- LAWRENCE -- Superwinds a hundred million light years long have helped
to sculpture the universe, astrophysicists announced Jan. 7.
-
- Although most people think of space as
empty, it does, in fact, contain highly dilute gases. These gases, moving
at incredible speeds, constitute the superwinds. They can span distances
equal to about 1 percent of the size of the observable universe.
-
- New evidence suggests that the winds
follow the long axes of what astrophysicists call superclusters, say University
of Kansas astrophysicists Adrian Melott and Dmitri Novikov.
-
- Superclusters are the largest known building
blocks of the universe. They are made up of smaller clusters of thousands
of galaxies separated by long stretches of nearly empty space.
-
- Melott, speaking on behalf of a team
of seven researchers, today told a press conference at the American Astronomical
Society annual meeting in Austin, Texas, that "this is our first detection
of exactly the kinds of winds we think should accompany the flow of matter
along the axes of superclusters.
-
- "It looks like we are beginning
to develop a good understanding of the formation of structure in the universe."
-
- In the April 17, 1998, issue of the journal
Science, Jack Burns, professor of physics and astronomy at the University
of Missouri, who also was involved in the research presented today, published
his argument that as gas, stars and galaxies fall together into smaller
clusters, the merger gives rise to local winds.
-
- These local winds bend the jets of gas
that stream out in opposite directions from the cores of some galaxies.
-
- The jets -- thought to originate from
giant black holes -- are sometimes bent into "U" or "V"
shapes, Melott said. The jets usually don't exceed a million light years
in length. The new research shows that the local winds blowing inside the
clusters and bending the jets are, like the superwinds, oriented along
the long axes of superclusters.
-
- The research team believes that the superwinds
feed matter into galactic clusters, Melott said, and determine the direction
of the local winds in much the same way as a breeze on Earth determines
the direction of smoke that rises from a chimney.
-
- Melott said the team's discovery was
based on an analysis of the direction of local winds that distort jets
of gas in 12 different galactic clusters.
-
- The team compared the local wind directions
within the clusters with the alignment of other nearby galaxy clusters.
They found that the nearby clusters were aligned with the flow of the wind
inside the central cluster.
-
- The odds that mere chance is responsible
for that alignment are only about one in 50, Melott said, leaving the door
open for the superwind explanation.
-
- In addition to data taken from the National
Science Foundation's Very Large Array (a VLA radio telescope setup was
shown in the recent movie "Contact") the group relied on information
from other astronomers about distances to a variety of galactic clusters.
-
- Melott said that University of Maine
astronomers David Batuski and Chris Miller, using the Steward Observatory
at the University of Arizona, ascertained previously undetermined distances
to a number of the clusters.
-
-
- Two KU undergraduates, Michael Kaufman,
senior from McPherson, and Brian Wilhite, since graduated and from Olathe,
also contributed to the research, Melott said.
-
- Melott, commenting on the significance
of the work, said, "We've had no evidence until now of the particular
kinds of flows that bring about the structures we're looking at."
-
- The findings announced today will be
published in Monthly Notices of the Royal Astronomical Society, a British
journal.
|
