Which one of the following hypothesis/theory explains the origin of universe?

The Big Bang Theory is the prevailing cosmological model that explains the origin and birth of the universe [4]. It posits that approximately 13.8 billion years ago, the entire universe was contained in a single point of extreme density and temperature, which has been expanding in all directions ever since [4][5]. Evidence such as cosmological redshift and cosmic microwave background radiation supports this expanding universe hypothesis [1]. In contrast, the other options—Nebular Hypothesis, Binary Theory, and Planetesimal Hypothesis—primarily focus on the origin of the Earth and the formation of the solar system rather than the universe as a whole [1][2]. The Nebular Hypothesis, for instance, describes how planets formed from a rotating cloud of gas and dust associated with a youthful sun [2]. Therefore, only the Big Bang Theory addresses the fundamental origin of the entire universe.

Sources

1. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 1: The Universe, The Big Bang Theory, Galaxies & Stellar Evolution > 1.3. Evidence for Big Bang Theory > p. 3
2. [5] https://spaceplace.nasa.gov/big-bang/
3. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 2: The Solar System > Earlier Theories > p. 17
4. [2] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 1: Geography as a Discipline > Origin of the Earth > p. 13