Title-: Hello! Are we alone? If you're like me, you may want to know me

Abstract

 A   thin layer near the surface of Earth is teeming with life of huge diversity: from micro-organisms to plants, animals, and  possibly even more intelligent species humans !. Up till now, human forms the only known samples of intelligent civilized life in the Universe? We humans  accepted  that the laws and concepts of physics and chemistry  can be applied  throughout  entire cosmos. Is there  then a general biology as well throughout cosmos ? Is there then also life beyond our planet Earth?   Pinpoints of light in the night sky probably always made human speculate about the existence of many super earths and exo-planets, but the presence of  such  super earths/ exo planets orbiting  many stars/red dwarfs  other than our Sun has become a proven reality only within the last 20 years or so. While the vast majority of the more than   450 of 4034  exo- planets that are known to date are gas giants ^[1]  like our Jupiter and Saturn, some spectacular discoveries of about 20 planets of less than 10 Earth masses have already indicated that  they are rocky planets with conditions suitable to harbor life are probably . One of the big unknowns till date how likely it is for life to emerge once all conditions are right and how many of them are civilized. There is no lack of building blocks of life in space time^[1]!  The number of molecules fundamental to Earth's biochemistry that have already been found in the interstellar medium, planetary atmospheres and on the surfaces of comets, asteroids, meteorites and interplanetary dust particles is surprisingly large. Giant "factories", where complex molecules are being always synthesized,  might appear to make carbonaceous compounds ubiquitous in the Universe.  If the genesis of life arises from chemistry with a high probability, we may speculate whether this process occurred more than once on Earth itself also, leading to the existence of a terrestrial "shadow biosphere" with a distinct tree of Life. Moreover, there are several other promising targets within the Solar System, namely our moon,  Mars, Europa, Enceladus, and, for biochemistry based on a liquid other than water, “Titan”. Evidence for life is not easy to discover ; any chemical footprint needs to be unambiguously characteristic, and to exclude an  abiogenic origin. The most powerful probe would result from returning a sample to a laboratory on Earth. Search for Extra-Terrestrial Intelligence" (SETI) experiments had provided so far  a negative result. However these have probed only up to about 200 light-years distant, whereas the centre of the Milky Way is 25,000 light-years away from earth. And, even if there is no other intelligent life in the Milky Way, it could still be hosted in another of the remaining hundreds of billions of other galaxies.  Advanced efforts are now on the drawing board or already underway for the further exploration of the Solar System and the detection of biomarkers in the atmospheres of extra-solar planets, while searches for signals of extra-terrestrial intelligence are entering a new era with the deployment of the next generation of radio telescopes , or nano probes or DNA Viral probes. The search for life elsewhere is nothing but a search for ourselves, where we came from, why we are here, and where we will be going after death in this planet. It encompasses many, if not all, of the fundamental questions in biology, physics, and chemistry, but also in philosophy, psychology, religion and the way in which humans interact with their environment and each other. The question of whether we are alone in the Universe still remained unanswered before humankind, with no scientific evidences  yet supporting one possible outcome or the other. If, however, extra-terrestrial life does exist, an emerging new age of exploration may well allow living generations to witness its detection.