<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Bullet_Cluster" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Bullet_Cluster</a> is fairly good evidence that dark matter isn&#x27;t just unobserved regular matter. In these massive cluster wide collisions the dark matter seems to have &quot;kept going&quot; (you see very strong gravitational lensing where there appears to be nothing) while regular matter that we know is subject to forces besides gravity collided together, slowed down, and became very hot.