Histories of Astronomy Lecture Notes

These flashcards cover key vocabulary and concepts related to the lectures on the history of astronomy, solar system discoveries, and the search for extraterrestrial life.

William Herschel

An astronomer known for building the largest telescope of his time and discovering the planet Uranus.

Telescopes

Instruments that magnify distant objects, particularly used by Herschel to observe planets.

Uranus

The first planet discovered beyond Saturn, notable for its unique axial tilt and nearly circular orbit.

Caroline Herschel

William Herschel's sister who contributed to his astronomical discoveries through observations and data analysis.

Bode’s Law

A mathematical formula predicting the distances of planets from the Sun; used in the search for unknown planets.

Ceres

The largest object in the asteroid belt, reclassified from a planet to a dwarf planet.

Asteroid Belt

A region of space between Mars and Jupiter populated by numerous small, rocky bodies.

Neptune

A planet discovered based on the irregular orbit of Uranus, indicating the presence of another large planet.

Ice Giants

Classification for Uranus and Neptune, which have compositions significantly different from gas giants.

Retrograde Orbit

An orbit in which a moon orbits in the opposite direction of its planet's rotation, as seen with Neptune's moon Triton.

Nebular Hypothesis

The modern theory that explains the formation of the solar system from a giant cloud of gas and dust.

Gas Giants

The four planets beyond Mars (Jupiter, Saturn, Uranus, and Neptune) characterized by their large size and gaseous composition.

Doppler Effect

The change in frequency and wavelength of light from an object in motion, used in astronomy to determine the motion of stars.

Spectroscopy

A technique used to analyze light from stars and other celestial objects to identify their chemical compositions.

Light Year

The distance light travels in one year, commonly used to measure astronomical distances.

Quasar

A highly luminous object powered by a supermassive black hole at the center of a distant galaxy.

SETI

Search for Extraterrestrial Intelligence; an initiative to find signals or proof of life beyond Earth.

Exoplanets

Planets located outside our solar system, often discovered through methods like the Doppler-Wobble.

Habitable Zone

The region around a star where conditions are suitable for life as we know it, particularly for liquid water.

Dark Matter

An unseen substance that makes up a significant portion of the universe's mass, detected through gravitational effects.

Electromagnetic Spectrum

The range of all types of light, from gamma rays to radio waves, used in various astronomical observations.

Hubble’s Law

A law stating that the farther away a galaxy is, the faster it is moving away from us, indicating the expansion of the universe.