Speed Filter of the Skies: How Swift Visitors Elude Telescopes
Interstellar space is not a cosmic desert, but a super-fast highway. Trillions of asteroids and comets from other systems race past us, yet camera-telescopes only catch a few. Imagine a night highway: the headlights of a distant car flash brightly, but if it zooms by too fast, the camera shutter can't click in time.