Are we alone? Tiny spacecraft will head to Alpha Centauri to find out
This century, it will not. We are very far from a technology capable of achieving what Starshot proposes. Accelerating the spacecraft to a fraction of the speed of light using a laser would require power densities that would instantanously turn all known materials to plasma. The best mirrors and coatings are many orders of magnitude too dark. The required laser and energy bank would be, for all intents and purposes, a comics megaweapon capable of blowing spacecrafts from orbit, or, with proper space reflectors, incinerate enemy installations anywhere on the globe in seconds.<p>The craft would be completely unable to brake so it will pass past the target planets in a matter of minutes. It's unclear what kind of sensors could be employed to detect anything and we certainly lack the technology to beam and receive back signals sent by a postage stamp craft 5 light years away. Let me rephrase that: we haven't got even a theoretical model of a system that would allow communication at such vast distances with milliwatt power sources.<p>Needless to say, nobody is seriously working on this, nor will they for many decades at least.