Facts for Prelims (FFP)
Source: TH
Context: A study conducted by the Indian Institute of Astrophysics (IIA) aims to understand the connection between gravitational instabilities and galaxy evolution.
What are Gravitational Instabilities?
Gravitational instabilities refer to disruptions or fluctuations in the gravitational forces within a celestial object, such as a galaxy or a cloud of gas and dust. These instabilities can lead to the formation of structures like stars, planets, or galaxies as matter clumps together under the influence of gravity.
Findings of the study:
- The study shed light on the role of dark matter in regulating galaxy stability.
- It found that gravitational instabilities in spiral galaxies like the Milky Way rapidly convert gas into stars, depleting gas reservoirs.
- This led to higher star formation rates, lower stability, and lower gas fraction in such galaxies.
How are galaxies formed?
| Stage | Description |
| 1. Primordial Matter | Cosmic matter, including hydrogen and helium, is evenly distributed throughout the universe. |
| 2. Gravitational Attraction | Gravity causes slightly denser regions to form from the cosmic matter. |
| 3. Protogalactic Clouds | Denser regions accumulate gas, dust, and dark matter through gravity. |
| 4. Star Formation | Protogalactic clouds fragment into smaller clumps, giving birth to stars. |
| 5. Galaxy Formation | Stars within the clouds begin to orbit a common centre of mass, forming a galaxy. |
| 6. Galaxy Types | The type and appearance of the galaxy (spiral, elliptical, irregular) depend on various factors. |
