PANSPERMIA: HISTORY, WHO PROPOSED IT AND MAIN TYPES - SCIENCE

The panspermia is one of the theories about the origin of life on planet Earth. It supports the hypothesis that the origin of earthly life is in an extraterritorial place. It states that the first living things to inhabit the Earth originated elsewhere in space and were later transported to the planet via meteorites or other objects.

For years, many people have tried to answer the mysteries that surround human existence from various fields of study. In the same way, they have tried to solve the unknown about the origin of the existence of living organisms. However, these aspects remain in many ways a mystery to man.

Not only science, but many cultures and religions present their own conclusions about the origin of life. Despite so many opinions, the exact answer to questions about how life originated on Earth and what agents intervened in the process is still unknown. Panspermia aims to shed light on these views.

History of panspermia

According to studies of panspermia, life on Earth is not of terrestrial origin but comes from elsewhere in the universe. Scientists debate among themselves whether it is possible that an organism with the indicated properties arrived on Earth to bring out life on our planet.

This would imply that said source in turn comes from a place in the universe that has the conditions for its existence. Panspermia involves the transfer of bacteria or spores in asteroids, meteorites, comets or stellar dust (carriers of organic matter), which after a space trip lodged and proliferated on the primitive Earth.

If this is true, this life of microbial origin had to go through extreme situations and hostile environments before reaching Earth, such as temperature changes, violent expulsions of means of transport, collisions, the violent entry into the Earth's atmosphere and possible reactions in that receiving environment.

Scientific tests

It sounds quite impossible that any form of life can survive in these conditions, which raises questions about the credibility of panspermia.

However, the supporting scientists have conducted numerous tests to show what could be the definitive answer to the origin of life.

Some of these demonstrate the resistance that bacteria can have and the possibility of their stellar journey. For example, there is talk of the appearance of fossilized bacteria in the meteorite of Martian origin called ALH 84001 and of the presence of DNA molecules in the Murchison meteorite.

Seaweed studies

In another case, the seaweed Nannochloropsis oculata was able to withstand low temperature and impact tests similar to the conditions under which a meteorite could hit Earth. These algae were the product of in-depth study by some scientists at the University of Kent.

Finally the results were exposed in the European Congress of Planetary Sciences. This research also strengthens extraterrestrial life, since these small organisms would be protected in their transport process based on ice and rock. In this way they were able to withstand the extreme conditions of outer space.

Other studies with a longer history suggest the same principle that bacteria are the most resistant form of life. In fact, some were revived years after being frozen in ice or having been sent to the Moon, this test being commissioned from Surveyor 3 in 1967.

Who Proposed Panspermia? Pioneers

Many scientists claim to back panspermia with their studies. Among its pioneers and main advocates are the following:

Anaxagoras

This Greek philosopher is responsible for the first evidence of the use of the term panspermia (which means seed) in the 6th century BC. Although its approach does not reveal a precise similarity with the current findings, it is undoubtedly the first study on record.

Benoît de Maillet

This scientist assured that life on Earth was possible thanks to germs from outer space that fell into the oceans of our planet.

William thomson

He mentioned the possibility that, prior to life on Earth, seeds contained in some meteoric rock have coincided with this environment, generating vegetation.

He stressed that when the Earth was ready to host life, there was no organism on it to produce it. Therefore, rocks from space should be considered as possible carriers of seeds that travel from one place to another, being responsible for life on Earth.

Hermann Richter

This biologist also widely defended panspermia in 1865.

Svante Arrhenius

Winner of the Nobel Prize in Chemistry, this scientist from 1903 explains that life could reach Earth by traveling through space in the form of bacteria or spores in stellar dust or rock fragments, driven by solar radiation.

Although not all organisms could survive the circumstances of space, some could find appropriate conditions for their development, as in the case of Earth.

Francis Crick

He was a Nobel Prize winner thanks to research he conducted with other scientists on the structure of DNA. Francis Crick and Leslie Orgel proposed directed panspermia in 1973, opposing the idea of previous researchers.

In this case, they differ from the chance that the Earth coincided with organisms from space in optimal conditions for them to develop on it. They suggest that it is rather a deliberate and intentional act of an advanced civilization of extraterrestrial origin that sent these organisms.

However, they added that the technological advances of the time were not enough to carry out conclusive tests.

Types of panspermia

Various are the hypotheses and arguments that revolve around panspermia. As research progresses, six types of panspermia have been identified:

Natural panspermia

It determines that the origin of life on Earth is from an alien source that, by overcoming a stellar journey in extreme conditions and finding an optimal environment for its development, is housed in it.

Directed panspermia

He proposes that, while life on Earth could have been carried out by highly resistant bacteria that survived the hostile environment of space travel and arriving on Earth in fragments of rocks, asteroids or comets, it did not happen by chance.

Directed panspermia posits that life is the product of the deliberate action of advanced extraterrestrial civilizations that intentionally seeded life on Earth.

Francis Crick is one of the biologists who proposes and defends this research, making known in 1973 together with Leslie Orgel the progress of his studies. This intentional transport through space of small organisms could not only be from other planets to Earth, but also from Earth to other planets.

Molecular panspermia

He explains that what really travels in space are organic molecules, whose structure is so complex that when encountering an environment with suitable characteristics for its development, they trigger the reactions necessary to generate life.

Interstellar panspermia

Also known as lithopanspermia, it refers to the rocks that work like spaceships when being ejected from their home planet.

These rocks contain and transport from one solar system to another the organic material that will generate life, protecting it from the extreme conditions of space, such as changes in temperature, velocity of expulsion, entry into the host planet's atmosphere and violent collisions.

Interplanetary panspermia

It is also known as ballistic panspermia. It refers to rock vehicles ejected from one planet to another, but unlike interstellar panspermia, this exchange happens in the solar system itself.

Radiopanspermia

He argues that the microorganisms that travel in stellar dust are powered by radiation from the sun and stars.

Svante Arrhenius explained that very small particles, smaller than 0.0015 mm, can be carried at high speed due to solar radiation. Therefore, bacterial spores can travel this way.

Studies supporting panspermia

Allan Hills Meteorite 84001

Better known as ALH 84001, it is estimated to have lifted off from Mars millions of years ago and impacted Earth. It was found in 1984.

Scientists studied its structure for years and in 1996 discovered remains of fossilized bacteria, as well as amino acids and polycyclic aromatic hydrocarbons.

The idea arose that life could have its beginnings on Mars and traveled to Earth in the same way, as proposed by interplanetary panspermia.

For scientists, Mars is an important option to consider, as it is suspected of containing water in the past. However, although water is essential for life, its presence does not necessarily determine that it exists.

Regarding ALH 84001, most scientists have come to the conclusion that this finding does not confirm the existence of life outside planet Earth, since they could not identify if the material found is the product of contact with the receiving environment or the home environment. In this case, the Antarctic ice could affect its original shape.

Geraci and D'Argenio study

The biologist Giuseppe Geraci and the geologist Bruno D'Argenio from the University of Naples, in May 2001 presented the result of an investigation around a meteorite that they estimated to be more than 4.5 billion years old, in which they found bacteria of extraterrestrial origin.

In a controlled environment of cultivation they were able to revive these batteries and observed that they had DNA different from those of Earth. Although they were related to Bacillus subtilis and Bacillus pumilus, they appeared to be from different strains.

They also highlighted that the bacteria survived the temperature and alcohol wash conditions to which they were subjected.

Studies of the German Aerospace Center

To discern if bacteria survive in space or if it is impossible, scientists from the German Aerospace Center recreated an environment with clay particles, Martian meteorite and red sandstone mixed with spores of bacteria, and exposed them to outer space with the help of a satellite.

After two weeks the scientists identified that the bacteria mixed with red sandstone survived. Another study revealed that spores can survive solar radiation if they are protected inside meteorites or comets.

Stephen Hawking Studies

In 2008 the prestigious scientist Stephen Hawking made his opinion on the subject known, stating the importance of delving into extraterrestrial life and the contributions of said study to humanity.

Considerations about panspermia

Despite great efforts, panspermia has failed to announce irrefutable facts about the origin of life on Earth. Some approaches continue to generate doubts and questions that require further investigation and verification of these studies.

Organic matter is not considered life

Although organic matter - that is, matter composed of carbon like living things on Earth - found in meteorites is common in outer space, it cannot precisely be considered life. Therefore, the discovery of organic matter in space does not imply the discovery of extraterrestrial life.

It implies affirming that extraterrestrial life exists

In addition to this, to affirm that life on Earth comes from space is to affirm that outside this planet there is life and, therefore, an optimal environment with conditions for it to develop.

However, what the studies so far suggest in relation to the environments explored outside our atmosphere is that life would have great difficulty in developing. For this reason, it is worth asking: if there is extraterrestrial life, how did it originate and under what conditions?

In the event that technological advances show that there is extraterrestrial life, this still could not ensure that panspermia is true because it would be necessary to prove that the origin of life on Earth comes from those organisms. This conclusion is impossible without real events that support such a fact.

For now, it is hasty to support panspermia as a theory of the origin of life on Earth since it lacks proven facts.

Even so, this research continues to be an immense contribution to science in its quest to answer the origin of life on Earth and in the universe.

Themes of interest

Theories of the origin of life.

Chemosynthetic theory.

Creationism.

Oparin-Haldane theory.

Theory of spontaneous generation.

References

Joshi, S. S (2008). Origin of life: The Panspermia Theory. Recovered from: helix.northwestern.edu
Panspermia and the origin of life on earth. (SF) Recovered from: translate.google.co.ve
Gray, R (2015). Are we all aliens? Support grows for the panspermia theory that claims life on Earth may have arrived here from outer space. Mailonline. Recovered from: dailymail.co.uk
The origin of the theory of panspermia. (sf) Recovered from: academia.edu
Gannon, M. (2013) Did Earth life come from space? Tough algae suggests panspermia possibility. Space.com. Recovered from: space.com
Theory of panspermia. (sf) AstroMía. Recovered from

astromia.com
Moreno, L. (2013) William Thomson. Eager to know. Recovered from: afanporsaber.com

PANSPERMIA: HISTORY, WHO PROPOSED IT AND MAIN TYPES - SCIENCE - 2025