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Galaxy formation, particularly of elliptical galaxies, begins with the gravitational collapse of primordial gas clouds. These clouds are abundant in hydrogen and helium, the universe's most abundant elements. The process initiates when gravity draws this gas inward, causing the cloud to become denser and hotter.
As the gas cloud condenses, it triggers star formation. Since elliptical galaxies generally start with low angular momentum, their stars are evenly distributed, forming a smooth, spherical shape. This foundation is crucial, as it sets the stage for the galaxy's future structural integrity.
Interestingly, the lack of rotation in the initial gas cloud plays a major role in the final shape of elliptical galaxies. Without the same rotational dynamics seen in spiral galaxies, elliptical galaxies take on a unique and more uniform appearance.

Star formation in the early stages of elliptical galaxy formation is a fast-paced process. When the gas clouds collapse, they heat up and stars form rapidly. These stars are typically massive and shine brightly due to their large energy outputs.
The star formation period in elliptical galaxies, however, is relatively short-lived. When the most massive stars expend their nuclear fuel quickly, they end as red giants and eventually fade into cooler, less luminous stars. This creates a distinctive stellar population because most stars in elliptical galaxies are old and cool.
Due to the rapid star formation, the gas available for forming new stars depletes quickly. This sudden shortage of material brings star formation to a near halt, marking a significant transition in the galaxy's evolution.

Galactic mergers are a crucial factor during the growth phase of elliptical galaxies. Over time, smaller galaxies may collide and merge with a larger elliptical, altering its size and shape.
Such mergers add their stars to the elliptical galaxy, enriching its composition. The process, often dubbed 'violent relaxation,' redistributes the stars into random orbits. This results in the elimination of any prior organized rotational motions, solidifying the galaxy's elliptical form.
This sequence of events through galactic mergers not only enhances the mass of the galaxy but also expands its size, creating the classical elliptical shape we recognize in many of these galaxies today.

Once elliptical galaxies have absorbed enough smaller galaxies, their evolutionary path stabilizes. At this point, the rate of star formation plummets due to the exhaustion of gaseous material.
Without new star formation, the fate of elliptical galaxies is marked by aging stars. The existing stars age and burn out, leading to a passive evolution stage. This results in a nearly spherical collection of mature stars, with minimal activity due to the lack of gas and dust.
Elliptical galaxies exhibit distinct features, such as a central bulge and the absence of spiral arms, which highlights their evolutionary processes and differences from other galaxy forms. This evolutionary phase defines them as a mature and stable form of a galaxy.