By Bob Groeneveld
.
About 160 million years ago, a couple of heaps of gravel rolling along the asteroid highway that runs around the sun between the orbits of Mars and Jupiter bumped into each other.
The crash, which wouldn’t have been much more than a fender-bender, on an astronomical scale, occurred somewhat farther from us than we are from the sun.
But the collision nudged a relatively small piece of debris off the asteroid superhighway, spinning it out of control and steering it towards unforeseeable consequences.
About 100 million years after the crash, our planet got in the way of that errant bit of space junk, and it blasted a hole in the Earth’s crust, kicked up billions of tonnes of dirt and rocks with the force of tens of billions of Hiroshima-sized atomic bombs.
About 66 million years later, a couple of descendants of one of the survivors of the planet’s fifth Great Extinction Event stumbled across the 150-kilometre-wide Chicxulub Crater while they were searching for oil around Mexico’s Yucatan Peninsula.
The discovery by Glen Penfield and Antonio Camargo in 1978 seemed to confirm a theory postulated by father and son Luis and Walter Alvarez some years before that an asteroid or comet that crashed into Earth around 65 million years ago, give or take a million years, killed about 76 per cent of all species that were in existence at the time, including all of the dinosaurs.
I was sitting by our pond, watching a couple of young chickadees splashing in the fountain and bouncing around on the lily pads before me, pondering just how astounding it should be that such postulations and discoveries could lead to such amazing understanding of the details of the course of events that had spanned 100 million years – all tens of millions of years before our time.
It was when Mom and Dad chickadee started angrily shouting at me from the rhododendron bush next to the bench I was sitting on – demanding, as is their wont, that I refill their sunflower-seed feeder – that I realized I was directly confronted with a contradiction to the generally held dinosaur extinction theory.
Currently accepted theory originally held that the asteroid blasted the dinosaurs out of existence, but it is now understood that some dinosaurs survived. We now know those survivors’ descendants as birds.
The updated theory accepts that the chickadees cavorting in our pond are dinosaurs. In fact, they are descendants of the dinosaurs that survived the fifth Great Extinction Event.
Here’s a coincidence: they are about the size of the average mammal – our ancestral Chicxulub survivors – that escaped extinction those 66 million years ago.
And here’s the contradiction: if as the theory goes, mammals “won” because dinosaurs “lost” their dominance those tens of millions of years ago, then how is it that those tiny chickadees are still ordering me around?
And why do I, a representative of the winning mammals, happily acquiesce to the losers’ strident demands?