Origin & Evolution of Earth Notes

These flashcards cover key definitions and concepts from the notes on the origin and evolution of Earth, theories of the universe, and geological processes.

Nebular Hypothesis

A theory suggesting planets formed from a cloud of material rotating slowly around the sun.

Big Bang Theory (BBT)

The popular modern cosmological model that explains that all matter originated from a singular atom that violently exploded 13.7 billion years ago.

Accretion

The process by which particles collide and stick together to form larger bodies, leading to planet formation.

Hoyle's Steady State Theory

An alternative to BBT, suggesting the universe is always expanding but maintains a constant average density.

Galaxies

Massive systems composed of stars and interstellar matter, formed from gravitational attraction of particles post-Big Bang.

Planetesimals

Small, solid objects that formed from gas and dust in the protoplanetary disk and eventually coalesced to form planets.

Lithosphere

The rigid outer layer of the Earth, consisting of the crust and upper mantle.

Atmosphere

The layer of gases surrounding the Earth, composed primarily of nitrogen and oxygen, crucial for supporting life.

Degassing

The process through which gases were released from within the Earth during its cooling, leading to atmospheric evolution.

Origin of Life

Refers to the chemical reactions and assembly of organic molecules that led to the emergence of life on Earth approximately 3.8 billion years ago.

Juno Mission

NASA's mission studying Jupiter to gain insights into solar system formation, indirectly aiding understanding of Earth's origin and evolution.

Kola Superdeep Borehole

A scientific drilling project that has provided information about the Earth's interior but has only penetrated about 12 km deep.

Seismic Waves

Waves of energy generated by earthquakes, which provide information about the Earth’s internal structure through their behavior and speed.

P-Waves and S-Waves

P-Waves are primary waves that can travel through all states of matter; S-Waves are secondary waves that can only travel through solids.

Epicenter

The point on the Earth's surface that is directly above the focus of an earthquake.

Continental Drift Theory

A theory proposed by Alfred Wegener that suggests continents were once a single supercontinent called Pangaea.

Mass Movements

The downhill movement of soil and rock under the influence of gravity, often resulting in landslides.

Geomorphic Processes

Processes that shape the Earth's surface, categorized into endogenic forces (internal) and exogenic forces (external).

Weathering

The process of breaking down rocks at the Earth's surface through natural forces like water, wind, and biological activity.

Hydrosphere

The part of the Earth where water exists, as a liquid, solid (ice), or gas (water vapor), influencing climate and life.

Natural Climates

The various climatic zones defined by geographic factors affecting precipitation and temperature patterns.

Solar Radiation

Energy from the sun that drives the Earth's weather systems and maintains temperature balance.

Heat Budget

The balance of incoming and outgoing energy on Earth, maintaining thermal equilibrium.

Greenhouse Effect

The process by which greenhouse gases trap heat in the Earth's atmosphere, influencing climate.

Tidal Currents

The horizontal movement of water due to the rise and fall of tides, influenced primarily by the gravitational pull of the moon and sun.

Eutrophication

The excessive growth of algae in water bodies due to nutrient runoff, leading to oxygen depletion.

Coral Bleaching

The loss of color in corals due to the expulsion of symbiotic algae, often due to temperature stress or water pollution.

Marine Sediments

Material that accumulates on the ocean floor, derived from terrestrial, biological, and chemical processes.

Mangroves

Coastal ecosystems characterized by salt-tolerant trees and shrubs, important for biodiversity and protection against erosion.

Ocean Currents

Continuous, directed movement of seawater generated by various factors including wind, density differences, and the Coriolis effect.

Desalination

The process of removing salt from seawater to produce freshwater, increasingly used in water-scarce regions.

Pollution Control

Efforts and regulations aimed at reducing harmful substances in natural bodies of water.