One behavior that exists in the outer space is orbiting. In our solar system, the Sun is orbited by 8 planets and at least 3 dwarf planets, Earth is orbited by the moon, and the same holds true for other celestial bodies, including galaxies.
The Milky Way, our massive galaxy, is orbited by other tiny galaxies, the most prominent being the Large Magellanic Cloud (LMC). This large dwarf galaxy resembles a faint cloud in the southern hemisphere night sky. Now, it has been discovered that our galaxy has been behaving (or misbehaving) in a way that's baffled and awed a team of astronomers at the University of California, Riverside.
Scientists have found that at least six dwarf galaxies are not in their original orbiting path, now orbiting the Milky Way instead of the Large Magellanic Cloud. How did this happen? According to the research team, our galaxy has apparently kidnapped them. Two bright galaxies called Fornax and Carina, as well as four ultrafaint galaxies, formerly belonged to the LMC.
"The LMC hosted at least seven satellite galaxies of its own, including the Small Magellanic Cloud in the Southern Sky, prior to them being captured by the Milky Way," said lead study author Ethan Jahn in a release.
In 2 billion years, the LMC will collide with the Milky Way, which will catastrophically send our own solar system "hurtling through space." We're long gone by then, but the merger between these two galaxies has already started, scientists have observed.
Since the Milky Way is more massive, it has the capability of ripping pieces off of the Large Magellanic Cloud using gravity, thus absorbing its orbiting galaxies.
"This is the first time that we are able to map the hierarchy of structure formation to such faint and ultrafaint dwarfs," said Laura Sales, study author and assistant professor of physics and astronomy, at the University of California, Riverside.
The researchers made the discovery using the Gaia space telescope, in which they collected data by observing nearby galaxy movement and simulating them using state-of-the-art cosmological hydrodynamical technology.
Using the predicted velocities of material and the positions in the sky relating to the LMC, the UC Riverside team spotted two classical dwarfs, Fornax and Carina, and four ultrafaint dwarfs, all of which were former satellites of the LMC.
The results of the study will be published in the Monthly Notices of the Royal Astronomical Society's November issue.
