General overview of some of the science going on at Yerkes Observatory:
Until relatively recently, astronomers have been limited to studying objects
that either emitted or reflected visible light. Astronomers today are
increasing our knowledge of the Universe by studying forms of radiation
invisible to the eye, including gamma rays, X-rays, ultraviolet, infrared, and
radio waves. Although dust blocks visible light from objects such as young
stars, edge-on galaxies, and the center of our own galaxy, infrared and
radio waves penetrate the dust and allow astronomers to study these
Nearly everything in the Universe, from the coldest clouds of interstellar
dust to the jets from centers of active galaxies, glows in infrared radiation.
Objects too cool to glow visibly may shine brightly in infrared radiation.
Beginning in 1898, Hale and his colleagues began to measure infrared
radiation from celestial bodies. They successfully detected such radiation
from Jupiter and Saturn and the stars Vega and Arcturus.
Modern Infrared Research
Yerkes Observatory has maintained a leadership role in the development
of instruments for the study of infrared radiation. Yerkes researchers
developed instruments for the
Airborne Observatory (KAO) (1974-1995) and are now working on
instruments for SOFIA (Stratospheric
Observatory for Infrared Astronomy) (2001-).
Yerkes infrared detectors
were carried aloft as attachments to a 36-inch reflector aboard the
Airborne Observatory (KAO), named in honor of Gerard Kuiper, a former
Yerkes Observatory director.
The plane, a modified C141-A, was operated by the
Aeronautics and Space Administration (NASA). It cruised at
altitudes of up to 45,000 feet where the air is thin and dry enough to permit
detection of infrared radiation blocked elsewhere by atmospheric
moisture. The KAO was taken out of service in 1995 in order to
free up money for the next project, SOFIA.
Observatory for Infrared Astronomy) is a Boeing 747-SP,
and it will use a 97-inch (2.5 meter)
reflector. It will gather seven times as much
as the KAO and provide images that are three times sharper.
The Apache Point Observatory
Yerkes Observatory personnel develop detectors and other instruments
for mountaintop observatories where the thinner atmosphere permits better
observations. The University of Chicago is a member of the Astrophysical
Research Consortium (ARC) which operates such an observatory near
Alamogorgo, New Mexico. Here, at the
Apache Point Observatory,
astronomers use a 3.5-meter telescope to study infrared and visible light.
The innovative 3.5-meter telescope is designed to spare researchers the
time and expense of travel to its remote mountaintop location; it can be
operated with a computer from any place on Earth that has a computer link.
Yerkes faculty, graduate students, and technicians develop instruments to
expand the information-gathering capabilities of the telescope.
Map of the Universe
Yerkes researchers are also involved in the
Sloan Digital Sky Survey (SDSS),
which uses a 2.5-meter telescope at Apache Point.
SDSS will survey and measure distances to one million
galaxies, providing an accurate, three-dimensional map of the Universe.
Data obtained from this vast survey will be processed at
Fermilab in Batavia, Illinois.
Other Mountaintop Observatories
Yerkes scientists conduct astrophysical research at several mountaintop
locations, employing instruments designed, constructed, and tested at the
Observatory for specific telescopes elsewhere.
Yerkes infrared detectors have been used at the
Kitt Peak National
Observatory 4-meter reflector in Arizona. Similar detectors have been used
on Mauna Kea, Hawaii,
at the NASA Infrared Telescope Facility and the
Submillimeter Observatory. Instruments are under construction at
Yerkes for use on the new 10-meter Keck Telescope. One of the greatest
challenges is designing instruments for
telescopes at the South
Pole, one of the most remote, least hospitable places on Earth.
Astrophysics at the South Pole
Despite the harsh conditions, the South Pole is perhaps the best place on
Earth to conduct astrophysical research. Temperatures in summer average
20 degrees below zero Fahrenheit; in the winter they can fall to
125 degrees below zero Fahrenheit. The
extreme cold removes water vapor from the air. The dryness and high
elevation of the continent (about 10,000 feet above sea level) at the South
Pole greatly facilitate observations at visible and infrared wavelengths.
Several instruments for the South Pole were developed here at Yerkes.
Education and Outreach
As part of Yerkes' involvement in the
Center for Astrophysical Research in Antarctica (CARA),
Chicago high school students learn about
astrophysics in a cooperative effort involving Yerkes, other University
of Chicago units, George Williams College, and the Adler Planetarium.
The 24-inch here at Yerkes is currently used as part of
an NSF-sponsored project whereby middle and high school students
can work with real astronomical data.
Go back to the page about the science currently going
on at Yerkes Observatory.
Content originally generated in March 1995.
This file was last modified on 20 April 1999.