|FOR RELEASE: 10 a.m.
CST, Wednesday, January 6, 1999
Media Contact: Mario Aguilera, (619) 534-7572, firstname.lastname@example.org
NEW INVESTIGATION BY UCSD
ASTRONOMER QUESTIONS THE DISTANCE, COSMOLOGICAL USE OF QUASARS
Since they were discovered more than 35
years ago, science has largely accepted the idea that quasarssince they are thought
to be great distances from uscould be used as cosmological tools to study the
properties of the universe. Many astronomers have thought of quasars as windows to the
history of our expanding universe.
Striking new results announced today by
Margaret Burbidge, university professor of astronomy in the Physics Department of the
University of California, San Diego, show that these conventional views of quasars may not
At this mornings session of the
193rd American Astronomical Society meeting in Austin, Texas, Burbidge will
present data that suggest a group of quasars aligned in the sky with galaxy NGC 1068 are
much closer to Earth than previously believed. The study provides evidence that the
quasars are in fact physically associated with NGC 1068 and it appears they have been
ejected from the galaxy like cannonballs.
"This paper provides evidence that
quasars are not at great distances from us, and thus cannot be used for cosmological
investigations," said Burbidge, a member of the Center for Astrophysics and Space
Sciences at UCSD and a faculty member since 1962.
Using data from the Lick Observatory
outside of San Jose, Burbidge studied the group of quasars aligned across and around NGC
1068, a bright galaxy relatively close at 30 million light years away. Traditional ideas
in astronomy argued that each NGC 1068 quasar, because its observational spectra shifts
strongly toward the red end of the spectrum, or "redshifts," must be far behind
NGC 1068 at varying distances. The clustering of quasars appeared to be an accident that
we observe in our sky.
Burbidge, to the contrary, argues that
the clustering is no coincidence. Although the quasars do indeed have high redshifts,
Burbidges calculations say the quasars were ejected from the galaxy and remain near
it. The complete study will be published in the Jan. 20, 1999 edition of The
Astrophysical Journal Letters (volume 511).
"If you count the number of quasars
in the entire sky, you come up with about three per square degree," said Burbidge,
who has studied the spectra of stars, galaxies and quasars for more than 50 years.
"But if you measure the area in NGC 1068, it averages to about 70 per square
Burbidges study leaves open the
question of the process that leads to the ejection of a quasar from a galaxy. And it casts
doubt about the usefulness of strong redshift signals emanated by quasars.
Nearly 70 years ago Edwin Hubble showed
that the redshifts in the spectra of galaxies of stars were proportional to the distances
of galaxies. This result, when interpreted in terms of Einsteins general theory of
relativity, led to the belief that the universe is expanding.
Shifts in spectrum lines suggest that
objects are moving relative to the observer. Redshifts indicate objects are moving away
from us, and the further away they are the faster they are moving.
Since light travels to Earth at a finite
speed, when we see an object with a large redshift, and that redshift is due to its
distance away from us, we are looking back in time, seeing the object as it was when the
light was emitted. Thus many believed that the large redshifts in some quasars could be
used to study cosmology and to see the universe as it was billions of years ago.
Burbidges conclusions, while not
arguing that all redshifts are not cosmological, question the value of using
quasars to look at a younger universe because it now appears that all quasars are not at
great distances from us.
"There is no clear understanding of
this within the framework of the physics that we currently understand," said
Burbidge. "Thus once again astronomical observations are telling us something new
about the physics of the universe."