Hiding a subterranean alien megastructure
I need to know if it'd be possible for a underground ring-like structure of immense proportions and alien design to go unnoticed by modern day sonar, radar, and geological surveying.
For an idea of size, imagine a tunnel about the width of a football field or bigger (maybe 100-200 meters in diameter) that's buried 2- 5 kilometers underground and wraps around the entire planet (giving it a circumference of 40000 km).
Could something like this remain hidden until a mining project accidentally uncovers it in Africa, or would something this size have been detected by now with the technology developed in the 20th and 21st centuries?
This post was sourced from https://worldbuilding.stackexchange.com/q/95829. It is licensed under CC BY-SA 3.0.
0 comment threads