How a team including a Harvard astronomer turned a natural comet into an alien invasion using faulty logic and fuzzy math

The Setup: When Scientists Go Full Sci-Fi

Picture this: It’s July 2025, and astronomers spot something unusual streaking through our solar system. 3I/ATLAS, the third known interstellar visitor, has some interesting characteristics. Its orbit is nearly aligned with our solar system’s plane (but backwards), it appears larger than previous visitors, and it’s making relatively close passes by several planets.

Most astronomers see a fascinating natural object—an ancient comet from another star system, possibly 7 billion years old, offering insights into planetary formation across the galaxy. But a team led by Harvard’s Abraham Loeb sees something else entirely: potential alien technology, possibly hostile, arriving for an Earth rendezvous in December 2025.

Their July 2025 paper asks the provocative question: “Is 3I/ATLAS Alien Technology?” But when you dig into their reasoning using systematic logic analysis, something fascinating emerges—not evidence of aliens, but a masterclass in how smart people can reason badly when faced with unusual events.

The Logic Detective Work

What happens when you run scientific speculation through the equivalent of a BS detector? I recently analyzed the alien hypothesis paper using formal reasoning techniques, looking for logical inconsistencies, statistical errors, and cognitive biases. The results reveal universal patterns in how we think about extraordinary claims—patterns that show up everywhere from medical diagnosis to financial markets.

The analysis used several approaches:

Classical Logic: Checking for basic contradictions and invalid arguments
Temporal Logic: Examining time-related claims and confidence about future events
Statistical Bias Detection: Looking for survivorship bias, cherry-picking, and multiple comparisons errors
Evidence-Confidence Analysis: Checking whether claims match the strength of supporting evidence

Think of it as having that friend who always asks “But how do you know that?” except with systematic methods instead of just skeptical intuition.

What the Math Really Says

The paper presents nine pieces of “evidence” that 3I/ATLAS might be alien technology. Let’s examine the most revealing claims:

🎯 The Texas Sharpshooter’s Probability Game

The Claim: Multiple low-probability orbital features (0.2% for ecliptic alignment, 0.005% for planetary approaches) multiply together to show this can’t be natural.

The Problem: This is textbook “Texas Sharpshooter Fallacy”—shooting at a barn wall and then drawing targets around wherever the bullets landed.

The authors calculated the probability of these specific weird features without asking “How many different types of weird features could we have looked for?” If you examine any object for enough different anomalies, you’ll find some. It’s like being amazed that you met someone who shares your exact birthday, eye color, and favorite pizza topping, while ignoring that you met 500 people at the convention and checked 47 different characteristics for each one.

More fundamentally, the calculation assumes these orbital parameters are independent—but they’re not. Objects near the ecliptic plane are preferentially discovered by Earth-based surveys, and any detected interstellar object must pass through the inner solar system. The “coincidences” are partially baked into the discovery process.

📐 The Great Size Mix-Up

The Claim: 3I/ATLAS is “too large to be an asteroid” with a claimed diameter of ~20 kilometers.

The Reality: This represents a fundamental misunderstanding of how to measure comet sizes. The 20 km estimate treats the object’s brightness as if it came from a bare nucleus, when in reality the brightness includes an extensive dust coma surrounding a much smaller core.

Independent coma-corrected photometry indicates the actual nucleus is just 1-2 kilometers in diameter—not dramatically different from other interstellar objects. The apparent “size anomaly” dissolves when you account for the fact that 3I/ATLAS is behaving exactly like comets should: developing a coma as it approaches the Sun.

⏰ Future Fortune Telling

The Claim: “An optimal intercept of Earth would entail an arrival in late November/early December of 2025.”

The Issue: The paper expresses high confidence about specific alien arrival dates while simultaneously admitting the whole hypothesis is speculative. This creates a logical tension—you can’t say “I’m just speculating” and “the aliens will definitely arrive in December” in the same argument without undermining your own credibility.

This type of temporal inconsistency reveals how even careful scientists can slip into overconfident predictions when dealing with low-probability scenarios.

What Real Science Found Instead

While the alien hypothesis was making headlines, actual astronomers were doing what they do best: systematic observation and analysis. The results paint a completely different picture:

Gemini South and NASA IRTF spectroscopy in July 2025 detected water ice in 3I/ATLAS’s coma—exactly what you’d expect from a comet awakening as it approaches the Sun.

Multiple observatories confirmed visible coma and tail development, with composition matching D-type asteroids and primitive comets found in our own solar system.

The European Space Agency’s Richard Moissl stated definitively: “There have been no signs pointing to non-natural origins of 3I/ATLAS in the available observations. All observations are in agreement with basic assumptions about a space-weathered natural object with, so far, weak cometary activity.”

Even the paper’s own authors acknowledge: “By far the most likely outcome will be that 3I/ATLAS is a completely natural interstellar object, probably a comet.”

The Expert Reaction: “Nonsense on Stilts”

The astronomical community’s response to the alien hypothesis has been notably blunt:

Chris Lintott of Oxford, who helped simulate 3I/ATLAS’s galactic origins, called suggestions of artificiality “nonsense on stilts” and “an insult to the exciting work going on to understand this object.”

Samantha Lawler of the University of Regina noted that while remaining open-minded is important, “the evidence presented is absolutely not extraordinary” and “all evidence points to this being an ordinary comet.”

Jason Wright of Penn State provided devastating criticism of a fundamental misunderstanding: the paper incorrectly claimed that observed coma around 3I/ATLAS was merely “smearing” due to telescope tracking, when planetary scientists routinely adjust telescopes to prevent such artifacts. As Wright noted, “no large telescope has seen anything but coma.”

Why This Matters (Hint: It’s Not About Aliens)

The 3I/ATLAS alien hypothesis fails not because aliens are impossible, but because it violates basic principles of scientific reasoning. The same logical patterns revealed in this analysis show up everywhere humans encounter unusual events:

The Universal Reasoning Traps

Multiple Comparisons Error: Testing many hypotheses without adjusting for the increased chance of false positives
Post-Hoc Probability Calculation: Computing odds after the fact, without accounting for selection effects
Independence Assumption Violations: Treating correlated variables as independent
Confidence-Evidence Mismatches: Expressing certainty beyond what the data supports

These aren’t signs of bad science—they’re signs of normal human cognition bumping into statistical edge cases. Understanding these patterns helps us think more clearly about everything from medical diagnosis to market predictions to policy decisions.

The Real Educational Value

The authors describe their paper as “largely a pedagogical exercise,” and in an unintended way, they’re right. It’s an excellent case study in how even smart, well-intentioned scientists can fall into reasoning traps when dealing with unusual events.

The value isn’t in the alien speculation—it’s in learning to recognize when our pattern-seeking brains see significance where none exists, when we stack weak evidence to support extraordinary conclusions, and when we mistake the merely improbable for the impossible.

The December Test

The paper makes a testable prediction: if 3I/ATLAS is alien technology planning to visit Earth, we should see action when it makes its closest approach on December 19, 2025, at a distance of 55 million miles.

Spoiler alert: 3I/ATLAS will pass by as predicted, displaying perfectly normal cometary behavior as it heads back to interstellar space. No aliens will emerge, no probes will deploy, and no “reverse Solar Oberth maneuvers” will be detected.

What we will see is a magnificent natural phenomenon—a 7-billion-year-old visitor from another star system, offering genuine insights into the early history of planetary systems across our galaxy. That’s not as sensational as an alien invasion, but it’s far more scientifically valuable.

The Bottom Line: Better Reasoning, Not Fewer Questions

The goal isn’t to eliminate speculation about unusual phenomena—speculation drives discovery. The goal is to get better at recognizing when our reasoning needs a reality check.

Carl Sagan’s principle that “extraordinary claims require extraordinary evidence” isn’t about shutting down investigation. It’s about matching our confidence to the strength of our evidence, accounting for the ways our brains mislead us, and maintaining the intellectual humility that separates good science from wishful thinking.

Every day we encounter situations that seem too coincidental to be random: the perfect parking spot, the friend who calls just when you’re thinking about them, the stock that rockets up right after you sell it. Understanding the logical structures behind “this can’t be random!” thinking helps us navigate a world full of genuine patterns and meaningless coincidences.

3I/ATLAS reminds us that the universe is already plenty strange without invoking aliens. Sometimes the most extraordinary thing about an extraordinary claim is how ordinary the explanation turns out to be.

The patterns of reasoning examined here—from survivorship bias to confidence-evidence mismatches—appear across all domains where we try to make sense of unusual events. Understanding these patterns doesn’t kill curiosity; it helps us be curious more effectively.

And who knows? When we finally do find evidence of extraterrestrial intelligence, we’ll be better equipped to recognize it because we learned to think more clearly about the false alarms.

Harvard’s Alien Math Doesn’t Add Up (Literally)

How a team including a Harvard astronomer turned a natural comet into an alien invasion using faulty logic and fuzzy math

The Setup: When Scientists Go Full Sci-Fi

The Logic Detective Work

What the Math Really Says