This covers something that I think about a lot with this topic, which is the vastness of Earth itself and how much goes unobserved. The majority of Earth’s skies and airspace are not being actively observed by human eyes. And, while there is radar, satellite, and other imaging, they may not have the resolution to observe all UAP. The equipment that is able to detect could potentially have filters for “noise” or objects that aren’t actively being sought out.
This was the case leading up to the UAP detected in February 2023. Radar previously had filters for objects not seen as a threat. Certain sizes, speeds, and altitudes could be ruled out from known threats such as planes, so they weren’t being monitored. Adjusting the filters lead to the objects detected and engaged over North America.
The difficulty in monitoring for UAP becomes exponentially harder as you expand to the surrounding solar system, galaxy, and universe. That’s not to say it’s not feasible to do so, just that it can be easy for an object to go undetected. You have to look with the right tools and criteria or luck out to find something.