Earth is unique. It is the only planet yet known in the Universe to sustain life! Frrom microbes which create curd out of milk in half a day, and others that deliver us fever and common cold or the deadly flu! The birds range from as large as an ostrich on land to a bee Hummingbird, a mere 3 inches in length. The Humpback whale which covers the length of the oceans in a few months to some schools of fish which live out their entire lives in coral reefs. The evolution of all species according to Darwin’s natural selection law has now created a wide variety of creatures on this world with the most intelligent form now in control where ever control is possible.

                                                        Image 1: Earth as seen from the Moon.

But the question now facing us is if the Earth really is unique? Or is it just rare? Or is it downright normal?

The Scale Of The Universe

We live on a fragile island of island of life, in a universe full of possibilities. The perspective of this World as the centre of the Universe according to the the model given by Ptolemy, with everything, from the Sun to the Moon to the planets, and even other stars revolving around the Earth has changed to the one as we know it today, owing to the revolutionary scientific theory by Nicholas Copernicus, based on the model by Aristarchus: the Earth is one of the planets revolving around a medium sized ordinary star, the Sun, which is one of the 400 billions of stars of our galaxy, the Milky Way with have of them much bigger and brighter than the Sun. Then again neither is the Milky Way different in any way in the Observable Universe which itself contains around 100 billion such galaxies.

Image 2: It is here that we are located, on one of the arms of the gigantic Milky Way as denoted by the arrow.

A Modest Search

Everything in this vast universe has the same modest origin, of that of the primordial mixture of Hydrogen and Helium. Everything, the laptop on which I am working, the building where we live, the Earth, the Solar System, the most distant star visible is a by-product of the same cosmic dust. Hence this leads us to guess and that there must somebody out there living as we are. Even if our galaxy is devoid of any life, there are still 100 billion galaxies out there, giving a total estimated count of 10 to the power 22 stars! Thus began the organisation SETI, or the Search for Extra-terrestrial Intelligence, around  60 years ago, which is a determined organization working on the possibility, if not probability, of finding some cosmic company out there sending out signals in the optical and radio wavelengths.

Image 3: The Hubble Deep Field Image showing a large number of galaxies in which the Milky Way is also one among them! And that is where we are!

The Drake Equation

In 1961, astronomer Frank Drake gave the famous Drake equation at the first scientific meeting on SETI to estimate the number of civilised alien planets that can be found in our Milky Way itself. It is a statistical equation that can be used to find the number, N, of civilizations capable of radio communications, not primordial life as:

 Image 4: Frank Drake, who gave the Drake Equation estimating the number of advanced alien civilizations in our own galaxy.

The Drake equation is:

N = R * f_p * n_e * f_l * f_i * f_c * L

Where:

N = the number of civilizations in our galaxy with which communication might be possible,

R = the average rate of star formation in our galaxy,

f_p = the fraction of those stars that have planets,

n_e = the average number of planets that can potentially support life per star that has planets,

f_l = the fraction of planets that could support life that actually develop life at some point,

f_i = the fraction of planets with life that actually go on to develop intelligent life,

f_c = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space,

L = the length of time for which such civilizations release detectable signals into space.

The original estimates of this simple yet ingenious equation are 20 <N <50,000,000. It shows that it is possible to find as many as 50,000,000 races of beings which are at least as technologically advanced as human beings are! This might just reduce the cosmic loneliness, even at least in theory!

From a millennium the question which was being asked to the priests and philosophers for guidance and instruction if there are cosmic intelligent beings out there are now not just a topic of debate and discussions. The tools of the 21^st century such as the high resolution ground and space based telescopes has enabled us to observe rather than believe what is supposed to be.  Instruments operating in almost all wavelengths of the electromagnetic spectrum from the radio, infrared to visible, UV and X ray, since the 1980s till now, the number of known exoplanets has gone up from 0 to around 3500 in around 2600 solar systems with more being discovered with each passing day and the construction of better telescopes like Hubble space telescope, Kepler Space Telescope, Spitzer Space Telescope to the newer James Webb space Telescope, Wild Field Infrared Survey Telescope and such.

Extremophiles

                             Figure 5: A few extremophiles discovered by biologists.

According to astrobiologists, the question as to whether we have cosmic neighbours can be addressed scientifically for the first time in human history now. The discovery of extremophiles in the wildest range of temperature, pressure,  pH, salinity, desiccation, oxygen and radiation and their study on Earth is leading us closer to understanding the minimum conditions for life in the universe to exist.

Thus being in this goldilocks era, astrophysicists, amateur astronomers and space enthusiasts are making the most intensive search for alien life to the most sensitive scale yet by procuring the some of the huge telescopes yet built by man.

               Figure 6: Left: The Australian Parkes Observatory in South Wales

                               Right:  The American Green Bank Observatory in West Virginia.

One of the most famous astrophysicists of the time to know the importance of finding alien life and to extend his support and join the hunt is the British Stephen Hawking. The program, aptly named, Breakthrough Listen, has been searching the nearby 100 galaxies in the radio wave wavelength using two of the most powerful dishes, i.e., the Australian Parkes Observatory in South Wales and the American Green Bank Observatory in West Virginia. Aiding in the optical section is the telescope at the Lick Observatory. The hunt started around one and a half years ago(January 2016) funded by the Russian internet billionaire Yuri Milner as a $100 million initiative to go on for 10 years.

The program is nearly 50 times more sensitive than any previous searches and it covers around 10 times the sky, scanning the entire center of the galaxy and the entire length of the Milky Way. The vast amount of data that has been accumulated and being collected are analysed and searched for alien signals by millions of volunteers working online. The data has been uploaded on the website seti@home from April 2016 and it is just a matter of downloading the software and going!

One of the most recent discoveries that could find a potential alien life is a dwarf planet around 3 billion light years from us that is giving off short radio bursts with increasing power. Is the star hosting a civilization capable of sending such decodable radio signals into space for detection or is it one more new discovery that will add to the growing astronomical dictionary is a still open question.

ET in Literature

Figure 7:  From the left- All Around the Moon book cover, The 12^th Planet book cover,  ET movie poster, Avatar movie poster

Human’s innate need to explore the world around them, or in this case, the universe and not be in the “dark” can be seen from ages depicted in literature. Popular books such as From the Earth to the Moon(1865), Around the Moon(1870), Chariots of the God (1968), Gods from Outer Space (1969), The 12th Planet (1976),  Our Cosmic Ancestors(1990) or the more recent Ancient Aliens and the Lost Islands: Through the Wormhole(2013) and so many more, movies such as A Trip to the Moon(1902), The Thing from Another World (1951), Star Wars (1977), Alien (1979), ET Extra Terrestrial(1982), Avatar (2009), Prometheus(2012)show that Humans imagined alien form to exist in the world beyond us from generations.

Are We Alone?

So, now it is only a matter of time before thus vexing question of whether we are alone, and in that case, its such a waste of space! But what if we are not? What if there are others asking the same questions as we are about the cosmic origins, about the meaning of this life? What if they are looking at the same stars as we are? Only from a different side. What a discovery both would be!