'Nova's' Mashup of Time Shrinks Us Down to Size
Making North America, a three-part Nova mashup of geology, archeology, botany and zoology, provides an engaging history of all the different looks our continent has tried over hundreds of millions of years.
The present New York City was once incorporated into a mountain range as high as the Alps. The Southwest was an ocean, then a desert. Africa and the Americas at one time were part of the same land mass.
But the real message of this show, subtle yet unmistakeable, is that next time we start thinking we’re important, we might want to realize that over the longer span of universal time and history, we aren’t.
We think an hour is a long time. Or a day. The forces that shaped North America evolved over tens of millions of years.
Nature is nothing if not patient. (The Grand Canyon, top.)
Right now, as we speak, California’s San Andreas fault is compressing the middle of the state, bringing Los Angeles closer to San Francisco.
It’s only by a couple of inches a year, but unless something dramatic happens with the tectonic plates engineering this shift, L.A. and S.F. will eventually be next-door neighbors.
No one alive today will see it, of course, and that’s one of the unavoidable points here.
None of us are around long enough to actually see the big stuff, the constant morphing of our planet. In almost every case, we have to absorb it in the abstract.
The geologists and scientists in this three-part series (which starts Nov. 4, and continues Nov. 11 and 18 at 9 p.m., PBS, check local listings) make a strong case that if you consider the planet’s history over enough time, it’s being reshaped as continuously and effortlessly as a big ball of Play-Dough. (Host, Dr. Kirk Johnson, left.)
At one time, for instance, North and South America and Africa were one megacontinent.
But it was not too big to fail, and some of the underlying stuff eventually bubbled up and ripped it apart, The Atlantic Ocean formed, Africa drifted East and North and South America were eventually connected by just today’s thin strip of Panama.
The “bubbled up” part, by the way, is important. Everything we call “land” today started under the surface as volcanic lava.
All that lava is the reason why today, unlike in the distant past, the whole planet isn’t pretty much covered with water. At one point Johnson’s people find rock etched with small, almost perfectly round circles. That’s where tiny eruptions once pierced the surface, leaving only those traces to be analyzed millions of years later.
Other volcanoes have been more emphatic. Hawaii was not only formed by volcanoes in the past, but continues to be reformed by volcanoes today. Since 1983, more than 12 billion tons of lava has popped out.
Volcanoes are also interesting, Johnson notes, because they’re one of the few major natural phenomena that happens in “human time.”
While we can’t see the drift of continents or atmospheric change, we can watch lava come out of a volcano, see it bubble and flow and cool. This Nova explains a whole lot about why the world looks the way it does at this particular moment.
It also doesn’t let us forget that yesterday and tomorrow, it did and will look quite different.