Human Diversity

Universe

The vast collection of stars, planets, and other celestial bodies.

Scientific theory

A model that accurately describes a large class of observations and makes predictions about future observations.

Light-year

The distance that light travels in one year, approximately 5.88 trillion miles.

Copernican system

The heliocentric model of the solar system proposed by Nicolaus Copernicus, where the sun is at the center and the planets orbit around it.

Laws of motion

Laws formulated by Sir Isaac Newton that describe the behavior of objects in motion and the force of gravity.

Antinomies of pure reason

Contradictions in Immanuel Kant's Critique of Pure Reason regarding the beginning and limits of the universe.

Red shift

The shift of light towards longer wavelengths, indicating that an object is moving away from the observer.

Big Bang

The theory that the universe began with a tremendous expansion from a hot, dense state.

Expansion of the universe

The continuous increase in the distance between galaxies over time.

Spectra

The characteristic signature of light emitted by galaxies, used to determine their velocities.

Redshift

The increase in wavelength that a ray of light undergoes when its source is moving away from the observer.

Doppler effect

The change in pitch or frequency that a sound wave or light wave undergoes when its source is moving towards or away from the observer.

General theory of relativity

A theory in physics that describes the force of gravity as a curvature of spacetime caused by mass and energy.

Quantum mechanics

A branch of physics that deals with the behavior of particles at the atomic and subatomic level.

Singularity

A point in time and space where the temperature, density, and curvature of the universe are all infinite.

Big Bang

The term coined to describe the initial explosion that is believed to have created the universe.

Cosmic Microwave Background radiation (CMBR)

The faint background of microwaves throughout space that is leftover radiation from the early universe.

Sun

A star that is relatively close to Earth and appears larger and brighter than other stars.

Gravitational pull

The force of gravity that attracts objects towards each other.

Star

A celestial object that is hot and bright, primarily composed of hydrogen and helium, and produces its own light through nuclear fusion.

Red giant

A stage in the life cycle of a star where it has exhausted its hydrogen fuel and starts burning helium, causing it to expand and become larger and brighter.

Supernova

A massive explosion that occurs when a star collapses under its own weight, releasing a tremendous amount of energy and often leaving behind a dense dead body called a neutron star or a black hole.

Type II Supernova

A supernova explosion that occurs when a massive star can no longer hold itself up against gravitational collapse.

Type Ia Supernova

A supernova explosion that occurs when a white dwarf star collects matter from a nearby companion star, causing a sudden and violent explosion.

Nebular Hypothesis

The theory that suggests that the solar system formed from a rotating disk of gas and dust called a nebula.

Planets

Bodies that revolve around the Sun and are part of the solar system.

Nebular hypothesis

Theory suggesting that all members of the solar system originated from a mass of heated gaseous material in motion.

Cooling and condensation

Process in which rings of matter formed and later broke up into different planets.

Archaean Era

The earliest period of the Earth's geological history, characterized by high temperatures and the suspension of substances, including water, in the atmosphere.

Volcanic upheavals

Frequent volcanic activities during the early stages of Earth's history, as fire and water struggled for dominance.

Origin of life

The scientific ideas and hypotheses about how life may have arisen on Earth.

Oparin-Haldane hypothesis

The proposal that life on Earth could have gradually evolved from non-living matter through chemical evolution.

Miller-Urey Experiment

An experiment conducted in 1953 to test the Oparin-Haldane hypothesis, showing that organic molecules can be spontaneously produced under conditions resembling those of early Earth.

Building blocks

Simple inorganic molecules that can react to form more complex molecules, such as amino acids and nucleotides.

Polymers

Larger, more complex molecules formed by the combination of building blocks, such as proteins and nucleic acids.

Genes-first hypothesis

The idea that the first life forms were self-replicating nucleic acids, such as RNA or DNA.

Metabolism-first hypothesis

The hypothesis that self-sustaining networks of metabolic reactions may have been the first simple life forms, predating nucleic acids.

Organic molecules from outer space

The possibility that organic molecules necessary for life may have arrived on Earth through meteorites.