Elon Musk has said that we must become an interplanetary species. This appeals to an existential motivation that should concern us all, because it is almost certain that Earth will be engulfed by our sun eventually. It would be tragic if human and animal kind were to be wiped out without having made a serious attempt to export the life and culture of our planet to other planets. So, what can we do about it?
Mars is the best alternative planet in our solar system, but it is clearly not well suited to support lifeforms from Earth. You wouldn't want to live there. Even if we were to start terraforming it by introducing carefully tailored microbes that could survive and start to produce a habitable atmosphere over time, the process could take millions of years.
If we look to the nearest potentially habitable destination planets, they are extremely far away, at least ten light years away. Even at speeds of transport at the extreme edge of today's technology, it would take around a hundred thousand years to get to the nearest one. The chances of human survival for so many generations on a self-sustaining spaceship are negligible. Though it is hard to accept, humans cannot transport physical lifeforms to other galaxies on vehicles as imagined in Star Trek or Star Wars.
Our best bet for becoming an interplanetary species is to broadcast human and animal DNA for other intelligent lifeforms to discover and assemble on their own planet. If and when we discover how to do the assembly ourselves, and to grow life in artificial wombs, then we could also broadcast detailed instructions to replicate that process.
Recently, some scientists have published an update to the Arecibo message that was broadcast in 1974. Their proposed message contains some important concepts that build up to describing the four nucleobases of DNA, but it stops short of sending a specific DNA sequence that could enable the reproduction of a human or animal on the destination planet.
Humans are much less likely to be able to travel across the galaxy in physical form than we are of being able to broadcast our DNA and a full set of instructions to grow a human in the form of a radio message. Even though we cannot replicate ourselves in this way currently, the timeline for that is on the order of a hundred years.
This plan assumes that intelligent life exists elsewhere in the universe to receive our message. In fact, we probably will need to target our transmission at one planetary system at a time in order to send it with enough energy to get there. These factors reduce the probability of success and extend the timeline to success, but they are still more likely to work than physical space travel.
I think that we should prioritize DNA broadcast over trips to Mars.
Blurry Visions 