"A solid stores energy in the vibrations of the atoms about their equilibrium positions. In the simplest approximation, which Einstein considered, each atom vibrates with the same frequency, ν, in each of three dimensions, so a solid containing N atoms can be thought of as 3N one-dimensional simple harmonic oscillators."

“The n-point correlation functions have proved useful not only as descriptive statistics but also as dynamic variables in the Newtonian theory of the evolution of clustering. ... The functions are generalized to mass correlation functions in position and momentum, and the BBGKY hierarchy of equations for their evolution is derived. This yields a new way to analyze the evolution of mass clustering in an expanding universe.”

“I don't think there is a final theory of anything. It's theories all the way down.”

“Another somewhat confusing usage is the name "the big bang" for the standard model. It is not appropriate, because it connotes a spatially isolated event, an explosion, that marked the start of everything. ... But the name has a very evident appeal and I expect that people will continue to use it.”

“I have been working in cosmology for 55 years ... I'm the last man standing, so to speak, from those early days.”