If Aliens Attack: Visitors to Earth Will Likely Be Robots

The alien invaders in the new movie "Battle: Los Angeles" are anything but friendly looking. Mechanical components are built right into their stringy bodies, a weapon protrudes from an arm, and machinery bristles along their armored exoskeletons. But like us, the aliens possess slimy internal organs and they can bleed.

This portrayal of extraterrestrials, however, strikes some scientists as unrealistic. Should any real visitors — or conquerors — from space come to our planet, the scientific odds strongly suggest the aliens will be completely artificial forms of life.