Key to the universe found on the
Iron Range?
By BOB VON STERNBERG, Star Tribune
Last update: December 18, 2009 - 5:05 PM
A long-elusive key to understanding the
universe may have been discovered a half-
mile below the Iron Range.
Scientists announced Thursday that they
believe they have detected evidence of dark
matter in data collected at an underground
physics lab in Soudan.
Dark matter most likely accounts for most of
the universe's total matter, but its existence
has never been proven. If it ever is, it could
unpack mysteries about the behavior of stars
and galaxies.
According to the Department of Energy's
Fermilab, which is conducting the search for
dark matter at the Soudan lab, "judging by
the way galaxies rotate, scientists have
known for 70 years that the matter we can
see does not provide enough gravitational
pull to hold the galaxies together. There must
exist some form of matter that does not emit
or reflect light."
In the announcement, the lab said the
Cryogenic Dark Matter Search experiment
has "detected two events that have
characteristics consistent with the particles
that physicists believe make up dark matter."
But, it cautioned, there is "a chance" that the
events could be the signatures of
background particles that merely mimic the
signals of dark matter.
According to Fermilab, dark matter "may
have provided the gravitational scaffolding
that allowed normal matter to coalesce into
the galaxies we see today. In particular,
scientists think our own galaxy is embedded
within an enormous cloud of dark matter. As
our solar system rotates around the galaxy, it
moves through this cloud."
Particle physics theories suggest that dark
matter is composed of Weakly Interacting
Massive Particles (WIMPs). WIMPs would
rarely interact with normal matter, but may
occasionally bounce off, or scatter from, an
atomic nucleus like billiard balls, leaving a
small amount of energy that is detectable
under the right conditions.
The Soudan lab has been searching for
WIMPs since 2003. It uses 30 detectors
cooled to nearly absolute zero in an attempt
to detect WIMP scatters.
"This is a very intriguing result -- we really
don't know if this is a background or a
signal," said Lauren Hsu, a researcher at
Fermilab who announced the experiment's
results Thursday. "As an experimenter you
always wish you had more data."
Researchers and physicists at the University
of Minnesota, one of nine universities
conducting the research, planned to hold a
seminar on the experiment this afternoon.
Iron Range?
By BOB VON STERNBERG, Star Tribune
Last update: December 18, 2009 - 5:05 PM
A long-elusive key to understanding the
universe may have been discovered a half-
mile below the Iron Range.
Scientists announced Thursday that they
believe they have detected evidence of dark
matter in data collected at an underground
physics lab in Soudan.
Dark matter most likely accounts for most of
the universe's total matter, but its existence
has never been proven. If it ever is, it could
unpack mysteries about the behavior of stars
and galaxies.
According to the Department of Energy's
Fermilab, which is conducting the search for
dark matter at the Soudan lab, "judging by
the way galaxies rotate, scientists have
known for 70 years that the matter we can
see does not provide enough gravitational
pull to hold the galaxies together. There must
exist some form of matter that does not emit
or reflect light."
In the announcement, the lab said the
Cryogenic Dark Matter Search experiment
has "detected two events that have
characteristics consistent with the particles
that physicists believe make up dark matter."
But, it cautioned, there is "a chance" that the
events could be the signatures of
background particles that merely mimic the
signals of dark matter.
According to Fermilab, dark matter "may
have provided the gravitational scaffolding
that allowed normal matter to coalesce into
the galaxies we see today. In particular,
scientists think our own galaxy is embedded
within an enormous cloud of dark matter. As
our solar system rotates around the galaxy, it
moves through this cloud."
Particle physics theories suggest that dark
matter is composed of Weakly Interacting
Massive Particles (WIMPs). WIMPs would
rarely interact with normal matter, but may
occasionally bounce off, or scatter from, an
atomic nucleus like billiard balls, leaving a
small amount of energy that is detectable
under the right conditions.
The Soudan lab has been searching for
WIMPs since 2003. It uses 30 detectors
cooled to nearly absolute zero in an attempt
to detect WIMP scatters.
"This is a very intriguing result -- we really
don't know if this is a background or a
signal," said Lauren Hsu, a researcher at
Fermilab who announced the experiment's
results Thursday. "As an experimenter you
always wish you had more data."
Researchers and physicists at the University
of Minnesota, one of nine universities
conducting the research, planned to hold a
seminar on the experiment this afternoon.
