Do you have evidence that "mainstream science" is wrong about space/time?
There's lots of evidence!
First of all, just to give one piece of evidence myself and in my own words, the concept of spacetime is tied directly to what is called the isotropic constancy of the speed of light. This property of light is very weird. Most people do not understand it so let me briefly explain.
Let's say you were traveling at the speed of a bullet and as you past by a stationary experiment partner, you both fire a gun. Your bullet would proceed away from you at the normal speed of the bullet while your bullet would proceed away from your stationary partner at twice that speed. Your partner's bullet on the other hand, would proceed away from him at the normal speed of a bullet but that bullet would appear to you to be stationary and would simply fall to the ground. Pretty straight forward stuff, right?
Now, let's say that you're traveling at almost the speed of light and just as pass your stationary partner, you both fire a laser beam in the direction that you are traveling. Relativity says that both your laser beam and the one fired by your stationary partner will both proceed away from you at the speed of light AND that both your laser beam and the one fired from your stationary partner will ALSO both proceed away from your partner at the speed of light. In effect, it would look to you like light from your partner's laser decided to double in speed and it would seem to your partner that your beam just sort of oozed slowly out of your laser.
Now, there are two things wrong with that. First of all, and most importantly, it is irrational. It is quite literally a self-contradictory proposition. Secondly, it is the ONLY THING in all of existence that supposedly displays this property. Nothing else in all of physics seems to double its speed based solely on the fact that you, the observer, happen to be moving.
Now, Einstein's theories get around this physical contradiction by adding a 4th mathematical dimension and that's how "spacetime" was born. And the math works! Make no mistake, I am not saying that the math doesn't work or that Einstein's equations aren't useful. They do work and they are very useful. It isn't the math that's wrong, its the interpretation that is false. You cannot use one form of logic to declare a contradiction to be the truth. That doesn't work because you'd be using logic to undermine the veracity of logic. No! Contradictions DO NOT exist in reality. If you think you've found one, check your premises. You'll find that one of them is false.
As for alternate cosmological theories, I have become convinced that the Electric Universe Theory is on the right track. Even mainstream science is slowly starting to come around on accepting the idea that both electrical charge differentials and magnetic fields (both of which make up the electromagnetic force, which is literally millions of times stronger than the force of gravity) exist on astronomical scales and may play a part in various aspects of the phenomena that we observe with our telescopes.
Now, that is by no means all of the evidence against the concept of spacetime. There are several good sources around. Here's a few of the better one's that I've found....
Importantly, I just want to say that I do not endorse these website per se. I haven't read everything they say and some of what I have read I don't understand and some of it I outright disagree with. However, on particular topics, they are excellent sources of information that you won't find on the Discovery channel or read in your high school text books....
The following site gives good information about the isotropic constancy of the speed of light and other aspects of mathematics based physics...
Physic's New Suit
This next site has a lot of very well done YouTube videos on a wide variety of subjects related to the Electric Universe Theory which simply puts forward the idea the the electromagnetic force, which is literally millions of times more powerful than gravity, has a large roll to play in the cosmos, as apposed to modern mainstream cosmology which insists that gravity is the ONLY force of any consequence on astronomical scales.
Avoid anything and everything on the following website that uses the phrase "alien sky". Unfortunately there seems to always be some portion of alternative theories that has to include something that is legitimate nonsense and which makes it easy for people to discount the entire thing as crackpot silliness. Just focus on the "Space News" YouTube videos and look for any of them that talk about Einstein or Relativity or the speed of light, etc. Their series on 10 reasons why the universe is electric is also worth your time as is their full length documentary called "Thunderbolts - The Tutorial", all of which are free on YouTube....
The Thunderbolts Project
This next one isn't about Einstein's "Space-Time" per se but about debunking the Big Bang Theory which supposedly created spacetime. This site, I fully endorse every syllable of, by the way....
Evidence Against the Big Bang Theory
As an aside, I heard someone the other day (podcast/ lecture?)suggest that should society collapse and "most of what passes for science these days" is forgotten about for an extended period of time, at some point it would all be rediscovered because, well, facts are facts.
Well, that is as textbook an example of question begging as has been posted on this website in years!
The comment is only true in so far as what is being put forward as science these days is actually fact, right?
So, putting that forward as an argument that modern science is factual would be to assume the answer to the question being debated. As I said, textbook question begging.
Do you have some particular issue with "mainstream" science? Is there a non-mainstream science you consider more accurate in understanding the world?
Mainstream science is atheistic in its worldview which means that it cannot help but lead to error because, as we are told in God's word...
Proverbs 9:10 “The fear of the Lord is the beginning of wisdom, And the knowledge of the Holy One is understanding.
Modern physics and cosmology, in particular, are aggressively anti-theistic. ANY explanation, no matter how feeble or irrational is superior, in their minds, to any explanation that even leaves open for discussion the existence of God.
This worldview is the root and the cause of whatever issues I might have with modern science, but I do not have any issue with science, per se. In fact, I love science! Science, when done properly, is nothing more than the systematic application of sound reason in an effort to understand the universe in which we live. I believe in a God who is not merely rational but who is Reason itself and that He created the universe through Reason and that nothing that was made was made without Reason (See John 1:1-5). And so, it is completely expected that natural processes are discoverable and understandable. Indeed, if it were not so, it would falsify my religion!