article_snippet.sent: Panspermia is a theory that suggests life spreads across the known physical universe, hitchhiking on comets or meteorites.
article_snippet.sent: The idea of directed panspermia, however, suggests that lifeforms are deliberately sent out through the universe by intelligent civilizations .
article_snippet.sent: Dr Wainwright said the ball, which is about the width of a human hair, could be an example of directed panspermia.
article_snippet.sent: However, the idea of directed panspermia has been proposed by some heavyweight scientists.