Space Microbiology: Does Space Have Life?

 

Earth is the only living planet in the universe till now. There is the expanse that exists between earth and celestial bodies that is called outer space or space. The space is highly vacuum but not empty as meteorites are present in space. There is absence of oxygen in the space.

But the absence of oxygen in space does not mean that nothing can survive there. It is known to all that the smallest living organisms are microbes that are present everywhere even in outer space also. Various researches are going on to know about the existence of life beyond earth.

Thus, researchers are trying to discover the presence of micro-organisms in outer space as micro-organisms are considered as the primitive form of life. Some researches are going on to know that the microbes present on earth can grow in space environment or not.  

According to the theory of origin of life on earth, bacteria were the first living organisms which were originated in early earth’s conditions. The study of the existence of micro-organisms and the survival efficiency of the earth’s microbes in outer space is called space microbiology.

Space environment conditions

Before the study of life in outer space it is very important to know about the environmental conditions of outer space. There is the most extreme environment present beyond the earth’s insulating atmosphere.

Space has hard vacuum conditions (10^-6 to 10^-9 torr). This hard vacuum condition can cause outgassing (means release of molecules from the surface of materials in gaseous form).

The space also contains atomic oxygen. The atomic oxygen is formed when molecular oxygen splits by the short wavelength ultraviolet radiation. The atomic oxygen makes space environment very oxidizing in nature. This can cause mutation in organisms.

There is the presence of ultraviolet radiation in space. Ultraviolet radiation is the damaging radiation that comes from the sun and has the ability to alter the genetic material of any organism which led to mutations. The space environment also contains particulate or ionizing radiations.

The ionizing or particulate radiation is produced by charged particles which are present in the form of galactic cosmic rays, solar proton events, and trapped radiation belts in the space. The ionizing rays can also cause mutations in living organism’s genetic material.

Space environment also contains space plasma which consists of equal amount of positively charged oxygen ions and free electrons, which varies with solar activity. Besides, the above components the space has extreme temperature in range of -120°C to 120°C.

In space all organisms have to face microgravity that means the weight of anything present even any living organism in space will be less than their weight on earth.

Some micro-organisms isolated from space station

Although the presence of micro-organisms in space is not fully accepted yet due to its extremely harsh conditions, but there are some research reports that tell about the presence of some microbes in the space station or sample collected from space.

According to a research article one new bacterial species named Solibacillus kalamii was isolated from HEPA filters international space station. According to the research Solibacillus kalamii possesses an extraneous layer on its cell surface which can protect it from radiations.

But this research has been be fully accepted, as HEPA filters are installed in space station which inhibit the entry of any type of dust, microbes, etc. in the space station and the waste collected in space destroys as soon as it gets exposed to earth’s environment.

According to a research many bacteria and fungi were isolated from the international space station. It was found that 26% of total bacteria were Staphylococcus aureus, 23% were Pantoea and 11% of total bacteria were Bacillus.  

Bacteria were isolated from different space stations and it was observed that different bacteria were isolated from different space station this happened because of difference in microflora of different humans.

The researches going on under the discipline of space microbiology involves observing the difference in growth of known microbes growing under space and earth’s condition by sending microbial sample in space via space station.

These types of researches are done to know if any novel molecules are being produced by microbes in outer space condition which can be used for human welfare.

According to some articles, it has been observed that the pathogens grown in space condition are less virulent than the microbes grown in earth’s condition as harsh conditions of outer space decrease the virulence of pathogens by mutating virulent genes.

In some researches it was observed that the pathogens survived under space conditions become more dangerous than earth’s pathogens as the mutations in virulent genes caused by UV radiation in space made pathogens more virulent than previous.

Besides, alteration in virulence extreme conditions of space can also affect the resistance of microbes towards anti-microbial agents. The UV radiation can cause mutations in resistant genes and can increase or decrease the resistance of pathogens.

Researches that support the existence of microbes in space

In laboratories the space’s extreme conditions like microgravity, cosmic rays, UV radiation and others are artificially created and experiments were done. The results tell that the presence of UV radiation is the major cause of inhibition of microbial growth.

The UV radiations can kill the microbes but if the microbes will reside under some protective layer then they can survive for few hours or weeks and the bacterial or fungal spores can live 6-10 years in space under protective layer like meteorites.

       

Written by – Bhavana Thakur