Earth Science and Geologic History Flashcards

Vocabulary flashcards covering the origin of the universe, solar system formation, stellar nucleosynthesis, and the geologic timeline of Earth as presented in the lecture.

Redshift

The shift of light waves coming from distant galaxies toward longer, redder wavelengths, indicating that galaxies are moving away from each other and the universe is expanding.

Doppler Effect

The apparent change in wavelength and frequency of a wave relative to an observer, where objects moving away shift toward longer wavelengths and objects moving closer shift toward shorter wavelengths.

Logarithmic Scale

A measurement scale where each unit step increase along an axis represents a ten-fold increase or an order of magnitude.

Chondrite Meteorites

Meteorites that have not been substantially altered, melted, or squished since their formation, serving as the best source of evidence for the solar system's original elemental composition.

Oddo-Harkins Rule

The principle stating that elements with even atomic numbers are more abundant than neighboring elements with odd atomic numbers due to the fusion of helium units with atomic mass $4$ in stars.

Solar Nebula

A large, cold rotating cloud of gas and dust produced by a previous supernova from which the solar system condensed.

Nebular Hypothesis

The prevailing explanation for solar system formation, stating that a spinning gas cloud flattened into an accretion disk, forming a protostar at the center and protoplanets orbiting in the same plane.

Stromatolites

Layered rock mounds formed by colonies of single-celled microbial organisms during the Archean eon approximately $3.8\,\text{billion}$ years ago, representing early evidence of life.

Ediacarans

The earliest known multicellular organisms that appeared in the Proterozoic eon, characterized by soft bodies that lacked hard skeletons or shells.

Cambrian Explosion

A rapid diversification event occurring about $541\,\text{million}$ years ago characterized by the sudden widespread appearance of complex organisms with hard shells and skeletons in the fossil record.

Permian-Triassic (PT) Extinction

A mass extinction event occurring over $60,000$ to $100,000$ years at the end of the Paleozoic era that eliminated $57\%$ of all known land and marine species.

Anthropocene

An informal, proposed geological epoch marking the period during which human activities have significantly impacted Earth's ecosystems and geologic record.