The Necessity of Leaving Earth Within 2 Billion Years

The timeline for human life is finite. If we don’t kill ourselves off, or totally deplete our planet, then we have only about 2+ billion years to find a way to continue on with our species. That’s much shorter than is often thought, so we clearly must adjust our timetables for the need to develop a means to not only live outside our solar system, but our galaxy.

Cosmology

Empirical evidence strongly indicates that the Earth is about 4.5 billion years old. Indications are that it will be another 4-5 billion years before the elderly Sun expands and either: engulfs and devours the planet, or otherwise leaves it to be a burnt and dessicated hunk of rock. Four billion years. Seems like enough time to figure out some way to haul our collective asses to some new place to live, doesn’t it? The trouble is, we have, only about half that long.

Earth finds itself in that happy place know as a “habitable zone” (HZ). That is the thin range of distances a planet can orbit where the temperatures for it will be “just right” for items such as liquid water. The trouble is, it’s a moving target. In about 2 billion years it’s estimated that the Sun’s environment will have changed enough that the Earth will be outside of this HZ. So, we might not be a cinder, but we wouldn’t want to live here, either. Of course, by then we’ll probably have moved on to Mars or some moon in the outer Solar System—or maybe to planet someplace else in our galactic neighborhood—so what’s the problem?

Andromeda.

I’m talking about that friggin’ big galaxy that is on a collision course with our own galaxy, the Milky Way. Recent studies have concluded that the Milky Way isn’t just a smaller sibling of Andromeda, but about as large. While it’s nice for the ego to not be the runt of this galactic pair, it does have some serious consequences. Because of this greater-than-previously-thought mass, it turns out that Andromeda and the Milky Way are probably going to collide a lot sooner than was previously thought. The target date? About 2 billion years, maybe a little more.

So…what happens when galaxies collide? It’s really pretty:

Then again, it’s also rather apocalyptic from our perspective. The consequence of the new data means that that cool simulation will likely have to be a touch more violent as there’s less chance of a glancing blow and, with the Milky Way’s newly-calculated mass which causes it to spin faster,  well… think of two china dinner plates being thrown at each other and you sort of get the idea.

The Sun’s fate (and consequently our planet’s) is murky in the big-picture sense (whether ir gets flung into space or crashed into by that honkin’ big galaxy depends on which side of the collision we’re on), but very clear in the trees-for-the-forest sense: we’re toast. You see, not only does the Earth lie in the Sun’s HZ, but the Sun and our solar system lies in our galaxy’s HZ. Not too many stars, nor too few. Not too much radiation or wind. It’s a pretty cozy place to be, actually, and it’s going to go bye-bye.

Anthropanology

I think this quote from Babylon 5 sums things up nicely:

Ask ten different scientists about the environment, population control, genetics and you’ll get ten different answers, but there’s one thing every scientist on the planet agrees on. Whether it happens in a hundred years or a thousand years or a million years, eventually our Sun will grow cold and go out. When that happens, it won’t just take us. It’ll take Marilyn Monroe and Lao-Tzu, Einstein, Morobuto, Buddy Holly, Aristophanes .. and all of this .. all of this was for nothing unless we go to the stars.

— Babylon 5, “Infection” (0104)

We have to leave. If we don’t leave, then all of what we’ve done, and all that we could yet do, will have been for naught.

Like most of us, I have a tiny spark of hubris that says that my species is special. We’ve thought great thoughts. We’ve done great things. But it has no meaning unless there is someone in the future to carry on.

Consider the forgotten people and civilizations just within the past ten thousand years…a mere hint of a blink in the entirety of time. If we didn’t seek them out, if there weren’t archaeology, then we wouldn’t know they existed. But think of what meaning has returned to all that they did by the fact that some part of them survived to eventually go forth to find them again.

For them, it was easy. Their civilaztions got buried in the sand, swallowed by the jungle, drowned by the sea, or something else equally mundane. When we think of this on a galactic scale, it’s clear that we need to start thinking much bolder than just putting a few trinkets in the graves we dig for ourselves.

I’m a science guy. I’m a space guy. They are as much a part of my life as breathing. I’ve enjoyed the discoveries our space-faring cybernetic surrogates have been instruments of. It all adds to our knowledge. But it isn’t just about exploration. For the survival of our species, we need to figure out not only how to get off this rock of ours but how to survive in a newly dangerous neighborhood. We can’t be comfortable with the idea of simply going to other planets to perpetuate our species. In 2 billion years, that’s going to be just as tragic as if we’d simply stayed at home. Our future has to take us beyond simply exchanging one planet for another.

Theology

Human mythology and theology often speak of floods and how large vessels were built to protect the “worthy”. Unless we manage to develop some sort of inter-galatic teleportation device, our only hope for survival of our species in the very long term is to construct our own places to live. By making Arks capable of holding vast quantities of people and the culture and knowledge we deem to be important, we can survive the galactic collision and more. By being mobile (at least to an extent), we can roam through space and become the sorts of explorers we’ve only started to be.

The base of all of this, of course, is faith. While science will keep us alive, we have to believe that our existance is worth the effort. That only comes from faith. If not faith in some ethereal entity or place, then faith in ourselves. It takes a degree of ego to think that we are worthy of living when all others die, but that is what will allow us to undertake a project so large that past civilizations would have thought of us as Gods. We’d know the truth, that we are nothing more than very advanced tool-makers.

We need to make our goal, in these coming megennia, to learning how to build and live in space. This means being able to mine and manufacture the resources we need from whatever materials are available: planets, asteroids, comets, etc. Our goal will be to construct vast synthetic worlds capable of holding not thousands, but millions…each. The survival of the species demands the effort and the costs.

Cybernetology

Many space scientists bemoan the very idea of human space exploration and habitation. Their only interest is in looking over the next horizon, and for that they are more than happy to rely on robots. Who knows? Maybe that’s the way to go. If we can build our own versions of “Cylons” or “Terminators” and let them be our progeny, our legacy, to continue with our memory, then perhaps that’s the best solution.

This is when things get tricky. Are we the sum of our knowledge and hopes—thus making robots a possible substitute? Do souls matters? Could a robot, being the only remaining vessel for who we are and what we were, be able to be the instruments of a soul? Or does that always require a human?

And there’s the rub. If we believe that we are the chosen of some higher entity, then we have to embrace the fact that Earth is just a place where we hang our hat for now. If we instead think that we, like Earth, are only way-stations, then perhaps it doesn’t have to be us that goes to the stars… just reasonable facsimilies who will continue our legacy.

The fact is, we still have much to learn. The International Space Station is a good second step. The Mars rovers, Spirit and Opportunity, are also good beginnings. But there is yet so much more to do if we are going to ensure that we mattered, that there was a point to us existing at all. For that, we need vision and will. Sadly (for me, at least), I’ll not survive to see the result. I do hope that we don’t stop trying. There are many dreams we haven’t come close to fulfilling. I’d hate for something as mundane as a galactic collision to stop us in our tracks.