What's your lifeboat for our species?
The best option is not screwing up our planet. If asteroid strikes is the concern, then funding a planetwide network of residents living in underground bunkers with supplies to last decades is probably cheaper and more effective than going to Mars.
That isn't even close to the best option. That's like saying: "don't make backups, just don't screw up."
edit: to be more specific, "make makeups, but also try not to screw up"
That does not even belong in the same category. Data backups in computer systems are cheap, and people/organizations not doing them even cheaper!
On the other hand, doctors don't make backups of the gravely ill[1] before a dangerous surgery. That is beyond our current capabilities, so "do not screw up" is as good as it gets.
Yet another example, civil engineers do not make backups of skyscrapers[2] before doing maintenance work, even major maintenance work. While technically feasible, the economic cost would be prohibitive.
My gut feeling is that a "backup planet" would fall somewhere in between cases [1] and [2].
It's very hard to imagine what we could do to Earth so that it becomes even less hospitable than mars.
If "lifeboat for species" is the goal, then going to Mars is a solution in that direction but not a particularly good one - building an underground colony in Antarctica or a self-sustainable isolated underwater colony would achieve the goal better, be reachable quicker, and at a lower cost. However, 'lifeboat for species' right now is not an explicit end goal for anyone who would be capable to fund that.
We're not looking for a lifeboat, humanity is simply looking for another planet to screw up.
- Expanding into a new environment drives evolution.
- The technological innovations that will be needed to sustain a settlement on Mars will be hugely valuable back home.
- There is presently no frontier where new political or social ideas can be attempted without interference. Again -- the results of these "experiments" can be exported back home.
The last two are huge. The main exports from a Mars colony would probably be ideas and technology. Those also have the advantage of being able to be transmitted wirelessly and having no mass.
Evolution is usually very unpleasant for the individuals being naturally selected away. How is this a good thing?
BTW... if we don't transition off fossil fuels in the next 50-ish years we are going to experience some of Ye Olde Tyme Evolution here on Earth. Personally I think Mars would be a better place to be in that scenario. There was a sci-fi film called Alternative Three made about that.
We are looking at space exploration in the wrong way. All space organizations seem to have entered this sort of competition where manned missions to just about anywhere currently reachable in limited time is the goal. Nobody is pausing to think that maybe we should look into better travelling options to be able to explore far off planets and objects. The probability increases with reachable area.
It absolutely isn't. It is very, very unlikely that one can break the laws of physics no matter how much time it takes to research it or how advanced one becomes.
Still - it is important to research it in-case we've missed or gotten something wrong.
FTL travel is completely unnecessary for interstellar travel, thanks to relativity. If you're traveling 1000 light years at 0.99999999999999999c, you will get there very nearly instantly. Of course, you've basically taken a one way ticket - if you turn back around, 2000 years will have passed back home even though you're only a few seconds older.
Of course, 0.99999999999999999c is itself no mean feat (to say the least - the energy costs for even 0.5c would be incredible), but there's nothing about it that violates the laws of physics.