Photo: Two Specks and a Wire

The close conjunction of Venus and Jupiter is over now, and while they've begun pulling away to go off to their respective corners of the sky, they're still relatively close together and shine brightly enough with reflected sunlight to burn through even the light pollution you'll find being thrown up over downtown Vancouver on a Friday night. Venus is the brighter one at the top, thanks to its proximity to Earth, and while it isn't responsible for casting that light on the wire, once I realized the effect it was too good to pass up.


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The Outward Surge

It's a fact; overpopulation is a problem here on Earth. While it's not necessarily as front-and-center as it was back in the 70s, it remains that the sheer number of humans will be the ultimate cause of environmental issues to a greater and greater degree. So perhaps it's not much of a supposition to suppose that there are a lot of people who, given the opportunity, would pack up and move to an offworld colony. Even more if said colony is on another habitable planet, rather than some L5 space station or Martian dome. Granted, this wouldn't realistically make a dent in population; not unless you've got a fleet of ships capable of lifting millions of people per day, and that in itself causes its own problems - it's hard to imagine a society that could absorb millions of newcomers just like that.

That doesn't happen too much in science fiction, either - colonies tend to follow the pattern of the European colonization of North America, with massacre and abuse of the natives optional depending on what point you're trying to get across with the story. When colonies do happen, though, they tend to happen fast. It's hardly unusual to encounter a setting where humans have been exploring the cosmos in earnest for a short time, and yet near space is peppered with colonies: Mass Effect is just the most recent prominent example of this, and possibly one of its purest distillations.

How realistic is this, though? Or, rather, how realistic is it that this sort of policy would be successful, and not fraught with high-profile incidents that would put the brakes on reckless settlement? For the purposes of this argument, I'll overlook the unlikelihood of there being multiple Earth-compatible planetary environments just there for the choosing. Really, how safe would it be if the immediate response to the discovery of a habitable planet was to settle it without delay?

Keep in mind that the challenges involved in settling a new world are ones that humans have not faced in more than ten thousand years, when people first crossed the Bering land bridge to the American continents - though I suppose you could also argue the Polynesian settlement of New Zealand eight hundred years ago had the same aspects as well. Any planet without a preexisting sapient population would be wilder than any part of Earth has been for generations, wholly untamed.

Plus, there are the dangers that would come from it being, you know, an entirely different planet, and the regular rules of Earth no longer applying. At least the Polynesians or the first inhabitants of North America would have had some idea of what to expect. A new planet could have any number of hidden dangers, from extreme seasons to hostile life forms to environmental poisons that aren't immediately obvious. A more appropriate trajectory, I think, would be to precede any planetary settlement with a long period of observation and initial exploration; enough so that if the planet does try to kill you, it will at least be in a way that doesn't happen every year or every other month.

Remember, it took more than a hundred years for European presence in North America to really stick - and don't forget about places like the Roanoke colony, which just up and disappeared. New planets would represent incredible investments - but one bad one early enough could wreck the whole thing.

Prisoners of Gravity

One of the biggest questions regarding the existence of advanced extraterrestrial life can be boiled down to three simple words, the Fermi paradox: where are they? The universe has existed for billions of years, with more than enough time to permit the evolution and development of life and civilizations capable of being noticed even across interstellar distances - theoretically, at least. We won't know for sure until we actually start finding them. But the question of why has been grappled with constantly for decades, with everyone approaching it from a different angle.

Larry Niven once suggested an interesting possibility that I hadn't seen before - that, whether by fluke or environmental pressures or whatever else, perhaps the intelligent beings of the universe were almost all aquatic. It's perfectly possible to be intelligent and live in the water - dolphins and cephalopods could be all of the way there, and it's just taken us this long to realize it. But aquatic beings are held back by the nature of their environment: you can't really build a technological civilization when you live in the water.

The other day, I had an idea along these lines that I don't recall seeing anywhere besides the works of Hal Clement - what if extraterrestrial intelligences are kept where they are by gravity? I'm not thinking about something extreme like Mesklin, with 3 g at the equator and at least 275 g at its poles, but rather something we've already observed: Gliese 581 d, a potentially terrestrial, potentially habitable world twenty light-years away.

There's only one niggle, if the information we've gathered about it is accurate: the planet's a bit clingy. Specifically, it's estimated to be twice the size of Earth, and have seven times its mass. By no means does this preclude life; it just means it wouldn't be exactly like home. Owing to my lack of mathematical skill, I wasn't able to calculate the surface gravity for a potential planet with this size and mass - so let's be charitable and assume a planet with 2.83 g, just to be charitable, to see what we've got with nearly three times Earth's gravity pulling you down. Call it Earthissimo, like my astronomy lecturer did back in university.

For one, falling would not be a pleasant experience.

Local life forms would be short and bulky - in that kind of gravity, there's nothing to be gained by going up. Without the high mountains that lower gravity makes possible, land would tend to be lower and more eroded - conceivably, there could be high-gravity archipelago worlds. If you're interested, Extraterrestrials: A Field Guide for Earthlings by Terence Dickinson and Adolf Schaller goes into a bit more detail.

That's just biology - I'm more interested in technology. There's nothing about a high-gravity planet that fundamentally prevents an intelligent civilization from arising there, but one that did would face far greater challenges in some respects than we do. Culturally, it could theoretically have the deck stacked against it from the beginning. On a high-g planet, very few things fly and falls are exceedingly dangerous even from what we'd think of as trivial heights. That sort of environment could easily breed what would be, by human standards, an intensely conservative mindset - something like that, introduced early enough and reinforced enough by the environment, could put serious brakes on any kind of serious technological development, or perhaps just leave the people there in a long Bronze Age.

But let's look at Earthissimo. The people there have struggled against the chains of gravity enough to build a technological civilization that we might recognize in the broad strokes - details, of course, would differ immensely. The important issue, however, is access to space - without that, there's no chance of aliens coming to us. It's with access to space that the real challenges lie.

While it's certainly difficult to get to Earth orbit or beyond, it's certainly doable - a big part of the problem is that there aren't yet any economies of scale in the space industries, but even then you've still got to deal with accelerating to 9.4 kilometers per second even to reach the 300-kilometer altitude of the International Space Station. If you're leaving Earth entirely, escape velocity is 11.2 kilometers per second.

How envious the space freaks of Earthissimo would be of us. With all that extra mass pulling things down, it's not easy to get to orbit - Earthissimo's to-orbit velocity would be 44.91 kilometers per second, and if you want to escape entirely, you'll need to have a ship that can accelerate to 63.5 kilometers per second. The problem is that chemical rockets, such as the ones we used as we began to claw our way into the heavens, are insufficiently beefy. Rocket launches from Earthissimo would be incredibly complex and incredibly expensive - enough so that it's easy to imagine that the people there just wouldn't bother with it at all. Hell, we're having enough trouble getting it off the ground here!

So maybe that's another explanation. There may be worlds upon worlds of people out there who can look up at the stars, at the blackness of space, and know that because of the dirt beneath their feet-equivalents they'll never be able to touch them.

The Twilight's Last Gloaming

They've been breathless. Media organs worldwide have put out article after article about the discovery of an "Earth-like" planet orbiting Gliese 581, a red dwarf star twenty light-years from here: just down the street in astronomical terms. This isn't the first time that system had been the center of attention - last year the discovery of Gliese 581 e, orbiting on the outer edge of the star's habitable zone, marked the smallest planet yet discovered. It didn't take long for Gliese 581 g to break this record; the planet - quickly dubbed "Gloaming" by io9, which is admittedly a far more interesting name than "Gliese 581 g" - orbits well within the star's small "habitable zone," that being the area where the existence of liquid water on the surface is possible.

A chart of the Gliese 581 system superimposed on the inner Sol system. This image is a work of a National Science Foundation employee, taken or made during the course of the person's official duties. As a work of the U.S. federal government, the image is in the public domain.

The only problem is that the scientific vocabulary doesn't exactly intersect with the standard vernacular; indeed, there are plenty of occasions where a scientific term can easily be interpreted as something completely different by a layman. When scientists say "Earth-like," they mean that it's a rocky planet roughly similar in size to Earth. As far as the media is concerned, calling it "Earth-like" means we're just one breakthrough in theoretical physics away from being to sell vacation timeshares there.

Because really, it's "Earth-like" in many of the same ways that Mars is Earth-like. It orbits so close to its sun that it's tidelocked in the same way that Luna always presents the same face to Earth - one hemisphere of Gloaming is in constant light and the other in constant darkness, with only a thin "twilight band" around the terminator presenting the possibility of a more moderate climate. What's more, its surface gravity is likely even stronger than Earth's, presently estimated at between 1.1 and 1.7 g... and you thought launching stuff to orbit from Earth was expensive! That is, if anyone would want to live there in the first place: from what I've read, the extrapolated environmental conditions in the twilight band are disturbingly reminiscent of Yellowknife in December.

I don't know about you, but I think I've been down this road before - anyone else remember 70 Virginis b? It occupied the news for a brief time back in 1996, when it was believed it orbited within its own star's habitable zone, until further measurements refined our understanding of a far more elliptical, and far less salubrious, orbit. Admittedly the evidence for Gloaming's potential habitability is greater - but that's still all it is. While I think it's a bit early to throw Earth 2 marathons in honor of the discovery, I do find it comforting that so many people do seem so excited about this prospect.

What Gloaming's discovery really makes clear to me is that there's a massive eagerness for us to be told, authoritatively, that We Are Not Alone - or, failing that, that we've discovered where They might live, or have lived, or be yet to live, considering that technological civilizations would likely be separated just as vastly by time as they would by space.

Nevertheless, it's still an inspiring discovery. We've spent decades, centuries even, looking up at the night and guessing at what's there, hidden beyond our sight. Gloaming won't be the last we find, and in the meantime we need to encourage this interest, this thirst to know and understand what's out there, beyond. In a world of unstable economic recovery, an uncertain present, and unchecked greed, it's helpful to be able to look through our telescopes and see the future.