Lecture Notes Review

Vocabulary flashcards for review.

Miller-Urey experiment

A landmark experiment demonstrating that organic building blocks of life, such as amino acids, can form easily and naturally under conditions thought to resemble early Earth.

RNA World

A hypothesis suggesting that RNA, rather than DNA, was the first hereditary molecule of life, capable of both storing genetic information and catalyzing chemical reactions.

RNA

A simpler molecule than DNA that can hold hereditary information and catalyze chemical reactions, making it a suitable candidate for the first genetic material.

Ribozymes

RNA molecules that can catalyze chemical reactions, providing a mechanism for early life to perform essential functions without proteins.

Clay catalysis

The role of clay minerals in facilitating the natural formation of RNA strands by providing a surface for molecules to concentrate and polymerize.

Lipid pre-cells

The formation of vesicles spontaneously under conditions similar to those where RNA forms, providing a means of compartmentalizing and concentrating molecules.

Plausible scenario for origin of life

A sequence of events where organic molecules become abundant, RNA production is catalyzed by clay, pre-cells act as factories, RNA evolves, and DNA-based life emerges.

Panspermia

The hypothesis that life originated elsewhere in the universe and migrated to Earth, possibly via meteorites or other cosmic debris.

Martian meteorites

Examples of material blasted from one world to others by impacts, supporting the plausibility of panspermia.

Extraterrestrial life

Life beyond Earth, the search for which drives much of astrobiology.

Universality of Physics, Chemistry, and Biology

The principle that the same physical laws operate on Earth as in the rest of the universe, allowing us to apply our knowledge of science to the search for life elsewhere.

Extrasolar planets

Planets common around other stars, increasing probability of another life-sustaining planet.

SETI

An acronym for the Search for Extraterrestrial Intelligence, which involves listening for signals from alien civilizations.

Astrobiology

The study of the possibility of life beyond Earth, encompassing various scientific disciplines such as biology, chemistry, and astronomy.

Geocentric Model

An Earth-centered model of the universe, which prevailed in ancient times and placed Earth at the center of all celestial motion.

Celestial Sphere

An ancient concept proposed by Anaximander, representing the sky as a giant, hollow sphere with stars embedded in it, rotating around Earth.

Epicycles

A component of the geocentric Ptolemaic model, representing a circle within a circle used to explain the retrograde motion of planets.

Planet

Derived from the Greek word for 'wanderer,' referring to celestial bodies that appeared to move across the sky relative to the fixed stars.

Ptolemaic Model

A geocentric model of the universe developed by Ptolemy, featuring epicycles and deferents to explain the complex motions of celestial objects.

Stellar Parallax

The apparent shift in the position of a nearby star relative to distant stars as Earth orbits the Sun, providing evidence that stars lie at different distances.

Heliocentric Model

A Sun-centered model of the universe, which places the Sun at the center of the solar system and has Earth and other planets orbiting around it.

Atomists

Ancient philosophers who believed that the world is formed by an infinite number of indivisible atoms, laying the groundwork for modern atomic theory.

Aristotelians

Adherents to Aristotle's philosophy, who believed that all Earth matter must fall to the center of the universe, influencing scientific thought for centuries.

Copernican Revolution

A paradigm shift initiated by Nicholas Copernicus (1473 - 1543) with the proposal of a heliocentric model of the universe.

Tycho Brahe (1546 - 1601)

A Danish astronomer who built the largest naked-eye observatory, using giant protractors to make highly accurate measurements of celestial objects.

Johannes Kepler (1571 - 1630)

A German astronomer and mathematician who formulated the laws of planetary motion based on Tycho Brahe's observations.

Kepler’s 1st Law of Planetary Motion

The law stating that each planet orbits the Sun in an ellipse, with the Sun at one focus of the ellipse.

Perihelion

The point in a planet's orbit where it is closest to the Sun.

Aphelion

The point in a planet's orbit where it is farthest from the Sun.

Semi-major axis

One half of the longest diameter across an ellipse. It is effectively the radius of the ellipse and goes from the center to the edge of the ellipse.

Eccentricity

A parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a perfect circle, and values 0 < x < 1 are ellipses.

e = (center-to-focus distance) / (semi-major axis)

The formula for calculating the eccentricity of an ellipse. e = \frac{c}{a}, where e is eccentricity, c is the center-to-focus distance, and a is the semi-major axis.

Earth cannot move

An argument against the heliocentric model, suggesting that if Earth moved, objects would be left behind due to inertia.

Supernova explosion

An observation that demonstrated comets lie beyond the moon, indicating that they are heavenly objects rather than earthly phenomena.

Galileo Galilei (1564 - 1642)

An Italian mathematician and astronomer who provided observational evidence supporting the heliocentric model through his use of the telescope.

Newton’s 1st Law of Motion

Also known as the Law of Inertia, stating that an object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by a force.

Newton - The Revolution Concludes

Newton's laws of motion and gravity provided a physical explanation for Kepler’s Laws, describing the motion of the planets.

Issac Newton (1642 - 1727)

An English physicist and mathematician who developed the laws of motion and universal gravitation, revolutionizing our understanding of the physical world.

Newton’s Law of Universal Gravitation

The law stating that every particle attracts every other particle in the universe with a force proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

Fact of Gravity

The observed phenomenon that objects fall to the ground due to the force of gravity.

Aristotle’s Theory of Gravity

The incorrect assertion that heavier objects fall to the ground faster than lighter objects, which was disproven by later experiments.

Einstein’s General Theory of Relativity

A theory that describes gravity not as a force but as a curvature of spacetime caused by mass and energy.

Gravitational Well

A conceptual model representing the gravitational field around a massive object, often visualized as a bowling ball on a mattress.

Summer Solstice, Winter Solstice, Equinox

Key seasonal markers related to the path of the Sun in the sky and used to define the calendar.

Radical Change in Human Perspective

The shift in understanding of the universe where Earth shifted its central role and was understood to be just another planet orbiting the sun.