This uneven distribution of galaxies traces the concentration of dark matter, an invisible web-like structure stretching throughout space.

Knew the camp--its ways, its invisible structure and rules--much better than he ever would.

For Ban, one of the most important themes in his work is the "invisible structure".

Cynthia flew near him and reached out to touch the invisible structure.

It should not have been difficult for me to speak, to say the usual "Good morning, Mama," but at times she seemed impenetrable, as if contained within an invisible structure.

Bruenor had heard of the invisible structure as a boy, but had never seen it firsthand.

He was staring at the huge naval yard, its individual structures long invisible as they fell away astern, and his eyes were cold and empty as space itself.

Realizing my inability to solve these problems, I decided that all I could do was to explore the invisible structure itself.

I can scarcely describe the strangeness of the experience - threading the unseen ways of an invisible structure reared by forgotten hands on an alien planet!

"The visible structure of the park is now being supported by the invisible structure of this highly skilled work force," Mr. Rabinowitz said.