The idea of extraterrestrial life has always sparked controversy and debate. In the 16th Century, Giordano Bruno was arrested and executed during the Roman Inquisition, essentially for claiming the existence of an infinite Universe and other worlds. The Roman Catholic Church considered the mere idea of worlds existing, with life, outside of our planet to be ‘blasphemy.’ Many have been persecuted, imprisoned, martyred, executed, or tortured throughout time for having beliefs outside of what was considered the expected norm. Thank God we live in the 21st Century and people are a lot more enlightened now, right?
Let’s look at this question in a practical matter. Are we alone in the Universe? Unfortunately, due to the staggering vastness of space, we simply do not have that information or the evidence to prove that we aren’t alone. The same vastness, however, offers us the probability that we likely share the Universe with some kind of other life form. Science Fiction, whilst entertaining, has perpetuated the scenario of complex, ultra superior societies that dwell many light years away, which has empowered the skepticism of extraterrestrial life. In reality, extraterrestrial life could be as simple as microbial life, but nevertheless, the possibility of complex societies can’t be ruled out completely.
Edwin Hubble discovered in 1923, when he peered through the most powerful telescope at the time, that the Andromeda ‘Nebula’ was in fact the Andromeda Galaxy. This was the first time our civilization was given a glimpse into another world. Until that moment, it was believed that our Galaxy, The Milky Way, was the only galaxy in the Universe. When he looked deeper into the night sky, he saw that there wasn’t just the Andromeda Galaxy, but in fact there were billions of galaxies in our Universe.
NASA’s Hubble Ultra Deep Field imaged above gives us an idea of how vast our Universe could possibly be. The Hubble Space Telescope was pointed at a seemingly empty region of space for 4 months to gather whatever light it could. The image processed shows that each spec of the hundreds of dots of light you see are galaxies– not stars, but entire galaxies. It’s astonishing, of course, to understand that this region of space is but a mere fraction of the known Universe.
This doesn’t prove the existence of extraterrestrial life, of course, but it looks like our probability is getting a little higher. Let’s go back to the Milky Way Galaxy for a moment, our home in the Universe.
Kepler Space Telescope was designed solely to discover exoplanets orbiting other stars in our galaxy. Since it’s launch in 2009, how many planets do you think it has discovered outside of our solar system? 10? 20? 100? In early 2015, Nasa announced that Kepler had discovered its 1000th planet, some of which are “Earth-like” planets.
Our Milky Way Galaxy, one of the 100 billion galaxies+ in the known Universe, contains over 300 billion stars, 100 billion planets, is roughly 100,000 light years in diameter and is the second largest galaxy in the Local Group.
So what does this mean? Does it mean that there are vast alien empires, like in Star Wars, in our Universe? Perhaps, but what we do know for sure, however, is that life as we know it is comprised of only 6 different ingredients; Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulfur (CHNOPS). How organic elements fused together to make living organisms will likely forever be a mystery, but since these 6 ingredients are abundant in our Universe, it’s only a numbers game to figure out the probability of life existing on other worlds.
In the observable universe there are around 70 billion trillion (7 x 1022) stars. That’s a breathtakingly large number of stars. Assuming there are at least 1 ‘Earth-like’ planets in every galaxy, that would leave us with over 100 billion planets capable of sustaining life in our Universe. And that’s just life as we know it. There could be non-carbon based life in the Universe.
So, are we alone in the Universe? Understanding what we know about the Universe, I would say that there would have to be some form of life out there, whether it’s a civilization like ours or merely microbial sludge living on rocks. There has to be something, the numbers are too great, the chances are too high. I can’t say for sure, but it’s rather arrogant to assume we’re the only life forms in such a ridiculously grand Universe, isn’t it?