Living things can be transferred between planetary bodies.

Panspermia is the hypothesis that life exist throughout the entire Universe and may be distributed via space dust, asteroids, comets or spacecraft contamination; this idea dates back as far as 500 B.C.
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Living things cannot survive interplanetary travel long enough to colonize other locations.

Life is too fragile to survive harsh space travel conditions and likely emerged abiotically.
Created at: 
2020-04-04
  Updated at: 
2020-04-06
Curator:
Maria Catalina Granada   Subscribe ...

Background

Survival of life under space conditions

Conditions in Space: (1) High radiation damage, (2) Extreme temperatures, (3) Collisions, (4) Dehydration, (5) Lack of oxygen, and (6) Low pressure.

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There are numerous examples of organisms temporarily surviving space conditions like UV and dehydration.

eBacillus subtilis spores found viable after 6 years exposure to space conditions.

eBacillus subtilis spores survive in interstellar conditions

eTardigrades can survive space conditions like extreme dehydration and radiation.

eRock colonizing eukaryotes, like lichen and fungi, show partial survival in space.

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Biological organisms are so sensitive that they could not survive a high-speed impact.

ePanspermia implies a biologically weak protocells could survive harsh conditions during space travel.

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Organisms are capable of surviving the landing during panspermia.

eBacterial spores, cyanobacteria, and lichen embedded in a Martian analogue rock survive meteorite-like levels of shock.

Historical records

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Life on Earth had different origins and have varying survival rates.

eBacterial spores, cyanobacteria, and lichen embedded in a Martian analogue rock survive meteorite-like levels of shock.

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All life on Earth depends on relatively the same mechanisms.

eLife seen on Earth relies on relatively the same metabolic mechanisms.

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Evidence of panspermia has never been found anywhere on Earth or surrounding planets.

eDespite a range of modifications to the Panspermia theory, no proof of life existing outside of Earth has ever been found.

Evidence for abiotic origins

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It is possible that life had an abiotic origin on Earth because research shows similar lab conditions result in building blocks needed for life to exist.

eIt is possible to generate amino acids, the building blocks of life, by simulating early-Earth conditions.

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A primitive Earth was able to abiotically produce self-replicating molecules that we now know are essential to life.

eThe first self-replicating system was RNA.