Researchers are struggling to understand WHAT is ‘pulling’ our
galaxy, the Milky Way, and other galaxies towards IT at an incredible
speed of 22 million kilometers per hour.
Just as the movement of tectonic plates shows the properties of the
interior of the Earth, the motions of galaxies provides information
about the main constituents of the Universe: Dark Matter and Dark
Energy. Dark matter is an invisible material whose presence can be
demonstrated only by its action on the movements of galaxies and stars,
not emitting or reflecting light. Dark energy is THE mysterious force
behind the universe and its acceleration.
This unknown force which has been dubbed as “The Great Attractor” is
pulling our galaxy and everything around it towards a specific point in
space, located approximately 250 million light-years away. Basically, the Great Attractor
is considered by researchers as a ‘gravitational anomaly’ located
within the vicinity of the Hydra-Centaurus Supercluster at the center of
the Laniakea Supercluster. Adding to the mystery is the fact that the
‘Great Attractor’ happens to lie in a direction in the sky referred to
as the ‘Zone of Avoidance’. Towards that direction, there is so much
dust and gas that our satellites and telescopes can’t see very far in
the visible spectrum.
The Great Attractor is certainly there (because we see its
gravitational influence), but the major portion of the mass that must be
there cannot be seen in our telescopes. (source)
Researchers discovered indications of the mysterious force back in
the 70’s. As time passed by and our telescopes got bigger and better we
were able to learn more about that specific region in space. In time,
astronomers discovered that there is a giant supercluster of galaxies
known as the Norma Cluster, which has a mass of about 1,000 trillion
suns or thousands of galaxies. The exact position of the mysterious
force was pinpointed in 1986.
We can only observe that the Milky Way and everything around is being
pulled by that ‘something’ and that mysterious force must be something
massive, strange and fascinating, something that is both extraordinary
and scary.
A gigantic concentration behind the Great Attractor: An ‘even’ Greater Attractor?
As we mentioned above, efforts to study the Great Attractor in the
past were hampered by its location in the ‘Zone of Avoidance,’ but, a
study called CIZA was the first to search and investigate the nature of
the Great Attractor a couple of years ago.
The mass of the Great Attractor isnt strong enough to pull everything
towards it, this is why, when we look at an even bigger picture we find
that numerous galaxies including the Great Attractor are in fact moving
towards something that is even larger than the Great Attractor.
“X-rays can penetrate even regions that are extremely obscured by gas
and dust, and galaxy clusters are sources of X-rays. This is what
prompted us to attempt to map the distribution of galaxy clusters behind
the plane of the Milky Way using X-ray observations,” explains Ebeling,
who initiated the survey in 1998.
The CIZA project managed to find a significant
concentration of galaxies which are located behind the great Attractor,
finding an even GREATER Attractor behind the original one, near the
Shapley Supercluster located approximately 500 million light-years away
or four times the distance to the Great Attractor region.
“One of our goals was to uncover the true mass of the Great Attractor. What we found is that it is not that great after all,” says Kocevski.
The study confirmed for the first time that the presence of
structures more distant than the Great Attractor directly influence the
Milky Way and are pulling our galaxy and many others towards it.
While researchers such as Kocevski believe that mass concentrations
such as the Great Attractor were fairly common in the Universe, implying
that the early Universe contained much more mass that previous
estimates, other researchers remain skeptical about the CIZA study and
the mysterious force that continues to pull every one of us towards it,
near the Zone of Avoidance at the center of the Laniakea Supercluster.
X-ray observations with the ROSAT satellite then revealed that Abell 3627 is at the center of the Great Attractor.
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