Hypothetically speaking, if an extinction level asteroid/meteor impact was known to occur in ~25 years time, what realistic options does humanity, and life in general on Earth, have? Could we feasibly design a space operation to alter the course of or destroy the object? Is it possible to sustain some remnant of life in bunkers/protective shelters for the amount of time that would be needed for the environment to return to a habitable state? Do we have the technology/capacity to store/create enough energy and perishable supplies for this to happen? Could we feasibly design any sort of space faring colonization mission or long term "housing" in space or on a spacecraft? Or would we have to resort to launching a probe containing the artifacts (and maybe DNA) of human society for some alien race to find in the future, ala The Inner Light? Would we be doomed to hoping that a small segment of the population survives and hopefully persists long enough to rebuild civilization as we know it? What if we had 50 years, does anything change?