Assertion: unseen dark matter | /r/HasProperty | invisible
Facets:
Source sentences:
text: It postulates that the galaxies (including our own Milky Way) are spinning as fast as they are because there is more matter in those galaxies than can be seen by summing only the mass of stars and gas, and that this unseen (dark) matter is invisible because it doesn't interact with the electromagnetic force from which all forms of light come.