31. Increasing evidence indicates that the average mass density of the universe falls well below levels needed to confirm cosmologists'favorite models. 32. Also, unless the terrain varied in mass density , the gravitational field of the earth can be modeled as a point. 33. SoBtan calculated the mass density of accreted material as it is directly related to the energy density of quasar light. 34. The highest strings must be under the greatest tension, yet must also be thin to allow for a low mass density . 35. If the universe is expanding faster and its mass density is low, Frenk suggested, large structures can no longer grow larger. 36. The divergence of the gravitational field is equal to the mass density , which is non-negative everywhere and positive in some places. 37. This relationship between the speed, tension, and mass density can be arranged into a new equation, v = T / ? 38. Since the mass density is proportional to the number density through the average molecular mass " m " of the material: 39. He starts the book with quantum physics explaining ? ( dark matter and all mass density ) and how it is measured. 40. The designer of a short piano is forced to use thick strings to increase mass density and is thus driven into inharmonicity.
