The study throws light on how gravitational instabilities affect the evolution of galaxies

The study throws light on how gravitational instabilities affect the evolution of galaxies


The results of a study by the Indian Institute of Astrophysics (IIA) may shed light on the relationship between galaxy evolution and gravitational instabilities.

What is the Gravitational Instability?

  • A crucial process for the emergence of cosmic structures is gravitational instability. It is the only long-range force that is now understood to be capable of fusing materials into structures. 
  • Numerous situations can lead to gravitational instability, including star formation, nebula creation, circumstellar disks, binary granular materials, and planet formation. 
  • The thermodynamics of the disk, which is frequently controlled by star irradiation, affects how the instability manifests itself in circumstellar disks. The instability may occasionally result in bound partners that are more likely to be brown dwarfs or stars than objects of planetary mass. 
  • Binary granular materials can also experience gravitational instability, as seen in the ascent of a granular bubble or the cascade branching of a descending granular droplet. This unsteadiness can lead to These instabilities can create opportunities for patterning within granular mixtures. 

What was the purpose of the research in the field of Gravitational instability?

  • The investigation of the connections between various galaxy features and gravitational instabilities in galaxies was the study’s main objective.
  • The goal of the study was to comprehend the relationships between variables like as star formation rate, gas fraction, timescale for gravitational instabilities to grow, and observed galaxy morphology.

What was the data source?

  • The Spitzer Photometry and Accurate Rotation Curves (SPARC) database contained information on a sample of 175 galaxies, which was utilised by the researchers.
  • Given that it probably offers comprehensive information on the physical characteristics of these galaxies, SPARC is an important tool for this research.

What was the role of the dark matter in the study?

  • The study explored the role of dark matter in regulating the stability levels of galaxies.
  • Dark matter is an invisible form of matter believed to make up a significant portion of the universe’s mass. Understanding its influence on galaxies is crucial.

What were the findings from the study?

  • The research identified the following particular traits in spiral galaxies, such as the Milky Way:
  • Higher Median Star Formation Rate: Compared to other galaxy types, spiral galaxies showed a higher rate of star formation.
  • Lower Stability: These galaxies exhibited lower stability levels, which suggested that gravitational instabilities were more likely to occur.
  • Lower Gas Fraction: The reduced gas fraction of spiral galaxies indicates that a significant quantity of gas is being transformed into stars.
  • Smaller Timescale for Growth: The spiral galaxies’ gravitational instabilities grew over a shorter period, which suggests that gas quickly turned into stars.

What do we understand about the evolution of Galaxies from the studies done?

  • The stability levels in neighbouring galaxies—which probably represent the present situation—were contrasted with those found at high redshift.
  • Greater distance and earlier stages of galaxy history are represented by high redshift galaxies.
  • This comparison aids in understanding the relationship between gravitational instabilities and the long-term evolution of galaxies as well as their potential cosmic evolution.


In conclusion, the IIA’s research improves our knowledge of the intricate connection between gravitational instabilities and galaxy characteristics. The study offers important insights into the processes shaping galaxies, such as star formation and gas depletion, and how these processes contribute to the overall evolution of galaxies from earlier stages to the present day by analyzing a diverse sample of galaxies and considering the role of dark matter.