Terraforming

The search for exoplanets (now at 5662 as of 1 May 2024) prompts the question of habitability. Is there life on any of these exoplanets? If distant worlds that could support life are uninhabited, can these planets be transformed to support human life? However, the problem of terraforming other worlds tens of light years from earth is a only a thought experiment given the time it would take to reach these worlds and the round-trip latency associated with subsequent communications.

A more proximate question pertains to the terraforming of Mars. The development of large launch capabilities like SpaceX’s Starship motivate careful thinking on this topic. What is the right approach? Should the first human visitors to Mars erect biospheres with the associated support equipment?  Or, perhaps robots should scout the planet and perform the necessary site preparation to welcome the first humans to the red planet?

A 2018 Cosmos article[1] wondered whether cyanobacteria could be used to terraform Mars. Cyanobacteria helped oxygenate the earth’s early atmosphere some 3 billion years ago. Perhaps they could be enlisted for similar service on Mars. Of course, the small ice caps, reduced sunlight, and lack of biogeochemical cycles complicate the situation. Nevertheless, this intriguing possibility prompts several observations.

First, the topic of terraforming implies that it is possible to terraform a planet. This is a design question. Designers consider alternative approaches and model their effectiveness in accomplishing intended goals. Some approaches may work well on certain planets but not on others. Lifting heavy equipment into space may be a possibility for Mars, but a budgetary impossibility for a planet circling Proxima Centauri. And some planets may not be habitable at all. They are not within the habitable zone of their stars, they lack water, atmosphere, a protecting moon, or a magnetic field. Flares from active stars may sterilize life as it seeks a foothold on some distant world.

Second, the existence of these design choices implies the existence of degrees of freedom. The designer has choices to make. No particular solution is required, but some solutions will work better than others. This prompts an interesting question regarding planet earth. Was life planted on earth to terraform the planet? Or, did life evolve? Can we tell the difference? How difficult is terraforming? If earth was terraformed, why did it take so long?

Third is the question of ownership. If we terraform a world, is it ours? For good or for ill, are we responsible for the changes we make to another planet? If the earth was terraformed, does it have an owner? What does earth’s owner expect from the life he planted here?

Image Credit: Kevin Gill from Los Angeles, CA, United States, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons