THE SOUTHWORTH PLANETARIUM
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Founded January 1970
            "Where Tuesdays are always super!"


THE DAILY ASTRONOMER
Tuesday, March 15, 2016
BOSS


Physical reality can stagger even the most fertile of imaginations.   The
structures within the Universe are so grand and the space separating them
so vast that the sheer extent of the Universe is utterly unfathomable.
Our weighty Earth, a behemoth from our perspective, is literally sub atomic
in relation to the cosmos that spawned it.    Miraculously, beings
inhabiting this minuscule point have mapped the visible Universe almost to
its definable boundaries.  In so doing, they have discovered not only stars
gathered in galaxies, but galaxies bound in clusters and clusters,
themselves, comprising super clusters.    These super clusters serve as
components to even larger constructs: great "walls" in which the light
outflow of entire galaxies appears as little more than morning Sun shone on
cobweb filaments.

Astronomers have recently announced the discovery of the greatest structure
yet found. Called BOSS, after the Baryon Oscillation Spectroscopic Survery,
this great wall extends for more than one billion light years.    It
consists of galactic super clusters tenuously bound by gravity.      As
BOSS is more than 4.5 billion light years away, astronomers can observe its
entire extent.

[The DA is now posted on the Southworth Planetarium's web-site:
http://usm.maine.edu/planet/da-7-december-2015
Click on the link to see today's article and a beautiful image of BOSS. ]

This superstructure consists of 830 separate galaxies and is about 10,000
times more massive that our Milky Way Galaxy.        Realize that, if we
made a scale model of the Milky Way Galaxy that reduced it to the size of
the North American continent, our solar system would fit inside a coffee
cup and one would need a microscope to find Earth.    This might give on an
idea about BOSS's immense size as it dwarfs the Milky Way.

Some astronomers dispute the assertion that BOSS is actually a structure.
Detractors don't believe these objects are actually part of a system, but
are instead so widely separated that their individual motions will govern
their positions as opposed to BOSS's overall attraction.       As an
example, Earth is considered part of the solar system because the Sun's
gravity dictates its motion.  Were Earth to suddenly be propelled away from
the Sun,  its trajectory would be determined by its independent motion as
opposed to the Sun's gravity.

The issue about what defines a structure will likely not be resolved
anytime soon.  Also, as the Universe is populated by many super clusters
"walls," it is likely that astronomers will find even larger objects than
BOSS.     What we do know is that the cosmos is grander and more dynamic
than we could have ever imagined.

Who would want it any other way?