Open Questions: Large-scale Structure of the Universe
See also: The cosmic microwave background
Sites with general resources
- Luminet is director of Astrophysics at the Paris-Meudon
Observatory. His current research is mainly concerned with the
topology of the universe. His page links to several tutorial
A Finite Dodecahedral Universe,
The Topology of the Universe, and
Mirror, Mirror Up Above. There is also a directory of
more technical research publications.
The IRAS PSCz Redshift Survey
- A redshift survey of 15,000 galaxies which provides data on
questions such as large-scale galaxy clustering.
Sloan Digital Sky Survey
- "The Sloan Digital Sky Survey is the most ambitious astronomical
survey project ever undertaken. The survey will map in detail
one-quarter of the entire sky, determining the positions and
absolute brightnesses of more than 100 million celestial objects."
The Web site includes information about the project, a
Q & A page, an
The 2dF Galaxy Redshift Survey
- Research project surveying redshifts (distance) of more than
250,000 galaxies, the largest such survey to date. Site includes
a "fly-through" movie of the survey.
Mock Galaxy Distributions
- A computer simulation project at Caltech.
Surveys, overviews, tutorials
Large-scale structure of the cosmos
- Article from
Shape of the universe,
Topology of the universe.
From Quantum Foam to Galaxies: Formation of the Large-Scale
Structure in the Universe
- Contains several pages discussing the formation of the
earliest galaxies and clusters. Includes computer simulations,
visualizations, and some
external links. Part of the
Center for Cosmological Physics site.
A cosmic hall of mirrors
- September 2005 article from
Physics World, by
Jean-Pierre Luminet. "Most astronomers think that the universe
is infinite, but recent measurements suggest that it could be
finite and relatively small. Indeed, as Jean-Pierre Luminet
describes, we could be living in an exotic universe shaped
rather like a football."
Measuring the Universe
- Visual materials from a presentation by
Constraining the Topology of the Universe
- Technical paper, published May 2004, by
Neil J. Cornish, David N. Spergel, Glenn D. Starkman, and
Eiichiro Komatsu. (PDF format) The research reported indicates
that the "diameter" of the universe is at least 78 billion
Measuring the Topology of the Universe
- 1998 semi-technical paper by Neil J. Cornish, David N. Spergel,
and Glenn D. Starkman. Describes how
"observations of microwave background fluctuations can yield
information not only about the geometry of the universe, but
potentially about the topology of the universe."
Topology of the Universe
- A brief tutorial on possible topologies of the universe, and
evidence from studies of the cosmic microwave background that
constrain the possibilities, by
Angelica de Oliveira-Costa.
Large Scale Structure
- A presentation by Scott Dodelson, in PDF format, from
an October 2001
Ripples in Space: The Origin of Structures in the Universe
- What we can learn from the anisotropy of the cosmic microwave
Cosmologists Confirm Web-Like Structure of Early Universe
- May 21, 2001 news story from Scientific American.
- August 2000 story from Scientific American on the puzzle
of magnetic fields in intergalactic space.
Rare Galaxies Shed Light on a Dark Universe
- Press release from the
Institute for Computational Cosmology on
a computer simulation of the clustering of
bright galaxies as a result of the distribution of cold dark matter,
and a comparison with data from the 2-degree Field Galaxy Redshift
Universe as Doughnut: New Data, New Debate
- March 11, 2003 feature article from the New York Times,
by Dennis Overbye. There are hints from the latest CMB observations
that the topology of the universe might be more complicated than
It's a low-density universe
- March 2001 news article about mapping the position and
velocity of over 141,000 galaxies by the 2dF survey.
Universe Maps Keep Getting Bigger
- March 1999 news article about early results of the 2dF survey
which plot positions of 30,000 galaxies.
Astronomers' colossal cartographic creation
- February 1999 news article about a map of galaxy positions for
- Reading the Blueprints of Creation
Michael A. Strauss
Scientific American, February 2004
- The Universe Takes Shape
Ken Grimes; Alison Boyle
Astronomy, October 2002, pp. 34-39
- The universe could have a topology more complex than that of
a sphere -- a torus, for example. Observations of the cosmic
microwave background by the Microwave Anisotropy Probe may
soon be able to determine what the topology actually is.
- Size Matters
Astronomy, March 2002, pp. 28-32
- Galaxies group together in clusters and superclusters, but
there seem to be no further structures of scale larger than
400 or 500 million light years. However, it is still not possible
to be very confident about how well we understand the distribution
of galaxies in the universe.
- The Shape of the Universe: Ten Possibilities
Colin Adams; Joey Shapiro
American Scientist, September-October 2001, pp. 443-453
- Much evidence now suggest that the universe is "flat",
having uniformly zero curvature. But this doesn't imply it is
infinite in extent. There are 18 possible Euclidean (flat)
3-manifolds, of which only 10 are orientable. Our universe
is probably one of these 10 types. Detailed maps of the
cosmic microwave background could make it possible to determine
the actual shape.
[Abstract and references]
- Big, Bigger...Biggest?
Science Week, August 12, 2000, pp. 104-105
- Maps of galaxies produced by the 2dF Galaxy
Redshift Survey indicate that superclusters are the largest
structures in the universe.
Mapping the Universe
Stephen D. Landy
Scientific American, June 1999, pp. 38-45
- The distribution of galaxies tells a lot about the early
history of the universe. Harmonic analysis is a key technique
for understanding the distribution data.
Is Space Finite?
Jean-Pierre Luminet, Glenn D. Starkman, Jeffrey R. Weeks
Scientific American, April 1999, pp. 90-97
- Whether the universe is finite or infinite in extent is a
fundamental open question. It depends on the topology of spacetime,
and observations of the cosmic background radiation that will be
feasible in just a few years should make it possible to determine
- Measuring the Shape of the Universe
Neil J. Cornish; Jeffrey R. Weeks
Notices of the AMS, December 1998, pp. 1463-1471
- An excellent technical article on how the topology of the universe
may be deduced from cosmic microwave background data. The idea is
that if the universe is finite (necessary if the overall curvature
is positive, but still possible even if the curvature is zero or
negative), temperature fluctuations in the CMB will repeat in a
predictable way that reveals the topology. The Microwave Anisotropy
Probe experiment should provide the necessary data.
[Article in PDF format]
Galaxies behind the Milky Way
Renée C. Kraan-Korteweg; Ofer Lahav
Scientific American, October, 1998, pp. 50-57
- About a fifth of the universe has been difficult or impossible
to observe because it's blocked by the disk of the Milky Way. Some
of the features hidden in that region include the core of the "Great
Attractor", a very nearby dwarf galaxy, and unsuspected galactic
- Beyond the Soapsuds Universe
Discover, August 1997, pp. 52-59
- The distribution of galaxies is far from uniform. This
non-uniformity constrains models of how the universe developed.
Future surveys will provide much more information about the
- Very Large Structures in the Universe
Jack O. Burns
Scientific American, July 1986, pp. 38-47
- Superclusters consisting of many galaxy clusters and extending
more than a billion light years in length are the largest structures
in the universe so far observed. They are probably the result of
very small perturbations in the distribution of matter in the
very early universe.
- The Large-Scale Structure of the Universe
Joseph Silk; Alexander S. Szalay; Yakov B. Zeldovich
Scientific American, October 1983, pp. 72-80
- The large-scale structure of the universe comprises vast galactic
superclusters and huge voids. The structure probably results from
density fluctuations of matter which gave rise to flattened clouds
of gas resembling flattened pancakes.
- Avishal Dekel, Jeremiah P. Ostriker, eds.- Formation of
Structure in the Universe
Cambridge University Press, 1999
- A technical but not highly mathematical treatment of the
subject. Topics include the role of dark matter, interpretation
of the microwave background, galaxy clusters and superclusters,
gravitational lensing, and the mass of the universe.
Copyright © 2002 by Charles Daney, All Rights Reserved