Chapter 2, lesson 1:🌎The Origin and Evolution of Our Universe🪐

Universe

The vast, encompassing space that contains all celestial bodies and cosmic phenomena.

Galaxy

A massive system composed of stars, stellar remnants, gas, dust, and dark matter, bound together by gravity.

Solar System

A gravitationally bound system comprising a star (like the Sun) and all the celestial bodies that orbit it, including planets, moons, asteroids, and comets.

Multiverse

A hypothetical set of multiple possible universes, including the one we live in.

Big Bang Theory

The leading explanation for the origin of the universe, stating it began from an extremely hot and dense state and has been expanding ever since.

Steady State Theory

A now largely abandoned theory positing that the universe is eternal and unchanging on a large scale, with new matter continuously created.

Cyclic Theory

A cosmological model proposing that the universe undergoes infinite cycles of expansion and contraction.

Theory of Inflation

A theory suggesting that the universe underwent an exponential expansion during its first few moments after the Big Bang.

Cosmic Microwave Background (CMB)

Radiation leftover from the Big Bang, providing crucial evidence for the universe's origin and its age.

Dark Matter

A form of matter that does not emit light or energy, making it undetectable by traditional means; its presence is inferred from gravitational effects.

Normal Matter

Matter that emits, absorbs, or reflects electromagnetic radiation, detectable with various instruments; includes atoms and molecules that make up stars, planets, and living things.

Electromagnetic Radiation

A range of waves emitted by the first moments of the universe, including radio waves, visible light, X-rays, and ultraviolet rays.

Einstein’s E=mc²

The equation that describes the equivalence of energy (E) and mass (m), with c as the speed of light; fundamental to understanding energy-matter transformation.

Formation of Elements

The process by which the first particles combined to form simple atoms after the Big Bang, primarily hydrogen and helium.

Gravitational Forces

The attractive forces between masses that govern the motion and structure of cosmic bodies, leading to the formation of galaxies and stars.

Nebulae

Large clouds of gas and dust in space, where new stars are born.

Nuclear Fusion

The process through which stars generate energy by merging lighter atomic nuclei into heavier ones, producing elements from hydrogen and helium.

Birth of the Solar System

The process that occurred as dust and gas around newly formed stars clumped together to form the planets, moons, and other celestial bodies of the Solar System.