Updated: Nov 4
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"Somewhere in the universe intelligent life may be watching the lights of ours aware of what they mean,"-Stephen Hawking.
What first comes to mind when you hear the word "alien"; a large saucer flying in the sky, some green creatures with antennas on their head coming out of it, or probably some famous pop culture references like Thanos and "the last son of Krypton". All these fictions are outcomes of humanity's biggest unanswered question "are we alone in this universe?". From aliens invading Earth to them being Earth's savior, these ideas have dominated comics, fiction stories, and movies for more than two decades and have given rise to various franchises. But where most people saw images of a curious mind, Stephen Hawking probably saw a glimpse of unknown truth.
Stephen Hawking is arguably one of the biggest names in the field of theoretical physics and cosmology. The former Lucasian Professor of Mathematics at the University of Cambridge is best known for the discovery of Hawking Radiation in 1976. But apart from his groundbreaking work on Black holes, the man was also famous for his controversial statements and predictions. One such bizarre prediction was the existence of life on other planets and they being an imminent threat to mankind.
In the year 2010, the Discovery Channel produced a science documentary mini-series written by Stephen Hawking named "Into The Universe with Stephen Hawking". It was in the first episode of that series where he first suggested that a sufficiently advanced alien civilization may be hostile, having depleted all the natural resources from their own planet seeking to colonize on others. In his own words
"Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they could reach,”
He also argued about the nature of extraterrestrial lifeform, whether they are intelligent species roaming across space in large spaceships like that in Star Trek or Star Wars (which in his words are his favourite movies) or if they are some weird creatures which we do not even consider as living organisms residing in the bottom of stars. Moreover, with quiet certainty Hawking claimed with the vastness of space and the countless star systems present, there might be one planet where alien life could be thriving or some asteroid in which microorganisms remain in a frozen state.
"So to my mathematical brain, the numbers alone make thinking about aliens perfectly rational"
According to him, there is a stretch of area in the solar system located between Earth and Mars, where the temperature is moderate, thereby leading to the formation of liquid water which in turn leads to the growth of life. Now among the countless stars (200 billion stars present in the Milky Way galaxy alone) present in countless galaxies (two trillion galaxies are observable till 2016), there might be another star system where, under favourable conditions, living organisms may have evolved in one of the exoplanets.
Image source: Wikipedia
In 2016, in "Stephen Hawking's Favourite Places", he reiterated his theories
“Meeting an advanced civilization could be like Native Americans encountering Columbus. That didn’t turn out so well.”
Hawking says in the film while exploring Gliese 832c, a planet that lies 16 light-years away and might foster alien life.
"As I grow older I am more convinced than ever that we are not alone. After a lifetime of
wondering, I am helping to lead a new global effort to find out,"
However, his theories are not completely accepted by his scientific peers. Many of them criticized his theories emphasizing two points mainly
1) the sheer difficulty of travelling in space
2)Human radio transmissions have been leaking into space for decades now, sending a beacon to anyone out there.
“Any society with the capability to threaten Earth is overwhelmingly likely to already have the kit required to pick up the leakage we’ve been wafting skyward for seven decades,”
“And since we’ve been busy for a lifetime filling the seas of space with bottled messages marking our existence and position, it’s a bit silly to fret about new bottles.”
said Seth Shostak, a senior astronomer at the SETI Institute, in a 2016 opinion piece for the Guardian.
Despite the constant criticism, Stephen Hawking persevered in his search for aliens. On July 20, 2015, at the Royal Society of London, The Breakthrough Listen Project was declared. Breakthrough Listen project is an effort to find intelligent extraterrestrial lifeforms and establish communication with them. The announcement included reading out an open letter that was signed by multiple scientists including Stephen Hawking acknowledging their support for finding extraterrestrial lifeform. During the public launch, Hawking said:
"In an infinite Universe, there must be other life. There is no bigger question. It is time to commit to finding the answer."
With $100 million in funding and thousands of hours of dedicated telescope time on state-of-the-art facilities, the project began in January 2016 and is expected to continue for 10 years. The aim of this project is to find signs of extraterrestrial civilizations by searching stars and galaxies for radio signals and laser transmissions. The search for radio signals is carried out on the Green Bank Telescope, the world's largest steerable radio telescope, in the Northern Hemisphere, and the Parkes Telescope, is the second-largest steerable radio telescope in the Southern Hemisphere. Moreover, till 2020, there had been no significant discovery or observation.
Parkes Telescope Green Bank telescope
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In the final paper, that he submitted to the Journal of High-Energy Physics just 10 days before his death, Hawking and his colleague Thomas Hertog at Katholieke Universiteit Leuven in Belgium propose a new theory about what happened as a result of the big bang, and what that means for the existence of multiple universes existing alongside our own.
Although the legendary scientist passed away in 2018, the flame of inquisitiveness that he fanned still burns bright as mankind still searches for answers to the question,
"Are we alone in this universe??"