Panspermia is one of the theories of the origins and creation of life on our planet, according to which life forms appeared on Earth from the outside of the Universe and are transferred through asteroids, meteoroids, and other celestial bodies that collided with planets (Wickramasinghe, 2011). The theory also runs that the life forms delivered to Earth can start the evolution process if the conditions for survival are appropriate. Although the theory can hardly compete with other hypotheses, there is still certain evidence that points to the extraterrestrial roots of life development.
One argument suggests that the life emerged soon after the collision of the Earth with other celestial bodies about 4 billions years ago. During this period, the Earth experienced sequences of meteor showers. At the same time, there is also the evidence that demonstrates that the bombardment phase occurred 3.8 years ago (Joshi, 2008). These investigations prove that living organisms would have faced extinction, should life not originate on Earth.
The theory of panspermia has a number of contradictions. In particular, provided the theory is true, there should a permanent planet containing these bacteria that are distributed through meteoroids and asteroids. The research of the universe assumes life would have faced serious challenges, surviving outside our planet. At the same time, it should be stressed that life on Earth can stand extremely high and low temperatures, from -196º C to 113º C (Joshi, 2008).
Moreover, there are species that can withstand high dozes of X-ray emission, high pressure, or UV radiation. The definition of life should be reconsidered as well when it comes to panspermia because not all living organisms are cable of activating their evolutionary processes.
Despite certain discrepancies and contradictions, there are research findings that cannot withdraw the ideas of transmitting seeds all over the universe. Specifically, Vaidya (2009) has commented on the flight of the Stardust spacecraft that captured the fractions of comet to analyze the samples and detect any displays of life in space. The scholar has concluded, “Stardust findings made it clear that some cometary materials formed in regions with temperature above 2000 K while others…appear to have been formed in regions below 40 K” (Vaidya, 2009, p. 227). Specific biophysical conditions of life distribution in space have been discussed by many researchers.
According to Wesson (2010), biophysical conditions of most bacteria transferred through the Milky Way are severe and, therefore, the living organisms are frozen and activated only when the conditions are appropriate for the evolution process. There is also a discovery about the simplest form of life – the extremophiles – existing on the Earth under severe conditions, but previously these conditions were considered normal.
In conclusion, it should be stressed that the theory of panspermia is one of the most tangible hypotheses explaining the emergence of life on the planet. It suggests the idea that life has been delivered to earth via asteroids and meteoroids that collided the Earth billions years ago. Despite the probability of this theory, there are many contradictions concerning its validity. Specifically, the origin of these seeds travelling through Universe is unclear because there should be the planet that distributes these living organisms.
Second, it is also impossible to state whether transmission of these organisms through the Milky Way can withstand the intolerable temperature conditions and radiation. Overall, the possibility of the evolution process deriving from panspermia has the right to existence due to a number of irrefutable findings.
References
Joshi, S. S. (2008). Origin of Life: The Panspermia Theory. Science in Society. Web.
Vaidya, P. (2009). Stardust Findings -Implications for Panspermia. Apeiron: Studies In Infinite Nature, 16(2), 225-228.
Wesson, P. (2010). Panspermia, Past and Present: Astrophysical and Biophysical Conditions for the Dissemination of Life in Space. Space Science Reviews, 156(1-4), 239-252.
Wickramasinghe, C. (2011). Astrobiology And Panspermia. Consciências, (4), 69-74.