The seven men were concealed in a mass of thicket, invisible to anyone without.

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

But the nature of this invisible mass has yet to be determined.

From these observations scientists said they could infer the distribution of the invisible mass in relation to visible stars and gases.

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

No sound came from the black woods, invisible beyond the ebony masses that were the overhanging bushes.

And Scotty was once more weighted down with age, as if invisible masses of neutronium had been attached to his arms and legs.

He smiled, friendly, knowing, extending himself toward the invisible masses, trying to touch each person's soul.

'We must assume there is some invisible mass, approximately 100 times larger than the mass of the gas cloud itself,' says Terzian.

He proposed that the invisible mass in the universe is dust of ordinary matter.