Detection of Extra-Terrestrial Life

Detection of Extra-terrestrial Life

The question "Are we alone?" has been pondered for countless years. According to statistics, every star in our Milky Way Galaxy should contain at least one planet, and tiny rocky planets are incredibly frequent, according to astronomers. With upwards of 100 billion galaxies in our universe and 100 billion stars in our own galaxy, the possibility of life elsewhere seems inevitable based only on probability. For the first time in human history, science is definitely on the threshold of being able to look for evidence of extraterrestrial life around the hundreds of nearby stars.

It was discovered more than 50 years ago that gases in a planet's atmosphere may be remotely sensed to look for evidence of life. A fundamental premise of life is that energy is stored and used chemically, and certain metabolic byproducts will take the form of gases. Biosignature gases are what we refer to as gases created by life that can build up in a planet's atmosphere to detectable amounts. 

In contrast to solar system entities, where in situ investigations are possible, but the number of planetary bodies with the necessary circumstances for life is constrained, exoplanets by virtue of their sheer number can give a vast number of worlds to investigate for indications of life.

Astronomers have been successful in creating a number of techniques to find and describe exoplanets during the past 20 years. Techniques for researching exoplanet atmospheres are included in these strategies. Broadband spectrophotometry has been utilised for hundreds of other exoplanets, however most of them are hot planets that orbit near to their host stars. Only a few exoplanet atmospheres have had their spectra examined thus far.

The next generation of advanced satellite telescopes will allow us to view a select few possibly habitable exoplanets with atmospheres that can be seen in great detail. The upcoming James Webb Space Telescope (JWST) is one of these telescopes. Small space-based direct imaging telescopes are another possibility; however, they are not currently planned to be built by the National Aeronautics and Space Administration (NASA). 

Now you must be thinking that why is it important to know about this? We must accept the fact of planetary variety if we are to not miss our chance to infer the presence of life beyond Earth. There will be a very limited number of possibly habitable planets accessible for observation. We need to be open-minded about which planets can support life and which atmospheric gases might have possible life signatures.

In the far future, we must build and deploy a very huge space telescope (far beyond 10 m in diameter) to identify more than 100 exoplanets that may one day support life and analyze their atmospheres for biosignature gases or the possibility that they do. We cannot obtain a probabilistic estimate of the commonality of biosignature gases without many Earth-like planets since false positives are inevitable. 

In other words, even while we might not be able to point to a planet and declare with certainty, "that planet has signs of life," we will inspire confidence that life not only occurs in the solar neighbourhood but is prevalent in our Galaxy if we find enough rocky worlds with biosignature gases.

One of the most important discoveries in the past 20 years of exoplanet discovery is the sheer diversity of exoplanets. Although they are fairly difficult to find, solar system analogues must be relatively uncommon because none have been discovered so far. It appears that less than 10–20% of stars like the Sun are capable of hosting solar systems. Instead, scientists have discovered that exoplanets and exoplanetary systems are incredibly diverse, containing planets of almost every imaginable mass, size, and orbital distance from their host star.

One of the most unexpected exoplanet discoveries is that planets that are twice the size of Earth or less rather than planets the size of Jupiter are the most prevalent. Other notable examples of exoplanet diversity are the abundance of circumbinary planets, compact multiple-planet systems, including at least one with five planets orbiting interior to what would be Mercury's orbit and hot rocky worlds that are anticipated to have surfaces heated by their star to over 2,000 K, which is hot enough to c.

Science anticipates this variability to extend to planetary atmospheres in terms of both atmospheric mass and composition since the range of exoplanet masses, sizes, and orbits serves as an illustration of the stochastic nature of planet formation. Furthermore, observations are not yet able to measure atmospheric composition or provide estimates of atmospheric mass, making the mass and composition of any given exoplanet's atmosphere unpredictable. 

Nevertheless, it is important to review some of the major elements influencing a planet's atmosphere. A planet's atmosphere either originates during planet formation through outgassing or is gravitationally pulled in from the nearby protoplanetary nebula. It is unknown and may vary greatly how much gas is either caught or released.

Due to the escape of light gases into space, continuous outgassing from an energetic young interior, and bombardment by asteroids and comets, the primordial atmosphere of terrestrial planets may be completely altered. Later on, the physical processes that are taking place at the top or bottom of the atmosphere continue to shape the atmosphere. These processes include volcanism, plate tectonics, and the thermal and nonthermal atmospheric escape of light gases.

The detection of life beyond Earth has the potential to be one of the most significant discoveries in astronomy history, and it can be made possible by the discovery and characterization of exoplanets. The presence of atmospheric biosignature gases-gases generated by life that may build up to detectable quantities in an extraterrestrial atmosphere can be used to infer the existence of life. Remote sensing via highly developed space telescopes will be used for detection. 

Lessons from the dozens of exoplanet atmospheres studied over the past decade, such as the difficulty in robustly identifying molecules, the potential for cloud interference, and the long-term limitations from a spectrum of spatially unresolved and globally mixed gases without direct surface observations, moderate the conviction that biosignature gases will actually be detected in the future. The strategy for determining whether there is life elsewhere in the universe is being developed.

We are at a pivotal point in human space exploration history. We can say with certainty that planets circling stars other than the Sun do exist and are commonplace on one side of this barrier. According to research from NASA's Kepler Space Telescope, one in five Sun-like stars should be home to an exoplanet the size of Earth in its habitable zone. 

The reliable detection of Earth-like exoplanets with habitable circumstances and evidence of life inferred by the detection of biosignature gases in exoplanetary atmospheres lies on the opposite side of this large barrier. We might be the first generation in human history to eventually transcend this boundary and discover whether there is life of any type beyond Earth if life is widespread in our neighbourhood of the Galaxy.