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On the Absence of Dark Matter in the Milky Way*
Pavle I. Premović
Laboratory for Geochemistry,
Cosmochemistry&Astrochemistry,
University of Niš,
pavleipremovic@yahoo.com, Niš, Serbia
The Milky Way is one of billions of
galaxies in the Universe. Cosmologists
estimated that the Milky Way is approximately 13.6 billion years old. It is a large spiral system containing hundreds of
billions of stars embedded in a large gas reservoir - mostly hydrogen and
helium. Most stars in this galaxy exist either as
single stars or as double
stars. One of the single stars is the Sun. Besides these two,
there are clusters of stars and stellar groups with tens to thousands of stars.
Most stars, as our Sun, have at least one planet orbiting them.
Current cosmology estimates
that 25 % of the Universe is made up of “dark
matter” and about 70 % of “dark energy” and the rest about 5% is
ordinary matter. These two things do not interact with ordinary matter
and light (and other forms of electromagnetic radiation) so it is
impossible to detect employing modern instrumentation. Their existence is mainly based on the
observable indirect evidence of their strong gravitational effect on the
galaxy’s stars. We
will here focus our attention on some recent concerns related to the dark
matter of the Milky Way.
The current
astronomical data suggest that the stars in the outer part of the Milky Way orbit much
faster than the inner ones which is against
the third Kepler’s law. This observation is explained by the presence of dark
matter associated with this galaxy[1]
whose gravitational effect makes the faster-than-expected orbital speeds of
outer stars. This matter forms a halo around our galaxy but ordinary matter is
mainly situated in its central part where most of stars dwell. It is
important to note here that the Earth resides in the halo of the Milky Way.
Based on the effects of gravity in the
Milky Way, scientists believe that there is a high concentration of dark matter
near the galaxy's center, around the supermassive black hole that resides
there. The current cosmology states that during
the history of the Milky Way, this matter has guided and sustained the
formation and evolution of our galaxy. It seems that dark matter
prevents the disintegration of the Milky Way due to its rotation and thus the
disintegration of its star systems with their planets, including the Earth. The
gravitational attraction of this matter keeps stars, dust, and gas together in our galaxy. In other words, dark matter
maintains the existence of the Milky Way. Simply speaking no
dark matter, no Milky Way, no the Solar system and its planets including
the Earth and its life.
Recently, Ou et al {2} published their
measurement of the speed of the stars in the Milky Way and suggested the stars closer to the edge of the Milky Way rotate more
slowly than expected. They reason that there is less dark matter in the center of our galaxy. Moreover, recent research carried out by
Gupta {4} appears to indicate dark matter is absent from the Universe.[2]
If this is true the following intriguing question arises: how a massive galaxy
such as the Milky Way was formed without dark matter?
Now, the second intriguing question appears: how does this galaxy survive
without dark matter for 13.6 Gy? The origin of the Milky Way in the Universe
without dark matter and its existence for so many billion years is a
cosmological mystery. We leave this mystery in the hands of cosmologists.
Entropy is a fundamental concept in
thermodynamics and statistical mechanics that measures the degree of disorder
or randomness in a system. This is a key concept for understanding the behavior
of physical systems.
In
physical science, a system may be an isolated system,
a closed system, or an open system. A physically
isolated system that does not exchange matter or energy with its surroundings. A closed physical system allows only the
energy exchange with its surroundings but not matter. An
open physical system can interact with its surroundings by exchanging both
matter and energy. The Milky
Way is a thermodynamically closed system. The current definition of the Second law (of thermodynamics) states that the entropy of a closed system tends to increase over
time. So, the entropy
of the Milky Way tends to increase.
The Milky Way can be considered a highly organized complex
cosmic structure. In a first approximation, this galaxy can be thermodynamically
viewed as a low-entropy physical system. Without dark matter, for this structure to be stable during 13.6 there would have to be a
constant external input of
energy. The question is, what is the source of this energy? Dark energy? Unlikely. Cosmologists have to deal with this issue
too.
Within biblical teaching, one can
hypothesize that the Spirit of God maintains, instead of dark matter, the
survival of the Milky Way, the Solar system, the Earth, and its life. For this reason, we remind the reader again of the sayings in the Letter
Diognetus: "God loved men. For their sake, He made the cosmos and
subjected everything on earth to them. To them alone He gave understanding and
speech, them alone He allowed to look up to heaven, them alone He formed in His
image,..."
References
{1} P. I. Premović, On the absence of dark matter in the galaxy NGC 1277. GSJ, April 2024.
{2} X. Ou, A.-C. Eilers, L. Necib,
A. Frebel, The dark matter profile of the Milky Way inferred from its
circular velocity curve. MNRAS, 528, 693-710 (2024).
{3} S. Comerón, I. Trujillo, M. Cappellari, et al., The massive relic galaxy NGC 1277 is
dark matter deficient - From dynamical models of integral-field stellar
kinematics out to five effective radii. A&A, 20, 1-30 (2023).
* See also {1}.
[1] The evidence for dark matter in the Milky Way comes from the rotation curve of this galaxy.
[2] Of note, there are few galaxies without dark matter. For instance, new findings by the research team led by Comerón {3} indicate dark matter is absent from the massive
lenticular galaxy NGC 1277.
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