In Netflix's new sci-fi movie, The Midnight Sky, George Clooney, plays Augustine Lofthouse, a scientist who remains behind at an arctic base after the rest of the crew evacuates. The reason? Earth is becoming totally inhospitable due to vague radiation-based global catastrophe, the exact details of which are never revealed other than it seems to have been man-made. The Midnight Sky puts an interesting spin on the "apocalyptic space drama" genre — rather than humans attempting to flee the planet in the wake of some space-born disaster, Augustine must traverse the arctic wasteland in order to get to a stronger signal so that he can warn a returning spacecraft not to come home.
Even though The Midnight Sky's apocalypse isn't the typical world-ending scenario we see in sci-fi, you can't help but wonder... Are there cosmic threats coming for us in the vastness of space? Assuming we don't destroy ourselves, the way they do in The Midnight Sky, is there anything to be worried about from up above?
Of the scenarios we’ll discuss, an asteroid impact is probably the most familiar, the most likely, and also the one we’re most equipped to handle. Our fascination with the threat of a fatal impact likely has something to do with the knowledge that it’s happened at least once before.
Of all the inhabited planets we know of (one) we have solid evidence of an asteroid impact causing massive global extinction. From an empirical standpoint, the probability of a catastrophic asteroid impact is 100 percent. The remaining question is, how likely is it to occur again? And that’s a little more difficult to answer.
A quick glance around the solar system illustrates the relative frequency of impacts. Our own Moon is positively riddled with craters, each one the result of a past collision. Of course, the atmosphere protects us from the vast majority of impactors, and it also helps that the most intense impact era ended billions of years ago.
Still, objects do find their way into our neighborhood from time to time, and they’re worth keeping an eye on. This is precisely what the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory is tasked with.
At the time of this writing, there are 21 NEOs being tracked by Sentry, an Earth Impact Monitoring program. One of which, Apophis, made headlines recently when scientists observed changes in its orbit, altering its impact probability.
Right now, there is no known object with a statistically significant chance of impact. According to the JPL, the chance of catastrophic impact in the foreseeable future is essentially nil. And, if an object were to enter a collision course with Earth, we’ve got lasers, bombs, and gravity at our disposal.
Also known as coronal mass ejections, solar flares are bursts of energy coming from a star. On occasion, stars unleash incredible bursts of radiation from their surfaces, and our Sun is no different. Solar flares happen fairly often, but most of the time our atmosphere and electromagnetic sphere protect us. More often than not, the biggest threat is to satellites or other objects not protected by Earth’s bubble. The risk is in a massive flare, more powerful than our natural defenses can handle.
The trouble is, we don’t have any good way of predicting when or if these massive flares will happen. One such flare occurred in 1859, creating a geomagnetic storm unlike anything we’d ever seen in recorded history.
A storm like the one in 1859 might shut down much of our technological infrastructure, electricity might be knocked out for weeks at a time before it could be repaired. Satellite communication might be all but non-existent. This might not have been a big deal in decades past, but much of modern civilization in the developed world is built upon satellite communication and electrical grids, both of which might be out of service long enough to severely disrupt our way of life.
That might sound bad enough, but it could be a whole lot worse. While NASA predicts the worst solar flares from our own star would not be a threat to the planet (or to humanity), scientists have observed sun-like stars elsewhere in the galaxy and seen evidence of incredibly energetic flares, more powerful than anything we've seen from the Sun.
If our Sun were to undergo one of these flares, it might unleash energy millions of times more powerful than what we regularly experience. Such a flare would eat away at the ozone layer, exposing us to deadly radiation, causing increased incidents of cancers along with the degradation of ecosystems, including plankton which supply the majority of Earth’s oxygen.
The very good news is, these sorts of solar activities are incredibly unlikely. We might have to do without internet or cell phones for a while, but the risk of our lives, with respect to solar flares, is minimal. We can probably continue to count on the Sun to feed life, rather than take it. Unlike what could happen if we fell victim to…
This phenomena is a relatively new discovery. Gamma-ray bursts are thought to occur during the deaths of massive stars as they explode with incredible energy. In ten seconds, gamma ray bursts produce energy equivalent to that of our own sun over the course of ten billion years.
These bursts require violent death, either via the collapse of a massive star, or the merging of neutron stars. Despite that, they happen fairly regularly. Nearly every day, we are awash in energy from gamma-ray bursts, sent across the cosmos. Were you capable of seeing in the right light spectrums, you’d see gamma ray bursts flickering like camera flashes on a regular basis.
Luckily, these bursts occur far enough away that their energies offer little harm to Earth and its inhabitants. While gamma-ray bursts are relatively common on a universal scale, the universe is big. In order for one to pose a threat, it would have be nearby and positioned just right. But, if a nearby burst were to happen, and in just the right way, it would be catastrophic.
Such an unfortunately timed, unfortunately aimed burst would strip the ozone layer in a matter of seconds and very probably wipe out a significant portion of life on Earth. Some scientists believe the Ordovician extinction, which resulted in the loss of nearly 70 percent of all life on the planet, was a result of just such a burst 450 million years ago. Moreover, life on Earth at that time was mostly in the ocean, which would have offered some protection from the results of a gamma-ray burst. If it were to happen now, the results would be far more devastating.
Luckily, the odds are in our favor. The likelihood of such a burst occurring near enough and in the right direction to wipe us out is minimal, we’re at much higher risk of home-grown cataclysms like nuclear war, human-caused climate change, engineered disease, or, well, whatever happened in The Midnight Sky. The universe is an apathetic place, but it isn’t out to get us. We’d do better to concern ourselves with threats closer to home.