SO, WHERE ARE THE ALIENS? (PhYLenZ-1)

An Introduction to Fermi Paradox and it’s Solutions 

The observable universe is 90 billion light years in diameter and is a home to about 100 billion galaxies.  Each of those galaxies is said to be home to 100 billion to 1000 billion planets. We can very confidently claim that there are trillions of planets in the universe that are habitable, so we must not be the only intelligent life in the universe right, or are we?

At this point we must realize that even if there is intelligent life beyond our home galaxy, we will never be able to find them or communicate with them, since it would take us billions of years to reach another galaxy even at the speed of light. Therefore, let us focus on our immediate galactic neighborhood i.e. the Milky way.

The Milky way has an approximate of 20 billion sun-like stars harboring their own solar system, about 1/5^th of these solar systems have a planet in the habitable zone, which equals 4 billion habitable planets. Considering that the Milky way is 13 billion years old and cooled off 1 to 2 billion years after its birth, and life on Earth is relatively young, about 4.5 billion years old (The earliest evidence for life comes from 3.4 billion-year-old mats of bacteria called stromatolites in Australia. Since even bacteria are biologically complex, scientists think they arose from life forms that got a foothold on Earth even earlier.), there has been a lot of time for other habitable planets to develop very advanced civilizations. So, if the aliens are there, why haven’t we found them yet?

The Fermi Paradox seeks to answer the question of where the aliens are. As the story goes, Italian Physicist, Enrico Fermi, famous for creating the first Nuclear reactor, came up with the theory as a casual lunchtime remark in 1950. What he didn’t realize was that, the theory had “cosmic” implications!!

"Fermi realized that any civilization with a modest amount of rocket technology and an immodest amount of imperial incentive could rapidly colonize the entire galaxy," the Search For Extraterrestrial Intelligence (SETI) Institute in Mountain View, California, said on its website. "Within ten million years, every star system could be brought under the wing of empire. Ten million years may sound long, but in fact it's quite short compared with the age of the galaxy, which is roughly ten thousand million years. Colonization of the Milky Way should be a quick exercise."

Fermi died soon after in 1954, and therefore never formally gave the solution of his paradox, but this job has been taken up by other researchers, such as Michael Hart [1], who wrote an article titled "An Explanation for the Absence of Extraterrestrials on Earth" in the Royal Astronomical Society (RAS) Quarterly Journal in 1975, which is believed to be first work on Fermi Paradox.

In his paper, Michael simply says that the reason that we do not have evidences of intelligent life is because “there is no intelligent life outside Earth”.

"We observe that no intelligent beings from outer space are now present on Earth," Hart wrote in the abstract. "It is suggested that this fact can best be explained by the hypothesis that there are no other advanced civilizations in our galaxy." He noted, however, that more research in biochemistry, planetary formation and atmospheres was needed to better narrow down the answer."

There are many scientists that are of the same opinion as that of Michael Hart, their argument being that there is no scientific evidence of Extra-Terrestrial life, so why should we believe in it? The argument is hard to disagree with, since, as the best-selling author Mark Manson says, “Science is a religion where evidence is worshipped.”. However, various other solutions to the Fermi Paradox have been given, which can at the same time, give us hope and terrorize us.

The next most probable theory says, that there is indeed intelligent life outside Earth, and the reason they have not visited Earth is because Space travel is too difficult because of the energy considerations,  asteroid belts, etc.!!!

A popular theory, given by Robert Hanson, known as “The Great Filter”, suggests that there has indeed been extra-terrestrial life in the past, but it could not pass “The Great Filter”, which are some events, ranging from nuclear wars to climate change to something we can’t even imagine right now, that eliminates some civilizations and prevents them from surviving in the Universe, and only a handful, if any, of civilizations will be able to pass the filter.(It can be thought of as the galactic version of “the survival of the fittest”.) Our planet may have already passed the Great Filter, whereas other civilizations could not, or maybe we will encounter it in the next couple of thousand years and turn into cosmic dust, much like our galactic neighbors.

Another theory suggests that maybe aliens visited Earth a long time ago, and we were too primitive back then to recognize them. After their visit, the aliens didn’t find the Earth to be of any use, and decided to not visit us again. I personally find this theory to be very naïve, since if aliens had visited us in the past, we must have found some evidence.

A group of scientists also claim that there is indeed an advanced civilization (Type 2 or Type 3 civilization in the Kardashev scale) in the universe which is constantly monitoring our progress, but we can’t trace them since they are light years ahead of us in technology. The reason they have not shown any activity on Earth is because they don’t find our planet any useful, or maybe they have kept the world we inhabit as an energy resource which can be utilized as and when required (much like how we utilize the forests, the place less intelligent creatures inhabit, as an energy resource). This theory might seem like the plot of the next Marvel Movie, but it talks about the future technology and well, nobody has seen the future! (except maybe, Dr. Strange.)

There have been interesting developments in Fermi Paradox in recent times.

 In 2015, a study looked at the likelihood of a world evolving with a habitable environment, using data from the Hubble Space Telescope and Kepler Space Telescope. It suggests Earth was an early bloomer. Even though the study excluded intelligent life, the study suggests that our planet’s birth came pretty in the universe's history. When Earth was formed about 4.6 billion years ago, the study said, only "8 percent of the potentially habitable planets that will ever form in the universe existed." In other words, most of the material available to form habitable planets is still around — giving lots of time for alien civilizations to form. 

 

Or perhaps life may be too fragile to survive for long (Something similar to the Great Filter). A 2016 study suggests that the early part of a rocky planet's history can be very conducive to life, as life could emerge after about 500 million years after the planet cools down and water is available. However, after that point the planet's climate could easily wipe life out. Look at Venus (which has a runaway greenhouse effect) or Mars (which lost most of its atmosphere to space). The study was led by Aditya Chopra, who was then with the Australian National University (ANU) in Canberra. 

 

There have also been suggestions that the paradox itself is flawed [2] and we should be looking for alternate ways in our search for our galactic neighbors.

 

Extensive research has been undertaken by institutes such as SETI (Search for Extra-Terrestrial Intelligence) and NASA on the existence of Aliens. The Transiting Exoplanet Survey Satellite (TESS) launched successfully in April 2018 to study nearby stars. NASA's James Webb Space Telescope, which expected to launch in October 2021, will examine planets for the chemical makeup of their atmospheres. The European Space Agency's PLATO (PLAnetary Transits and Oscillations of stars) is expected to launch in 2026. And larger ground-based observatories are also being envisioned, such as the European Extremely Large Telescope that should see first light around 2024.

The irony is, although we are searching for aliens in the extreme corners of our universe, we have not fully eliminated the possibilities of life in our own Solar System. The discovery of the fact that microbes can survive even in the most hostile conditions, has led scientists to the speculation that there may be life on Mars, the icy-Jovian moon Europa, or Saturn’s Enceladus or Titan.

The belief that we are the only civilization in the universe seems ridiculous to me. The odds are too high for that to happen, and if we really are alone in this vast universe, then it’s truly a miracle and humanity should be making all the possible efforts to sustain life for as long as possible.

But ultimately, these are all speculations without any concrete proof. So, until we find an evidence of extra-terrestrial life, we are left to look upon the starry night sky and wonder “Are we really alone?” 

BIBLIOGRAPHY:

1. http://adsabs.harvard.edu/full/1975QJRAS..16..128H

2.   Robert. A. Freitas Jr., There is No Fermi Paradox, I( ARL)S 62, 518--520 (1985)

3. https://www.space.com/25325-fermi-paradox.html

 AUTHORS:
  1) VARUN UPRETI (2nd Physics) [1st author]                                                                                         2) DEEPANSHU BISHT (2nd Physics)[2nd author]