4 ms·
Not human civilizations. 2 billion years is a lot of time... but it might be weak evidence that we are not the first technological species in this planet. If yo
by crpatino 11y ago
Not human civilizations. 2 billion years is a lot of time... but it might be weak evidence that we are not the first technological species in this planet. If you consider that we are probably not the only intelligent species on the planet just now, it sounds at least plausible to me.
- Torgo 11y agoSure, pseudoscience has unlimited explanations :-) I've also heard it explained as the engine from a crashed alien spaceship.