We may be able to expand into the solar system, and then eventually to the stars. How, though, can that work for a species with such a tendency towards violence and conflict as ourselves?

At first our solar system seems so hostile to Earth life, anywhere outside of Earth. Mars is certainly no paradise, However, longer term, maybe we find reasonably low cost ways to build large easy maintain habitats, kilometer scale and self sufficient. If so, many places in our solar system may become open to us. They may even be easier places to live than Earth itself, because we can design them with whatever climate, gravity etc we want and can site them in places in our solar system with no danger from earthquakes, tsunami, volcanic eruptions etc. They can be protected from ionizing radiation with layers of regolith (if necessary). We could complete such a structure on a timescale of a decade or two, far shorter than the time period of many millenia for terraforming, so we could actually encounter this in the near future. Here are some of the sections of this book about the idea:

• Instead of terraforming Mars in a multi-millenium project, why not terraform a lunar cave in a multi-decade project?
• Plenty of places to experiment with sending life to other places in our solar system - Asteroid belt resources, NEO's, caves on the Moon
• Space habitats made from asteroid and comet materials get plenty of sunlight - right out to Pluto (using thin film mirrors to concentrate it)
• Sending humans to Callisto or Ganymede
• Titan as potentially the easiest place for humans to live outside Earth
• Humans in habitats at the Venus cloud tops

However, I raised a question in the introduction, in the section: Further into the future, if we have millions in space - can we be one of the "wise ET's"? about whether we can colonize our solar system, and further afield without taking our propensity for extremism and warfare with us.

If we do take this violence, terrorism and extremism of all sorts that we get on Earth into space, how can humans remain in space for long? Any habitats in space will be so fragile to violent actions, that even lobbing a rock at them at a few kilometers per second would destroy it. Any group of millions of people with space technology would find that an easy thing to do. How could anyone survive a war in space like that?. With no air to breathe, there'd be no possibility of survivors hiding out in caves. If their environment control, hull integrity, or spacesuits are destroyed by the blast, they no longer have any way to survive.

This is not an issue right now, but if we ever have millions in space, then it might be a major problem for us. I had a look at this in the introduction, but with no recommendation particularly, except, to go slowly. There's no need right now for vast self sufficient colonies in space. So why rush into that future with its many problems and possibility for violence and danger?

Still, one way or another, we will probably expand into the solar system, first bases like the ones in Antarctica, then larger populations. Eventually we will have the ability to visit the planets in person, and the various colonies we set up throughout the solar system. I suggested in the introduction that perhaps, if we do it slowly enough, we will find the solutions we need. See:

• Further into the future, if we have millions in space - can we be one of the "wise ET's"?
• Signs of optimism, that we can be one of the wise ETs

However, what happens after that, if we start to colonize the stars? Let's look at this more closely. Perhaps in the next few centuries we will have the ability to visit other stars in person? It might seem great at first, to think of a "civilization" like ours spreading to fill the galaxy. But - is that so desirable long term? I would like to suggest here, that like the colonization of our solar system, it depends very much on how and why we do it.