ASTROBIOLOGY

 

ASTROBIOLOGY

 

 

The study of life in the cosmos is known as astrobiology.

Understanding life, the nature of the settings that support it, as well as planetary, planetary system, and stellar interactions and processes, is necessary for the search for life beyond Earth.

 

 

The study of habitable habitats within the Solar System and beyond, the hunt for planetary biosignatures of past or

current extraterrestrial life, and the investigation of the genesis and early evolution of life on Earth are the three main focuses of astrobiology research.

 

IMAGE CREDIT :- NASA 

 

With the advent of space exploration and the finding of exoplanets in the 20th century, the science of astrobiology was born. Early astrobiology research centred on the investigation of the possibility that life may exist on other planets and the quest for extraterrestrial life. As part of the Viking programme, which was the first US mission to land on Mars and look for signs of life, NASA started its astrobiology efforts in the 1960s and 1970s. Along with other early space exploration missions,

Theoretical foundations: -

Carbon and Organic Compounds:- 

The energy needed to form or break a bond with carbon, the fourth most abundant element in the universe, is precisely

right for creating molecules that are both reactive and stable.

The ability to form extraordinarily lengthy and complex

molecules is made possible by the ease with which carbon atoms connect to one another. As a result, astrobiological research assumes that, like all life on Earth, the vast majority of living forms in the Milky Way galaxy are based on carbon chemistry. Astrobiological research frequently focuses on identifying conditions that have the ability to host life based on the presence of organic molecules. However, theoretical astrobiology entertains the possibility for additional organic chemical basis for life.

 

   Liquid water:-

In general, it is believed that the existence of life as we know it depends on the presence of liquid water, a common

molecule that offers a favourable environment for the

synthesis of complex carbon-based molecules. Because alien life is assumed to be dependent on having access to liquid water, astrobiological research frequently focuses on finding habitats that may be capable of supporting liquid water. For hypothetical forms of biochemistry, some researchers suggest environments of water-ammonia mixes as potential solvents.

 

 

Environmental Stability:

Environmental stability is thought to be important for the existence of life when organisms adapt to the conditions of the surroundings in which they inhabit. As a result, planets circling Sun-like red dwarf stars are the main focus of astro biological study. This entails the necessity of a steady

temperature, pressure, and radiation levels. As a result, life may not have enough time to develop on planets orbiting very large stars; very small stars provide so little heat and warmth that only planets in extremely close orbits around them would not be frozen solid; in such close orbits, these planets would be tidally locked to the star; whereas red

dwarfs have long lifetimes that may allow the development of habitable environments on planets with thick atmospheres.

This is important.

Energy source:-

Any extraterrestrial life would presumably need a source of energy as well. Prior to recent advances in extremophile research, it was assumed that this would necessarily come from a sun-like star. However, modern astrobiological research now frequently focuses on identifying environments that have the potential to support life based on the

availability of an energy source, such as the presence of volcanic activity on a planet or moon that could provide a source of heat and energy.

 

 

It's crucial to remember that these presumptions are based on our existing knowledge of Earthly life and the

circumstances in which it can exist. These presumptions might alter as our knowledge of life and its potential to coexist in many surroundings advances.

 

  Elements of astrobiology: -

Astronomy:-

 

 

The majority of astrobiology-related astronomy research focuses on finding extrasolar planets (exoplanets), with the assumption that if life developed on Earth, it may also develop on other planets with a comparable composition. To that purpose, several sensors have been proposed, most notably the Terrestrial Planet Finder (TPF) and Darwin programmes from NASA and the European Space Agency, both of which have been scrapped. The French Space Agency launched the COROT space project in 2006, and NASA started the Kepler mission in March 2009. Several less ambitious ground-based initiatives are also in progress.

These missions aim to not only find planets the size of Earth, but also to directly detect light from the planet in order to

study it spectroscopically. It would be able to ascertain the fundamental makeup of an extrasolar planet's atmosphere and/or surface by looking at its planetary spectrum.[73] With this information, it might be feasible to determine how likely it is that life will be discovered on that planet. A NASA research team called the Virtual Planet Laboratory[74] is creating a wide range of virtual planets using computer

modelling to see what they would appear like to TPF or Darwin. Once these missions are operational, it is intended

that their spectra can be compared with those of these

hypothetical planetary spectra to look for characteristics that could point to the presence of life.

The Drake equation, which essentially expresses the probability of intelligent life as the product of factors like the fraction of planets that might be habitable and the fraction of planets on which life might arise, can be used to estimate the number of planets with intelligent communicative

extraterrestrial life:

 

 

Drake equation:-

N = R*.fp.ne.fl.fi.fc.L.

N = The number of broadcasting civilizations.

R = Average rate of formation of suitable stars (stars/year) in the Milky Way galaxy

fp = Fraction of stars that form planets
ne = Average number of habitable planets per star
fl = Fraction of habitable planets (ne) where life emerges
fi = Fraction of habitable planets with life where intelligent

evolves

interstellar communication

L = Years a civilization remains detectable

Biology:-

Biology cannot assert that a process or phenomenon must forcibly exist in an extraterrestrial body just because it is technically conceivable. What is speculative and what is not is defined by biologists.[77] In order to understand four aspects of the limits of life in a planetary context—the possibility of panspermia, forward contamination as a result of human exploration endeavours, planetary colonisation by humans, and the exploration of extinct and extant extraterrestrial life—astrobiologists turned to the discovery of

extremophiles, organisms able to survive in extreme environments.

 Up until the 1970s, it was believed that the Sun provided all of the energy needed for life. On the surface of the Earth, plants use sunlight to photosynthesize carbohydrates from carbon dioxide and water, which releases oxygen.

DIVYAJYOTI CHOUDHURY,

SRMIST KTR  , CHENNAI.