Yes, because they are 'close enough' that the errors aren't that bad and the price paid in accuracy is more than compensated for by faster analysis.
$$\Lambda$$ is for things on a cosmic scale, it doesn't come into solar system dynamics. If you care about high accuracy, much more so than just hitting the Moon with a rocket, then you need GR. This is precisely the thing needed in the GPS network. In order to get your position accurate to within a few metres gravitational phenomena need to be modelled to parts per billion and atomic clocks must be used to get precise timings. If you used Newtonian gravity and not GR in the GPS network it'd be worthless, it simply wouldn't work. So if you've ever used a GPS route planner then you've used a technology Newton simply can't explain.
No, I mean physical predictions. Being mathematically consistent is a necessary step
before physical experiments are done. Einstein predicted several things which Newton didn't, additional precession in the orbit of Mercury, photon gravitational redshift, photon gravitational lensing and frame dragging. It took a while for technology to catch up with some of them but all have been tested and found to agree with GR's prediction to the limit of our ability to test.
See
http://en.wikipedia.org/wiki/Tests_of_general_relativity
It would appear you don't even know how $$\Lambda$$ enters into GR and where its relevant so I think your off hand dismissal of it and your misunderstanding of the role mathematics plays suggests you need to spend a bit more time reading up on things before you make your mind up.
And you think mathematicians (typically a general relativity group is in a mathematics department) don't know about pressure, entropy, thermodynamics etc?! Have you ever even looked at a relativity textbook? You make it sound like there's GR mathematicians on one side doing hypothetical stuff without a care if its valid and then physicists who do stuff related to real phenomena like pressure etc. There's no clear cut line, someone doing GR might be considered a physicist by pure mathematicians and a mathematician by astrophysicists. I did a maths degree then a PhD in a physics and astronomy department on a topic entirely mathematical.
The people who say the universe is expanding understand the general relativity relevant to cosmology and they have experiments which measure a variety of things (like emission spectra of supernova, which requires quantum mechanics, stellar dynamics, nuclear physics, thermodynamics and magnetohydrodynamics to model) which they then try to frame in terms of various cosmology models, which led to the conclusion the universe is expanding
faster than it used to. You'll find that GR researchers are more than competent at thermodynamics and the like.
You claim there's no evidence but there is, you just haven't looked, just like you haven't looked to see what GR really involves or what the people doing it know and consider.
You say you prefer to talk to physicists but you appear not to have talked to anyone, given your huge misconceptions.
You just proved my comment about you having no clue about what physicists do, you don't even know what a model involves. You talk about intellectual curiosity but you haven't shown any if you don't know what is even expected of basic claims. Seriously, open a book some time.
For instance, if I asked Einstein 'What's your model of gravity' he would have given me the Einstein-Hilbert action and then explained that a metric satisfying the field equations associated to the metric will have an action equal to the Einstein-Hilbert action from which I can derive the relevant equations of motion for test objects within the space. From that I could model satellites in orbit or black hole formation.
Quantitative stuff which provides
quantitative predictions which can be tested.
Now compare that to what you have, 'any vortex will do'. How can anyone
quantitative model anything with that? You complain there's no evidence for universe expansion and then you provide
nothing to back up your own claims.
What's the equations of motion?
Thanks, I never covered that in my courses on classical dynamics, quantum mechanics, fluid mechanics, electromagnetism, statistical physics, quantum theory, electrodynamics, special relativity, general relativity, statistical field theory, stellar dynamics, quantum field theory, advanced general relativity, standard model or black holes. Despite all those courses being lectured for
mathematics students none of them covered the high school $$PV = nRT$$ formula
You seem to think all mathematicians follow the course of hardcore pure mathematicians, which involves only the abstract. Even those hardcore ones are required to do basic mathematical physics stuff initially. As it happens I went down the quantum mechanics and relativity route, which is covered by many a mathematics course as they are highly mathematical.
In fact if you did a little bit of reading you'd find out that a great many of the famous people in physics were mathematicians. Dirac was a mathematician by degree and position and he invented quantum field theory. Stokes was a mathematician and he developed fluid mechanics. Witten has a Fields medal. Newton invented calculus.
For all your talk about 'talking to physicists' and intellectual curiosity you haven't really got a clue how physics is done.
Are you unfamiliar with the concept of citations too? They are used in physics papers all the time, which would explain why you don't know about them....
