If some UAP are nonhuman technology, they might belong to an autonomous system stationed near Earth long ago. It would need no repeated interstellar trips; its creators could be distant, absent, or extinct. SETI research offers precedents, but an observer would not by itself prove an ancient factory, a protective mission, or an ability to influence consciousness. 1. A presence that outlives its creators The Sentinel Probe Hypothesis proposes that a nonhuman system reached our solar system and...

If some UAP represent nonhuman technology, they might be equipment belonging to an autonomous system stationed near Earth long ago. A persistent observer could deploy vehicles, maintain itself, and respond to changes in the biosphere without biological crews repeatedly crossing interstellar space. Published SETI research supplies precedents for this architecture. Local factories, ancient residence, defensive intervention, and neural interfaces require separate evidence. The test is whether ob...