Astronomy Review

Comprehensive practice flashcards covering astronomy concepts including planetary motion, eclipses, celestial bodies, and the life cycle of stars.

Earth's Habitability

The moon helps make Earth more habitable by stabilizing the Earth's axial tilt.

Geocentric model

One of the two models of our solar system where Earth is at the center.

Heliocentric model

One of the two models of our solar system where the Sun is at the center.

Earth's Seasons

Caused by Earth's axis tilting as it revolves around the Sun, with each season lasting 3 months.

Length of a Day

Determined by the rotation of the Earth completing one turn on its axis, lasting 24 hours.

Phases of the Moon

Caused by the revolution of the moon around the Earth, taking $29.5\text{ days}$ to complete a cycle.

Tides

The rise and fall of the sea caused by the gravitational pull of the moon and sun.

Solar eclipse

An astronomical event that occurs during the New Moon phase when the moon passes between the Sun and Earth.

Lunar eclipse

An astronomical event that occurs during the Full Moon phase when the Earth's shadow covers the moon.

Umbra

The fully shaded inner region of a shadow cast by an opaque object during an eclipse.

Penumbra

The partially shaded outer region of the shadow cast during an eclipse.

Moon's Orbit Tilt

The moon's orbit around the Earth is tilted $5\text{ degrees}$, which is why solar and lunar eclipses are rare.

Terrestrial Planets

The four inner planets (Mercury, Venus, Earth, Mars) characterized by a rocky composition.

Gas Giants

The four outer planets (Jupiter, Saturn, Uranus, Neptune) characterized by a gaseous composition.

Asteroid belt

The region of the solar system located between the orbits of Mars and Jupiter.

Kuiper belt

The region of the solar system located beyond the orbit of Neptune.

Comets

Cosmic snowballs of frozen gases, rock, and dust.

Asteroids

Large, rocky or metallic bodies that orbit the Sun.

Meteoroids

Small rocky or metallic fragments traveling in space.

Meteors

A meteoroid that enters Earth's atmosphere and burns up.

Meteorites

A meteoroid that survives its passage through the atmosphere and hits the ground.

Exoplanets

A planet that orbits a star outside of the Solar System.

Star

A massive, luminous sphere of plasma.

Light Year

A measure of distance equivalent to approximately $9.5 \times 10^{12}\text{ km}$ ($9.5\text{ trillion km}$).

Nuclear Fusion

The process by which stars produce energy by fusing hydrogen into helium.

Red Star Properties

Stars with a temperature of approximately $3,500\text{ K}$ and low luminosity.

Yellow Star Properties

Stars with a temperature range of $5,000-6,000\text{ K}$ and medium luminosity.

Blue Star Properties

Stars with a temperature range of over $10,000-30,000\text{ K}$ and high luminosity.

HR Diagram

The Hertzsprung-Russell diagram which plots luminosity on the y-axis and average surface temperature on the x-axis.

Main Sequence Star

A stable star in the main stage of its life cycle.

Red Giant

A large, aging star that has expanded in size.

White Dwarf

A small, dense star that is the leftover core of a star that has exhausted its fuel.

Supernova

A powerful and luminous stellar explosion occurring at the end of a star's life.

Black Hole

A region of spacetime where gravity is so strong that nothing, including light, can escape.