Number 657 #1, October 14, 2003 by Phil Schewe, James Riordon, and Ben Stein
Cosmology Theories Come and Go
Cosmology theories come and go as new information becomes available.
The geometry and nature of the universe must be one of the most fascinating
questions for the human species. Early Egyptians thought the universe
was a rectangular box. Alexandrian Greeks pictured the cosmos as a set
of concentric crystalline spheres, a view adopted by the medieval Catholic
Church, which executed Giordano Bruno for holding that the universe
was infinite in extent. In the 20th century Hubble's surveys of receding
galaxies supported the idea of an expanding spacetime scaffolding. This
model, now called the big bang, is generally the accepted overarching
theory, but it has been amended several times to include an early "inflationary"
phase and, more recently, the existence of dark energy, an entity or
mechanism which apparently allows the expansion of the universe visible
to our telescopes to be speeding up, and not slowing down. Also not
slowing down is the list of new cosmological ideas. Last year's entrant
was the "ekpyrotic"
model, according to which our universe and all the energy and matter
residing therein arises from the collision of two immense membranes
embedded in an even larger multi-dimensional volume. Last week's interesting
new cosmology development was the suggestion that the universe is finite
and has a dodecahedral (soccerball) geometry (Luminet et al.,
Nature, 9 October 2003). Meanwhile,
this week's leading cosmology news, presented at a meeting in Cleveland,
featured observations of very distant (8 to 10 billion light years away)
and unusually bright supernovas, recorded by the Hubble Space Telescope.
This accords with the dark energy model which holds that the general
expansion of the universe was relatively slow 10 billion years ago and
afterwards got much faster, owing to the propulsive effects of the dark
energy winning out over the attractive and slowing effects of gravity
(paper by Adam
Reiss; also see Science News
Online, 11 October ).