Scientists at the Harvard-Smithsonian Center for Astrophysics (USA) have found that living organisms are able to disperse throughout the Milky Way with the help of various space objects, including meteorites, asteroids and comets. This is reported by Science Alert.
According to the hypothesis of panspermia, microorganisms or substances necessary for the origin of life are able to move from planet to planet through outer space. Individual cells that are able to survive the effects of vacuum and ionizing radiation can, together with meteorites or even spacecraft, fall on other celestial bodies, where their vital activity is resumed. Some scientists believe that living organisms (or their predecessors) could have come to Earth along with comets billions of years ago.
Previous studies have shown that the transfer of living organisms from planet to planet within the solar system is indeed possible. However, the new work has demonstrated that panspermia can occur between planetary systems within one galaxy and even between galaxies close to each other.
According to scientists, objects like the interstellar asteroid Oumuamua, nicknamed the "alien ship", can serve as "carriers" of life. Planetary systems that contain gas giants serve as gravitational traps for such asteroids. Systems of two or three stars are capable of capturing even free-flying planets that have left orbit around the parent star as a result of a cataclysm. Other astronomers estimate there are about 100 billion such planets in the Milky Way.
Scientists have calculated how many rocky objects carrying living organisms can be thrown out of one system and be captured by another throughout the Milky Way. If life has existed for a million years, then there will be more than a million interstellar "carriers" of life, the size of Oumuamua. Thus, the likelihood of galactic panspermia is influenced by factors such as the size of objects, their speed and the duration of life in the system. Even in the worst cases, different regions of the galaxy are able to exchange potentially habitable celestial bodies.
