Overheard on the web: "We finally found the solution to the Fermi paradox". Note that the AI is called Evil! Intelligent design, anyone?
The Fermi paradox just got worse. Why haven´t we seen *the unmanned space probes* of the purported extraterrestrial civilizations? But maybe we simply haven´t been looking hard enough. Sabine never makes an explicit tie-in to Avi Loeb´s quixotic quest for such probes in our planetary backyard, but if the paper is correct, maybe the rest of us should go looking, too!
Sabine Hossenfelder strikes again.
Does life come from outer space, but eventually reaches a "great filter", explaining the Fermi paradox? Microscopic life might be extremely common in the universe, but space-faring civilizations probably aren´t. Somehow, it feels like a "waste of space" if panspermia is true but almost never gives rise to a United Federation of Planets...
OK, this was interesting. Is there *some* opening for techno-cornucopianism somewhere? But even if we can *communicate* faster than the speed of light, can we also *travel* faster? What would be the energy source in such a case? Soylent green or what?
Note that Sabine debunks the idea that "quantum entanglement" means "spooky action at a distance".
I admit that this was a bit over my head, but the idea that more "common sense" in quantum physics leads to the idea that we *can* send messages faster than light is obviously interesting. And yes, Sabine actually says that she went into science hoping to find a way to communicate with extraterrestrials!
Professor Dave will attack in 10, 9, 8...LOL.
I didn´t know Seventh Day Adventism was a "science fiction" religion? OK, I actually suspected it, but this is a confirmation of sorts. According to the video above, intelligent physical-biological aliens do exist on other planets but they are unfallen (!) and therefore have no contact with Earth.
The Bible never mentions what *we* would call "space aliens", so the exegesis is more strained than usual. Especially so since the video explicitly makes a distinction between real aliens and spiritual beings (angels or demons). Note that the AI narrator misquotes the parable of the lost sheep!
What prompted the video above is (of course) the strange claim by Trump that he will direct the federal government to disclose all secret UFO files. The Adventists who made the video suspect a mass deception and strongly imply that the last days may soon be upon us. Mass deception there will indeed be (one way or another), but hardly the literal apocalypse described in the Book of Revelation and elsewhere.
But you knew that already. So let´s move on. I actually toyed with the idea of "unfallen worlds" myself, but from a slightly different angle. Since we live in a gigantic "cosmic void", maybe that´s why no alien civilization ever comes visiting us? The distances are enormously large even by space standards, so why bother? Hopefully the strange and wonderful alien worlds in distant galaxies are indeed unfallen...
A propos a discussion on another blog...
This question sits right at the boundary between physics, philosophy of limits, and what people sometimes call cosmic pessimism. There is no single “proof” that interstellar travel is impossible — but there are several deep, mutually reinforcing arguments suggesting it may be permanently infeasible for any technological civilization, not just us.
I’ll lay out the main ones.
The universe enforces a hard speed limit: light speed.
From Albert Einstein’s relativity, the energy required to accelerate mass increases without bound as you approach . Even at modest fractions of light speed, the energy cost becomes absurd.
Example:
A tiny 100-ton probe at 0.2c requires energy comparable to the entire annual output of a major nation — just to accelerate it, not to slow it down.
For crewed ships or colony ships:
You need propulsion
Radiation shielding
Life support for centuries
Deceleration fuel at the destination
This is not “hard engineering”.
It is thermodynamic brutality.
The Solar System is energetically cheap. Interstellar space is not.
At relativistic velocities, even a dust grain hits with the energy of a bomb.
At 0.2c:
A grain of sand delivers explosive-level kinetic energy
Hydrogen atoms become hard radiation
To survive, a ship needs:
Shielding thicker than meters of metal or ice
Or massive electromagnetic fields
Which themselves require huge power and mass
This creates a feedback loop:
More shielding → more mass → more energy → more shielding
This is a classic runaway constraint.
Every speculative drive hits a wall:
| Concept | Fatal problem |
|---|---|
| Fusion rockets | Fuel mass > payload |
| Antimatter | Impossible to produce at scale |
| Light sails | Laser arrays must be planetary-scale |
| Bussard ramjets | Interstellar gas is too thin |
| Warp drives | Require negative energy not known to exist |
| Wormholes | Require exotic matter + stability we have no evidence for |
Nothing in known physics allows cheap relativistic mass transport.
You can send tiny probes.
You cannot send civilizations.
Even at optimistic speeds:
Nearest stars: decades to centuries
Colonization waves: millennia
Galactic travel: millions of years
But technological civilizations are fragile.
On Earth:
Industrial civilization is ~200 years old
Writing ~5,000 years
Empires collapse in centuries
Interstellar projects require:
Unbroken political, economic, and cultural continuity for longer than any civilization has ever survived.
That may be a deeper barrier than physics.
If interstellar colonization were easy, the galaxy should already be full.
This is the Enrico Fermi paradox:
“Where is everybody?”
We see:
No probes
No megastructures
No astroengineering
No alien signals
The simplest explanation is:
Interstellar expansion is not viable, even for advanced civilizations.
Even self-replicating AI probes — far easier than sending humans — should have filled the galaxy in a few million years.
They haven’t.
This suggests either:
They are impossible
Or they are universally avoided
Or civilizations reliably destroy themselves before building them
All three point to a hard barrier.
Putting this together yields a bleak but coherent picture:
Stars are islands. Civilizations are trapped on them.
You can explore your own solar system.
You can send robotic scouts to nearby stars.
But no species migrates between stars in a meaningful way.
The universe looks empty not because life is rare — but because distance is fatal.
If aliens could travel between stars cheaply:
Earth would have been visited billions of years ago
The Solar System would show obvious artifacts
Since it doesn’t, the simplest inference is:
They can’t get here.
Not because they aren’t smart — but because the universe is bigger than technology.
The dream of starflight may be psychologically irresistible — especially to a species like ours, so shaped by exploration myths — but the universe may be telling us something very Buddhist in spirit:
Desire does not cancel limitation.
We may be a brilliant, tragic species:
able to see the stars,
but never to reach them. 🌌
Another content-creator (Petrov) claims that the recent Fermi Paradox study proves the opposite: that we probably are alone. Or is it another study? Haven´t watched all of his video yet.
You already know my take on the Fermi paradox: we live in a cosmic backwater nobody cares about, but in general, the universe is *teeming* with life, including intelligent life. With outmost probability, however, they neither won´t nor can´t travel here, the distances simply being too large. They probably can´t even contact each other.
Everything is alright in the world.
A YouTuber who calls himelf The Angry Astronaut argues that 3I/ATLAS is an asteroid ship or comet ship. That is, a space craft disguised as a natural object. Well, I suppose that´s a way to square the circle!
Mr Angry claims that a Bayesian analysis made by Grok gives a 40 trillion to one chance that the object isn´t artificial. Maybe this will become the go-to explanation if the mystery object doesn´t land on Earth, doesn´t do anything obviously UFO-like and just disappears into outer space again, mission accomplished.
Note the tie-in to the Fermi paradox and the Dark Forest hypothesis. Interesting, to be sure, but I suspect this will become another nothingburger, the hype in a sense becoming more important than the comet itself...
Even my father wonders about 3I/ATLAS and why everyone is suddenly observing radio silence on the topic. The reason is presumably that the interstellar wanderer is currently behind the sun (from our perspective). Just wait until it re-emerges! As far as I understand, this will happen the night between Wednesday and Thursday, but I suppose I could be wrong.
THEN WE´LL KNOW. Personally, I don´t think anything will happen, but I wouldn´t be surprised if the disinfo on the web goes into *freakin´ overdrive*. Keep your heads cool, fam. All fifteen of them...
And if something does happen, well, at least we can say that we solved the Fermi paradox. Euthyphro's dilemma will remain on Friday, I´m afraid.
Actually quite interesting.
For instance, black holes seem to destroy "information", despite the laws of nature supposedly making this impossible. A pretty good argument for Gnosticism or even Satanism, if you ask me! Yepp, that´s the kind of "free association" I indulge in when watching science influencer videos on YouTube, LOL.
Note also that Sabine considers complexity and emergence to be paradoxes. I agree: emergence sounds like "something out of nothing", which is (allegedly) not possible.
Maybe Reality is broad enough to include...you know...God or something.
Hare Krishna guru solves Fermi paradox. *We* are the aliens. Didn´t see that coming, did´ya?
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| An unlikely scenario? |
Some more ChatGPT stuff...
What is the most plausible solution to the Fermi paradox? Is there any positive evidence, so to speak, that we are alone?
The Fermi Paradox asks: “If intelligent extraterrestrial life is common in the universe, why don’t we see any evidence of it?” Despite the vastness of the cosmos and the high probability of Earth-like planets, we observe no signals, no probes, no visits, and no artifacts — a “Great Silence.”
There is no proof that we are alone, but several solutions to the paradox have been proposed. Let’s go over the most plausible explanations and examine whether any of them point — even circumstantially — to humanity being alone, at least in our region of space.
Idea: Complex, intelligent life is extremely rare due to an unlikely combination of factors (stable star, plate tectonics, large moon, magnetic field, etc.).
Plausibility: High
Positive evidence?
Earth-like conditions may be rarer than we thought.
Despite thousands of exoplanets, we’ve found no clear Earth analogs yet.
The long stability of Earth’s climate (~3.8 billion years) may be unusually lucky.
➡️ Implication: We may not be completely alone, but intelligent life might be rare enough that no one is close enough (in time or space) to contact us.
Idea: Somewhere on the path from basic chemistry to interstellar civilization, there is a step that is extremely hard to pass — a “filter.” It may lie behind us (we’re rare survivors) or ahead (doom awaits us).
Plausibility: High
Positive evidence?
We see no Kardashev Type II or III civilizations (those harnessing the energy of stars or galaxies).
The silence of the universe may suggest that intelligent life tends to self-destruct (e.g., via nuclear war, climate collapse, AI, etc.) or never escapes its planet.
➡️ Implication: We may be rare survivors — or the Great Filter is still ahead, which is ominous.
Idea: We haven’t seen alien civilizations because they don’t emit detectable signals (or we’re looking the wrong way).
Plausibility: Moderate to high
Positive evidence?
Despite searching, no confirmed alien radio signals or megastructures (like Dyson spheres) have been found.
Our instruments are improving, but we're still barely scratching the surface.
➡️ Implication: Alien life may be out there but hard to detect — though the continued absence of technosignatures strengthens the idea that intelligent civilizations are extremely rare or short-lived.
Idea: Civilizations rise and fall on different timescales and may not overlap.
Plausibility: High
Positive evidence?
Civilizations might last only a few thousand years — a tiny blink in cosmic time.
The universe is 13.8 billion years old; if intelligent life arose even 500 million years ago, it might be extinct by now or have evolved beyond detectable activity.
➡️ Implication: We might exist in the wrong time slice to encounter others.
Idea: Advanced civilizations are silent by choice or so alien we wouldn’t recognize them.
Plausibility: Medium
Positive evidence?
None direct, though the idea that alien motives and forms might be incomprehensible is hard to rule out.
SETI assumes aliens want to talk or expand — this may be a human bias.
➡️ Implication: We’re not necessarily alone — just ignored or unable to comprehend the signals.
Aliens are hiding (the “zoo hypothesis”) — less scientific, hard to test.
We’re in a simulation — philosophical, not falsifiable.
They’re already here (UFOs) — no verifiable, physical evidence so far.
Not in a strict empirical sense — absence of evidence is not evidence of absence — but:
No technosignatures in billions of stars surveyed.
No artifacts on the Moon, Mars, or nearby space.
No alien probes, radio signals, or Dyson spheres.
No signs in the cosmic microwave background, which a galaxy-spanning civilization might alter.
That’s not proof. But the deeper and broader our search goes without result, the more the data seem to support the hypothesis that intelligent life is rare or short-lived.
In purely probabilistic terms, the most likely scenario is:
The universe may be full of life, but intelligent, technological civilizations are exceedingly rare and widely spaced.
If that’s true, we might be the only ones in our cosmic neighborhood — or even in our entire galaxy — at this time.
That possibility, while sobering, also makes our stewardship of Earth and our future even more significant.
Would you like to explore one of these explanations in more depth — such as the Great Filter or technosignature searches?
The Rare Earth Hypothesis is one of the most compelling and sobering answers to the Fermi Paradox. It argues that while microbial life may be common in the universe, complex, multicellular, and intelligent life is extremely rare — perhaps even unique to Earth — due to a long chain of improbable, finely tuned conditions.
Proposed most notably by Peter Ward and Donald Brownlee in their 2000 book Rare Earth: Why Complex Life is Uncommon in the Universe, the hypothesis claims:
Earth is rare not just because it harbors life, but because it supports complex life due to a highly improbable set of environmental, geological, and astronomical circumstances.
In other words, microbial life might be abundant, but Earth-like planets that can sustain animals, plants, and intelligence are exceptionally rare.
Here’s a list of the critical factors Ward and Brownlee argue are necessary — and rare — for Earth-like complex life:
Not too hot or cold for liquid water.
Earth is just the right distance from the Sun.
Our Sun is stable and in the main sequence.
Many stars (red dwarfs, variable stars) have violent outbursts or tidal locking, hostile to complex life.
Prevents extreme temperature swings.
Earth's orbit is unusually stable over long periods.
Stabilizes Earth’s axial tilt.
This helps maintain a stable climate, which supports long-term evolution.
Drives the carbon-silicate cycle, regulating CO₂ and thus Earth's temperature.
Also creates diverse ecosystems (e.g., continents and oceans).
Unclear how common plate tectonics is elsewhere.
Shields life from solar and cosmic radiation.
Caused by Earth’s molten iron core and rotation.
Acts as a gravitational shield, reducing the number of catastrophic asteroid/comet impacts.
Too many impacts: life can’t evolve; too few: less delivery of organic materials early on.
Not too close to the galactic core (high radiation).
Not too far (low metal content).
Earth is in a “galactic habitable zone”.
Earth has remained in a narrow temperature range for billions of years.
Feedback systems like the carbon cycle help avoid “runaway” states like Venus.
Even with all these conditions, complex life arose very late on Earth — only ~500 million years ago.
Intelligence emerged just once, and just in the last few million years.
Exoplanet surveys (like Kepler) have found thousands of planets — but truly Earth-like planets with the right atmosphere, magnetic field, plate tectonics, and stable climate are rare or unconfirmed.
Mars, Venus, Europa — potentially habitable, but not Earth-like in all critical ways.
The “Goldilocks” zone is necessary, but not sufficient.
If the Rare Earth hypothesis is correct, then:
The emergence of intelligent life might be one-in-a-galaxy, or even one-in-a-universe.
The universe may teem with microbial life, but civilizations capable of communication or space travel are vanishingly rare.
There may be no one to hear us, and we may never hear anyone else.
Far from being a pessimistic view, some take it as a call to responsibility:
“If we are alone, then the fate of conscious life rests entirely with us.”
Critics argue that:
Some criteria (like plate tectonics or moons) may not be as rare as Ward and Brownlee thought.
Life might adapt to harsher or different conditions (e.g., around red dwarfs).
It may be too Earth-centric, underestimating the diversity of possible biochemistries.
We may just not have looked long enough — our search is still very new.
| Factor | Rare on Earth? | Essential for Complex Life? |
|---|---|---|
| Stable climate | ✅ Yes | ✅ Yes |
| Plate tectonics | ✅ Yes | ✅ Probably |
| Magnetic field | ✅ Yes | ✅ Probably |
| Large moon | ✅ Yes | ✅ Possibly |
| Gas giant protector | ✅ Yes | ✅ Possibly |
| Galactic location | ✅ Yes | ✅ Probably |
The Rare Earth hypothesis doesn’t argue that life is impossible elsewhere — only that Earth-like conditions, capable of supporting complex, intelligent observers, are extremely rare.
Would you like to explore whether any particular factor, like plate tectonics or magnetic fields, might truly be rare among exoplanets?
Great choice — both plate tectonics and planetary magnetic fields are crucial components of the Rare Earth hypothesis, and current research suggests they may indeed be rare or at least not guaranteed features of Earth-sized exoplanets.
Carbon cycle regulator: Plate tectonics drives the long-term carbon-silicate cycle, which stabilizes global temperatures.
Surface diversity: Creates mountains, continents, oceans — diverse ecosystems.
Chemical recycling: Replenishes essential nutrients (like phosphorus and iron) from the mantle to the biosphere.
Potential for origin of life: Hydrothermal vents, a byproduct of tectonics, may have been cradles of early life.
We only know for sure that Earth has active plate tectonics. Here’s what we know or suspect about other bodies:
| Planet | Plate Tectonics? | Notes |
|---|---|---|
| Earth | ✅ Yes | Only known example. |
| Venus | ❌ No | Has a stagnant lid; extremely hot interior may prevent subduction. |
| Mars | ❌ No | May have had ancient tectonics, but the crust is now static. |
| Europa, Enceladus | 🟡 Maybe | Icy shells may show tectonic-like behavior — not confirmed. |
We don’t yet have direct observations of plate tectonics on exoplanets, but scientists try to infer their likelihood based on:
Planet size and mass: Larger terrestrial planets ("super-Earths") may have thicker crusts, making subduction more difficult — inhibiting tectonics.
Heat flow: Sufficient internal heat is needed to drive mantle convection. Smaller planets lose heat faster and may become geologically dead.
Water: Subduction may require water to lubricate the crust — dry planets (like Venus) may be tectonically stagnant.
Plate tectonics might occur elsewhere, but:
It requires a delicate balance of internal heat, crust thickness, water, and time.
May be transient (starting and stopping).
Is likely not universal, even on rocky planets in the habitable zone.
Shields the atmosphere from solar wind and cosmic rays.
Prevents atmospheric erosion, especially for lighter molecules like water vapor.
Reduces surface radiation — crucial for complex, surface-dwelling life.
Earth’s magnetic field is generated by the dynamo effect: convection in the molten iron outer core.
| Body | Magnetic Field? | Notes |
|---|---|---|
| Earth | ✅ Strong | Vital for shielding and atmosphere retention. |
| Mercury | ✅ Weak | Unusually small planet to have a magnetic field. |
| Venus | ❌ No | Possibly due to slow rotation and lack of core convection. |
| Mars | ❌ No (now) | Once had a field; lost it, and lost most of its atmosphere soon after. |
| Gas Giants | ✅ Yes | Strong fields, but they are not habitable. |
We have no direct way yet to detect exoplanetary magnetic fields. However, scientists can estimate likelihood based on:
Rotation rate: Faster-rotating planets are more likely to have active dynamos.
Interior structure: Needs a liquid, conductive core and sufficient heat.
Size: Larger planets retain heat longer, but may develop stratified layers that block convection.
🧪 Recent findings suggest that:
Super-Earths may struggle to maintain Earth-like magnetic fields over long timescales.
Planets around M-dwarf stars are especially vulnerable: tidal locking reduces rotation, and intense stellar wind strips away atmospheres without a magnetic shield.
Some research suggests a feedback loop between plate tectonics and the magnetic field:
Plate tectonics helps cool the core, promoting the convection needed for the dynamo.
The magnetic field helps preserve an atmosphere, which stabilizes climate, which helps sustain tectonics over time.
This creates a kind of co-evolved system, and if either component fails, the rest may unravel.
| Feature | Importance | Earth Has It | Likely Common? | Comments |
|---|---|---|---|---|
| Plate tectonics | 🔥🔥🔥 | ✅ Yes | ❌ Probably not common | May require water, right mass, right heat. |
| Magnetic field | 🔥🔥🔥 | ✅ Yes | ❌ Possibly rare | Tied to rotation, core state, internal heat. |
🔎 These aren’t strict disqualifiers — microbial life may not need either — but complex surface life likely does.
Thus, the combined rarity of both features gives strong circumstantial support to the Rare Earth Hypothesis.
Would you like to explore how these factors affect specific exoplanet candidates like those in the TRAPPIST-1 system or around Proxima Centauri?
