1.   The silence echoed with large drips falling from the invisible curved mass above.

2.   Astronomers were counting on there being a big pile of these red dwarfs to account for much of the invisible mass of the universe.

3.   The abundance of this invisible mass, whatever it is, could dictate the fate of the universe.

4.   The energy was coming from the transfer of gas from the companion star into a disk of matter surrounding the invisible mass known as a black hole.

5.   They questioned whether the light could be from the actual dark matter itself, but agreed that it could be starlight tracing the presence of the invisible mass.

6.   However, four children from that invisible mass have identities.