This game is played by two people, using small rackets, called battledores, made of parchment or rows of gut stretched across wooden frames, and shuttlecocks, made of a base of some light material, such as cork, with trimmed feathers fixed around the top.
An alternative model which once enjoyed equal status with the big bang is the steady state theory, first proposed in 1948 by Hermann Bondi, Thomas Gold, and Fred Hoyle. This model, too, assumes that the universe is expanding, but proposes that it has no beginning or end in space and time.
The third section discusses observations that highlight limitations of the Big Bang theory and point to a more detailed model of cosmology than the Big Bang theory alone provides. As discussed in the first section, the Big Bang theory predicts a range of possibilities for the structure and evolution of the universe. The final section discusses what constraints we can place on the nature of our universe based on current data, and indicates how WMAP furthers our understanding of cosmology.