Oddly-Shaped Dwarf Galaxy with No Dark Matter Baffles Scientists

Dark matter, the invisible and mysterious forces that permeate the universe, has been a topic of interest for scientists for generations. One thing we're sure of is that these forces exist in halos that surround most of the known galaxies.

The halo's mass applies a strong gravitational influence on the galaxy and its neighbors. However, one setback to the standard view of dark matter is the appearance of oddly shaped dwarf galaxies that do not have halos.

Bizarre Dwarf Galaxy

XSP: NASA/ESA Hubble Space Telescope's Advanced Camera Images
IN SAPCE - UNDATED: This handout image of the giant, active galaxy NGC 1275, obtained August 21, 2008 was taken using the NASA/ESA Hubble Space Telescope?s Advanced Camera for Surveys in July and August 2006. It provides amazing detail and resolution of fragile filamentary structures, which show up as a reddish lacy structure surrounding the central bright galaxy. These filaments are cool despite being surrounded by gas that is around 55 million ?C. They are suspended in a magnetic field which maintains their structure and demonstrates how energy from the supermassive black hole hosted at the centre of the galaxy is transferred to the surrounding gas NASA/ESA via Getty Images

According to the Standard Model of cosmology, the halos or shells of dark matter protect galaxies from their neighbor's gravitational influences. However, astronomers from the University of Bonn and Saint Andrews, Scotland, looked at the Fornax Cluster, 62 million light-years away, and stumbled upon a bizarre celestial phenomenon.

The cluster contained various dwarf galaxies that had perturbed and distorted shapes. The discovery was odd, especially when working under the theory of dark matter halos surrounding most of the universe.

Dwarf galaxies are small and faint, commonly seen riding along in clusters near larger companions. The Milky Way Galaxy has its own set of dwarf galaxies surrounding it.

Recently, studies suggest that at least one of the dwarf galaxies near our galaxy, Tucana II, has a significantly massive dark matter halo.

Meanwhile, in the Fornax Cluster, the dwarf galaxies are believed to be disturbed by gravitation tides coming from larger bodies in the cluster. These tides occurred when gravity from one body pulled on the different parts of another celestial body. The distorted shapes of the dwarf galaxies seen by astronomers indicate a problem with our theories and understanding of dark matter.

Pavel Kroupa, a professor at the University of Bonn and Charles University, Prague, explains that the perturbations in the dwarf galaxies are not expected according to the Standard Model of Cosmology because it is believed that the halos of dark matter should be able to shield the dwarfs from tides raised by the cluster.



Unraveling the Secrets of Distorted Dwarf Galaxies

Kroupa and Elena Ascencio analyzed the observation of oddly-shaped dwarf galaxies in the Fornax Cluster. They aimed to understand the extent of gravitational distortions and the underlying causes.

The level of expected distortions depends on various factors, one of which is the internal characteristics of the dwarfs. Also, its distance to the cluster's center is where the gravitational influences are stronger.

The governing rule is that galaxies with large sizes but not many stars can easily be disturbed by strong gravitational tides. The same is true for galaxies closest to the cluster's core.

Asencio explains that the comparison showed that if one wants to explain the phenomenon under the Standard Model, the dwarfs of the Fornax cluster should already be destroyed by the cluster's gravity even when the tides it raises are sixty-four times weaker than the own gravity of the dwarf. However, this is counterintuitive and debunks earlier studies, reports ScienceAlert.

The findings suggest that Newton's law of universal gravitation should be revamped to account for the recently observed galaxy properties. The latest observations have major implications for the fundamentals of physics.

The team expects to find even more distorted, oddly-shaped dwarfs in other clusters.


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