Dwarf Galaxies Have An Interesting Orbit Around the Milky Way

Three small uniquely shaped galaxies have been discovered to be revolving around the Milky Way. This new discovery changes our perspective on how our own galaxy works, as well as ones near and far.

This discovery was made by an international team of scientists and astrophysicists mainly from the Instituto de Astrofísica de Canarias (IAC), the University of La Laguna (ULL), and the Space Telescope Science Institute (STScI). They discovered the presence of three small galaxies considered to be dwarf galaxies, that are going about what is considered a transverse rotation in the plane of the sky. 

These galaxies had remained undetected for the longest time because of their small size. They leave very faint traces of themselves and are hard to find, even when searched for. These galaxies pertain to a very specific role in cosmology, and always provide new insight for those studying them. 

“Dwarf galaxies have a particular interest for cosmology. The standard cosmological model suggests that this type of galaxies was the first to form. Many of them, the majority, have been destroyed and cannibalized by large galaxies such as the Milky Way. However, those that remain can be studied and contain valuable information about the early Universe,” says an article written by the IAC.

The specific type of galaxy that these three are classified as are called dwarf spheroidals. They are considered to be very diffuse, have low luminosity, and are presumed to contain a lot of dark matter, but not much gas. They have a lot of rotation, but the movement is very sporadic. All we know about their internal rotation is that it happens predominantly away from their centers, which makes them act interestingly with other galaxies.

The Milky Way’s strong gravity severely distorts the rotation of the three dwarf galaxies. This creates the unique transverse rotation that the dwarf galaxies have.

“The importance of this result is because, in general, the internal kinematics of galaxies, in this case their rotation, is an important tracer of their evolutionary history, and of the conditions in which the system was formed,” explains Alberto Manuel Martínez-García, doctoral student at the IAC and the ULL, and first author of the article.

The new galaxies have quite literally opened our eyes to new worlds, and give us hope for new discoveries to come.

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