ET Lives in a Multi-Planet Solar System

[CygnusX-1]

by Ken Croswell

If ET exists, he probably lives in a solar system with many planets. That's the implication of a new study that finds that the more planets a solar system has, the more circular their orbits tend to be.

Link (including a color chart showing the correlation of orbital eccentricity with number of planets in a solar system): Scientific American.

 

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Typical base rate fallacy in the article. A system with multiple planets might have a larger probability to have small eccentricities (which is not surprising), but without the fraction of systems with n planets this does not tell anything about the probability that life would be in multi-planet systems.
Also, the diagram can be misleading: most planets are in the 1-planet category, so the dots would extend more towards larger eccentricities even without any correlation.

Original paper (without that error)
Figure 1 gives a better idea how large (or not large) the differences are.

 

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The authors recognize that most of the planets are in the 1-planet category but go through statistical tests to show that their result is statistically significant.

The Scientific American diagram has exactly the same information as Figure 2 of the paper, except that it's presented in a more attractive manner.

 

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The authors recognize that most of the planets are in the 1-planet category but go through statistical tests to show that their result is statistically significant.

I didn't say anything against the publication, that looks good.
The Scientific American article uses it to draw a conclusion that the data does not allow.

The Scientific American diagram has exactly the same information as Figure 2 of the paper, except that it's presented in a more attractive manner.

Unfortunately that is the easiest one to misinterpret.

 

[CygnusX-1]

The Scientific American story does not misrepresent the paper. The paper itself states, "If low eccentricities indeed favor high multiplicities, habitability may be more common in systems with a larger number of planets."