Question about dark matter/energy and other dimensions According to drummer and lyricist Henrik Ohlsson, the title Dark Matter Dimensions refers to the "appreciation and acknowledgement of the unseen worlds and dimensions, because without the existence of these unseen forces our physical universe would never be able to exist". So could dark matter be regular matter, just in other dimensions?
 A: Dark matter simply refers to matter that does not emit light. In other words it does not interact with the electromagnetic field. We have never been able to observe it directly, since our telescopes can only see incoming light from the universe.
But we can infer it's existence due to the fact that gravitational lensing due to galaxies is a lot stronger than we'd expect. We tried to account for all of the mass of a galaxy due to stars, planets, gases, etc, but there is still a lot of mass unaccounted for. Without this unaccounted for mass, we would not see gravitational lensing as strongly as we do. So there is some sort of additional mass that we cannot see that is in galaxies.
It is unlikely that dark matter is matter in another dimension. When we observed black hole mergers, the resulting gravitational waves had the same energy when they reached us as we would predict if space only had 3 dimensions. It is unlikely that there are any 'hidden' dimensions, as we have only observed gravity to act in 3.
