Free Original Storworld Ideas, part 6: Nanites in Space Weapons and Aliens

Nanites are a staple of science fiction, but perhaps should be used even more. Because of their light weight, they can easily be accelerated up to near the speed of light, which means they would be useful for exploration and offensive war. They'd also have the potential to spy, aid communications, and medical applications, including defense from other nanites. They might become so ubiquitous that they could spread like a plague for anyone not carrying nanites themselves...