Astronomy Basics Quiz

Study Notes

Constellation: Defined region of the sky containing a specific group of stars.
Asterism: Informal grouping of stars not officially recognized as a constellation.
Geocentric Model: Earth is at the center of the universe.
Heliocentric Model: Sun is at the center of the solar system.
Local Sky: The half of the celestial sphere visible from a specific location above the horizon.
Zenith: The point in the sky directly above an observer.
Polaris: Known as the North Star, significant for navigation.
Circumpolar Stars: Stars that do not rise or set but remain visible all night.
Celestial Sphere: An imaginary sphere encompassing the Earth to map stars and celestial objects.

Ecliptic: The apparent path of the Sun against the backdrop of stars over a year.
Altitude: Measurement of an object’s height above the horizon.
Azimuth: Direction or angle from a specific cardinal point.

Prograde Motion: Planets move towards the East in the sky.
Retrograde Motion: Planets appear to move towards the West, creating an optical illusion.
Claudius Ptolemy struggled to explain retrograde motion in the geocentric setup.
Nicolaus Copernicus developed a heliocentric model successfully accounting for retrograde motion.
Galileo Galilei contributed evidence for the heliocentric model by discovering Jupiter's moons and phases of Venus.

Orbital Direction: All planets orbit the Sun counterclockwise.
Inner Planets (Terrestrial): Smaller, rocky, few moons, no rings.
Outer Planets (Jovian): Larger, gaseous, many moons, possess ring systems.
Asteroids and Comets: Numerous rocky asteroids and icy comets exist throughout the solar system.

Oort Cloud: Home to long-period comets located in a distant spherical shell surrounding the solar system.
Asteroid Belt: Located between Mars and Jupiter, containing rocky asteroids.
Kuiper Belt: Region featuring icy comets located beyond Neptune.

Meteoroid: Small fragment derived from asteroids or comets.
Meteor: A meteoroid that enters the Earth’s atmosphere and creates a bright streak.
Meteorite: A meteoroid that survives passage through the atmosphere and impacts the Earth's surface.

Solar Nebula Theory: Explains solar system formation as gas collapses, heats, spins faster, and flattens into a disk.

Mercury: Smallest planet, lacks moons, surface resembles the Moon.
Venus: Earth-sized, clockwise rotation, no moons, has the highest surface temperature.
Earth: Largest terrestrial planet, suitable for life.
Mars: Known for its rusty surface due to iron oxide.
Jupiter: Features the Great Red Spot and has four large moons.
Saturn: Composed mainly of hydrogen and helium; rings are not solid structures.
Uranus: Ice giant that uniquely rotates on its side.
Neptune: Another ice giant, the first planet discovered using a telescope.
Pluto: Shares an orbital zone with comets in the Kuiper Belt, classified as a dwarf planet.