The planets were terraformed to be similar to Earth during the golden age thus altering the original gravity of planets to be able to support human life. (Is my hypothesis)

I've been thinking this same thing since the Beta. I've been thinking that they should have modified the gravity as such: Earth -- 100%*** Gravity (Standard) Moon -- 60% Gravity (A little more than what the moon is currently, but we should at least notice a difference) Venus -- 95-105% Gravity (I think Venus should be relatively similar to Earth, but with a slight tweak either way) Mars -- 125% Gravity (For some reason I feel like Mars should have more gravity pull than all of the other planets) Anyway, I know that adjusting gravity is not necessarily a hard task for game developers, especially since they had an option to adjust gravity pull in Halo Reach. ***I may have my percentages opposite of what they should have. I don't remember if less percentage is less gravity pull or more gravity pull, but I hope that either way you get my point.

This topic is heavy man.

Once you get to the end of the game Neo tells you that it was all a make believe world !

Well the traveler's space magic... You know what? That's good. Those words should tell you all you need to know. Also: gameplay above all because, you know, it's a game.