As a PhD physicist who follows the Fermi paradox topic, I think the evidence comes down on the view that, if aliens exist at all, they must either, every single one of them virtually, be non-intelligent or not interested in interstellar travel or communication. Not even robotically.
There’s only two other highly unlikely possibilities.
Here’s why. (And the fact most potential aliens would have millions of years head start of existence on us is only part of it).
In the Star Trek Voyager episode “Blink of an Eye” we get a fascinating view into alien SETI-like research looking for . . us. Gotta love Trek. This is a memorable ep (but with some crazy general relativity violations). CREDIT | Paramount
Liquid water
It’s because earth’s liquid watery signature should be pretty easy to detect from-a-distance by aliens not too dissimilar in intelligence to us. We’ve just come close to doing this for a planet 26 light years away with the James Webb Space Telescope.
From a distance, we’d look highly attractive to carbon-based interstellar space-faring life.
Aliens should be here.
Even if no carbon-based alien ever truly ‘colonized the entire galaxy’, they should have at least found us, or at least one of the nearby ones should have.
Although our present ability to directly detect large amounts of liquid water on exoplanets is limited, the James Webb Space Telescope (JWST), launched on Christmas Day 2021, can do it.
And likely, just did.
Undoubtedly, if we got really interested, we could expand our repertoire of space telescopes for more systematic study of the plethora of exoplanets we’ve already discovered and their habitability, including the presence of liquid water.
Habitable zone
Single transit data for exoplanet candidates. Awesome looking data indicating a (tiny) less than 1-in-100 part drop in light intensity. The next transit can confirm it and create a signal-to-noise improved signal. CREDIT |
Most of our methods for detecting exoplanets and their properties do not directly observe the planet, but rather infer its presence and properties from its effects on the star it orbits or how it interacts with light from its star.
The two most common methods are:
- Transit Method: We observe the tiny dip in brightness of the star as the planet passes in front of it. This method has allowed the Kepler…