MIGRATION THEORY: MAIN CHARACTERISTICS - SCIENCE - 2024

The migration theory, also known as panspermia, is a theory that defends that the origin of life did not occur on Earth but elsewhere in the universe.

Life would have arrived on planet Earth transported by meteorites, asteroids or comets. According to some theorists, he could even have done it aboard a spaceship, although this part of the theory is unofficial.

The basic idea behind the migration theory is that some single-celled organisms, known as Extremophiles, could survive the conditions of space.

These organisms could travel through the universe and colonize new planets over millions of years.

Basic ideas of migration theory

Although there are several versions of the panspermia theory, most have a number of main ideas in common.

The most important is that life on the planet arose from single-celled organisms that arrived on Earth hundreds of millions of years ago.

The migration theory does not pretend to explain the origin of life in the universe, but only offers an explanation to the question of how living beings emerged on the planet.

It also serves as a possible theory to try to clarify how life extends through space.

Despite sharing some basic ideas, scientists and other proponents of panspermia disagree on the exact mechanism that helped single-celled organisms spread between planets.

There are basically five versions of the theory: radiopanspermia, lithopanspermia, accidental panspermia, targeted panspermia, and pseudopanspermia.

The 5 main versions of the migration theory

1- Radiopanspermia

Stars and other celestial bodies in space emit a large amount of energy in the form of radio waves.

Radiopanspermia theory proposes that some particles, such as small single-celled bacteria, could be transported through space powered by this energy.

However, several experiments have concluded that even the most resistant bacteria are destroyed if they are fully exposed to the conditions of space.

To survive outside of a planetary environment, they need some protection, such as that provided by an asteroid or meteor.

Therefore, the theory of radiopanspermia is no longer considered as possible in most scientific circles.

2- Lithopanspermia

This version of the migration theory proposes that some microorganisms could reach Earth through meteorites, asteroids or other celestial bodies that collided with the planet.

These celestial bodies were able to travel through the universe after being thrown from the collision between two planets, and after surviving the harsh conditions of space and surviving the entry of the atmosphere, they colonized Earth.

3- Accidental panspermia

According to the defenders of this theory, the first unicellular organisms could reach the planet accidentally, in waste dumped on Earth by a more advanced civilization.

Thus, accidental panspermia proposes that there are other advanced life forms in the universe and that organisms on Earth arose through a mistake they made.

4- Directed panspermia

This version of the theory shares with the previous one the belief that there are other advanced life forms in the universe.

However, defenders of directed panspermia believe that life on Earth is the result of a conscious decision by these civilizations to populate the planet.

Some proponents of this theory even believe that the civilization that brought life to Earth could be made up of humans living on other planets.

5- Pseudopanspermia

This variant of the theory differs from the others mainly in one idea. Its defenders think that there are no living beings capable of surviving the conditions of space and reaching Earth intact.

However, they do believe that organic matter could reach the planet in an asteroid or meteorite, and form a breeding ground on Earth that later gave rise to the first living things.

References

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3. "Origin of life: the panspermia theory" in: Helix. Retrieved on: December 20, 2017 from Helix: helix.northwestern.edu
4. "Panspermia theory" in: Panspermia. Retrieved on: December 20, 2017 from Panspermia: leiwenwu.tripod.com
5. "Early life theories - panspermia theory" in: Thought Co. Retrieved on: December 20, 2017 from Thought Co: thoughtco.com