The Extraterrestrial Hypothesis : Fact and Fallacy

[DROBNJAK]

Yeah, that's a very interesting question. How was it proven that space-time is actually curved, not some field. Physicist are known to fall for 'sexy' explanations and fanciful mathematical methaphores. Maybe light is not bent because space-time is curved, but because gravitational field simply bends paths of photons. How can one separate these two observations experimentally?

 

[Randall]

Yeah, that's a very interesting question. How was it proven that space-time is actually curved, not some field. Physicist are known to fall for 'sexy' explanations. Maybe light is not bent because space-time is curved, but because gravitational field simply bends paths of photons. How can one separate these two observations experimentally?

Space itself cannot be proven to be curved ( at least not at present ). It can only be thought of as curved for the convenience of establishing accurate plots for the paths of real world objects. Proving space is not curved however can be done via the mind experiments and illustrations in my previous posts. Another one you can probably imagine yourself quite easily is that the position of the stars visible around an eclipse are actually not in the observed positions because the trajectory of the light from the stars has been affected in the presence of the Sun's mass.

Knowing this, we can calculate the actual position of the star and plot a direct line to it. If space itself were actually curved, it would be impossible to do that. But there's nothing stopping a straight line from being plotted between you and the actual location of the star. No hyperspace is needed to do that. During a real eclipse you could physically do it without any problem as well as physically look in that direction with your own eyes.

To get to that star, the course simply has to be adjusted to compensate for the observed deflection of the observed light. Other other factors like the time it's taken the light from the star to get here, the star's velocity relative to you, etc, would need to be taken into consideration, but just imagine that all being done. Hypothetically if you could transport yourself along that straight line in an instant, you would end up right at the star's real world location.

Logically this means that if you can travel in a straight line through space past a massive object, compensating for the gravitational effects as you go, and staying within this spatial construct, then it cannot be space that is curved. Rather it has to be the paths of objects in free motion as they pass by massive objects and are affected by gravitation ( not by space ). Diagram reinserted below for help in clarifying.

In this mind experiment, what is preventing a straight line path ( red line ) from being plotted and
jumping Galactica directly to the coordinates of the real star position?
Besides nothing ( that is ).​

​

 

[Randall]

Here's another interesting question: We know that light rays are bent when they travel through mediums of varying densities. That's why a straight edge placed in a glass of water appears to be bent when it's not. We also know that atmospheres cause the path of light to bend on the way through them, and we also know that the Sun's atmosphere extends millions of miles into space, and the heliosphere extends even more. So how much refraction does the stellar atmosphere cause for the light from distant stars?

I can't seem to find this answer anyplace in order to determine the extent to which that's been taken into account during the experiments where they're looking for deflection caused by gravitation. I assume it must have been taken into account. But haven't seen any proof of it. So how do we know the predictions made by the math intended to prove space is curved don't simply match coincidentally with the refractive index of stellar atmospheres? Again I assume they've got that figured out, but I'm just curious to know.