Avi Loeb: What Is 3I/ATLAS?

Dec 23, 2025

In this engaging discussion, Avi Loeb, a Harvard astrophysicist and author known for his groundbreaking research on interstellar objects, delves into the mysteries of 3I/ATLAS. He highlights its unusual alignment and anti-tail geometry, sparking debates about whether it’s a comet or something technologically advanced. Loeb also tackles the significance of recent anomalies, the implications of its trajectory toward Jupiter, and the potential for life in the Jovian system. Plus, he shares insights on navigating today's AI misinformation landscape. Prepare for a thought-provoking journey beyond our solar system!

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Brightness Dominated By Coma Not Nucleus

3I/ATLAS arrived July 1st and its brightness is dominated by a gas plume rather than a solid nucleus.
Initial size estimates assuming reflected light implied an implausible ~20 km body, so most light comes from surrounding gas.

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Keep Observations Before Concluding Origin

Continue monitoring 3I/ATLAS through Jupiter encounter and downgrade technological likelihood only if no anomalies persist.
Collect more data before drawing strong conclusions; persistent anomalies warrant serious consideration.

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Persistent Sunward Jet Defies Comet Norms

3I/ATLAS shows a persistent, tightly collimated sunward jet (anti-tail) stretched over a million kilometers.
Standard cometary physics struggles to explain such a narrow, long sunward jet instead of the usual sun-ward-deflected tail.

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Join us LIVE with Harvard astrophysicist Avi Loeb for the final verdict on the interstellar object 3I/ATLAS, the third confirmed visitor from beyond our solar system. We examine the newly proposed 14th anomaly: the remarkably rare alignment of 3I/ATLAS’s rotation axis within about 8 degrees of the sunward direction at distances greater than 5 AU, a configuration with a probability of less than about 0.5 percent if random.

This alignment has major implications for how we interpret the object’s anti-tail jet geometry, rotational dynamics, and overall physical behavior, adding to a growing list of anomalies that strain standard cometary explanations. Whether you are interested in jets, rotation periods, anti-tail physics, or what these observations imply about natural versus technological origins, this livestream offers a rigorous, evidence-driven deep dive. We will lay out the data, compare competing interpretations, and ask the central question: is 3I/ATLAS simply an unusual comet, or something fundamentally different?

Run of Show

00:00 – 02:00 Intro and context: Discovery of 3I/ATLAS, orbital properties, and why it has drawn intense attention.

02:00 – 05:00 What is an interstellar object: Comparison with 1I/Oumuamua and 2I/Borisov.

05:00 – 10:00 Anomalies 1 through 5: Brief recap of the earliest reported oddities, including trajectory and activity.

10:00 – 15:00 Anti-tail observations and physics: Explanation of the sunward anti-tail and why it is unusual.

15:00 – 20:00 Rotation period and periodic behavior: Discussion of the roughly 15.5 to 16.2 hour signal and its interpretation.

20:00 – 25:00 Recap of the first 13 anomalies: How they are ranked by likelihood and what they suggest.

25:00 – 30:00 The 14th anomaly: rotation-axis alignment: Geometry, probability estimates, and why this feature stands out.

30:00 – 35:00 Possible mechanisms for axis alignment: Assessment of natural processes versus alternative explanations.

35:00 – 40:00 Jet collimation and structure: Why the sunward jet remains narrow and persistent.

40:00 – 45:00 Implications for outgassing models: Where standard cometary physics succeeds or fails.

45:00 – 50:00 Natural versus non-natural scenarios: Clear comparison of competing hypotheses.

50:00 – 55:00 Future observations and missions: What additional data could resolve the debate.

55:00 – 60:00 Audience Q and A: Live questions with Avi Loeb.

60:00 – 65:00 Wrap-up and final thoughts: Synthesis of the evidence and implications for future research.

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