Intelegent life off Earth

For human like life to evolve it is generally agreed that conditions similar to Earth are needed. That should be one in a thousand planets, unless we can have intelligent life chemically a lot different than most Earth life forms. Humans have studied chemistry at higher temperatures and lower temperatures and pressures. Somewhat different chemistry for very simple life seems likely, but we have not found chemical systems that look promising, for near vacuum, nor without carbon and water, for advanced life, except computers. In many respects humans are computers with some peripherals built in, so advanced machine beings are a reasonable possibility on other planets, but that is another thread. Assuming intersteller travel is practical for some advanced beings, they can presently be a lot of places where they could not have evolved.

Let's consider where human earthlings could live with rather simple life support and without a very long supply line for most supplies. The planet, moon or asteroid needs to orbit in the habitable zone, with brief exceptions. That illiminates comet type orbits = very eliptical which are outside the habital zone long term and periodically. So the solar orbit needs to be close to round, not too far from the sun or surface ice will not melt and the water will be trapped in icecaps at the poles and/or far below the surface such as Mars.

Too close to the Sun may be ok if the planet keeps one face toward the sun, or the poles have zero tilt like Mercury. Either of these conditions result in a long term temperate zone of small area, but big enough for a few thousand humans. Please comment, embellish or refute. Neil