ELI5 Aurora Borealis - what would it be like inside the northern lights?

What is the Aurora Borealis? How do the various colors come about? Why are the northern lights primarily seen at the poles? Isn’t the magnetic north moving and what does that mean for where to spot the Aurora Borealis? What would it be like to be inside an Aurora? Is it even possible? Can you see the northern lights from space?
... we explain like I'm five
Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: venbrou, speckledjim, target880, anomalousenigma, itsapeljax, uncledan2017, jermleeds, zhendejiade99, thejeeronian, moogiemcfly and karlrutabaga
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