As Adam Frank has said over on the 13.7 blog, “Earth and Mars have been swapping spit (astrobiologically speaking) for eons … [and] it is entirely possible we were Earth’s first alien invasion.”
As Adam Frank has said over on the 13.7 blog, “Earth and Mars have been swapping spit (astrobiologically speaking) for eons … [and] it is entirely possible we were Earth’s first alien invasion.”