ASTR-117 Exam Review Vocabulary

Flashcards for ASTR-117 exam review, focusing on vocabulary.

Miller-Urey Experiment

An experiment conducted to explore the possibility of life originating from inorganic chemistry, potentially introduced from space. It simulates conditions of early Earth to test the formation of organic compounds from inorganic substances.

Deep-sea vents

Locations on the ocean floor where geothermally heated water vents into the sea. These vents are considered as a possible origin point for life on Earth due to the chemical-rich environment they provide.

Catalysts

Substances that facilitate RNA strand construction, playing a critical role in the origin of life by speeding up chemical reactions necessary for forming complex molecules.

Lipid pre cells

A hypothesized step in the development of early life, involving the formation of cell-like structures from lipids that could encapsulate and protect early genetic material.

RNA self replication

A crucial mechanism in the emergence of life, allowing for natural selection to act on RNA molecules, improving their replication fidelity and efficiency until life arises.

Cell membrane

A selective barrier that separates organic material from the inorganic environment, crucial for maintaining the internal conditions necessary for life processes.

Carbohydrates

A major molecular component of cells, serving as a primary source of energy and playing a role in cell structure. Examples include sugars and starches.

Lipids

A major molecular component of cells, including fats, oils, and waxes, that are essential for energy storage, cell membrane structure, and signaling.

Proteins

A major molecular component of cells, performing a vast array of functions, including catalyzing biochemical reactions, transporting molecules, and providing structural support.

Enzymes

Proteins that act as biological catalysts, accelerating biochemical reactions within cells, which are essential for life processes.

Nucleic acids

DNA and RNA, essential for storing and transmitting genetic information in cells. DNA contains the instructions for building proteins, while RNA helps carry out these instructions.

Amino acids

The building blocks of proteins, linked together to form polypeptide chains. There are 20 common types found in proteins, each with a unique chemical structure.

Handedness (of Chirality)

Refers to the property of chirality in molecules, where life on Earth predominantly utilizes left-handed amino acids in proteins and mostly right-handed carbohydrates, a unique characteristic of terrestrial biochemistry.

Eukaryotes

Complex cells characterized by a nucleus and other membrane-bound organelles. These are generally larger and more complex than prokaryotic cells.

Prokaryotes

Simple cells lacking a nucleus or other membrane-bound organelles. This group includes bacteria and archaea.

Super-kingdoms (or Domains)

The highest level of classification, dividing life into three categories based on chemical properties: Bacteria, Archaea, and Eukarya.

Tree of life

A diagram illustrating the evolutionary relationships between all living organisms on Earth, showing their common ancestry and diversification over time.

Universe

Modern astronomy reveals the vastness and age of the universe, influencing our understanding of our place within it.

Elements of life

The essential chemical elements found in life forms are also prevalent throughout the universe, observed in nebula clouds.

Physical laws

The same fundamental physical laws govern the entire universe, including Earth, implying a consistent set of principles underlies all cosmic phenomena.

Cosmic Address

Describes the hierarchical structure of our location in the cosmos, from our solar system within the Milky Way Galaxy to our galaxy's place in the Local Group and beyond, encompassing planets, moons, asteroids, and nebulae.

Planets

An astronomical body orbiting a star or stellar remnant, massive enough to be rounded by its own gravity and having cleared its orbit of other objects.

Moons

A natural satellite orbiting a planet, bound by gravity.

Asteroids

A minor planet, predominantly found in the inner Solar System, composed of rock and metal.

Comets

A small Solar System body made of ice, dust, and gas that, when near the Sun, heats up and releases gases in a process called outgassing, creating a visible atmosphere or tail.

Local Group

A group of galaxies that includes the Milky Way, consisting of more than 70 galaxies in total, which are part of larger galaxy clusters.

Superclusters

Vast regions where galaxies and clusters of galaxies are grouped together, forming large-scale structures with varying densities and voids in between.

Laniakea

The supercluster that contains the Milky Way, named 'Laniakea,' which means 'immense heaven' in Hawaiian.

Astronomical Unit (AU)

The average distance between Earth and the Sun, approximately 150 million kilometers, used as a unit of measurement in astronomy.

Lightyears

The distance that light travels in one year, approximately equal to 10 trillion kilometers, used to measure vast distances in the universe.

Alpha Centauri

A three-star system that is the closest to the Sun, located about 4.4 light-years away.

Orion Nebula

A star-forming region located in the Orion Constellation, approximately 1350 light-years from Earth/Sun, visible as the tip of Orion’s Sword.

Ordinary (Baryonic) Matter

Matter composed of protons, neutrons, and electrons, making up approximately 5\% of the Universe's content.

Dark Matter

A mysterious substance that makes up approximately 25\% of the Universe and plays a crucial role in the formation of galaxies.

Dark Energy

An enigmatic form of energy constituting about 70\% of the Universe, believed to be responsible for the accelerating expansion of the universe.

Big Bang

The prevailing cosmological model for the universe, describing its expansion from an extremely dense and hot state.

Early universe

The universe in its earliest stages was much smaller and hotter, characterized by the presence of Quark-Gluon Plasma, a state of matter made up of fundamental particles.

Cosmic Microwave Background (CMB)

The residual radiation from the Big Bang, observable in every direction of the universe, even in the coldest regions.

Nebular hypothesis

The theory that stars and planets form from the gravitational collapse of clouds of gas and dust.

Nuclear fusion

The process by which lighter elements, starting with hydrogen, are fused together at high temperatures and pressures to form heavier nuclei, releasing energy.

Supernova

The explosive death of massive stars, which release heavier elements into the universe.

Cosmic Calendar

A method of scaling the history of the universe to a single year to better comprehend the timing of significant events.

Observable Universe

The portion of the universe that we can observe, limited by the age of the universe and the distance light has traveled since the Big Bang.

Fine-Tuned Universe

The observation that the conditions in the universe are precisely suited for the formation of life, leading to discussions about the Anthropic Principle.

Anthropic Principle

The principle that the conditions in the universe are just right for the emergence of life.

Atoms

The basic units of matter, consisting of protons, neutrons, and electrons.

Molecules

Structures formed when two or more atoms are held together by chemical bonds.

Kinetic energy

The energy of motion.

Potential energy

Stored energy that has the potential to do work.

Radiative energy

Energy carried by light and other forms of electromagnetic radiation.

Electromagnetic wave

A form of energy that can travel through space, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Photons

Discrete packets of light energy.

Wavelength

The distance between successive crests of a wave, a characteristic property of light and other electromagnetic radiation.

Frequency

The number of crests of a wave that pass a point per unit time, a characteristic property of light and other electromagnetic radiation.

Spectroscopy

The analysis of light to identify the composition and properties of matter, providing a 'fingerprint' of atoms and molecules.

Doppler effect

The change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. Used to determine if an object is moving towards or away from us.

Extraterrestrial life

Life that may exist beyond Earth.

Universality of Physics, Chemistry, and Biology

The idea that the same physical laws, chemical principles, and biological processes operate throughout the universe.

Extrasolar planets

Planets that orbit stars other than our Sun, common throughout the galaxy.

Habitable worlds

Worlds with conditions suitable for life to exist.

SETI (Search for Extraterrestrial Intelligence)

An organized effort to search for signs of intelligent life beyond Earth, including the possibility of other civilizations conducting their own searches.

Astrobiology

The interdisciplinary study of the conditions necessary for the origin and ongoing existence of life in the universe.

Geocentric Model

An outdated cosmological model that placed Earth at the center of the universe.

Celestial Sphere

An imaginary sphere of gigantic radius with the earth located at its center, used to map celestial objects.

Epicycles

A circle within circles, used in the Ptolemaic model to explain the retrograde motion of planets.

Planet

Celestial bodies that wander across the sky relative to fixed stars, generally moving eastward.

Ptolemaic Model

The geocentric model of the universe developed by Ptolemy, incorporating epicycles to explain planetary motion.

Heliocentric Model

The model of the universe with the Sun at the center.

Stellar Parallax

The apparent shift in the position of a nearby star relative to distant objects as viewed from different points in Earth's orbit around the Sun.

Atomists

Ancient philosophers who believed that the world is formed by an infinite number of indivisible atoms, implying the existence of other worlds.

Aristotelians

Followers of Aristotle who adhered to a geocentric universe, believing that Earth is unique and the heavens are fundamentally different.

Ether or Quintessence

The fifth element, also known as quintessence, believed to make up the celestial realm.

Byzantine Empire

The eastern continuation of the Roman Empire, which preserved much of Greek and Roman knowledge during the Middle Ages.

Copernican Revolution

The shift in understanding the cosmos initiated by Copernicus, which moved Earth away from the center of the universe and replaced it with the Sun.

Kepler’s Laws of Planetary Motion

Laws describing the motion of planets, which