Understanding Cosmic Features and Phenomena

These flashcards cover fundamental concepts related to the structure of the universe, the nature of celestial bodies, and key astronomical phenomena.

Geocentric

A model in which the Earth is at the center of the universe, and all celestial bodies, including the moon, orbit around it.

Heliocentric

A model in which the Sun is at the center of the solar system, and the planets, including Earth, orbit around it.

Cepheid variables

A type of pulsating star that changes brightness, used to measure cosmic distances.

Doppler effect

The apparent change in the frequency of sound or light waves due to the motion of the source relative to the observer.

Redshift

A phenomenon where light from objects moving away from the observer is shifted towards the red end of the spectrum.

Universe

All of space and time, including all matter and energy, galaxies, stars, planets, and the cosmic background.

Milky Way Galaxy

Our galaxy, which contains billions of stars, including our Sun, and is named for its appearance of a milky band of light.

Luminosity

The intrinsic brightness of a celestial object, often used to determine distance from Earth.

Cosmic expansion

The observation that the universe is expanding, with galaxies moving away from each other over time.

Astronomical spectrum

The range of light wavelengths emitted by celestial bodies, observed to determine their composition and motion.