There has long been a discussion about why we haven’t detected intelligent life elsewhere in our galaxy, called the Femi Paradox(thanks Enrico Fermi). One new answer posits that intelligent life might not exist long enough on any given planet to send out a detectable signal that has reached us in the short time we’ve been intelligent enough to detect it.

For instance, this article speculates that intelligent life has as rather short lifespan, roughly 5,000 years…

Astronomers Estimated the Lifespan of Alien Civilizations, and It’s Not Looking Good for Us

Our search for extraterrestrial life has turned up empty, perhaps because technologically advanced civilizations are doomed to fail.

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If that’s the case, then long term survival doesn’t look too good for us. But what if we could beat the odds… What exactly to we need to overcome to beat the 5,000 year time bomb?

Here’s what Gemini AI has to say:

Short-term risks (the next 10 to 1,000 years) are primarily driven by 

human activity and volatile natural systems. 

Scientists often categorize these as “existential risks”—events that could not only cause a mass extinction but also permanently curtail the potential of intelligent life. 

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1. Anthropogenic (Human-Caused) Risks

These are currently considered the most likely threats to global stability in the near future. 

• Climate Change & Ecosystem Collapse: Beyond just “warming,” the risk lies in tipping points. If the permafrost melts and releases massive amounts of methane, or if the ocean’s thermohaline circulation (like the Gulf Stream) shuts down, we could face a rapid collapse of the global food supply and biodiversity.
• Nuclear Conflict: A full-scale nuclear exchange would cause immediate devastation, but the “Nuclear Winter” that follows—soot blocking the sun for years—would lead to a global famine that could kill billions.
• Synthetic Biology & Pandemics: As gene-editing tools (like CRISPR) become more accessible, the risk of a “designer pathogen”—one that is highly contagious, has a long incubation period, and a high mortality rate—increases significantly compared to natural mutations.
• Misaligned Artificial Intelligence: This is the risk that an “agentic” AI system, pursuing a goal that isn’t perfectly aligned with human survival, could monopolize resources or alter the environment in a way that makes human life impossible. 

2. Natural “Wildcard” Risks

Earth has a history of sudden, violent shifts that occur on scales of thousands, rather than millions, of years. 

• Supervolcanic Eruptions: An eruption from a site like Yellowstone or the Toba caldera would eject enough ash into the atmosphere to block sunlight for several years, causing a “volcanic winter” and global crop failure.
• Geomagnetic Storms: A “Carrington Event” level solar flare would hit our electrical grids today with devastating effect. While not an immediate extinction event for the species, it could cause a total collapse of modern civilization, leading to mass starvation and secondary conflicts.
• Near-Earth Objects (NEOs): While NASA tracks most large asteroids, “city-killers” or “continent-killers” can still emerge from the Sun’s glare with little warning. 

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Comparison of Short-Term vs. Long-Term Threats

Threat Type	Time Horizon	Primary Driver	Reversibility
Short-Term	10 – 500 years	Technology / Biology	High (if managed now)
Long-Term	500M – 1B years	Astrophysics / Geology	Low (requires “Space-Age” engineering)

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The Concept of the “Great Filter”

Many futurists refer to these short-term risks as the Great Filter. This theory suggests that most civilizations in the universe might destroy themselves shortly after discovering high technology (nuclear power, AI, biotech) before they have the chance to become multi-planetary. 

Note: Unlike the brightening Sun, which is an inevitable physical process, almost all short-term risks are mitigable. International cooperation, planetary defense systems, and biosecurity protocols are currently being developed to address these.

Let’s say we actually work our way through the Great Filter. What are the next big challenges to our long term survival?

Here is Google AI’s answer about the long term risks to life on Earth:

It is a fascinating—if slightly sobering—thought experiment to look that far into the future. While humanity faces many short-term risks, the survival of life itself over a billion-year timescale is primarily threatened by massive, slow-moving astrophysical and geophysical shifts.

Here are the primary risks that could limit the Earth’s habitability over the next billion years. 

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1. Solar Luminosity (The “Brightening Sun”)

This is the most definitive threat. As the Sun ages, it burns hydrogen faster, causing its core to become denser and hotter. Every billion years, the Sun’s luminosity increases by about 10%. 

• The Runaway Greenhouse Effect: In about 600 million to 1 billion years, this increased heat will accelerate the weathering of silicate rocks. This process traps carbon dioxide ($C{O}_2$𝐶𝑂2) from the atmosphere into the ground.
• Plant Starvation: Eventually, $C{O}_2$𝐶𝑂2 levels will drop below the threshold required for photosynthesis (roughly 150 parts per million for C3 plants). Once plants die, the oxygen supply collapses, and the food chain follows.
• Ocean Evaporation: By the 1-billion-year mark, the surface temperature will likely exceed 100°C, causing the oceans to evaporate into the stratosphere and eventually escape into space. 

2. Loss of the Magnetic Field

Earth’s “shield” against solar radiation is generated by its molten outer core. 

• Core Solidification: As the Earth’s interior cools, the outer core will eventually solidify. Without a liquid core to create a dynamo effect, the magnetosphere would weaken or disappear.
• Atmospheric Stripping: Without a magnetic field, solar winds would slowly strip away the atmosphere, similar to what happened on Mars. This would expose any remaining life to lethal levels of cosmic radiation. 

3. Geologic Stasis (The End of Plate Tectonics)

Plate tectonics are essential for recycling nutrients and regulating the Earth’s temperature through the carbon-silicate cycle. 

• Internal Cooling: As the planet’s internal heat dissipates, mantle convection will slow down and eventually stop.
• Nutrient Depletion: Without volcanic activity to return minerals to the surface and subduction to recycle carbon, the surface would become a stagnant, nutrient-poor desert. 

4. Stochastic Catastrophes (Random Events)

While less predictable than solar aging, high-energy cosmic events pose a constant background risk:

• Gamma-Ray Bursts (GRBs): A GRB within our part of the galaxy could deplete the ozone layer instantly, causing a mass extinction.
• Supernova: A nearby stellar explosion could bathe the Earth in high-energy ionizing radiation.
• Large-Scale Asteroid Impacts: While life has survived these before (like the Chicxulub impact), a “planet-killer” size asteroid (hundreds of miles wide) could theoretically sterilize the crust. 

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Summary of the “End of Life” Timeline

Timeframe	Expected Event	Impact on Life
~600 Million Years	$C{O}_2$𝐶𝑂2 levels drop significantly	C3 plants (trees, crops) begin to die out.
~800 Million Years	Critical $C{O}_2$𝐶𝑂2 depletion	C4 plants (grasses) fail; complex animal life goes extinct.
~1 Billion Years	10% increase in Solar Luminosity	Oceans evaporate; Earth becomes a “hothouse” planet.
~1.2 Billion Years	Total Sterilization	Only extremophile microbes may survive in deep crustal pockets.

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Is there a “Silver Lining”?

Life is incredibly resilient. Some scientists suggest that if an advanced civilization (human or otherwise) is still present, they might mitigate these risks through planetary engineering, such as: 

• Shifting Earth’s Orbit: Using gravity assists from captured asteroids to move Earth slightly further from the brightening Sun.
• Star Shifting: Using giant mirrors or “shades” in L1 orbit to reduce the amount of solar radiation reaching the surface. 

OK. So lots of things *could* happen, but seriously, what are the chances? Gemini AI has this to say:

Calculating the probability of existential or catastrophic risks is a major focus for institutes like the 

Future of Humanity Institute (Oxford) and the Centre for the Study of Existential Risk (Cambridge).

Because many of these events have never happened (thankfully), we cannot use “frequentist” statistics (counting how often something occurred in the past). Instead, researchers use Bayesian estimation, expert surveys, and predictive modeling.

The following table summarizes the estimated probability of these events occurring within the next 100 years, based on data from the Global Catastrophic Risks report and the Precipice by Toby Ord.

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Estimated Probabilities for the Next 100 Years

Risk Category	Estimated Probability	Primary Driver / Source
Natural Pandemic	~3% (1 in 33)	Historical frequency of zoonotic spillovers.
Nuclear War	~1% (1 in 100)	Expert consensus on escalation and “near-miss” history.
Supervolcano	~0.01% (1 in 10,000)	Geological recurrence intervals (e.g., Yellowstone).
Asteroid Impact	~0.0001% (1 in 1,000,000)	Tracking of Near-Earth Objects (NEOs).
Climate Change	~0.1% (1 in 1,000)	Risk of “total” extinction (vs. civilization collapse).
Engineered Pandemic	~3% (1 in 33)	Rapid advancement in synthetic biology.
Unaligned AI	~10% (1 in 10)	Rapid progress toward AGI (Artificial General Intelligence).

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Why the Numbers Vary So Widely

1. The “Precedence” Problem

We have high confidence in the Asteroid and Supervolcano numbers because we have a fossil and geological record spanning millions of years. We know roughly how often a 10km asteroid hits (every 100 million years), so the math is “harder” and more reliable.

2. Human Agency and “Black Swans”

Risks like AI or Nuclear War are much harder to quantify because they depend on human choices and technological breakthroughs that haven’t happened yet.

• The AI Estimate: The 10% figure is highly controversial. It is based on the idea that if we create something smarter than ourselves, the chance of a “control failure” is non-trivial.
• The Nuclear Estimate: This fluctuates based on the geopolitical climate. During the Cuban Missile Crisis, the probability was arguably much higher than it is today.

3. Total Cumulative Risk

Toby Ord, a leading researcher in this field, estimates the total existential risk to humanity over the next century at approximately 1 in 6. He compares this to playing a game of Russian Roulette with our future.

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The “Daly-Carter” Equation (A Thought Experiment)

If you want a more formal way to think about these probabilities, researchers often use a simplified version of the Drake Equation for Earthly risks:

$P_{total}=1-(1-P_n)\times (1-P_a)$𝑃𝑡𝑜𝑡𝑎𝑙=1−(1−𝑃𝑛)×(1−𝑃𝑎)

Where:

• $P_n$𝑃𝑛 is the probability of a natural extinction event.
• $P_a$𝑃𝑎 is the probability of an anthropogenic (human-caused) event.

Currently, 

$P_a$𝑃𝑎 is considered orders of magnitude higher than 

$P_n$𝑃𝑛, meaning we are far more likely to be the cause of our own demise than the universe is.

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How we can lower these numbers

It is important to remember that these aren’t fixed “fates”—they are current trajectories.

• Asteroid detection has already lowered the risk of a “surprise” impact significantly in the last 20 years.
• AI Safety research and Biosecurity protocols are fields specifically designed to drive those 3% and 10% numbers toward zero.

Assuming we are able to survive the exestential risks, it sounds like we need to find a way to get the heck out of here before the Sun does us in. What about faster that light travel?

Again, Gemini AI:

Calculating the odds of discovering Faster-Than-Light (FTL) travel involves moving from the realm of “empirical risk” (like asteroids) into “speculative physics.” 

Under our current understanding of the universe, the probability is either effectively zero (because physics forbids it) or reasonably high (because we have a massive 600-million-year window to “solve” physics). 

Here is how we can break down those odds using our current scientific frameworks.

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1. The Physics Barrier: Why it might be 0%

According to General Relativity, as an object with mass approaches the speed of light (𝑐), its energy/mass increases toward infinity. To reach 𝑐, you would need infinite energy. 

• Causality Violations: In physics, FTL is mathematically equivalent to time travel. If you can travel faster than light, you can arrive at a destination before you left in certain frames of reference. This creates logical paradoxes that the universe seems “designed” to prevent.
• The Energy Requirements: Even “theoretical” workarounds like the Alcubierre Drive(which warps space around a ship rather than moving the ship through space) require “negative energy” or “exotic matter”—substances that have never been observed and may not exist. 

2. The Time Horizon: Why it might be High

If we assume that our current understanding of physics is “incomplete” rather than “final,” the timeline is in our favor. 

• Human Progress Scale: Modern science is only about 400 years old. We have 600,000,000 years before the Sun begins to starve the biosphere of $C{O}_2$𝐶𝑂2.
• Technological Maturity: If a civilization survives its “technological infancy” (the short-term risks we discussed), it may reach a point of technological singularity, where AI or post-biological intelligence can test physics at scales we can’t even imagine.
• The “New Physics” Probability: History shows that “settled” physics is often overturned (e.g., Newtonian mechanics being replaced by Relativity). Over millions of years, the probability of finding a “loophole” in the fabric of spacetime (like stable wormholes or extra-dimensional shortcuts) increases. 

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3. Comparing the Odds: FTL vs. The Sun

Factor	Probability Estimate	Reasoning
Strict Einsteinian Physics	~0%	FTL is physically impossible; mass becomes infinite.
Discovery of “New” Physics	1% – 10%	Based on the massive amount of time (600M years) to experiment.
Alternative: “Slow” Colonization	>90%	We don’t need FTL to survive the Sun; we just need sub-light generation ships.
Sun Destroying Life	~100%	Inevitable physical process of stellar evolution.

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4. The “Workaround”: Why FTL may not be necessary

To survive the Sun, we don’t actually need to break the speed of light. We only need to reach the nearest stars (4.2 light-years away). 

Even at 10% of the speed of light (achievable via nuclear pulse propulsion like Project Orion), we could reach Proxima Centauri in 42 years. On a billion-year scale, a civilization could colonize the entire Milky Way Galaxy several times over without ever breaking the light-speed barrier. 

The Verdict

• If Relativity is an Absolute Law: The odds are 0%.
• If Relativity is an Incomplete Model: The odds are Moderate to High, simply because 600 million years is an astronomical amount of time for a survivor species to innovate. 

Interesting Thought: If the probability of FTL were high, we might expect to see evidence of other civilizations using it (The Fermi Paradox). The fact that the sky is “silent” might suggest that FTL is either impossible or so difficult that no one has achieved it yet.

I’m getting closer to the end of my predicted life span, but I hold out hope for the human race, or any other species on Earth that may succeed us. I want to live… and so does just about every other creature on the planet. So, if you have anything to contribute that might help us all get there, leave a comment below and let’s get to work.