UNIVERESE – MILKYWAY

PRERNA FOR IAS

UNIVERESE – MILKYWAY

1. Dark Energy

Dark energy is a mysterious form of energy that makes up about 68% of the universe. Scientists believe it is responsible for the accelerated expansion of the universe. Unlike ordinary matter, dark energy cannot be directly observed because it does not emit, absorb, or reflect light. Its existence is inferred from astronomical observations showing that galaxies are moving away from each other at increasing speeds. Although dark energy dominates the universe, very little is known about its nature. Understanding dark energy is one of the greatest challenges in modern cosmology and may reveal fundamental secrets about the origin and fate of the universe.

2. Dark Matter

Dark matter constitutes approximately 27% of the universe and is invisible because it does not interact with light. Scientists cannot observe it directly, but they know it exists due to its gravitational effects on galaxies and galaxy clusters. Without dark matter, galaxies would not have enough gravity to hold themselves together. It acts as a hidden framework that influences the structure and evolution of the universe. Researchers believe dark matter consists of unknown particles that have not yet been detected. Discovering the true nature of dark matter is a major goal of modern physics and could transform our understanding of the cosmos.

3. Normal Matter

Normal matter, also known as baryonic matter, makes up only about 5% of the universe. It consists of atoms, which form everything visible around us, including stars, planets, living organisms, air, water, and everyday objects. Unlike dark matter and dark energy, normal matter can be detected through light and other forms of electromagnetic radiation. Scientists have studied normal matter extensively and developed the periodic table to classify its elements. Despite being the smallest portion of the universe, normal matter is responsible for all known structures and life. It forms the observable universe that humans can directly investigate and understand.

4. Stars