Day 090 - Aliens and dinosaurs

Submitted by Sam on 19 August, 2011 - 00:44

Extinction events like nuclear war or nanotechnological catastrophe could undoubtedly shorten the communicating phase of an advanced extraterrestrial civilization, but these kind of global mass extinctions can't always be the end of the story, as the Cretaceous-Tertiary mass extinction has already shown here on earth.

Our own mas-extinction event, which occurred roughly 65 million years ago, wiped out most of the life on earth, but crucially, not all of it. It is marked by a thin geological boundary separating dinosaur fossils from all other fossils, and is widely theorized to have been caused either by an asteroid impact or by increased volcanic activity which disrupted earth's ecology so massively that most living things were wiped out forever.

Some species survived the catastrophe, however, allowing life on earth to continue evolving, finally producing human civilization. That some of these species were reptiles as large as crocodiles suggests that the KT extinction event was not perhaps as all-powerful as a man-made (or alien-made) mass-extinction would be, but it nevertheless raises an important point. This is that life is hugely adaptable, and that even if the most 'highly-evolved' species on the planet is driven to extinction, there is more than likely always another to take its place.

Indeed, in the case of nuclear holocaust, mankind or an alien race could quite easily obliterate itself entirely, and yet leave a thriving new ecosystem of lesser lifeforms behind. In this instance, lifeforms adapted to resist heat and radiation would continue to live on long after the extinction event, able to continue evolving over many generations to produce higher forms of life once more. Insects are good candidates as survivors of a man-made extinction event that we could rely on to perpetuate life on a ravaged earth, perhaps one day evolving once more into a society capable of dropping atomic bombs again.

If not insects, then there are extremophilic bacteria which thrive in conditions that would be hazardous to all other life. In fact, some bacteria are well-suited to a whole range of hazardous environments, and could survive and flourish even in the harshest of post-apocalyptic worlds. The bacterium D. radiodurans is one such polyextremophile, and can live through huge doses of radiation (it has the unique ability to repair its own damaged DNA), and can survive in vacuums, acid, extreme cold and dehydration. T. gammatolerans is even more radiation resistant still.

So, even if every intelligent civilization always destroys itself, there will almost always be organisms left after the extinction event to continue evolution. And if intelligence is a logical development of evolution, then after a few hundred million years (which is not very long at all on the galactic timescale) a new civilization will emerge capable of broadcasting its existence to the universe, and, incedentally, capable of destroying itself once more. And yet despite the possibility for cyclical extinctions and rebirths of extraterrestrial civilizations, we still have not detected even the faintest hint of another intelligence in our universe. If self-extinction cannot provide a universal answer to the Fermi Paradox, then where is everybody?

Attribution Noncommercial Share Alike
This text, Day 090 - Aliens and dinosaurs, by Sam Haskell is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike license.
Drupal theme by Kiwi Themes.