ELI5: Explain Like I'm 5

Faster-than-light neutrino anomaly

Okay, so imagine you are playing a game of tag with your friends. You are running as fast as you can, but your friend keeps tagging you before you can reach the safe spot. This is because you are not as fast as your friend, so they can catch up to you easily.

Now, scientists have been studying tiny particles called neutrinos which are like very small pieces of matter that can travel through things like solid walls and the earth, and they were curious to find out how fast they could travel. They did an experiment where they sent these neutrinos from one place to another, and they found something very strange. The neutrinos seemed to be arriving at the second location faster than they should have been able to travel. This was called the faster-than-light neutrino anomaly.

Just like how your friend was able to tag you faster because they were faster than you, scientists were confused because nothing is supposed to be faster than light, which is the speed that anything travels in the universe. This means that the neutrinos were traveling faster than they should have been able to!

Scientists were surprised by this because it means that they need to go back and check their calculations and make sure they didn't make a mistake somewhere. They also need to do more experiments and research to try and figure out what's happening with these tiny little neutrinos, and if they really can go faster than light. It's a big mystery that they are trying to solve.
Related topics others have asked about: