Earth collided with an interstellar cloud millions of years ago  Earth.comAn interstellar cloud may have caused an ice age on Earth. Here's how  Space.comInterstellar winter: Did galactic clouds cause an ice age on Earth?  New AtlasCosmic cloud exposed Earth to interstellar space 3 million years ago  New ScientistAstrophysicists calculate the likelihood that Earth was exposed to cold harsh interstellar clouds 2 million years ago  Phys.org