It may not take an asteroid strike to transport life from one planet to another.
Fast-moving dust could theoretically knock microbes floating high up in a world's atmosphere out into space, potentially sending the bugs on a trip to another planet — perhaps even one orbiting a different star, according to a new study.
"The proposition that space-dust collisions could propel organisms over enormous distances between planets raises some exciting prospects of how life and the atmospheres of planets originated," study author Arjun Berera, a professor in the School of Physics and Astronomy at the University of Edinburgh in Scotland, said in a statement.
"The streaming of fast space dust is found throughout planetary systems and could be a common factor in proliferating life," Berera added.
Berera isn't the first person to propose that organisms could hop from world to world throughout the cosmos. That basic idea, known as panspermia, has been around for thousands of years. It has received renewed interest recently, however, as scientists have demonstrated that some organisms — such as certain bacteria, and micro-animals known as tardigrades — can survive for extended periods in space.
But researchers have generally regarded comet or asteroid impacts as the only viable way to get simple life-forms off a planet and into space, whence they could perhaps blunder their way to a different habitable world. (We won't consider here the "directed panspermia" idea, which posits that intelligent aliens have seeded the galaxy with life or its building blocks.)