Dear readers, today marks a very special day. Today is the day I finally discovered the NASA Astrobiology website, which is essentially a haven for amateur exobiologists like myself. (Yes, exobiologist: while astrobiology focuses mostly on carbon-based life forms, exobiology takes into consideration the fact that there may be other types of creatures, such as lithovores – silicon-based life forms.)
Anyway, in honour of today, this blog post will be about the history of exobiology, starting from hundreds of years ago and moving up to the present time.
Many ancient beliefs held traces of exobiology in them. Most cultures around the globe had some belief in ‘worlds’ populated by different creatures – gods, demons, humans, etc. Of course, it is possible that these gods and demons are nothing more than figments of an overactive imagination – but then again, it is equally likely that they are actually what they are made out to be: otherworldly beings. There is even a PBS series on this, Ancient Aliens, that discusses the idea that perhaps humans are not the ones responsible for such ancient wonders as the pyramids of Egypt – highly advanced extraterrestrials with superior technology are.
Moving on a few centuries – as the Catholic Church gained more power in Europe, belief in such creatures was condemned as heresy and quashed. Many prominent astronomers, such as Galileo Galilei and Nicolaus Copernicus, were forced to keep their radical ideas secret for fear of being persecuted by the Church. However, by the late nineteenth century, exobiology was rapidly picking up followers. Percival Lowell, an American astronomer, looked at Mars through his telescope in 1895 and observed what he believed to be a series of canals crisscrossing the planet’s surface. These ‘canals’ became fodder for much speculation concerning intelligent life on Mars, and it was only in 1965 – seventy years later – when NASA’s Mariner 4 took photos of Mars’s surface and determined that Mars was not in fact a wet planet, but a barren, dry, crater-filled world.
Just three years after Lowell’s canal-sightings, in 1898, British author H.G. Wells penned The War of the Worlds, a science-fiction novel about a Martian invasion of Earth. This sparked a new exobiological subculture; one that relied far more on fantastic flights of imagination than scientific evidence. Many comics and movies of that era – and this one, for that matter – had extraterrestrial characters and stories set light-years away from this planet.
In the latter half of the 20th century, scientific interest in exobiology picked up once again and the Search for Extraterrestrial Intelligence (SETI) was founded by Frank Drake, an American astronomer. In 1972 he, along with Carl Sagan, another famous astronomer, designed the Pioneer plaque – a giant pictorial representation of the history of life on Earth, to be carried on spacecraft in order to explain our origins to any extraterrestrial beings the astronauts happened to meet. (They didn’t meet any, but better safe than sorry.)
But Drake’s greatest contribution to exobiology was his creation of the Drake Equation, a multi-variable equation that yields the rough number of intelligent, communications-savvy extraterrestrial civilizations in our galaxy. Now, if only we knew the values of half the variables.
Today, more exobiological breakthroughs are happening even as I write. Recently, a study has been commenced wherein a 500-million-year-old bacterial gene has been injected into a sample population of E. coli bacteria, to see if evolution will proceed in the same way it did billions of years ago. More and more exoplanets are being discovered, and quite a few of them are Earth-like in nature. Signals are being constantly detected by SETI instruments, although all of them so far have turned out to be false alarms – Earthling radio signals or nearby pulsars. And, of course, there are hundreds of books, movies and TV series, both nonfiction and fiction, being churned out every year, helping to inform (and occasionally misinform) the general public about the fascinating world of extraterrestrial science.