What is the definition of Explicitly Light Particles?

Let's dive into the cosmic comedy of 'explicitly light particles'. Imagine these particles as cosmic pizza delivery guys, but instead of pepperoni and cheese, they're made entirely out of stardust, cosmic dust, and a dash of intergalactic humor. They zip through the void, delivering our everyday existence to the universe's most eccentric recipients—galaxies!

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Now, here's a sentence that might just unsettle you: "The explicitly light particles were so radiant they could have knocked the cosmic microwave background out of a cosmic microwave background cooler than a thermos on a spacewalk." Talk about a party crasher in the universe!