A recent study has suggested that humans may be alone in the observable universe. Our own existence is fragile: we could be wiped out by a nuclear winter, artificial intelligence or an asteroid impact. Call it a contingency plan, or a moral duty, but it seems as if we should start thinking about propagating organic life throughout the universe. This process is known as directed panspermia and it has staggering implications.
The panspermia society convincingly argues that any attempt at carrying out directed panspermia should rest on a strong ethical framework. They outline their own ethical argument, which concludes that the purpose of humanity is to “safeguard and propagate life”, and any action which does this is in line with our overall purpose and therefore morally good. According to this trail of ethical reasoning, directed panspermia is a morally good process. This view is not shared by some philosophers, who argue that many animals on Earth do not have lives worth living.
An example of this is a stable population of bullfrogs. Each female bullfrog will lay up to 20,000 eggs, but because the population is stable, only one female tadpole (on average) will live long enough to mate; the others will be consumed by predators or will die of starvation. The ethical argument here is that the net welfare level of the bullfrogs in this population is negative, so it would be foolish to try and propagate this net suffering throughout the entire universe.
Once we have overcome this tricky ethical debate, we will need to choose the right organisms to send to habitable exoplanets. On Earth, life as we know it would not have been possible without anaerobic cyanobacteria. Our atmosphere used to contain much higher levels of carbon dioxide, and these organisms converted it all into oxygen via photosynthesis. This process may be essential on other planets to allow the development of intelligent life, so cyanobacteria are strong contenders for a panspermia mission. The only issue with cyanobacteria is that they are unicellular organisms. The jump from unicellular to multicellular organisms may have only occurred once on Earth, and it may be so unlikely that it never occurs on other planets. It would be wise to include some multicellular organisms on the mission, to allow intelligent life to evolve much more quickly than it would from unicellular organisms.
In order to survive the journey to habitable exoplanets, the microorganisms chosen would have to be resistant to radiation and able to survive for long periods of time with limited sources of oxygen and nutrients. This could be achieved via genetic engineering or by selecting polyextremophiles, which are able to survive in a combination of different extreme conditions.
When we’ve got our microorganisms ready, we will need to safely transport them to a chosen habitable destination. Thankfully, there is no shortage of habitable exoplanets in our galaxy. We would need to focus on solar systems with young stars, in order to give our microorganisms ample time to evolve into intelligent life; however getting them to a chosen destination will be no easy feat. There are many theoretical proposals for microorganism transportation, one of which includes hitching a ride on a passing interstellar comet (similar to the recently observed Oumuamua comet).
Much of the technology to make such a mission possible already exists. A team working under a governmental or private space agency could conceivably carry out a directed panspermia mission within the next few decades. There would be no tangible results within our lifetimes, but public excitement and the satisfaction of propagating organic life throughout the universe should be reason enough to carry out the mission and secure funding. Let’s create a future universe teeming with life.