|bRHmaaND = UNIVERSE....WHAT ONE SEES IN SPACE IS ONLY 5 PERCENT OF THE TOTAL....SO WHAT IS THE REST....BUT THEN HOW & WHEN ARE WE GOING TO KNOW EVEN T|
Posted by Vishva News Reporter on April 18, 2003
As if it weren’t strange enough that the cosmos is loaded with invisible and
elusive matter, a new theory has the stuff wandering through the early universe
like a drunken sailor. The idea is a serious attempt to examine dark matter —
which is far more prevalent than normal matter — by modeling its behavior,
despite the troubling fact that no one knows what it actually is.
Scientist suspect the bulk of dark matter involves tiny particles they’ve yet
to detect. The two leading candidates are called axions and neutralinos.
Whatever they are, they are known to interact gravitationally with regular
matter, because observable matter can’t account for the speed with which stars
move around galactic centers.
Saul Perlmutter of the Lawrence Berkeley National Laboratory says: "Though,
that physicists should remain humble about the time it might take to figure out
the remaining mysteries." .....but veD says this is such an infinite knowledge
that we may have to wait for infinite number of years to come???....
To gain in-depth knowledge of this research news from
MSNBC SCIENCE .....which will amaze YOUR of with infinite
vibhuti (powers) of
creator bRHmH as per Chapter 10 of
bhgvD giitaa, please click on the
theoretical take on dark matter
Simulated particles of dark matter come together in a primary galaxy in
one of the last scenes of the computer simulation, along with several
significant satellite knots.
Robert Roy Britt
PHILADELPHIA, April 15 — As
if it weren’t strange enough that the cosmos is loaded with invisible
and elusive matter, a new theory has the stuff wandering through the
early universe like a drunken sailor. The idea is a serious attempt to
examine dark matter — which is far more prevalent than normal matter —
by modeling its behavior, despite the troubling fact that no one knows
what it actually is.
THE RESULT is an animation
showing how thousands of relatively small and invisible dark matter galaxies
might have developed and still reside in the vicinity of our own Milky Way.
Chung-Pei Ma, an astronomer at the University of California,
Berkeley, unveiled the new theory here last week at a meeting of the
American Physical Society. Ma envisions dark matter particles behaving like
bits of dust bounced around by water molecules in a microscopic process
called Brownian motion.
Brownian motion was discovered in 1827 by botanist Robert Brown, who
noticed a pollen grain moving erratically for unseen reasons under his
microscope. Einstein later figured out that molecules were bouncing randomly
off the pollen. The concept was applied decades ago to better understand the
behavior of stars in dense clusters.
Ma describes Brownian motion as being something like the
unpredictable path of a drunken sailor. She and her colleague, Ed
Bertschinger of MIT, were surprised that the basic principle of Brownian
motion could be applied on a galactic scale, but the results fit a line of
theoretical thinking that predicts dark satellite galaxies should exist.
MODELING THE INVISIBLE
Scientist suspect the bulk of dark matter involves tiny
particles they’ve yet to detect. The two leading candidates are called
axions and neutralinos. Whatever they are, they are known to interact
gravitationally with regular matter, because observable matter can’t account
for the speed with which stars move around galactic centers.
Dark matter particles appear not to interact with
electromagnetic forces, however. They don’t make or reflect light, which
explains why they can’t be seen.
“It has to be some kind of exotic particle, something we can’t
touch,” Ma said.
Until recently, scientists assumed dark matter was distributed evenly
in a massive halo around each galaxy. Not quite true, Ma and others have
come to believe. The halos are there, but so possibly are thousands of
clumps that can be thought of as dark, satellite galaxies, several
researchers have suggested in recent years. One idea for along these lines
was put forth in 2001 by a team led by Neil Trentham at the University of
Cambridge. Trentham said that for every normal, star-filled galaxy, there
might be 100 that contain primarily stuff we can’t see.
Dark matter satellite galaxies — if they exist — cannot be detected
by conventional telescopes because they don’t contain enough normal matter
to fuel star birth.
Ma and Bertschinger let millions of hypothetical dark matter
particles interact over billions of years in a computer model governed by
gravity. Many of the particles coalesce into central clumps as massive as
billions of suns, a neat fit with expectations for the process that would
build a normal galaxy.
But thousands of dark galaxies develop in the simulation, too, each
containing masses equal to several million suns.
“We then realized that the motion of dark matter can also be
described statistically by a similar equation used for the Brownian motion,”
Ma told SPACE.com. “This equation is very different from Newton’s law [of
gravity] used in the computer model. This doesn’t mean Newton’s law is not
applicable — it means the new equation that we found provides a new language
for describing how dark matter clumps.”
A paper describing the new work will soon be submitted to the
Astrophysical Journal for possible publication.
FINDING DARK MATTER
Dark matter makes up about 23 percent of the universe’s
mass-energy budget. Normal matter, the stuff of stars, planets and people,
contributes just 4 percent. (The rest of the universe is driven by an even
more mysterious thing called dark energy.)
A small portion of dark matter has already been identified and is no
longer mysterious. Tiny particles called neutrinos, once thought to be
massless, are now known to make up a sprinkling of the total dark matter
column of the budget. Cold dead stars, recently found to be plentiful, also
contribute modestly to this accounting.
satellite galaxies exist, astronomers should be able to detect some of them.
Their gravity would bend light traveling toward Earth from more distant
objects, distorting and possibly magnifying them. This so-called
gravitational lensing effect is used already to study distant objects by
peering through and around visible, intervening galaxies or galaxy clusters.
Finding and cataloguing these dark matter galaxies would help
researchers understand what they’re made of.
“Different dark matter models [for material that is cold or warm]
predict different number of these dark galaxies,” Ma said. “So if we can
estimate the number and masses of these galaxies, it can constrain the
nature of dark matter.”
Saul Perlmutter of the Lawrence Berkeley National Laboratory,
speaking at the same meeting of physicists, said knowledge of dark matter
has come a long way since the first strong hints of it emerged in the 1970s.
Researchers no longer wrestle with whether it exists or how much there is
but instead can focus on its properties, Perlmutter said.
He added, though, that physicists should remain humble about the time
it might take to figure out the remaining mysteries.
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