As we stare out into the void of space, sift through strands of DNA and samples from the deepest seas & oceans, we search for clues as to what life is and why life even exists. But before we can begin our search out there in the ink black of the wide beyond, we must first understand life itself right here on Earth…
In this first installment, I’ll be looking at how powerful a force life is here on Earth and explore the prospects of life existing elsewhere in the universe.
I recently watched several talks from the TED conferences which got me thinking about a number of themes that are a constant fascination to me, revolving principally around life and the universe.
I won’t say biology and astrophysics, since I’m not qualified in either of those fields, despite these two disciplines forming the backdrop to life and the universe respectively.
I truly believe that life is both a force and an inevitable function of nature. Beyond any emotions we might share with other mammals, beyond even the desire to live is the need to survive, or to be more accurate, to be survived by.
The chemical destiny of all life
Acting as both the engine and the index of life itself, DNA (Deoxyribonucleic Acid) is an amazingly delicate yet resoundingly robust structure that allows for the full diversity of life we see here on Earth, along with all life that has ever existed.
As sophisticated biological process go, DNA is both elegant and ancient. The functions it is part of and required to perform rank it highly amongst the most complex operations any man-made computer might hope to achieve.
But despite its apparent complexity, life is of reducible complexity. What that means is, living organisms are an amalgam of components, all of which are themselves often comprised of yet smaller components. When these components are broken down, their complexity is reduced, also. At which point, we’re then better able to understand how those basic components work and how such complexity arose in the first place.
This is a simplification of course, but it’s enough for you to understand that life isn’t so complex that such things cannot arise by entirely natural forces.
To put it another way, there are no gods — only chemicals, environmental variables and time enough to allow for such things as amino acids to form, offering a platform onto which the forces of nature built all living things.
Life as an inevitable process
It’s my opinion that life is an inevitable process of the universe. I see life as inevitable as galactic, stellar and planetary formation, and their motions.
You see, life persists in almost any environment. Even the most baron, hostile environments on Earth harbour life.
In the 500 million years or so it took for the Earth to cool down after its initial formation, life emerged. Even if life was introduced from elsewhere, it’s unlikely the conditions of the early Earth would have been suitable. So those panspermiatic life forms would have had to adapt and evolve:
“Panspermia is the hypothesis that ‘seeds’ of life exist already all over the Universe, that life on Earth may have originated through these ‘seeds’, and that they may deliver or have delivered life to other habitable bodies.”
Most common theories of how life came into being here on Earth centre around the warm, humid conditions of the early Earth. However, there are other more intriguing theories; such as one regarding how life might have evolved in ice:
“… strange things happen when you freeze chemicals in ice. Some reactions slow down, but others actually speed up—especially reactions that involve joining small molecules into larger ones.”
Given that both warm and cold conditions have their own unique influence on the formation on the key building blocks of life, might there not be an argument for a two-stage process? Some elements forming during the initial period of the warmer while others formed during colder times?
However, my theory is but amateur conjecture.
Life at the extremes
More evidence of the truly persistent nature of life can be found in those frozen and aridly dry regions of Earth, where it would appear that life has no place. Such organisms are known as extremophiles, who make their home in some of the most hostile conditions on Earth.
In some cases, organisms exist in environments not too dissimilar to those of the very early Earth; anaerobic places, like deep layers of sludge on the oceans’ floor, devoid of oxygen and light.
These places may well harbour specimens of life that have experienced almost no change since those first cellular organisms emerged over 3 billion years ago.
And most tantalizing of all, the hunt is on to find single-celled organisms that are so ancient they predate the evolutionary development of death. If such organisms do indeed exist, buried under layer upon layer of dense sludge, then they would be truly immortal.
Amongst the most hostile environments known are hydrothermal vents:
“A hydrothermal vent is a geyser on the seafloor. It continuously spews super-hot, mineral-rich water that helps support a diverse community of organisms. Although most of the deep sea is sparsely populated, vent sites teem with a fascinating array of life. Tubeworms and huge clams are the most distinctive inhabitants of Pacific Ocean vent sites, while eyeless shrimp are found only at vents in the Atlantic Ocean.”
Even at the crushing depths of over 2,000 meters below the surface of the ocean, hidden in otherwise desolate regions of the sea floor, these vents belch out super heated water at temperatures as high as 400°C (750°F), yet the water does not boil at these depths because of the tremendous pressure from the weight of the ocean above.
The life that persists around these deep sea vents isn’t restricted to chemosynthetic bacteria (those that use heat instead of light to derive nutrients from chemicals, rather than from the light of the sun, which is photosynthetic) although such organisms do form the very base of the food chain. These hydrothermal vents are an oasis in the ocean floor wasteland they’re situated in, providing life for a number of larger animals, such as the aforementioned shrimp, clams, lobster and a variety of fish.
At the very opposite end of the spectrum of life are those creatures that, like their distant hot water cousins, don’t just survive but thrive in their world; the world of these organisms is a frozen one:
“Methanogens are unique among organisms in their ability to survive a wide range of temperatures, from the freezing point of water to 185 degrees Fahrenheit and everything in between.
Archaea is an ancient domain of life that is separate from bacteria, plants, and animals.”
But these are natural environments. What of those environments scarred by the poisonous efforts of man? Life persists there, too:
“Scientists have discovered bacteria swarming in the toxic sediment beneath underground tanks that have leaked radioactive waste at the Hanford nuclear reservation, home to some of the most highly contaminated soil in the world.”
If life is able to thrive in such fantastically hostile environments, albeit relatively simple life, life can thrive almost anywhere in the universe.
And if life can also form in cold environments, then there is great hope for moons such as Titan and Europa. Indeed, it is theorized that Europa has a liquid ocean beneath its shell of ice. Maybe at the bottom of those oceans lurk hydrothermal vents.
In the second installment, I’ll be looking at the prospect of other intelligent life in the universe, our place in the grand scheme of things, and how we as a species may well be at a crossroads in our destiny…
- Stephen Hawking: Asking big questions about the universe
- Brian Cox: What really goes on at the Large Hadron Collider
- Brian Greene: The universe on a string
- Did Life Evolve in Ice?
- Hydrothermal Vents
- Bacteria in toxic soil could aid in contamination fight
- Extremophiles, Antarctica, and Extraterrestrial Life