Astronomy Study Guide Flashcards

Vocabulary flashcards covering key astronomical concepts, measurements, celestial bodies, and planetary science from the lecture notes.

Astronomical Unit (AU)

The distance from the earth to the sun, equal to $150\text{ million km}$.

Light year

The distance that light travels over $365\text{ days}$.

Solar system

The system composed of our sun and the planets.

Jupiter

The biggest planet in our solar system.

Mercury

The smallest planet in our solar system and the planet closest to the sun.

Mars

The planet closest to Earth.

Phases of the moon

What the moon looks like when viewed from the earth's surface as it reflects light from the sun, with $\frac{1}{2}$ in darkness and $\frac{1}{2}$ illuminated.

Lunar month

The time it takes for the moon to orbit the earth once, lasting $27\text{ days}$.

Solar eclipse

An event occurring during a new moon when the sun, moon, and earth line up in the same plane and light is blocked.

Lunar eclipse

An event occurring when the moon is full and the sun, moon, and earth line up in the same plane and light is blocked.

Umbra and penumbra

The names of the shadows cast during eclipses.

Axial tilt

The tilt of the earth as it spins on its axis and orbits the sun, causing seasonal variations in day length and direct sunlight.

Temperate regions

Areas on earth, such as NZ or Japan, that experience $4$ seasons, unlike the equator and poles which experience only $2$ seasons.

Constellations

Apparent clusters or groups of stars forming shapes in the night sky, useful for navigation, planting crops and farming, and fortune telling.

Star colours

Colors indicating star temperature, where blue is hot, yellow is medium temperature, and red/orange is colder temperature.

Apparent brightness

The brightness of a star based on its distance away from us, how big it is, and how hot it is.

Nuclear fusion

The process undergone by stars in which they fuse atoms together.

Star lifespan

The total lifespan of stars, ranging from $1\text{ million years}$ for big stars to $30\text{ billion years}$ for small stars.

The Sun

Our central star, which is $4.6\text{ billion years}$ old and will live for a total of $10\text{ billion years}$.