Big Bang Theory and Solar System Formation

Overview of Cosmic Concepts

• Cosmos refers to the universe studied under the branch of science called cosmology, investigating its origin, evolution, and fate.
• The universe is the totality of space, time, matter, and energy, existing for approximately 13.8 billion years.
• Key components include 4.6% baryonic matter, 24% cold dark matter, and 71.4% dark energy, with hydrogen, helium, and lithium as the most abundant elements.

Theories of the Origin of the Universe

• First Theory:
  • Suggests that 10-20 billion years ago, matter and energy existed in a hot, dense state before exploding due to random fluctuations.
• Second Theory:
  • Proposes that the density of matter remains constant in an expanding universe, allowing for continuous matter creation.
• Third Theory:
  • A cyclical cosmological model combining the Big Bang and Big Crunch, leading to endless self-sustaining cycles of expansion and contraction.

Expansion of the Universe

• Edwin Hubble's Discovery (1929):
  • Observed the redshift effect, indicating galaxies are moving away, supporting the idea of an expanding universe.
• Spectral lines shifting toward red suggest increasing distance between galaxies, disproving the notion of a static universe.

Solar System Structure

• The solar system's mass is concentrated in the Sun, while its angular momentum is distributed among the outer planets.
• Orbits: All planets have elliptical orbits and revolve around the Sun, with revolution periods increasing with distance from the Sun.
• Planets Composition:
  • Terrestrial Planets (Mercury, Venus, Earth, Mars):
    • Made of rocks with high melting points, have thin atmospheres, and higher densities.
  • Jovian Planets (Jupiter, Saturn, Uranus, Neptune):
    • Dominated by gases and larger in size, they feature much thicker atmospheres.

Inner and Outer Core of the Earth

• The inner core comprises about 1/3 of Earth’s mass, with a radius of approximately 3360 km and a temperature of about 4800°C.
• The intense pressure keeps the inner core solid, despite high temperatures, and thermal convection currents are caused by decaying radioactive material.

Earth's Crust Types

• Oceanic Crust:
  • Composed of basalt, heavier and dark, with a density of 3.0 g/cm³.
• Continental Crust:
  • Lighter, made of granite and other rocks, with density ranging from 2.7 to 3.0 g/cm³, and thickness between 20 to 70 km.

Planets in the Solar System

• Mercury:
  • Closest to the Sun, fastest revolution, lacks significant atmosphere, with extreme temperature variations.
• Venus:
  • Known as Earth's twin, has a very thick atmosphere composed mostly of carbon dioxide, with extreme surface temperatures.
• Earth:
  • Unique for its liquid water and ability to support life due to a suitable atmosphere and temperature range.
• Mars:
  • Characterized as the Red Planet, has two moons (Phobos and Deimos) and experiences a significant temperature drop at night.

Conclusion

• The universe is vast and complex, with various theories explaining its origins and structure, showcasing the intricate balance of forces and matter that allow galaxies, stars, and planets, including Earth, to exist.

This quiz explores the various hypotheses leading to the Big Bang Theory and the formation of our solar system. Learners will create conceptual maps and discuss the significance of these theories while engaging in group discussions. Dive into the cosmos and understand where we are in the universe!