first atronomers were mapping out the motions of the planets based on the geocentric model, the motions of the planets didn't make any sense. It appeared that, in addition to making a orbit around the earth, they were making an obit within an orbit... or that's how they orginally interpreted the motions, because of small amount of error between the expected and actual motions.

 

like this:

 

Not only that, but there appeared to be an orbit in the orbit in the larger orbit... and an orbit in the orbit in the orbit in the orbit...

 

you see what I'm getting at? The motion made more sense, and could be more easily desctibed with a heliocentric model.