Well ok this is what this report says "•At our current level of technology, and allowing for no fundamental breakthroughs in physics but allowing for reasonable engineering development along known lines, the fastest spacecraft that we are currently capable of building would be an Orion Nuclear Pulse Rocket. Wikipedia has a good general description at the link below, but the basic concept is that we build a REALLY BIG spacecraft - perhaps twice the mass of a current US Navy aircraft carrier - and set off nuclear bombs behind a gigantic bowl and shock absorber. Such a device ought to be able to attain about 10% of the speed of light, but it would take about 2 years to reach that speed, and two years to slow down and stop. We would NEVER send out such a ship one light-year out and come back; we'd keep going to a potentially habitable star, but IF we needed to, we could probably do it in about 100 years. " This is of course from we know right now we could only 10% of the speed of light. Our closest start by the way is Proxima Centurai about 4 light years away.
Traveling at 10% of the speed of light that would be 40 years.
So lets say we are only able to the get to the closest habitable place in 200 years.
Right now in a few short decades we are already able to keep humans in space for months.
Is it not reasonable to say that a few centuries from now we will be able to have the technology to keep humans in space for a few centuries based on what we accomplished in the past Century?
Is not possible still in your mind for this to be accomplished?
Were talking about less of a Century of space exploration development here.
Is 200 or 300 years such a long time?
Who knows what we will learn in 300 years.
But one thing is for sure we wont learn it Unless we try to learn it.
So don't give up because you don't have all the answers yet
Keep on exploring the possibilities because physics that we understand now says it is possible.
And if it is possible to ensure that life will keep on existing even if there is Global catastrophe,
Doesn't that make it worth it to keep on investing on a safeguard for something that its guaranteed to happen sooner or later?