Two new satellites named Sextans II and Virgo III have unexpectedly emerged in the dark region near the Milky Way galaxy, which houses Earth.
According to Space.com, with their sudden appearance in astronomical data, Sextans II and Virgo III have joined the assembly of approximately 60 known dwarf galaxies that are congregating around the Milky Way, the massive spiral galaxy where our planet resides.
The research team, led by Professor Masashi Chiba from Tohoku University in Japan, states that these mysterious objects promise to help us understand a mysterious “force” of the universe: dark matter.
Believing that many satellites of the Milky Way remain undiscovered due to their extreme distance and faintness, Professor Chiba and his colleagues conducted a new search using the Subaru Telescope located near the summit of Mauna Kea in Hawaii, leading to the discovery of the two aforementioned galaxies.
Enlarged image showing the position of the Virgo III galaxy, located in the constellation Virgo as viewed from Earth – (Photo: NAOJ/TOHOKU UNIVERSITY).
The existence of these newly identified dwarf galaxies is strongly related to the activity of dark matter.
Dark matter is a persistent cosmic mystery because it does not interact with light or normal matter, which makes up stars, planets, moons, and even us.
However, dark matter accounts for about 85% of the universe and does interact with gravity, potentially influencing the motion and dynamics of light as well as everyday matter.
This allows scientists to infer the presence of dark matter and ultimately conclude that large galaxies are surrounded by vast halos of this mysterious substance, playing a crucial role in the evolution of galaxies.
In the early universe, they formed gravitational wells where gas and dust coalesced to form stars within galaxies. Eventually, these halos also merged, leading to the formation of large galaxies like the Milky Way.
This model also suggests that if dark matter exists, it will not only shape a single large galaxy but also create hundreds of satellites surrounding it.
For example, the massive Andromeda Galaxy, which is slightly larger than the Milky Way, is thought to have around 500 satellites, while the Milky Way has at least 220.
However, we have only observed over 60 satellites of the Milky Way and 39 of Andromeda.
Therefore, discovering the faintest satellite galaxies of the Milky Way or Andromeda is also an indirect way to grasp how dark matter influences the evolution of cosmic objects.
Most recently, research on Sextans II and Virgo III promises to yield exciting insights.
Scientists also noted that even the leading contributor to the exploration of the Milky Way’s satellites, Subaru, has only observed a portion of the sky.
Thus, many more pieces of the puzzle are likely to be found as humanity develops more comprehensive telescopes that are at least as powerful as Subaru.
