Apparently it's due to fracking. Here's an article I found about it: https://www.npr.org/sections/krulwich/2013/01/16/169511949/a-mysterious-patch-of-light-show

Apparently it's due to fracking. Here's an article I found about it: https://www.npr.org/sections/krulwich/2013/01/16/169511949/a-mysterious-patch-of-light-shows-up-in-the-north-dakota-dark https://www.npr.org/sections/krulwich/2013/01/16/169511949/a...