Martin Rees, president of Britain’s Royal Society and Astronomer Royal, thinks so:

Technology has advanced so that for the very first time we can actually have the realistic hope of detecting planets no bigger than the earth orbiting other stars. [We'll be able to learn] whether they have continents and oceans, learning what type of atmosphere they have. … Were we to find life, even the simplest life, elsewhere that would clearly be one of the great discoveries of the 21st century. I suspect there could be life and intelligence out there in forms that we can’t conceive. And there could, of course, be forms of intelligence beyond human capacity, beyond as much as we are beyond a chimpanzee.

Today and tomorrow, a group of scientists is meeting in London to discuss the possibilities and consequences of discovering alien life. It seems theoretical physicist and cosmologist Paul Davies believes they are looking in the wrong place; instead of trying to communicate with other life forms in faraway space, they should focus instead on searching for “aliens”—or “weird” microbes—in volcanic vents, salt lakes, and deserts here on Earth (which could help make the case that exotic life could have emerged elsewhere in the universe as well). What we imagine extraterrestrials will look like depends on where and how we expect to find them, Stephen Battersby explains in New Scientist:

If our aliens come from a planet with a range of habitats not too different from those on Earth, they might well have some of the same characteristics. A well-lit world like ours would probably produce beings with eyes—so maybe a recognisable face after all. And our cosmic correspondents would presumably need some manipulating organs to fiddle with the nuts and bolts of their technology. They might even have hands, but then again why not a prehensile tail or a trunk instead?

Evolutionary palaeobiologist Simon Conway Morris thinks aliens could very well be like humans—greedy, covetous, and exploitative, helping themselves to our water and fuel if they come to Earth:

Extra-terrestrials … won’t be splodges of glue … they could be disturbingly like us, and that might not be a good thing—we don’t have a great record.