Scientists find ‘Shiva’ and ‘Shakti,’ earliest building blocks of Milky Way

 

Scientists find ‘Shiva’ and ‘Shakti,’ earliest building blocks of Milky Way

Scientists have discovered what could be the Milky Way's earliest building blocks and named them "Shiva" and Shakti."

 

Astronomers at the Max Planck Institute for Astronomy have unveiled a groundbreaking discovery: the potential earliest building blocks of the Milky Way, dubbed "Shiva" and "Shakti." These remnants are believed to stem from two galaxies that merged with an early version of our galaxy around 12 to 13 billion years ago, contributing significantly to its expansion.

The identification of these components, named Shiva and Shakti, was accomplished by combining data from the European Space Agency’s Gaia satellite and the SDSS survey. This discovery can be likened to finding traces of a nascent settlement that eventually evolved into a sprawling metropolis, albeit on a cosmic scale.

Galactic collisions and mergers set numerous processes into motion. Each galaxy carries its own reservoir of hydrogen gas, and when they collide, these clouds become destabilized, leading to the formation of numerous new stars. Prior to the merger, each galaxy also hosts its own set of stars, and these "accreted stars" represent only a portion of the stellar population in the newly amalgamated galaxy. The challenge lies in discerning which stars originated from each predecessor galaxy once the merger is complete.

However, fundamental principles of physics provide valuable clues. When galaxies collide and their stars intermingle, most stars retain certain basic properties associated with the speed and direction of their original galaxy. Stars originating from the same predecessor galaxies exhibit similar values of energy and angular momentum, both of which are conserved for stars moving within a galaxy's gravitational field.

In their research, astronomers analyzed Gaia data in conjunction with stellar spectra data from the Sloan Digital Sky Survey (SDSS). The latter provided intricate details about the chemical compositions of stars. "We observed that, for a certain range of metal-poor stars, stars clustered around two specific combinations of energy and angular momentum," explained one researcher involved in the study.

For this investigation, astronomers utilized Gaia data alongside detailed stellar spectra from the Sloan Digital Sky Survey (DR17). The SDSS offered crucial insights into the chemical composition of stars. "We observed that, for a certain range of metal-poor stars, stars clustered around two specific combinations of energy and angular momentum. Shakti and Shiva might represent the first two components merging into the 'heart' of our Milky Way, setting the stage for its transformation into a larger galaxy," noted researcher Khyati Malhan, who bestowed the names Shiva and Shakti upon the two constituent galaxies.

The discovery of Shiva and Shakti marks a significant milestone in our understanding of the origins and evolution of the Milky Way. By unraveling the mysteries of galactic mergers, astronomers gain insights into the complex processes that shape the universe on a grand scale, shedding light on the cosmic drama that unfolds over billions of years.