Aliens may be travelling from one planet to another via meteorites, new study suggests

Astronomers are exploring an unconventional theory that could help narrow the search for extraterrestrial life - the idea of alien life forms "hitchhiking" between planets on meteors in a process called panspermia.

The fringe panspermia hypothesis suggests that microbial life can travel from one planet to another by hitching rides on meteorites or other debris moving through space. If true, it raises the possibility that any alien lifeforms that exist may have attempted to colonize multiple planets, including Earth.

In a recent study, astronomers Harrison B. Smith and Lana Sinapayen proposed a plan for how to detect potential signs of such "alien panspermia" across the over 5,000 confirmed exoplanets that represent some of the most promising candidates for hosting life.

"If panspermia is possible, then it means that scientists could theoretically narrow their search for alien life, even if they don't know specifically what they're looking for," Smith told LiveScience.

The key, according to the researchers, would be to look for commonalities between characteristics of exoplanets that are physically separated from each other. All life forms, whether terrestrial or extraterrestrial, alter the natural balance and atmospheric conditions of the planets they inhabit.

Smith and Sinapayen suggest that if alien life managed to spread between distant planets via meteorites, they would likely attempt to "terraform" each new world to recreate conditions similar to their home planet. This could produce statistical anomalies detectable across exoplanet data.

"If these individual planets show similarities to others within the cluster, it could indicate alien life has travelled to it and began colonization or at least something strange was happening in space," the researchers explained.

However, they acknowledge the limitations of their approach. Panspermia remains an unproven hypothesis, and the proposed technique would require extensive data on exoplanet atmospheres and characteristics to be effective.

Still, with thousands of confirmed exoplanets and growing evidence that the ingredients for life are relatively widespread, exploring unconventional possibilities like alien panspermia could open new avenues in the search for extraterrestrial biology.

"If we go looking for life in the usual way," said Smith, “we may miss important opportunities.”