The Universe and The Solar System

• Our Universe is 4.6% Baryonic Matter, 24% Cold Dark Matter (CDM), 71.4% Dark Energy.
• Baryonic Matter refers to ordinary matter consisting of protons, neutrons, electrons. Objects include Clouds of cold gas, Planets, Comets and Asteroids, Stars, Galaxies
• Dark Matter refers to the matter that has gravity but does not emit light. It binds the universe
• Dark Energy is the source of anti-gravity. It is non-particulate and has repulsive gravity. It tears the universe.
• Hydrogen, helium, and lithium are the most abundant elements.
• Stars are the building blocks of galaxies born out of clouds of gas and dust.
• Protostar is an early stage of a star resulting from the gravitational collapse of gases.
• Thermonuclear Reaction is a nuclear fission reaction responsible for the energy produced by stars
• Main Sequence Stars are stars that fuse hydrogen atoms to form helium atoms in their cores; outward pressure resulting from nuclear fusion is balanced by gravitational forces.
• Planetary nebula is a ring-shaped nebula formed by an expanding shell of gas around an aging star.
• White Dwarf is what stars become after they have exhausted their nuclear fuel.
• Neutron Star is a celestial object of very small radius and very high density, composed predominantly of closely packed neutrons
• Black hole is a region of space having a gravitational field so intense that no matter or radiation can escape.
• Light year is the distance light can travel in a year.
• The Universe is 13.8 billion years old. Its diameter is possibly infinite (at least 91 billion light years).
• Edwin Hubble proved that the universe is expanding. He announced his significant discovery of "red-shift" in 1929.
• Red Shift is increase in Lambda, decrease in frequency (moving away) while Blue Shift is the opposite.
• The apparent frequency of a sound changes due to the relative movement of the source and/or observer is called The Doppler Effect.
• The Cosmic Microwave Background is the remnant heat left over from the Big Bang. It is accidentally discovered by Arno Penzias and Robert W. Wilson in 1964.
• The Steady State Theory states that new matter is created as the universe expands thereby maintaining its density.
• The Big Bang Theory states that the universe is 13.8 billions years old and started from a tiny dense hot mass to its present size and much cooler state. The theory rests on two sides. General Relativity and Cosmological Principle
• The Kuiper Belt comprises numerous rocky or icy bodies a few meters to hundreds of kilometers in size
• The Oort Cloud marks the outer boundary of the solar system and is composed mostly of icy objects.
• Most of the mass in the solar system in concentrated in the Sun (99.8%) while angular momentum is held by the outer planets
• Orbits of the planets are elliptical and are on the same plane.
• Most planets rotate prograde (meaning same direction as the orbit)
• Terrestrial Planets have:

  • high densities
  • thin or no atmospheres
  • rotate slowly
  • rocky material
  • poor in ices and lower contents of H, He, and novel gases.
• Jovian Planets have:

  • low densities
  • thick atmospheres
  • rotate rapidly
  • many natural satellites
  • fluid interiors, rich in ices
• During the 1700s, Emanuel Swedenborg, Immanuel Kant, Pierre-Simson Laplace thought of a rotating gaseous cloud that cools and contracts in the middle to form the Sun and the rest into a disc that becomes planets.
• The sun occupies 99.8% of the total mass while having only 2% angular momentum