COMET NEOWISE: PAST AND FUTURE VISITOR

Even if the Covid-19 crisis didn’t have everyone in lockdown desperately looking for distractions, Comet NEOWISE would have captured a lot of attention because it’s the first easily seen comet since Comet Hale-Bopp in 1997. You may have made the effort to see it yourself if you live in the Northern Hemisphere, most recently a little after sunset in the northwestern sky below the Big Dipper. The comet itself is a small smudge and to the naked eye the tail is actually easier to detect if you’re not looking straight at it. The view is a lot more impressive through binoculars or a small telescope, although what really makes the whole thing noteworthy is knowing that what we’re seeing is a 5 km-diameter ball of slush trailing a plume of gases that extends millions of kilometers through space. Its orbit takes it more than a hundred billion kilometers from the sun and requires 6800 years to complete. So it’s the scale of the thing that’s mind-boggling, rather than the actual visuals themselves.

With the huge span of time involved in NEOWISE’s relentless course through the cosmos, it’s impossible to resist thinking about conditions on Earth when the comet last passed our way, and what our little blue planet will be like when it returns about the year 8863 CE.

Humans of circa 4800 BC didn’t know anything about the physics of astronomy, but they would have been much more familiar than we are with the stars in the night sky. The appearance of a comet would have been big news, and could have been seen as a portent to any number of events (disastrous or auspicious, depending on the needs of the local astrologer). But the entire human population at the time was probably less than forty million. The first Agricultural Revolution was in its late stages, meaning that tribes of hunter-gatherers had largely turned to living in small villages in set locations rather than roaming the countryside, raising a few domesticated animals and crops like millet and spelt. In China, people had begun to fire pottery in kilns and may just have begun experimenting with metals like bronze. It would be another few hundred years before the predecessor of Indo-European languages began to be spoken, and nearly a millennium before the Sumerian culture developed the first written language.

Advances in technology, language, and social organization occurred gradually over the next four thousand years until the Industrial Revolution brought an explosion of change in the late 1700’s CE. The last 2 ½ centuries have seen much greater change than the 6 ½ millennia before them. With that in mind, is it possible to forecast what our planet and our race will be like the next time Comet NEOWISE streaks through the night skies?

Climate modelling tells us that if we humans hadn’t interfered by pouring megatons of carbon dioxide into the atmosphere, the Earth would have begun to slowly cool on its way toward the next ice age. The human race has survived a number of ice ages in the past, though with a much smaller population to feed. But now that ice age has been diverted or postponed. In fact, the coming centuries will be a very difficult time because of too much heat, with melting ice caps, rising sea levels, expanding deserts, and seriously acidified oceans. The climate changes we’ve triggered will force us to adapt in order to survive, and that adaptation could take many forms. We might need to biologically engineer our bodies to store and use water more efficiently, withstand higher heat, and digest more hardy forms of food plants (cactus burgers anyone?) Or we might need to move underground and inhabit colonies in vast caverns or silos (like in Hugh Howey’s Wool stories). There’s not enough water in Earth’s ice caps to flood the whole planet as portrayed in the 1995 Kevin Costner movie Waterworld, but we might still choose to live on the oceans where we could produce lots of food via algae farms enriched by cool, nutrient-rich water from the ocean depths. Or we might even be forced to leave our home planet and either exist in giant space habitats in orbit, on the Moon, or within hollowed out asteroids (none of them likely to support large numbers of people), or set out to find other habitable worlds around other stars (Mars is the best option for a colony within our solar system and it’s not a good one—the technology to make it human-friendly within a reasonable timeframe would be better put to use in mitigating the effects of climate change on Earth). Who knows where the human race will live by the year 8863?

Potential futures are not all gloom and doom by any means. Consider the United Federation of Planets in the Star Trek universe, to be founded in the year 2161, and the multi-species habitats of Babylon 5 in the 2250’s. These include (mostly) peaceful coexistence with alien species too. Mind you, as much as I’m a devoted fan of Star Trek and heartily approve of its generally positive outlook (dependent on advanced technology, especially reliably fast space travel) there are a lot of other elements to take into consideration when predicting the path that the human race will take.

In just one generation, we’ve seen incredible progress in communications and information technology that results in new social challenges every day. The Covid crisis itself is an example—a sudden shift toward self-isolation creating social interaction that’s (for now) almost exclusively online. Back in the 1950’s SF writers like Arthur C. Clarke and others depicted future societies in which people rarely left their homes and only interacted remotely via holographs or ubiquitous wall displays. For all we know, the coronavirus may have triggered a wholesale change that will only accelerate.

Then there’s bio-engineering: within the coming century, we’ll have the ability to preselect almost every characteristic of our offspring and make any number of radical changes to our own bodies. Whether out of necessity, or at the whim of fashion, the physical form of humanity will change, and by 8863 it could change a lot.

And that’s if we still inhabit a physical form at all. If futurists like Ray Kurzweil are right, within the next few centuries we’ll find ways to transfer our consciousness into digital form, and either inhabit mechanical bodies, or choose to live in entirely virtual worlds within ultra-powerful computer networks. By the 89th Century we will have left silicon circuitry far behind and discovered how to use the atomic structure of any ordinary matter as digital media—we could inhabit the very rocks, trees, and grasses that make up our planet.

And don’t even get me started on Time Travel!

So when you go out tonight looking for Comet NEOWISE, think about the stories it could tell about the last time it toured through the inner solar system, and take a moment to imagine what our world could be like the next time it comes. Earth and its neighbourhood might be a very different place.