Comet Countdown: Are We Due For Global Extinction?

Chris Ferrie
5 min readJan 25, 2024

Comets — those enigmatic cosmic snowballs — have captivated humanity for millennia. Their dazzling tails, eccentric paths, and potential for catastrophic impact have woven them into myths, legends, and even doomsday prophesies. But beyond the spectacle, lies a sobering reality: these celestial wanderers, while beautiful, can be deadly… like everyone dead…ly.

A dance with destruction

Throughout history, our planet has tangoed with the destructive side of comets. The most famous? The Chicxulub impact, 66 million years ago, is believed to have wiped out the dinosaurs, along with lots of other species. But it wasn’t alone. Countless lesser-known impacts have shaped our planet’s history, carving craters and forever influencing the story of our planet. Of course, these events were ultimately good for us since our species probably would not have arisen without them. But, for those alive when they happened, it would not have been pleasant. Nor will it be pleasant for us when the next one arrives.

Scientists have modeled the potential consequences of a large comet impact, and the picture isn’t pretty. The timeline could look something like this:

Leading up to impact: Early warning systems detect the incoming threat, which ideally would be centuries but could be as short as years or days, depending on where the comet came from. Panic and fear grip the world, causing humans to do human-level-stupid stuff, but ultimately, most survive to witness the event.

Impact: The comet slams into Earth, releasing an unimaginable amount of energy. The point of impact experiences instant vaporization, triggering earthquakes and mega-tsunamis. Depending on the location, millions will perish more or less instantly.

Days after: Dust and debris cloud the atmosphere, plunging the planet into a darkness colder than winter. Temperatures plummet, photosynthesis ceases, and a global famine becomes inevitable. War, displacement, and disease are widespread.

Years after: The long-term effects are even more devastating. Acid rain, toxic dust fallout, and disrupted ecosystems will have triggered mass extinctions. Human society collapses, and only a few are able to survive on limited resources.

Decades after: Billionaires emerge from the bunkers to check on their stocks only to find an unrecognizable world unfit for human survival.

Millennia after: Earth and life recover with the emergence of new ecosystems and species to fill those niches.

The end is not nigh

Fear of cometary doom is nothing new. Throughout history, comet sightings have sparked panic and hysteria. In 1066, Halley’s Comet was seen as a harbinger of William the Conqueror’s invasion. During its 1910 return, news that Earth might pass through the tail of the comet preceded the sale of “anti-comet” umbrellas and sugar pills. In 1997, Hale-Bopp’s arrival spawned doomsday cults and mass suicides. This was far more disappointing because, by that time, the space age had matured to the point of us already having visited a comet!

Our highlight reel includes:

Giotto (1985): Flew past Halley’s Comet, capturing the first close-up images of its nucleus.

Suisei (1985): Another Japanese mission that flew past Halley’s Comet, obtaining images and data.

Vega 1 & 2 (1986): Flew past Halley’s Comet and Venus, conducting various scientific investigations.

Deep Space 1 (1998): Flew by Comet Tempel 1 and ejected an impactor probe, providing insights into the comet’s composition.

Stardust (1999): Flew by Comet Wild 2, collected dust particles, and returned them to Earth for analysis.

Rosetta (2004–2016): Orbited and landed a probe (Philae) on Comet Churyumov-Gerasimenko, studying its surface and composition in detail.

Deep Impact (2005): Launched an impactor probe into Comet Tempel 1, creating a crater and revealing its internal structure.

Suffice it to say that we have learned that comets are not messages sent by the gods, cryogenic chambers for ancient aliens, or even sentient beings worth attempting telepathic contact with. They are, however, still capable of hitting the planet — and a big one does so once every 100,000 years or so.

Fear of comets is, in some sense, justified. But, it should not be the same fear as being the victim of some random violent crime you didn’t see coming while walking down a dark alley — it should be a much deeper existential fear for all of humanity. The universe does not care about us. An extinction-causing comet (or asteroid) will eventually hit the Earth with nearly 100% certainty, but not any time soon.

The call to action

This is starting to sound like the plot of a Hollywood disaster movie. So, hero, what are you going to do about it?

The first thing you should do is buy a copy of 42 Reasons to Hate the Universe (And One Reason Not To), which will inform you that comets are but one of 42 things that ought to be keeping you up at night. On the bright side, it’ll also teach you how to laugh about it. It’s a thrilling ride through cosmic history, science, and our place in the universe, with a healthy dose of humor to keep you grounded. Remember, knowledge is power, and when it comes to celestial threats, knowing your enemy is half the battle.

Back in the real world, you can support science. Inform yourself and others about missions like DART, NASA’s recent groundbreaking step in planetary defense. By intentionally crashing a spacecraft into a small asteroid, DART successfully altered its orbit, proving the feasibility of deflecting potentially hazardous objects. This mission opens up a new era in protecting our planet from future cometary threats.

But don’t just cheer on missions like DART — advocate for increased funding, join citizen science initiatives, and push for international collaboration. Every voice raised is a cosmic shout for planetary protection. In doing so, challenge the popular narratives endorsed by attention-seeking social media algorithms. Don’t fall for the doom and gloom — question, investigate, and demand transparency, both from influencers as well as governments, science organizations, and the media. We need a realistic understanding of the risks, not sensationalized headlines that fuel panic and the sales of comet-deflecting salt crystals.

Accept the vastness of the universe, the humbling reality that we’re still toddlers taking our first steps on the cosmic playground. Embrace the mystery, the wonder, the endless possibilities that even a single comet holds. Remember, the universe isn’t a Hollywood script. It’s a dynamic, unpredictable, often hilarious drama unfolding before our very eyes. And instead of fearing the comets, let’s channel that fear into curiosity, action, and a collective commitment to understanding and protecting our place in this grand cosmic circus.

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Dr. Chris Ferrie



Chris Ferrie

Quantum theorist by day, father by night. Occasionally moonlighting as a author.