Neil deGrasse Tyson explains why dark matter matters (and is kind of our frenemy)
Neil deGrasse Tyson in 'The Martian'

Excerpt: Astrophysics for People in a Hurry The collision of star clusters, seen here, help provide insights into dark matter, one of the more mysterious aspects of our universe. NASA The following is an excerpt from Astrophysics for People in a Hurry by Neil deGrasse Tyson So dark matter is our frenemy. We have no clue…