Explore Alliance Presents: How Do You KNOW? – Episode #29: 'Dark Matter Part 2'

In the second part of Dr. Barth's discussion on dark matter, he touches on why did galaxies form, the missing matter problem, and the Great Attractor. 

https://explorescientificusa.com/pages/explore-alliance-presents-how-do-you-know-with-dr-daniel-barth

The activities and materials provided free for the How Do You Know? program are based upon Dr. Barth’s award-winning book: Astronomy For Educators. This book is used as a resource in more than 5,700 schools across the United States and in more than 50 countries world wide. The book is published as an Open Educational Resource Text by the University of Arkansas Library Press.