Cosmic Microwave Background Experiments in Antarctica

This page is a web version of a display I made for the Adler Planetarium's Antarctica Day, which was May 11, 2002.

The CMB is a relic radiation left over from the Big Bang; it is the signature of a once young, hot, dense Universe.

The CMB was discovered in 1965 as excess noise in a microwave receiver.

The CMB formed when the Universe was about 300,000 years old, long before the first stars and galaxies formed.

Superimposed on a nearly uniform background are tiny variations of about 10 parts per million. These variations in the density of the early Universe look like hot and cold spots through a microwave telescope. These small variations eventually grew into galaxies and clusters of galaxies.

The variations in the CMB were first discovered by the COBE satellite in 1991 and we have been conducting experiments to measure it with greater precision ever since.

Directly probe conditions of the early Universe

Powerful tool for examining properties of the Universe, including:

• The geometry of the Universe
• Whether the Universe will expand forever or collapse
• The amount of matter in the Universe
• The amount and nature of dark matter and dark energy
• The expansion rate of the Universe
• The age of the Universe
• The primordial seeds of galaxies and clusters

We want to reduce the interference from Earth's atmosphere.
So we go somewhere high, dry and cold:

• From balloons: Experiments carried by long duration balloons around Antarctica fly at 120,000 feet, above most of Earth's atmosphere.
• From the ground: The South Pole is at an altitude of about 10,000 feet, is the driest place on Earth, and has a stable, cold atmosphere above it, making it a great location on the ground.

 

Telescope buildings

Close-up of the Python telescope

 
 

Boomerang being readied for launch	A close-up look at the Boomerang telescope
The Boomerang map of the CMB	Boomerang images show that the overall geometry of space is not curved. If the geometry of space is curved, then the bending of light by the curvature of space will distort the images, making the spots appear larger or smaller, depending on the curvature.

 

 

MAPO, the telescope building. The big plywood ground shield is for DASI. Viper is inside the smaller shield behind it.	Viper telescope and control building. The silver-colored panels shield the telescope from stray signals from the ground.
Inside Viper: the primary mirror.	Inside Viper. ACBAR is the detector system.

 

DASI is an interferometer, a cluster of telescopes working in unison.

DASI operating at sunset, March 2000

DASI images of the CMB

 

TopHat being tested before launch

Baby seal seen outside the TopHat lab

TopHat launch

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Disclaimer: Any opinions expressed here are are not the responsibility of the University of Chicago or the Department of Astronomy and Astrophysics. This material is based upon work supported by the National Science Foundation under the AAPF program. Any opinions, findings and conclusions or recomendationsexpressed in this material do not necessarily reflect the views of the National Science Foundation (NSF).

last modified 5/13/02