Galaxies, the celestial marvels that adorn our universe, exhibit diverse shapes and sizes. Notably, the Milky Way stands out as a spiral galaxy, characterised by the graceful spiral arrangement of stars, dust, and gas emanating from its core.
However, the rarity of spiral galaxies in our galactic vicinity has intrigued astronomers for decades. A recent study, published in the peer-reviewed journal Nature Astronomy, may offer a long-awaited explanation.
Delving into the Past
Scientists deployed a supercomputer to rewind the cosmic clock to around 13.8 billion years ago, a time when our galaxy and its cosmic companions were in their nascent stages of formation. Through sophisticated simulations, they traced the evolutionary trajectory of our galactic neighbourhood, seeking insights into the factors that contribute to the scarcity of spiral galaxies.
The simulations unveiled a turbulent cosmic history. Galaxies situated in densely populated clusters, akin to our Milky Way's cosmic abode, underwent frequent collisions and mergers. These cosmic encounters were pivotal in shaping the galactic landscape.
Collisions and Galactic Metamorphosis
Galaxy collisions can lead to the creation of entirely new galactic forms. When two spiral galaxies collide, the result is believed to be the formation of an elliptical galaxy. Both observations of our nearby universe and the simulated scenarios echoed this phenomenon. Despite the chaotic dance of galactic collisions over the vast expanse of the universe's existence, our Milky Way emerged relatively unscathed, surrounded by a majority of elliptical galaxies in our galactic neighbourhood.
Co-author Carlos Frenk from the Institute for Computational Cosmology at Durham University expressed, "Our simulation reveals the intimate details of the formation of galaxies such as the transformation of spirals into ellipticals through galaxy mergers." The findings shed light on the intricate cosmic ballet that has shaped the galaxies in our celestial vicinity.
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