Stationary star-like object suddenly moving for a period of time, then disappearing or stopping.Whilst stargazing near Steven's Pass, we observed what appeared to be a star, to shift from being stationary to suddenly begin moving, traversing slowly across the sky in a southwest to northeast direction. After watching it move for about 30 seconds or less, it disappeared from view, either suddenly stopping, or extinguishing lights (if it had lights), or for some other unknown reason.As stars do not move like this, conventional aircraft do not exhibit these characteristics, and asteroids/comets etc. do not suddenly begin movement from being stationary, this - to us at least - was a flying object that we could not identify.((RESPONSE TO WITNESSES))Dear((deleted)) Family, Thank you very much for your report! I found it particularly interesting, in that I, too, sometimes find myself in the Cascade Mountain passes, gazing at the beautiful night sky. My first suspicion is that you may have observed a satellite that "flew" into the Earth's terminator, a.k.a. the shadow behind the Earth. When satellites fly into that shadow, they disappear from the sight, given that they are no longer being brightly illuminated by the Sun. I suggest that you watch the sky again in the near future, to see whether you can observe a similar phenomenon. If you do, please let us know, since we would like to "flag" the report to let the readers know what caused the sighting. It is only a guess, on my part, but we have handled MANY reports of satellites, and yours is certainly not inconsistent with a satellite sighting. Thank you very much for sharing the information with our Center! Cordially, Peter Davenport((END RESPONSE))