Just last month, scientists announced the discovery of the first possibly habitable planet, orbiting a star 20 light-years from Earth. That's relatively close in astronomical terms, but beyond today's reach.
Estimates based on three key factors — finances, technologies and energy sources — all come to the same conclusion: The first missions to others stars will not be possible for another two centuries.The two centuries figure given above is far too conservative, in my intuitive opinion. I think it will be considerably sooner. But I'm not a physicist. On the other hand, I am at least going to attempt to read Mr. Millis's important new book, Frontiers of Propulsion Science, which should be challenging, to say the least. To read the rest of the article, click here.