Panspermia is a hypothesis about the appearance of life on Earth. Evidence of panspermia

Among the theories about the origin of life on Earth, the hypothesis of panspermia takes a special place. This concept is quite exotic. It says that life on our planet has a cosmic nature. Her embryos were brought to Earth from another heavenly body (for example, a comet) or even an alien ship. Panspermia is an idea whose appearance is associated with the name of the ancient thinker Aristotle. A supporter of the theory was the one who lived in the 17th-18th centuries. Gottfried Leibniz. However, only at the beginning of the 20th century panspermia ceased to be only a philosophical reasoning and acquired various scientific substantiations and models.

Radiation panspermia

In 1908 Swedish scientist Svante Arrhenius put forward a concept called the theory of radiation panspermia. The physicist suggested that the first spores of bacteria appeared on Earth after migration from the far corners of the universe. The reason for this "resettlement" Arrhenius considered the pressure of sunlight (or the light of another large star).

This hypothesis of panspermia has many supporters. The most probable ancestral home of life these scientists call Venus, from where the heat-resistant bacteria could get to Earth at a time when the two planets were at the smallest distance from each other.

Light pressure factor

The existence of light pressure even before Arrhenius was experimentally proved by the Russian physicist Pyotr Lebedev. In addition, he analyzed the effect of this phenomenon on spores of lycopodium (plauna). In connection with this in the XIX century, the theory of panspermia was supported by Ferdinand Kohn, Justus Liebig, Hermann Helmholtz and other eminent scientists of his time.

At the same time, in the 20th century this concept was criticized by many different researchers. Among them were Joseph Shklovsky, Karl Sagan and many others. Opponents deny evidence of panspermia on the grounds that long-term space migration can not do without obtaining a harmful dose of radiation for a dispute.

Space guests

In a generalized form, the theory of panspermia states that a vacuum in which bacteria can stay for a long journey can not interfere with their vital activity, since at extremely low temperatures the cells are in a frozen state (anabiosis). Theoretically, such guests could "wake up" right after their arrival on Earth, where, thanks to a concatenation of many circumstances, there were comfortable climatic conditions.

The above ideas were refuted by modern scientists. Studies in laboratories have shown that in a cosmic vacuum the cell simply explodes because of the ultra-rapid evaporation of its own water. As a result of this process, microorganisms are destroyed by excessive internal pressure. This is the main argument of specialists who believe that radiation panspermia is a myth.

Litopanspermia

Another type of panspermia is lithospanspermia. The founder of the theory Melvin Calvin believed that the rudiments of life could get on our planet together with a meteorite. Until now, this concept of panspermia has not been backed up by appropriate texture.

The tiny remnants of meteorites burned in the atmosphere do fall to Earth. Such materials have been studied by a wide variety of scientists, but no one has ever been able to detect traces of life on them or in them. Scientists recorded only certain biological substances (for example, fatty acids and amino acids).

Comet concept

Another hypothesis about the appearance of life on Earth, associated with panspermia, is the so-called comet theory, set forth in Fred Hoyle's book The Cloud of Life. In this publication, the author tried to prove the consistency of his concept on the example of global virus epidemics (including the example of the Spaniards of the early twentieth century). Hoyle suggested that such a massive disease (pandemic) can be explained by their cometary origin. Just like viruses, life could get to Earth, the author claimed.

There are also arguments among opponents of the theory of the cometary origin of bacteria. Most virologists agree that, for example, the flu epidemic in Hong Kong in 1968-1969. Much more logically explained by the transmission of infection from person to person and its evolution in the fight against the immune system, rather than the idea of its cosmic roots. In addition, lithospansmia is a hypothesis that can not explain how a meteorite with bacteria got into the solar system from another stellar system, where, perhaps, there are signs of life.

Directed panspermia

In the 1970s. In the scientific community there was one more bold theory of the origin of life on Earth - directed panspermia. This hypothesis would not have been, had it not been for the then-popular theme of extraterrestrial intelligence. If you believe directional panspermia, then the first embryos of life were on Earth by the will of a civilization that exists somewhere in the depths of space. Perhaps, spores and bacteria were sent on a special apparatus, and this was done to create a colony or conduct a scientific experiment.

Supporters of the idea of directed panspermia as its proof remind that all terrestrial organisms have in their structure metals rare for our planet, including molybdenum. Another argument is the nature of the genetic code. The origins of this phenomenon have not yet been fully understood. Because of the many white spots, the most incredible assumptions appear, in particular, the hypothesis of directed panspermia. Her apologists believe that all terrestrial organisms originated from a common ancestor (microorganism), which appeared here due to extraterrestrial civilization. Meanwhile, there is still no clear evidence of the existence of the aliens and their visits to Earth.

Cosmic dust

Another panspermic hypothesis is reduced to the assumption that the Earth was formed from cosmic dust, which already had embryos of life. In this case, the bacteria could survive only if the stable temperature on the new planet was maintained. However, research scientists have shown: in the early stages of its existence, the Earth was a hot ball, which continued to cool for many millions of years.

Nevertheless, cosmic dust as a carrier of life could reach our planet much later. This is another hypothesis that panspermia offers. To put it briefly, these assumptions are untenable, that in the 1970s. Proved, among other things, the Soviet scientist Lev Mukhin. Any complex organic compounds must first cross the dense layers of the atmosphere before they find themselves on Earth, where they burn together with meteorites and other cosmic objects.

"Living" precipitation

New disputes about the cosmic nature of earthly life began in 2001, when a unique red rain took place in the Indian state of Kerala. Exclusiveness of this natural phenomenon was not only in the unexpected color of precipitation. Witnesses of the rain reported that before the shower they witnessed an extraordinary thunderstorm and powerful flashes of light.

The phenomenon of red rain attracted the attention of scientists and amateurs from all over the world. Further studies showed that the true cause of the unnatural color was the particles that were in the water in the form of suspended matter. The culprits of the sensation turned out to be disputes. For the supporters of panspermia, this fact has become yet another argument in favor of the concept of the cosmic sources of earthly life.

Could billiards of years ago have passed over the Earth the first such rain out of a dispute that was never on the planet before? Most experts interpreted the events in India differently. The scientists found that the spores that fell with the red rain belonged to the epiphytes, a common plant species that is growing everywhere in this part of the world. Thus, the precipitation was only an episode of the cycle of organic substances in nature. Nevertheless, the episode with the red rain in Kerala demonstrated how hypothetically the settling of the Earth by life could occur.

The search continues

To date, no one has ever been able to detect signs of life outside the Earth (including in meteoritic matter that hit the third planet of the solar system from space). Periodically in the media there is a sensational information about such finds, but in actual fact it turns out to be a misinterpretation of facts or deliberate lies. Often, inorganic compounds, such as bacterial compounds, are accepted for organisms. Besides, getting to the Earth, space matter is "polluted" by terrestrial life, which even more confuses observers.

All these arguments show that panspermia is a dubious hypothesis, which has no evidence base. However, scientific skepticism does not prevent a significant number of enthusiasts from continuing to search for arguments that support such theories.