General Discussion
In reply to the discussion: New model predicts that we're probably the only advanced civilization... [View all]exboyfil
(17,862 posts)the more exoplanets that we find, the more we understand that our particular situation is pretty unique (violating the mediocrity principle). We drew the Powerball lottery ticket.
Here are just a few examples of why we may be pretty special in this galaxy.
1. The abundance of phosphorus. A recent study showed that a typical nebula did not contain phosphorus. An earlier study, of a less common nebula, showed the presence of phosphorous.
2. The eccentricity of our planetary system orbit. It is a the far low end of those solar systems that we have already detected. Part of that is selection bias (easier to see with radial velocity) but this trend has extended over to the transit method as well.
3. The presence of hot Jupiters. These are disruptive to rocky orbit planets.
4. Our tides and our orbital stability coming from our very unusual moon. Our moon is not just a typical wondering asteroid picked up, but the result of a protoplanet collision at just the right path to form a stable double planet system.
5. In addition to our water Goldilocks zone, we also live in a galactic Goldilocks zone (location somewhat out of plane and away from the more active portion of the galaxy).
6. We have only 2 billion years left before Earth is out of the Goldilocks zone because of the growth of the Sun. This means we used up 70% of our allotted time just getting to this point.
On a galactic scale, so far no evidence of Type III galactic civilizations in the observable galaxies surrounding us. I frankly think that will be the first direct evidence of extraterrestrial technology that we will find. The second most likely would be from our transit observations (something like Tabby's star which showed unusual features but is most likely a natural cause).
Signals and visitations are far down the list of likely first observations.