|Surely expansion of universe is going faster than light as we can see longer (in light-years) than the universes age... |
We cannot see longer in light years than the universe's age, because light does not travel faster than light. I think the best Hubble image for distance is around 13.2 billion light years, which is short of the predicted age of the universe.
|which could should mean Einsteins and all equations ever created and proposed would collapse in a number substitution.|
Actually, general relativity predicts the expansion. The equation I wrote above is missing the cosmological constant, a term which if you follow all the maths through, should really be included. I just left it out because it was a pain writing that equation out in a post like this and it is often excluded anyway. This is energy inherent in space itself.
Also, you do a number substitution to use the equation. In fact, that's what Einstein did to predict the correct orbit of Mercury and the angle of deflection of light as it passed the sun, which was confirmed experimentally around five years later during a solar eclipse.
Anyway, if you want to get a better understanding of gravity, I suggest you follow Susskind's lectures on relativity: https://www.youtube.com/watch?v=JRZgW1YjCKk
although you will need to learn calculus to a decent level before-hand if you haven't already.
|As I am talking theoretically, I would assume tachyons exist which is one exotic particles, therefore it is safe to say they can go faster than speed of light. |
When you talk theoretically, you don't just say stuff like let's assume tachyons exist because it's convenient. You say, let's assume they exist. Now let's work out the consequences of this. Assuming none of the consequences contradict current proven theory and do not contradict themselves, then you can start talking about applying it to the real world. When you say, let's just assume tachyons exist well you may as well say well let's just assume Santa Clause exists and he can help solve global warming by giving rides in his sleigh instead of people flying in planes.
Edit: That last sentence sounds a bit harsh, but it's not meant to be. The point is just that if you start making theories, they should still be based as much as possible on proper science and should have reasons for existing. Instead of just saying tachyons exists, why should they exist? Or instead of saying 'we can build a gravity machine' find a plausible way of how to do this which isn't easily refuted with known science. Then you're getting into really interesting and proper theoretical physics.