The universe we know—the bright stars scattered across the night sky, the swirling galaxies millions of light-years away, and the dense, shadowy black holes lurking in deep space—holds far more than meets the eye. Between these grand celestial phenomena, a steady stream of particles races through space and time, gliding invisibly through matter and passing through entire planets, stars, and galaxies without a trace. These elusive messengers, known as neutrinos, are among the most mysterious subatomic particles we know. They dance undetected through our world and beyond, seemingly ghostlike but undeniably present in every corner of the cosmos.