Imagine a particle so ghostly that over 100 trillion of them could pass through you every single second without you noticing anything at all. Spooky, right? Well, believe it or not, these particles, called "neutrinos," not only exist, but they are so abundant that they are the second most common particle in the universe (after photons, the particles that make up light).
So, you might not get visited by a phantom this Halloween, but you'll definitely encounter plenty of cosmic ghost neutrinos, yet you won't notice a single thing. In fact, you're encountering them right now.
The ethereal nature of neutrinos, understandably nicknamed "ghost particles," means that despite how common they are, and the fact we are being constantly pelted with trillions of them, scientists haven't been able to

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