Lesson 1: GEOCHEMISTRY & STELLAR EVOLUTION

Geochemistry

Study of chemical composition and changes in Earth materials

Geochemical prospecting

Use of chemical properties to find economic mineral deposits

Environmental geochemistry

Focuses on monitoring metal dispersion and organic contaminants

Inorganic geochemistry

Analysis of rocks, ores, minerals, water, and soils

Organic geochemistry

Focuses on carbon-bearing compounds in geologic environments

Isotope geochemistry

Study of element concentrations and isotopes in Earth and solar system samples

Medical geochemistry

Focuses on the impact of geochemical processes on human and animal health

Aqueous geochemistry

Studies the role of elements in natural waters like copper, sulfur, and mercury

Trace elements

Elements in minerals in small amounts not included in the chemical formula

Cosmochemistry

Study of chemical composition in the universe and its formation processes

Big Bang

Model for the universe's evolution from a dense, hot state to expansion and cooling

Cosmology

Study of the origin, evolution, and nature of the universe

Expanding universe

Indicated by galaxies moving away at high speeds and background radiation

Doppler effect

Change in wave frequency due to the source's movement relative to the observer

Edwin Hubble

Astronomer who first observed galaxies moving away from Earth

Background Radiation

Pervasive Big Bang afterglow at 2.7 Kelvin

Cosmologists

Scientists studying the physics of matter and energy

Four Basic Forces

Gravity, electromagnetic, strong nuclear, weak nuclear

Cosmic Inflation

Enormous expansion of the universe post-Big Bang

Nuclear Reactions

Conversion of lighter elements to heavier in stars

Chemical Makeup

Composition of elements in the universe

Stellar Evolution

Matter organization from galaxies to atoms

Galactic Clusters

Groups of galaxies in the universe

Asteroid Belt

Region between Mars and Jupiter with asteroids

Trojan Asteroids

Asteroids sharing orbit with planets at Lagrangian points

Interstellar Medium

Space between stars containing gas and particles

Main Sequence Stars

Stars fusing hydrogen to helium in their core

Red Giants

Stars expanding after running out of hydrogen in core

Planetary Nebula

Cloud of dust and gas from outer layers of a red giant

Arcturus

Red giant in the northern constellation Boötes and Gamma Crucis in the southern constellation Crux (the Southern Cross)

Betelgeuse

Red supergiant star in the constellation of Orion

White dwarf

Remnant core of a red giant star, usually Earth-size but hundreds of thousands of times more massive, gradually cooling over billions of years

Neutron star

Stellar remnant packing more mass than the Sun into a sphere about as wide as New York City's Manhattan Island is long, formed from a main sequence star with 8-20 times the Sun's mass

Pulsars

Rapidly rotating neutron stars with bright X-ray hot spots that spin in and out of view like lighthouse beams

Magnetars

Neutron stars with magnetic fields up to 10 trillion times stronger than a refrigerator magnet's and up to a thousand times stronger than a typical neutron star's

Luminosity (L)

Total energy radiated by a star per second, proportional to its mass, with surface temperature indicating its volume

Blue giants

Massive stars with high luminosities and high surface temperatures

Red dwarfs

Stars less massive than the Sun, plotting at the lower end of the main sequence

Triple alpha process

Process where three helium nuclei convert into the nucleus of carbon-12 when the core temperature approaches 100 x 106 K

Evolutionary tracks

Illustrate the importance of a star's mass to its evolution, with more massive stars being brighter and having more eventful lives as red giants

Red Giant

Stage in a star's evolution where it expands and increases luminosity.

Supernova

Gigantic explosion in massive stars, blowing away outer envelope.

White Dwarf

Remnant of a low-mass star with high density and low luminosity.

Neutron Star

Collapsed core of a massive star, composed of a 'neutron gas'.

Black Hole

Region in space with intense gravitational field, trapping light and matter.

Isotope

Atoms of the same element with different atomic mass number.

Nucleosynthesis

Process creating new atomic nuclei from protons and neutrons.

Proton-Proton Chain Reaction

Dominant energy production process in lower-mass stars.

CNO Cycle

Catalytic cycle in higher-mass stars producing helium from carbon, nitrogen, and oxygen.

B2FH Theory

Theory of nucleosynthesis by Burbidge, Burbidge, Fowler, and Hoyle.

Oddo-Harkins Rule

Phenomenon where elements with even atomic numbers are more abundant.

Abundance of Iron

Notably higher abundance of iron compared to elements with similar atomic numbers.

Technetium and Promethium

Elements not found in the solar system due to unstable isotopes.

Elements with Atomic Number > 83

Elements lacking stable isotopes, occurring at low abundances as daughters of radioactive isotopes.

Hydrogen/Helium Ratio

Ratio of hydrogen to helium atoms in the solar system, approximately 12.5.