Ast 1001: Introductory Astronomy - Chapters 1-6 Review

Flashcards covering key vocabulary from Chapters 1, 5, 6, 2, 3, and 4 of the Ast 1001 lecture notes, focusing on the universe, light, the solar system, and orbital motion.

Nebulae

The birth and death sites of stars within the filamentary web of the universe.

Supernova

The explosion of super massive stars that occur when they run out of energy, facilitating the formation of new stars.

Cosmic calendar

A scale that compresses the entire history of the universe into a single year, where life on Earth appears on September 22 and modern humans appear at 11:58 PM on December 31.

1 AU (Astronomical Unit)

The average distance between the Earth and the Sun, equal to approximately $150$ million km.

Hubble's Discovery

The observation that all galaxies outside our local group are moving away from us, and the more distant a galaxy is, the faster it races away.

Photon

A particle of light characterized by a specific wavelength and frequency; its energy is directly related to its frequency.

Isotope

Atoms with the same number of protons but a different number of neutrons.

Emission line spectrum

A spectrum consisting of specific wavelengths of light produced by a low-density warm gas, appearing as upward peaks.

Absorption line spectrum

A continuous spectrum with sharp downward points created when a cloud of gas absorbs specific wavelengths of light.

Blueshift

The shortening of the wavelength of light emitted from an object moving toward the observer.

Redshift

The lengthening of the wavelength of light emitted from an object moving away from the observer.

Refracting telescope

A telescope design that primarily uses lenses to collect and focus light.

Reflecting telescope

A telescope design that uses mirrors; most modern research telescopes are of this type.

Interferometry

A technique allowing two or more small telescopes to work together to achieve the angular resolution of a much larger telescope.

Adaptive optics

A technology for ground-based telescopes where rapid changes in mirror shape compensate for atmospheric turbulence.

Gravitational waves

Ripples in the fabric of space-time that serve as cosmic messengers.

Runaway greenhouse effect

The process responsible for the hellish conditions on Venus, making it hotter than Mercury at $425^{\circ}C$.

Galilean moons

The four largest moons of Jupiter: Io (active volcanoes), Europa (possible subsurface ocean), Ganymede (largest in solar system), and Callisto (cratered ice ball).

Nebular theory

The scientific theory that the solar system formed from the contraction of a giant cloud of interstellar gas.

Frost line

The boundary in the solar nebula; inside it, it was too hot for hydrogen compounds to condense, while outside it, it was cold enough for ices to form.

Planetesimals

Small particles of rock, metal, or ice that built up through collisions and eventually accreted into planets.

Radiometric dating

A method of determining the age of rocks by analyzing the proportions of various atoms and isotopes, such as the decay of radioactive nuclei.

Zenith

The point in the local sky directly overhead an observer.

Meridian

An imaginary line passing through the zenith and connecting the North and South points on the horizon.

Ecliptic

The apparent path the Sun and planets travel through the celestial sphere across the sky.

Sidereal day

Earth's actual rotation period, which lasts $23$ hours and $56$ minutes.

Synchronous rotation

The phenomenon where the Moon rotates exactly once with each orbit, keeping only one side visible from Earth.

Apparent retrograde motion

The phenomenon where a planet appears to move westward relative to the stars instead of its usual eastward drift.

Kepler's First Law

The law stating that the orbit of each planet around the Sun is an ellipse with the Sun at one focus.

Kepler's Second Law

The law stating that a planet sweeps out equal areas in equal times, moving faster when nearer to the Sun.

Acceleration of gravity ($g$)

The rate at which falling objects accelerate on Earth, approximately $10\,m/s^2$, ignoring air resistance.

Conservation of angular momentum

A principle explaining why objects like the Earth continue to rotate and orbit indefinitely, and why objects rotate faster as they shrink in radius.

Escape velocity

The speed an object must reach to gain enough orbital energy to break free from a gravitational bond.

Tidal friction

The force that gradually slows Earth's rotation and has caused the Moon to lock into synchronous rotation.