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From: John Savard <quadibloc@servername.invalid>
Newsgroups: rec.arts.sf.written
Subject: Alien Technology? Probably Not. (HD 110067 orbital resonances)
Date: Tue, 21 May 2024 08:33:47 -0600
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I bumped into a news article noting that astronomers had found
exoplanets around HD 110067 which were all in resonant orbits.

To find out the details, I had to go to Wikipedia:

https://en.wikipedia.org/wiki/HD_110067

The orbital periods of the planets in the system are in the ratios
54:36:24:16:12:9, and so as you go from the inside out, one
encounters, between pairs of adjacent planets, resonances with the
ratios 4:3, 4:3, 3:2, 3:2, and 3:2.

According to the news article, the possibility of detecting a signal
from alien technology in the system is being looked at.

However, in our own Solar System, there are a lot of resonances too,
although, with the exception of a 3:2 resonance between Pluto and
Neptune, they're all only approximate.

Thus, with Mars, Earth, Venus, and Mercury, we have the ratios 17:9,
8:5, and 23:9.

With Neptune, Uranus, Saturn, and Jupiter, we have the ratios 2:1,
3:1, and 5:2.

As many of these ratios aren't as simple as those in HD 110067, I
would suspect the reason we don't have exact resonances is because
some gravitational forces work against the resonance continuing to get
closer, and instead pull the orbits away from resonance. With the
simple ratios in HD 110067, perhaps things worked out differently,
causing the system to naturally move towards all the resonances being
exact.

John Savard