MessageToEagle.com - The more scientists study dark matter, the lesser they know and they are not particularly optimistic about their results.
The most accurate study so far of the motions of stars in the Milky Way has found no
evidence for dark matter in a large volume around the Sun.
According to widely accepted theories, the solar neighbourhood was expected to be filled with dark matter, a
mysterious invisible substance that can only be detected indirectly by the
gravitational force it exerts.
But a new study by a team of astronomers in Chile has found that these theories just do
not fit the observational facts.
This may mean that attempts to directly detect dark matter particles on Earth are
unlikely to be successful.
A team using the MPG/ESO 2.2-metre telescope at the European Southern Observatory's La Silla Observatory, along with
other telescopes, has mapped the motions of more than 400 stars up to 13,000 light-years from the Sun.
From this new data they have calculated the mass of material in the vicinity of the Sun, in a volume four times larger
than ever considered before.
"The amount of mass that we derive matches very well with what we see -- stars, dust and gas -- in the region around the Sun,"
says team leader Christian Moni Bidin (Departamento de Astronomía, Universidad de Concepción, Chile).
"But this leaves no room
for the extra material -- dark matter -- that we were expecting. Our calculations show that it should have shown up very clearly
in our measurements. But it was just not there!"
Click on image to enlarge
This annotated artist’s impression shows the Milky Way galaxy. The blue halo of material surrounding the
galaxy indicates the expected distribution of the mysterious dark matter. New measurements based on the movements
of stars show that the amount of dark matter in this region around the Sun is far smaller than predicted and have
indicated that there is no significant dark matter at all in our neighbourhood.
The blue sphere centred on the Sun’s position shows the approximate size of the newly surveyed volume,
but not its precise shape. (Credit: ESO/L. Calçada)
Dark matter is a mysterious substance that cannot be seen, but shows itself by
its gravitational attraction for the material
around it. This extra ingredient in the cosmos was originally suggested to explain why the outer parts of galaxies, including
our own Milky Way, rotated so quickly, but dark matter now also forms an essential component of theories of how galaxies formed and evolved.
Today it is widely accepted that this dark component constitutes about the 80% of the mass in the Universe, despite the
fact that it has resisted all attempts to clarify its nature, which remains obscure. All attempts so far to detect dark matter
in laboratories on Earth have failed.
By very carefully measuring the motions of many stars, particularly those away from the plane of the Milky Way, the team could
work backwards to deduce how much matter is present. The motions are a result of the mutual gravitational attraction of all
the material, whether normal matter such as stars, or dark matter.
The Coma Cluster of galaxies
Astronomers' existing models of how galaxies form and rotate suggest that the Milky Way is surrounded by a halo of dark matter.
They are not able to precisely predict what shape this halo takes, but they do expect to find significant amounts in the region around the Sun.
But only very unlikely shapes for the dark matter halo -- such as a highly elongated form -- can explain the lack of dark matter
uncovered in the new study.
The new results also mean that attempts to detect dark matter on Earth by trying to spot the rare interactions between dark matter
particles and "normal" matter are unlikely to be successful.
"Despite the new results, the Milky Way certainly rotates much faster than the visible matter alone can account for.
So, if dark matter is not present where we expected it, a new solution for the missing mass problem must be found. Our results
contradict the currently accepted models. The mystery of dark matter has just become even more mysterious. Future surveys, such
as the ESA Gaia mission, will be crucial to move beyond this point." concludes Christian Moni Bidin.
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MessageToEagle.com - The more scientists study dark matter, the lesser they know and they are 
A violent collision between two galaxy clusters in which so-called normal matter has been wrenched apart from dark matter through a
violent collision between two galaxy clusters.
Astronomers have observed this cosmic event using a combination of powerful observatories in space and on the ground.
The evidence for dark matter stems primarily from observations of the velocities of galaxies within galaxy clusters.
Researchers know about its existence and that there is no empty space in the universe.
The inter-galactic space is filled with a large amount of unseen matter.
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An important question still remains - Where is most of the dark matter in the universe?
This alien intruder from another galaxy is in many ways different from other exoplanets observed by astronomers.
Located about 2000 light-years from Earth in the southern constellation
of Fornax (the Furnace), the Jupiter-like planet orbits a dying star of extragalactic origin and risks to be engulfed by it.
Little is known about this force and its its repulsive gravity, which is causing the expansion of the universe to accelerate.
The riddles of dark matter and cosmic inflation, along with dark energy, these are the three pillars of modern cosmological
theory," and none of them can be explained with physics that we know," Michael Turner, director of the Kavli Institute for Cosmological Physics says.
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