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In the early 2000s, scientist Joe Kirschvink of the California Institute of Technology suggested that life originated on Mars and only then came to Earth. Later, other scientists cautiously spoke out in favor of the hypothesis.
What is panspermia
Panspermia is the idea that life originated somewhere outside the Earth and only then was transferred to our planet through outer space. This concept originated in ancient Greece, but in the twentieth century it again attracted attention thanks to the Swedish physicist and chemist Svante Arrhenius. In 1908, the scientist suggested that bacterial spores could be carried by the solar wind from star to star and end up on habitable planets.
Too implausible theory
At first, the scientific community refuted the developments of Arrhenius. Given the vastness of space and the tiny space occupied by the planets, it seemed statistically unlikely that spores could make such a journey.
Even if that happened, the seeds would most likely fall on the central star of the planetary system and burn out. In addition, they would not survive the time required to travel from one system to another. Even the most studied Martian meteorite, ALH 84001, took several million years to get from the Red Planet to Earth.
Interspace bacteria
Ten years after Kirschvink, another researcher, Stephen Benner of the Foundation for Applied Molecular Evolution, also spoke in favor of this hypothesis. Another prominent scientist who promoted panspermia was the physicist Fred Hoyle. His idea was that pathogens, such as influenza viruses, came to Earth from space. But this theory is not biologically plausible. Disease-causing agents evolve with their host, and since there are no humans on other planets, as skeptics suggest, a life form from outer space could not have adapted so well to infect us. However, science knows that comets and asteroids may have brought the “building blocks of life”—amino acids—to the early Earth.
Experimental evidence
Bacteria without a thick protective layer are too vulnerable in space. But what if they were protected inside a meteorite under several layers of sedimentary rock? After the emergence of the hypotheses of Kirschvink and Benner, many experiments were carried out that showed that this is a completely possible scenario. Microscopic travelers would be able to survive a flight from Mars to Earth. Moreover, studies of the ALH 84001 meteorite have shown that its interior has never been heated above 40℃ – and any sterilization begins only at 60℃.
What if we are Martians?
The supposed transfer of life between Mars and Earth would require it to originate on the Red Planet first. This is entirely possible, given that early Mars was warmer, wetter, and very similar to today’s Earth. However, the planet quickly cooled down after its birth. One reason is that Mars was smaller and farther from the Sun. All this gives scientists the opportunity to cautiously proclaim that the hypothesis that we all originated on Mars is not complete madness. But it will be possible to prove or disprove it only in the course of future flights to the Red Planet.