we would be living in space or colonize some planets by the time the earth is gonna die

i dont see why a super-advanced civilization would want to conquer earth.

There are other planets with more minerals than Earth.

of course it's gonna end...it's no longer a matter of if it's a matter of when...those sci-fi craps abt the end of days according to mayan calender r all bullshit...when it ends it really ends...none of those crap that only human civilization end and the world will continue as it is...i'm talking abt the end of the universe as it is...of course by now ya'll figured out i'm talking abt judgment day...heheh
but ya'll can see the signs r all there...we r at the end of it all...all i know is that it'll be sudden...none will see it coming...but it'll happen on FRIDAY (that much i know)...
if u r a moslem then go get the books entitled "Siri Ensiklopedia Akhirat" by Syaikh Mahir Ahmad Ash-Shufi...it's a 10 part series ensiklopedia on judgment day explained in an easy to understand BM according to the Quran and hadith...i enjoy it very much and it helps me to understand the topic better...i'm currently on the 4th book...hope it helps those looking for better explanation about the nature of Kiamat (Judgement Day)...

if u rely on philosophy  alone when talking about the end of the world then u r toast... unless of course u r agnostic...then ignorance is bliss...

since he have travel back in time and interact the the people in this time line, then what he know in 2036 would not applied to our timeline anymore because he have changed history.