Ian Sample asks a number of scientists 'What's next?' Their answers are here. Seth Shostak, senior astronomer at the Seti Institute in California says that we'll 'invent our successors':
I suspect that the first steps will be taken by mid-century. We could well be the last generation of humans to dominate Earth.Hang on a minute. I don't entirely like the sound of that. There's other intriguing stuff - like finding out if we're alone, and what it means to be a person. Oh yes? Just like that, huh? There'll still be an argument.