1.   Many cosmologists remain convinced that most of the invisible matter in the cosmos consist of exotic particles.

2.   Some observations have showed the presence of considerable amounts of invisible matter in ordinary form at the edge of the Milky Way and other galaxies.

3.   The idea that there may be regions where time runs backward could explain invisible dark matter.

4.   The idea that there may be regions where time runs backwards could explain invisible dark matter.

5.   The presence of invisible matter was determined years ago by astronomers who measured the motion of stars within galaxies.

6.   It has long been assumed that these were filled with a kind of matter invisible to current scientific equipment.