What I hate about SciFi stories involving humans in a mass exodus from Earth to colonize space...
Earth(Gaia, Earth-that-was, Home, etc.) was left inhospitable after [insert tragedy, war, natural phenomena here], so we took to the skies in an attempt to colonize and repopulate other planets.
Basic story structure for many/most SciFi stories in this genre, yes?
But riddle me this... if the planet is inhospitable... how did they make the crafts and round up the people to get off the planet in such a short time?
Do you have any understanding how much time and effort goes in to the creation of a spacecraft?
Especially those interstellar motherfuckers that are the stars of these tales.
It took about 10 years just to design the fucking Mars Rovers (Spirit and Opportunity) and all they do is roll around dirt, take pictures of rocks and read chemical compounds.
Can you imagine how much effort, time, money and manpower would go into making a cruiser large enough to A) successfully travel through interstellar space B) Hold enough people, supplies and life support to make these efforts anywhere near viable and not just a massive suicide mission?
And if these technologies or ships did exist, why did they wait until the 11th hour? Why weren't these people already halfway to Alpha Centauri before the need even arose?