Life in outer space
Is there life in outer space?
It may surprise you to realize that this is a question for which we already know the answer: Yes.
Earth is a wonderful example of how life can flourish and abound with astonishing diversity in the midst of the extremely harsh, radiation filled vacuum of space. And this highlights a perception flaw we have when considering life in outer space. We see Earth as distinct and separate from space, but it’s not, Earth is drifting through outer space. Earth is a brilliant example of how life can survive in space.
We live on a modestly sized planet orbiting a rather average star that is currently on the outer spiral arm of an unassuming spiral-barrelled galaxy. Space isn’t something out there somewhere away from us, we are in the depths of space.
Ah, so the question becomes… is there any other life in outer space?
The answer here is almost certainly yes as well, as although we haven’t found life, we have no reason to think that life doesn’t exist elsewhere. We have numerous reasons to think life abounds elsewhere in space. That we haven’t detected life is immaterial, and more a reflection on our inability to examine exo-planets in detail than anything else.
It is a poor sailor who never wants to see beyond the horizon – Plato
As for those who belittle SETI (the Search for Extraterrestrial Intelligence), one has to wonder what they would have said in the days of Christopher Columbus, or about the folly of Charles Darwin setting sail on the HMS Beagle? Exploration defines the quintessential character of humanity, as it is the only catalyst for learning. Whether it be exploring concepts in books or cataloging butterflies in a forest, whether it is a scientist looking for life on Mars or a young child looking for bugs beneath a rock, our curiosity defines us.
Horizons are immaterial. Horizons exist only from the perspective of the viewer. Horizons are an artificial boundary that can be probed and explored, and nowhere is that more true than in the search for life in space.
Astronomy is accelerating in its ability to expand our horizons. For hundreds of years, astronomers and philosophers like Immanuel Kant considered the idea of “island universes,” but it wasn’t until the 20th century that the notion of distinct galaxies emerged. Erwin Hubble took this image of Andromeda (inset) from the Mount Wilson Observatory. While the Hubble Space Telescope has given us this iconic image of Andromeda in astonishing detail and allowed us to view tens of thousands of galaxies stretching billions of years back in time.
The Sloan Digital Sky Survey has mapped almost a million galaxies in a small slither of space, implying that the overall number of galaxies in the visible universe must be somewhere in the hundreds of billions. It is a poor soul indeed that would not want to see this magnificent universe examined in greater detail.
One question that comes up quite often is, “If there is life elsewhere, why haven’t we found evidence for ET?” Seth Shostak in his non-fiction book Confessions of an Alien Hunter, notes that if our galaxy was a haystack then we’re sitting on at least one needle in our solar system. With our efforts so far to examine the stars around us, we have conducted a thorough search of a spoonful of hay and arrived at the conclusion there are no other needles in our sample, but our sample is clearly not representative of the haystack as a whole.
Extending the analogy further, scientists estimate there maybe as many as five hundred billion haystacks to consider, but we can only effectively examine one side of the haystack we’re in. We have no idea how many other needles there may be in our haystack, let alone how many needles there may be in all the other haystacks, but that haystacks have needles is beyond dispute as we’re sitting on one.
When it comes to life in outer space, we’ve got to remember that time is a factor as well.
Take a look at this planet. Do you think it could support life?
Because this is what Earth probably looked like during the Hadean eon shortly after the planet formed. Tectonic plates formed a thin crust over the planet. Due to the extreme pressure of the predominantly C02 laden atmosphere, a liquid ocean formed at a scalding 440-500F (beyond 230C). The newly formed Moon orbited at a fraction of the distance it does today, causing massive tidal waves hundreds of feet high to sweep the planet every four hours.
As Earth cooled, it was subject to the Late Heavy Bombardment with tens of thousands of meteor impacts reaching 12 miles in diameter (20km), roughly forty massive impacts left craters in excess of 600 miles in diameter (1000km), and there were a few whoppers that carved out basins 3000 miles in diameter, that’s roughly the distance from New York to Salt Lake City. And yet, somehow, in the midst of Dante’s inferno, life arose.
What would we have made of Earth if we’d spotted her from afar with the Kepler space telescope at this time? Would we have suspected that the simplest of microbes were already arising amidst this seething hell?
How about this world?
Could this world hold life?
Because as best we understand the evidence, Earth went through several “snowball” periods over the past few billion years. Each of them came perilously close to extinguishing life on Earth.
Our planet is 4.4 billion years old. For at least 3.8 billion years there’s been life on Earth, which is a staggering fact when you stop and consider that the universe itself is only 14+ billion years old. For just under a third of the time the universe has existed, there has been life on Earth! And on Earth, life has endured seemingly insurmountable odds to survive for over 80% of the planet’s history. These are particularly heartening facts when we consider our search for life elsewhere.
We may only have one confirmed example of life in outer space, but it is spectacular in its longevity, its tenacity and its diversity. We have no reason to think the same process hasn’t been replicated elsewhere throughout the universe.
