Buzz
The Earth has existed for about 4.5 billion years, and it's easy to imagine that both the planet (and humanity) might endure for billions of years more. However, our world faces many persistent challenges that raise doubts about its long-term habitability.
That said, we might not even have to worry about those problems, because there are numerous ways the world, as we know it, could be erased. Today. And only some of them are due to human folly, which, in a way, is oddly reassuring.
10. Gamma-Ray Burst
A gamma-ray burst (GRB) is an intense burst of high-frequency electromagnetic radiation. This burst can release an amount of energy far surpassing what the Sun would emit in ten billion years, all within mere seconds. Experts believe that GRBs may occur due to the explosion of stars or the collision of neutron stars.
If Earth were struck by a gamma-ray burst from within the Milky Way, it could chemically damage our atmosphere, depleting the ozone layer that shields us from harmful ultraviolet rays, potentially leading to a mass extinction. Some researchers even propose that gamma-ray bursts might also emit cosmic rays, which would induce radiation sickness in any survivors of the initial GRB impact.
While most bursts last less than two seconds, a longer GRB (lasting more than two seconds) could potentially lead to a mass extinction event on Earth. Fortunately, they typically originate from distant dwarf galaxies, though there have been instances closer to our galaxy, and scientists speculate that gamma-ray bursts might have been responsible for previous mass extinctions on Earth.
You can never be too sure.
9. Massive Solar Flare
In July 2012, a solar superstorm nearly caused the end of the world as we know it. If you're wondering how you missed all the coverage on this near-disaster, don't worry. There was none.
When the massive solar flare, or coronal mass ejection, came close to Earth’s orbit, our planet had just moved out of its trajectory, so NASA chose not to highlight it. Had it occurred a week earlier, it would have short-circuited our electrical systems. The flare would have caused destruction 20 times greater than Hurricane Katrina, and the aftermath would have taken at least two decades to recover from.
While this may sound disastrous, you might think it doesn’t qualify as a mass extinction event. However, some experts believe that a much larger solar flare may have triggered an extinction event around 12,000 years ago, when evidence suggests Earth was bombarded by intense UV rays due to damage to the ozone layer.
A 2017 study concluded that there is a “solid chance” a giant solar flare could strike Earth in the next century, resulting in up to $10 trillion in damages. They found that extreme super-flares on the Sun occur roughly once every 20 million years, and it seems we’re due for one. The odds of it causing an extinction-level event are about one in 1,000, which isn’t that bad, but the likelihood of a flare knocking out our electrical and technological infrastructure is more like one in eight.
So, you might want to stock up on candles.
8. Massive Flood Basalt Events
At the conclusion of the Triassic period, half of all species on Earth went extinct, making room for the rise of dinosaurs. This was triggered by a volcanic eruption of such enormous scale that it could have flooded the U.S. with 91 meters (300 feet) of lava—a truly colossal event.
This eruption, known as a flood basalt event, led to a spike in global temperatures, a doubling of atmospheric carbon dioxide, and ocean acidification. Some scientists argue that nearly all mass extinctions throughout Earth's history are linked to these volcanic eruptions, rather than the more commonly cited causes such as asteroids.
The initial impact of a flood basalt event is actually a cooling of the planet. The massive eruptions launch sulfur dioxide into the stratosphere, which reflects sunlight away from Earth. This would be followed by acid rain and respiratory problems. Livestock would perish, and airplanes would be grounded. Over time, however, the planet would warm up due to the carbon dioxide and water vapor released into the atmosphere by the event.
Research is still ongoing to determine the frequency of these flood basalt events and, more importantly, when the next one might occur.
7. A Possible Incident at The Large Hadron Collider
The Large Hadron Collider (LHC) is a 27-kilometer-long underground ring where particles are accelerated and collided at mind-boggling speeds. With the help of 9,300 magnets, scientists can trigger up to 600 million collisions every second in a subatomic demolition derby.
Conditions at CERN’s main facility, where the collider is housed, are carefully regulated. However, accidents can still occur with particle accelerators. In 1978, a Russian scientist placed his head in a particle accelerator and was struck by a burst of protons traveling close to the speed of light. He absorbed 76 billion electron volts but survived the incident, even though doctors initially believed he wouldn't.
In 2009, the LHC was shut down due to overheating. The issue was traced back to a piece of bread that had fallen onto an electrical substation above the collider. While most believed a stray bird caused the incident, a pair of renowned physicists, who feared the Higgs boson research was jeopardizing the universe, proposed a theory involving a time-traveling saboteur bird sent from the future to prevent the experiments.
With bread.
As strange as it sounds, these concerns about the collider are not isolated. Astronomer Professor Lord Martin Rees has cautioned that an error at CERN could lead to a “doomsday scenario,” in which the entire planet is drawn into a black hole, shrinking the Earth into a hyperdense mass just 100 meters (330 feet) wide. If that wasn’t alarming enough, there is also a theory that a mistake in the collider could cause an accident that might “engulf space itself.”
6. Alien Invasion
The quest to discover intelligent life in space has captivated many scientists and astronomers. However, not everyone agrees that seeking aliens is a good idea. Professor Stephen Hawking believed that, instead of trying to make contact with extraterrestrial life, it would be wiser for us to focus on staying hidden from them.
He suggested that, given the vast number of planets we now know exist, there must be other life-forms in the universe, some of which will possess far superior intelligence, technological expertise, and military power. Hawking also warned that, should they arrive, their intentions would likely be those of conquerors, not diplomats.
If aliens were to make contact with Earth, it is possible that China would be the first to detect them, due to their heavy investments in alien communication technology, including the construction of the world’s largest radio dish for this very purpose. However, should aliens reach out, there is no unified response protocol for how humanity should react, and nothing to prevent amateur enthusiasts from broadcasting messages to extraterrestrial listeners.
What if the aliens don’t make the first move and simply arrive? Considering the vast resources and time required for such a journey, it’s unlikely that their visit would be casual. As Stephen Hawking put it, “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.”
5. Swallowed By A Black Hole
Even without the involvement of CERN, there is a possibility that Earth could be consumed by a black hole. A black hole is essentially a region where mass is concentrated so intensely that the gravitational pull is so strong that not even light can escape it.
There are various events that could lead to the formation of a black hole. One example is the star in the Eta Carinae system, which is nearing the end of its life and could potentially go supernova. It's even possible that this explosion has already occurred, but the light from the event is still traveling across light-years.
When this star finally explodes, its core might collapse, creating either a neutron star or a black hole. Some have speculated that, if a black hole forms, it could consume the remains of Eta Carinae and might even pull the Earth into it. However, scientists agree that this scenario is extremely unlikely.
Although the chances are slim, it's not entirely out of the question that a rogue black hole could wander into our solar system. If this were to happen, it is likely that the Sun and all of its planets would be torn apart.
Well, that’s reassuring.
4. Nuclear War
The specter of nuclear warfare has cast a shadow over the Earth since the mid-1900s. While the threat has fluctuated over time, the danger of nuclear conflict seems to have become more pressing in recent years.
If a nuclear war were to occur today, it is predicted that the aftermath would resemble “the extinction of the dinosaurs.” The soot produced by the devastation would disrupt the climate, cooling the Earth’s surface while heating the upper atmosphere, leading to “potentially catastrophic consequences.”
During the Cuban Missile Crisis, nuclear war was narrowly avoided thanks to a mix of public bravado and private diplomacy from both sides. Khrushchev sent a letter to Kennedy stating, “If there is no intention to tighten that knot and thereby doom the world to the catastrophe of thermonuclear war, then let us not only relax the forces pulling on the ends of the rope, but let us take measures to untie that knot.”
Today, the threat of nuclear war is again considered “dangerously close,” with the world’s future possibly depending on the diplomatic expertise of various nations and their leaders.
3. Vacuum Decay
Our universe exists within a vacuum, and this vacuum is adjacent to the vacuums of other universes. However, not all of these vacuums are genuine. Some are “false vacuums,” which may be unstable, or “metastable.”
If our universe resides in a false vacuum, any high-energy event, such as a star exploding, could cause our universe to come into contact with the true vacuum of a neighboring universe. This would create a bubble that expands at the speed of light, consuming the entire universe in the process.
A universe residing in a false vacuum could also be “tunneled into” by a tiny particle breaking through the barrier that separates one vacuum from another. This would cause the false vacuum universe to be drawn into the other universe as well.
So, are we in a vacuum or a false vacuum? The answer isn’t clear. However, research on the measurements of the Higgs boson suggests that our vacuum could be metastable. If we were to be sucked into a true vacuum, it’s predicted that we would all be instantly annihilated as the bubble wall moves through our galaxy at the speed of light. There would be no survivors.
It’s not all bad news, though. The lifespan of a metastable universe is believed to be extraordinarily long, so we’re probably safe for quite a while. Plus, if we were sucked into a vacuum, it would happen so quickly that we wouldn’t even notice it.
So, there’s nothing to worry about.
2. Methane Burst
While many apocalyptic scenarios involve dramatic explosions and danger, what about a tiny microbe that releases methane?
It has been suggested that a similar catastrophe took place 252 million years ago, wiping out 90% of marine species and 70% of terrestrial life in one of Earth’s five major mass extinctions. Researchers believe that the microbe Methanosarcina, which produces methane, grew uncontrollably in the oceans. This caused the climate to warm, leading to the acidification of the seas and the mass extinction of life. The microbe thrived on the minerals created by large volcanic eruptions in Siberia, which boosted the concentrations of nickel needed for its growth.
So, how likely is it that another methane burst could obliterate life on Earth? It appears quite probable. The Arctic is believed to be a “ticking time bomb” for methane. It’s said that methane is trapped in the permafrost in the forms of methane hydrate and methane clathrate. If too much ice were to melt, a catastrophic mass extinction event could be set off.
1. Supervolcano Eruption
Campi Flegrei is a supervolcano located in the Bay of Naples. Its name, meaning “burning fields,” refers to the vast underground magma chambers that fill the area, much of which lies beneath the sea. Campi Flegrei hasn’t erupted for over 500 years (with the last eruption being a minor one), but experts warn that it could be nearing a critical point. In December 2016, volcanologists indicated that the volcano may be approaching “critical degassing pressure,” which could lead to a major eruption.
That would spell disaster. Around 39,000 years ago, the volcano released an astonishing 300 cubic kilometers (72 miles) of material in a single eruption.
Campi Flegrei is not the only supervolcano around. Lake Toba in Indonesia, Yellowstone Park in the US, and the Taupo caldera in New Zealand all house supervolcanoes with the potential to destroy vast regions and transform them into lifeless deserts if they erupt. Experts are working on predicting the likelihood of these eruptions. Researchers monitoring Yellowstone's supervolcano estimate an average eruption interval of 740,000 years, meaning Old Faithful should remain safe for another 100,000 years or so.
Let’s hope that all supervolcanoes follow such a predictable pattern.
