In a surprising, discover, astronomers have been left perplexed after finding “mountain ranges” in the Milky Way.
For us, the night sky looks like a blanket full of scattered stars, but astronomers exploring the cosmos are learning that in some regions of our galaxy the stars accumulate in such a way that they create characteristics similar to those here on Earth: currents, waves, arcs, and even mountains, reports space.com.
On Earth, for example, tectonic activity is responsible for creating depressions and mountains, but when we speak at a cosmic level, astronomers are unaware of how the stars are capable of – honoring a hermetic principle – creating such formations. Now, researchers are formulating theories about it, including forces from outside our galaxy that may have played an important role in this cosmic mystery.
A Galactic Mystery
Although not one hundred percent sure, astronomers speculate that the reason for this mysterious topography could be found in the Milky Way itself.
To get to the bottom of this mystery, a team led by astronomers from the University of Sydney, Australia, analyzed data from the European Space Agency’s Gaia Mission, which produced a kind of galactic census cataloging about 1 billion stars with their respective positions and distances. In particular, the researchers focused on a series of eight “crests” of the Milky Way that are distributed, forming a “cosmic mountain range.”
Astronomers found that these kinds of cosmic ridges are stacked in the middle layers of the galactic disk and that each one has a collection of unique stars covering its tops.
By taking data from another mission that studied the composition of the stars, they realized that they all had compositions similar to that of our sun.
And since an elementary composition can signal a stellar age, this showed astronomers that these young stars were not scattered in the same ways as older stars, which helps to understand how the galactic mountain ridges formed.
Right now, we only have theories that try to explain this phenomenon.
Only theories, for now
Two main theories are out there.
The first theory argues that the internal mechanisms of the galaxy are the key to its geography and shape. For example, gravitational interactions generate resonant waves that at the same time, create large groups of matter. Alternatively, friction between stars, gases, and galactic dust can lead to the birth of these topographic characteristics.
The second theory proposes that there is an external force, such as a dwarf galaxy, that causes the stars to stack up.
Computer simulations have shown that in the latter case, with external forces at play such as those of a dwarf galaxy much more pronounced peaks were present. “So the height of the ridges could be a way to distinguish between the performance of internal and external processes,” explained Shourya Khanna, lead author of the study.