A possible biosignature gas phosphine was discovered in the atmosphere of Venus' last week
Although scientific evidence of life in inconclusive at this point, scientist believe that the phosphine gases could be caused by microbes residing in the sulfuric-acid clouds of Venus'.
If they are microbes, they could have come from Earth by hitching a ride on a passing asteroid.
The theory was proposed by Harvard undergraduate student Siraj, and Loeb, who heads the university's astronomy department.
"The total number of [potentially life-bearing] objects captured by exoplanetary systems over the lifetime of the solar system is 10^7 to 10^9, with the total number of objects with the possibility of living microbes on them at the time of capture estimated to be 10 to 1,000," Siraj and Loeb wrote in the April study.
While Siraj and Loeb are not claiming that Venus' has life, they are encouraging scientiest to study the possibility.
If true, "extraterrestrial life" on Venus may not be so extraterrestrial after all.