7. Martian Meteorites with Possible Microfossils
Certain Martian meteorites discovered on Earth, such as the famous ALH84001, contain intriguing formations that resemble fossilized bacteria. Although the interpretation of these structures remains hotly debated, they fuel speculation that microbial life— or the building blocks of life—may have traveled between Mars and Earth via meteorites. As discussed in Smithsonian Magazine, these findings keep the door open for an interplanetary exchange of life.