Comprehensive Astronomy Study Guide | Solar System, Stars & Galaxies 2026/2027
What is our cosmic address? Earth → Solar System → Milky Way Galaxy → Local
Group → Virgo Supercluster (Laniakea) → Universe
What do we use to measure distances Astronomical Units (AU), light-years for stars, and
in the Solar System? parsecs/Mpc for galaxies.
What is a light-year? The distance light travels in one year.
How does looking farther away relate Looking farther away means looking farther back in
to time? time.
What is Earth's rotation? Earth spins every 24 hours.
What is Earth's orbit? Earth goes around the Sun every year.
What is precession? Earth's axis slowly changes direction over about
26,000 years.
What are constellations? Patterns of stars used to divide the sky into regions.
Why do stars appear to rise in the Because Earth rotates west to east.
East and set in the West?
What are circumpolar stars? Stars near the North or South Celestial Pole that
never set below the horizon.
What does the angle between Polaris Your latitude in the Northern Hemisphere.
and your horizon indicate?
, Comprehensive Astronomy Study Guide | Solar System, Stars & Galaxies 2026/2027
What is the ecliptic? The Sun's apparent path across the sky.
How does the ecliptic relate to the The zodiac constellations lie along the ecliptic.
zodiac?
What is a sidereal day? Earth's rotation relative to the stars (23 hr 56 min).
What is a solar day? Rotation relative to the Sun (24 hr).
Why do we have seasons? Because Earth's axis is tilted 23.5°, not because
Earth is closer to the Sun.
How does the position of the Sun Higher in summer, lower in winter.
change between seasons?
Why do we see phases of the Moon? Because we see different portions of the Moon's
sunlit side.
What is the difference between the Sidereal = Moon orbits Earth relative to stars (27.3
Synodic and Sidereal period of the days); Synodic = one full phase cycle (29.5 days).
Moon?
When do lunar eclipses occur? When Earth is between the Sun and Moon.
When do solar eclipses occur? When Moon is between the Sun and Earth.
Why don't eclipses happen all the The Moon's orbit is tilted about 5° to Earth's orbit.
time?
What is our cosmic address? Earth → Solar System → Milky Way Galaxy → Local
Group → Virgo Supercluster (Laniakea) → Universe
What do we use to measure distances Astronomical Units (AU), light-years for stars, and
in the Solar System? parsecs/Mpc for galaxies.
What is a light-year? The distance light travels in one year.
How does looking farther away relate Looking farther away means looking farther back in
to time? time.
What is Earth's rotation? Earth spins every 24 hours.
What is Earth's orbit? Earth goes around the Sun every year.
What is precession? Earth's axis slowly changes direction over about
26,000 years.
What are constellations? Patterns of stars used to divide the sky into regions.
Why do stars appear to rise in the Because Earth rotates west to east.
East and set in the West?
What are circumpolar stars? Stars near the North or South Celestial Pole that
never set below the horizon.
What does the angle between Polaris Your latitude in the Northern Hemisphere.
and your horizon indicate?
, Comprehensive Astronomy Study Guide | Solar System, Stars & Galaxies 2026/2027
What is the ecliptic? The Sun's apparent path across the sky.
How does the ecliptic relate to the The zodiac constellations lie along the ecliptic.
zodiac?
What is a sidereal day? Earth's rotation relative to the stars (23 hr 56 min).
What is a solar day? Rotation relative to the Sun (24 hr).
Why do we have seasons? Because Earth's axis is tilted 23.5°, not because
Earth is closer to the Sun.
How does the position of the Sun Higher in summer, lower in winter.
change between seasons?
Why do we see phases of the Moon? Because we see different portions of the Moon's
sunlit side.
What is the difference between the Sidereal = Moon orbits Earth relative to stars (27.3
Synodic and Sidereal period of the days); Synodic = one full phase cycle (29.5 days).
Moon?
When do lunar eclipses occur? When Earth is between the Sun and Moon.
When do solar eclipses occur? When Moon is between the Sun and Earth.
Why don't eclipses happen all the The Moon's orbit is tilted about 5° to Earth's orbit.
time?
