ET Inspections—Part 1

There is much research and speculation currently going on, regarding the possibility of life elsewhere in the universe. The search is vigorously proceeding, on the part of several scientific disciplines: astronomy, physics, biology, chemistry, and evolution. Now that thousands of planets have been discovered around nearby stars, we know that worlds exist where life might possibly be present. The recent discovery of hardy life forms right here on Earth, thriving in extreme environments (high/low temperatures, dessicated locations, high-acid spots, sunless pockets, etc.), tells us that life can flourish in what are extraordinarily harsh situations; once thought impossible for life to even exist.

At some point in the future, humans will travel to other worlds where life could potentially exist, and we will be inspecting them for possible forms of life. A pertinent question that could be posed is: Would we recognize life of a very different kind, if we visited its world? Just a few years ago researchers would have doubted that life could exist in some of the extreme places found here on Earth. It has prompted scientists to open up to the possibilities of bizarre life forms elsewhere.

Maybe a way to put the search for extraterrestrial (ET) life in a different perspective is to conduct a fanciful thought experiment. Suppose we think about some intelligent outer-space species that might have visited planet Earth to inspect it for life, at different times over our planet's existence. Suppose we look at what these ET visitors would have observed, and what they might have concluded from their inspections.

Visit 1, four billion years ago. That would have been only a half-billion years after Earth had formed. It would be a molten, heaving surface of lava, with spewing volcanoes. No life possible then.

Visit 2, three billion years ago. While cruising our solar system, the visitors would also have checked into both nearby Venus and Mars. All three planets would have been water worlds with thick atmospheres, and were quite warm. Had they looked closely on Earth at that time, they'd have detected some single-cell, simple life forms. Nothing intelligent. Not much going on here, but some possibilities for the far distant future. Would the outer-space visitors have found similar kinds of primitive life on Venus or Mars? It's certainly plausible. We humans may someday find out, when we have conducted our own inspections of our partner planets.

Visit 3, two billion years ago. For millions of years around that epoch, Earth's temperature had dropped far below the freezing temperature of water. Our visitors would have encountered what scientists call “Snowball Earth.” The planet would have been essentially encased in ice. At first glance, it would be doubtful that life could have existed under such conditions, but had the space voyagers probed a little deeper, they'd have found that single-cell critters did live beneath the ice, deep in the oceans. Astronomers today think that similar kinds of life may be found by humans one day in ice-entrapped oceans on Saturn's moon Europa. Still, our ET visitors would just find primitive life here on Earth—no intelligence yet.

More visits next time...