From what I understand, most known exoplanets are gas giants, and almost all orbit their sun at about the distance of Mercury, because those are easier to detec

From what I understand, most known exoplanets are gas giants, and almost all orbit their sun at about the distance of Mercury, because those are easier to detect. That leaves a lot of harder-to-see exoplanets we can only guess at. There are about 20 stars within a dozen light years, so I wish we could send probes to them and take a closer look. It would be a gift to our grandchildren. The risk is that in the time they would take to get there, our detection capabilities may have improved so much they'd wind up being useless, but I sort of doubt it. Being 7-12 light years closer has got to make a difference. EDIT: Here is an amazing video showing all known exoplanets orbiting one star, so you can see their relative sizes, distances, etc.: http://vimeo.com/47408739 http://vimeo.com/47408739