We’ve all heard about the fine-tuning of physical constants–just change them ever so slightly and a different kind of universe emerges. Then, there’s simply our location in our galaxy that allows us to see outwards to the galaxy itself, and beyond. Now, even the radioactivity in the earth’s core seems to be conducive to life.
At Phys.Org there is a press release on this paper (behind paywall).
“What they found is that if the radiogenic heating is more than the Earth’s, the planet can’t permanently sustain a dynamo, as Earth has done. That happens because most of the thorium and uranium end up in the mantle, and too much heat in the mantle acts as an insulator, preventing the molten core from losing heat fast enough to generate the convective motions that produce the magnetic field.
With more radiogenic internal heating, the planet also has much more volcanic activity, which could produce frequent mass extinction events. On the other hand, too little radioactive heat results in no volcanism and a geologically “dead” planet.
“Just by changing this one variable, you sweep through these different scenarios, from geologically dead to Earth-like to extremely volcanic without a dynamo,” Nimmo said, adding that these findings warrant more detailed studies.”
I wonder what the state of the Drake Equation is like these days.
2 Replies to “The Privileged Planet, Redux”
“Privileged Planet” by Gonzalez is probably a bit data by now, but it’s still an interesting book.
One of the MANY, many details about Earth being “privileged” is the jaw-dropping precision of the collision between proto-Moon and proto-Earth. The collision not only allowed Earth to steal Moon’s metallic core. It also allowed Earth to get rid of a huge chunk of our original crust, which is why Moon seems to be the SAME material, straight through. If The Designer had NOT spent 35 million years lining up that collision, and getting the speed at impact JUST right, we wouldn’t be here. And Earth would be another Venus with a crust too thick for Tectonic Plates, and a metallic core too small to generate van Allen Belts.
All so SIMPLE and yet all REQUIRED to be so amazingly precise. I just go, “Oh, wow…”
Hear, hear! The radiogenic heating issue is just one more massive piece of evidence of the deep uniqueness of life on Earth and of our civilization. To the point that it looks statistically like we may be the only intelligent life out there at least in our galaxy. So much for the Star-Trek-like fantasies of SETI researchers. Unfortunately there is still one spoiler to near certainty on this issue – the stubborn issue of the existence of numerous high quality but unexplained observations of apparent vehicles from outside our Earth in the UFO phenomenon. Cognitive dissonance time, unless it is imagined that these apparent vehicles are from some other dimension, Universe continuum, or time.