On the one hand, global climate change is likely to make things very — strictly in the curse sense — “interesting” for the human race as this millennium progresses. The effects already are obvious, visual, striking, and — one would think — undeniable.
Randall Munroe, of xkcd, has created another of his brilliant graphics, this one showing the history of climate change. It’s well-worth checking out (do it now). It makes the point in a visually striking, and — one would think — undeniable way.
On the other hand, it’s very — in the usual sense — “interesting” that we’re here at all.
And on that awkward segue, for a Friday, this is just a list of those interesting coincidences that worked out in our favor:
Carbon: All life on Earth is carbon-based, but carbon is a volatile element that should have either boiled off or been absorbed into Earth’s core long ago. So there is a mystery: Why is there so much life-giving carbon around?
One hypothesis is that a large (Mars-sized) planet hit us after our core was largely formed and donated most of the carbon we see in the Earth’s mantle, crust, and atmosphere.
That collision doesn’t happen; we’re not here.
The Moon (Ia): Our Moon is thought to be the result of a more ancient collision with a Lagrange object. As a result of that collision the Earth’s core ended up with the iron core of that object.
All that iron gives us the power dynamo running in the core that gives rise to the magnetic field that shields us from solar radiation.
The Moon (Ib): It appears that same magnetic field also shields us from the electric stellar wind, which can strip away a planet’s atmosphere. The recent discovery of this powerful wind has altered our perception of the habitability of exoplanets.
The Moon (II): Many believe that life evolved from sea-going to land-going through tidal pools.
All useful ecological niches get filled. An environment that oscillates between sea and air facilitates creatures who develop the ability to breath air.
Our extreme tides, of course, are caused by our large Moon.
It would be hard, I believe, for any species to evolve much technology without fire. And it’s very difficult for a sea-going species to discover and use fire.
Mitochondria: These are the power plants inside our cells. Without them, multi-cell life probably isn’t possible.
It’s thought that they originated as ancient single-cell symbiotes of other ancient single-cell creatures. This chance relationship became codified in all life that evolved from those original cell pairs.
Without that chance, complex life may not have evolved. (We may discover that single-cell life is common in the universe. Whether complex life, of any kind, exists remains to be seen.)
Heavy Elements: It takes an extra-powerful supernova to produce heavy elements such as gold or uranium; they aren’t made in any normal stellar fusion process. The very useful (and perhaps life-allowing) presence of those elements on Earth means there was such a super-powered explosion fairly near our galactic neighborhood.
We might owe our ability to use atomic power to this coincidence. Like it or not, it’s an important part of technology and possibly vital to meeting our energy needs.
(Ironically, this means the otherwise kinda silly (but fun) movie, Cowboys & Aliens, actually did have some basis in possible fact as far as the alien’s goals. Gold really might be rare in the galaxy, and it is a useful metal (conducts electricity very well, doesn’t tarnish, good for using as contact plating).
Jupiter and Saturn: There is a hypothesis that massive planets in the outer solar system protect Earth from comet bombardment from the Oort cloud. It may be life owes some debt to that protection.
We’ve found a lot of star systems with giant planets orbiting close to their star. That’s partly because of how exoplanets are discovered in the first place.
But what if systems with small habitable planets close in protected by big giants in the outer system do turn out to be rare?
Saturn’s Rings: Not a requirement for life on Earth, but a beautiful and inspiring sight for humans once they invent even crude telescopes (let alone send robot spacecraft to take close-up photos).
Given that the rings aren’t stable and won’t last forever, and given that the rings of the other gas giants aren’t nearly as interesting, and given that the exoplanets we’ve seen so far often orbit very close to their star, isn’t it interesting we’re provided with the sight of Saturn’s rings at this point in time?
What happens if we discover that ring systems like Saturn’s are extremely rare?
Solar Eclipses: Also not a requirement in any way, but another “oh, gosh” coincidence that I find interesting: Both the Moon and the Sun have angular arcs of 0.5 degrees. That allows those compelling total eclipses we get once in a while.
One interpretation is that the creator threw that in for fun.
13.8 Billion Years: It’s really quite young in the putative age of the universe. If you assume one-trillion years, and call that “24 hours,” we’re currently just shy of 00:20 — twenty minutes after midnight!
The universe’s “day” has barely begun! Our showing up so early either means intelligent life does arise easily or that we’re kinda rare and special. Could go either way.
Physics: The oddities of the habitability of this universe are many in physics. There are 18 or so constants in particle physics — binding energies and particle masses — that no theory accounts for. They just are what they are.
Fair enough, but one thing that puzzles physicists is the extreme range of some of those values. A small magnet has more electromagnetic strength than the entire Earth’s gravity! We have no explanation for this extreme variation.
There is debate whether changing any of the 18 parameters would make the universe uninhabitable. Many believe small changes, at least to some of them, would do just that. Some believe (although this is hard to prove) that there is a narrow zone, like a habitable zone, within that parameter space. If they’re right, we live in a unique universe.
There is also that our universe is amazingly flat spatially. Various factors need to cancel out for this to be true, and the cancellation seems to be on the order of 10120! (That’s what’s meant by “amazingly” flat.)
Given we only have the one universe, it’s hard to guess the viability of even slightly different versions, let alone very different ones. Things definitely have worked out very well for us in this one, that’s for sure.
Infinite Universes? The multi-verse hypothesis of infinite universes (different from the many-worlds interpretation of quantum physics) owes much to being a way of dodging the weirdness.
This universe isn’t weird if many, many others also exist. But if it’s the only one, then it is very weird that it is the way it is.
Personally, I kinda like it that way!