PPT_Origin of the Universe and the Solar System (copy)

Universe

The totality of space, time, matter, and energy, estimated to be 13.8 billion years old.

Solar System

A collection of celestial bodies, including the Sun, eight planets, dwarf planets, and other minor bodies, located in the Milky Way galaxy.

Baryonic Matter

Ordinary matter consisting of protons, electrons, and neutrons that make up atoms, planets, stars, and galaxies, comprising 4.6% of the universe.

Dark Matter

Matter that has gravitational effects but does not emit light, making up 24% of the universe.

Dark Energy

A mysterious force that counteracts gravity and causes the universe to expand, constituting 71.4% of the universe.

Big Bang Theory

A cosmological model suggesting that the universe began as a hot, dense point and has been expanding since a violent explosion approximately 13.8 billion years ago.

Cosmic Microwave Background (CMB)

A faint glow of radiation filling the universe, discovered in 1964, providing evidence for the Big Bang.

Redshift

The phenomenon where light from distant galaxies shifts toward the red end of the spectrum, indicating that those galaxies are moving away from the observer.

Hubble's Law

A principle stating that galaxies recede from each other at speeds proportional to their distances, supporting the idea of an expanding universe.

Nebular Hypothesis

A theory proposing that the solar system formed from a rotating cloud of gas that cooled and contracted, leading to the formation of the Sun and planets.

Encounter Hypothesis

An early theory suggesting that planets formed from material pulled from the Sun during a close encounter with another star.

Steady State Model

A cosmological theory proposing that new matter is continuously created as the universe expands, maintaining a constant density of galaxies.

Georges Lemaître

A Belgian priest and physicist who first proposed the Big Bang theory in the 1920s.

Edwin Hubble

An astronomer who discovered the redshift phenomenon in 1929, providing evidence for the expanding universe.

Terrestrial Planets

The group of planets in the solar system that are rocky and include Mercury, Venus, Earth, and Mars.