Theory of Relativity on the Train

Every time when （不用加when）I am stuck in the middle of the crowds, a road stretches out of my brain, taking my imagination away as if my imagination it is on a rocket of lighteninglightning. When I close my eyes, I feel that I have left the world of noise far behind, (1) and am suddently somewhere spacious with such a peaceful tranquility that the heartbeat of time stops. No concept of time exists at this point. The world of mine and that of others are kind of separated -- absolute space and time are replaced by relative ones.

(1) - Use commas to separate different phrases when possible, we add a comma  to help the reader more easily understand the sentence structure.

Why  this experience of such a “relativity” (2) really matters is that it gives us a hint about the attitudes we hold toward our life. We may take the same train every day, standing next to each other and be breathing (3) in the air (which was) recycled between one another. (4) What is on our minds might be wildly divergent, deciding the kinds of living conditions we will be live in, on that day, at least or throughout our life at large. We can （better: "We could"） frown and complain that we are trapped in a curse that can never be dispelled, but we can also  (better: "but we could also") smile and set our minds free, and freely(5) take (3, again)  our heart on a journey. From a macroscopic view (or: "as a microscopic layer"), the world is uniform because we all live under one sky; from a microscopic view, there are no two leaves of a tree which are the same(6), neither are any two persons’ worlds.

(2) We usually only say "Why X matters", or "X matters this much", but never "What it matters". We can also say "What it matters to X", ("it matters to me whether I get the job"). 

Also, not a grammar mistake, but I would point out one thing: technically, you are experiencing *relativity*, not the theory thereof! But if you are specifically wanting to refer to the theory for artistic or other certain reasons, it might be ok!

To experience the theory would be to read Einstein's books. Whereas, it seems to me that in this case, you are not experiencing the *theory*, but just the relativity of space and time itself! :)

(3) "breathing" is a "gerund" in this case, a noun. every sentence needs a verb, you need a verb, so you have to use  "to be" + "breathing".

subject = We

verb = (may) be breathing

object = a

I hope that's right, I'm not an expert in English grammar -  :) 

(4) Don't make sentences too long - it makes it harder to read. Shorter, simpler sentences are better. Don't use more than 2 or 3 clauses, if you can. ("A, who was B, did C" --- 3 clauses is a good number)

(5) "And freely take" is better, it's better to put the adverb near the adjective it describes.

(6) Two problems here, one of them is not your fault. :)

#1 is "alike". *Usually* we use alike to mean similar. Technically your grammar is correct, however, it's not perfectly clear to me, I would prefer to say "There are no two leaves which are exactly alike"

I agree with the point of physicist that world is uniform. However, I am in favor of the view of spiritualist more that our own worlds are constructed upon our minds and spirits, which will make all the difference!

#2 - "leaves" sounds a bit ambiguous to me, "no two leaves" makes me wonder for a minute what kind of leaves are you talking about - "leaves of a tree? or leaves of paper?". However, if you said "Every leaf is unique, there is no other exactly like it", it would be much clearer. so, technically, only saying "leaves" is OK, just giving you some insight into how a native speaker will hear this sentence. 

I agree with the argument of physicists, that the world is uniform. However, I am also in favor of the view of spiritualists: （which is that) more that our own worlds are constructed upon our minds and spirits, which will make all the difference!

(I think i'd say "constructed in our minds and spirits") 

Really nice job! A well written essay, with very colorful and expressive language; 你真的很聰明，我的看法一樣。 很多富人的生活很慘，有時他們賺很多錢，或者學到很多科學知識，但是到最後有神經病，心臟問題等。要脫離紅塵 (可以說嘛？哈哈）