BUFFALO, N.Y.--In 2008, a research team led by a NASA scientist
announced a startling discovery: Clusters of galaxies far apart
from one another appeared to be traveling in the same
The findings contradicted the standard model of the universe,
which predicts that, as a whole, mass within our universe should
flow randomly, in all directions, relative to the background
radiation of the cosmos.
The one-way "dark flow" that the NASA-led group discovered
created a mystery. What could account for the unexpected motion?
Maybe another universe existed beyond the bounds of ours, dragging
our stars ever closer through the pull of gravity.
Then again, maybe not.
A new study from the University at Buffalo contradicts the dark
flow theory, showing that exploding stars in different parts of the
universe do not appear to be moving in sync.
Working with data on 557 such stars, called supernovae, UB
scientists deduced that while the supernovae closest to Earth all
shared a common motion in one direction, supernovae further out
were heading somewhere else. The difference in motion became
pronounced for stars 680 million or more light years away from
An article announcing the research results will appear in a
forthcoming edition of the peer-reviewed Journal of Cosmology and
Though the findings disagree with the "dark flow" hypothesis,
they coincide with the predictions of another model of the
universe: Lambda-Cold Dark Matter, the standard model of
"Our result is boring, in a way, because it matches your
expectation for the standard cosmological model," said UB physicist
William Kinney. "If it turns out that the NASA team led by
Alexander Kashlinsky is right, it would be exciting because there
would be some crazy thing going on that nobody understood. There
would have to be something very radical, like a big mass outside of
our universe that's pulling on stuff inside our universe. That
would be big news."
"But our data do not match theirs," Kinney continued. "With our
study, we're muddying the water. It's not yet clear who is right.
We have to do more figuring to build up a more detailed and
accurate picture of the universe."
Kinney, an associate professor, completed the study on
supernovae with De-Chang Dai, a UB postdoctoral researcher who has
since joined the University of Cape Town, and Dejan Stojkovic, an
assistant professor of physics at UB.
The supernova data the team used to complete their study came
from the Union2 data set, which the Supernova Cosmology Project at
the Lawrence Berkeley National Laboratory released in 2010. Though
Union2 incorporates astronomical observations from different
telescopes and different times, the data set controls carefully for
systematic bias and serves as a useful check for the possible
presence of systematic errors in the work of Kashlinsky and others,
The University at Buffalo is a premier research-intensive public
university, a flagship institution in the State University of New
York system and its largest and most comprehensive campus. UB's
more than 28,000 students pursue their academic interests through
more than 300 undergraduate, graduate and professional degree
programs. Founded in 1846, the University at Buffalo is a member of
the Association of American Universities.