Re: What would happen to Io if Jupiter were 1 AU from Sol?

I appreciate the imagination of your question. There are many things to consider here beginning with the circumstances which affect the formation of a planet or moon. For instance, the planets are arranged with the terrestrial planets close to the Sun and the gas giants further away from the Sun for a reason. That reason being that gas gets evaporated away if it is too close to the Sun so that only those planets far away will be able to accumulate enough gas through gravity to grow into gas giants. Asking if a certain planet or moon would survive if we moved it to a different place is tricky since, chances are, it might have never formed there in the first place.

Astronomers are working really hard right now to understand how planetary systems form. This research has been challenged by many new exoplanet (planetary systems besides our Solar System) discoveries made by Geoff Marcy and others. These new discoveries have revealed a number of gas giant planets which are orbiting at distances from their parent star which are well within 1 AU! Planetary formation models suggest that these planets may have formed farther away from the star but then later migrated closer due to gravitation interactions with other planets or the circumstellar disk from which they formed. Since we observe gas giant planets which exist within 1 AU from the Sun, it is just as plausible that the moons around the planet might also survive the migration.

As to whether life could survive on an Io-like moon around a Jupiter 1 AU from the Sun is anybody's guess. There is a lot of research going on just to figure out whether life could exist on Io and other moons like Europa and Titan at their present location in our solar system. It is true that an orbit 1 AU from the Sun puts both the planet and its moon with our habitable zone, however, Io is under a lot of gravitational stress from its orbit around Jupiter. It is constantly being heated by the gravitational heating from the pull of Jupiter which causes Io to suffer from much volcanic activity. This could be a good thing for life which depends on rich minerals produced by volcanos but whether it could survive such harsh conditions is still under debate.

Do keep an eye/ear out for future missions to Europa and Titan and other moons which will be looking for life signs. A better answer to your question may be right around the corner.

For all the information about exoplanets and planet formation you could possibly want, check out www.exoplanet.org!