While the spaces have been removed from this question, here are two hints. First, the plaintext is an article from Wikipedia, about Helium. The second hint is that the first word is "Helium."
Strength of Hint: 350 out of 1000
Good luck!
A joint project of Brendan Bard, Prof. Gregory Bard, and Prof. Seth Dutter, University of Wisconsin---Stout (January 30th, 2019)