Sun & Earth Interaction
What causes the seasons on Earth?
Earth's axial tilt causes sunlight angle and day length to change through the year → seasons.
What phase is the Moon when it is between the Sun and Earth?
New moon.
What is the name of our galaxy?
The Milky Way.
Which color star is hotter: red or blue?
Blue stars are hotter than red stars.
Name one property that makes Earth different from most other planets in the Solar System.
Earth has liquid water and a breathable atmosphere.
Explain how the Sun's gravity affects Earth in one sentence.
The Sun's gravity keeps Earth in orbit around it
What causes ocean tides on Earth?
Gravitational pull of the Moon (and Sun) on Earth’s oceans causes tides.
Put these in order from smallest to largest: solar system, planet, galaxy, universe.
planet, solar system, galaxy, universe.
Define apparent magnitude in one sentence.
Apparent magnitude is how bright a star appears from Earth.
Two planets have similar sizes, but one has a thick, dense atmosphere and the other has a very thin atmosphere. Which one has a hotter surface temperature, or do we need more information to know for sure?
Otherwise if similar distance then the one with thicker atmosphere will be hotter because it traps in the heat.
Name two ways the angle of sunlight changes between summer and winter.
(1) Sunlight hits more directly in summer; (2) sunlight spreads out more in winter; also day length differences.
Explain why a total lunar eclipse can only occur during a full moon
Because the Earth must be between Sun and Moon so Earth's shadow can fall on the Moon.
Explain what is used to measure distances between stars rather than kilometers.
Light-years
How does luminosity differ from apparent brightness?
Luminosity (absolute brightness) is total energy output; apparent brightness depends on luminosity and distance.
Which planet in our solar system has the fastest orbital speed around the Sun and why?
Mercury (or inner planets generally) has higher orbital speed; closer to the Sun means stronger gravity and faster orbital velocity (Kepler's laws).
Predict what would happen to Earth’s seasons if the axial tilt increased to 45 degrees.
Seasons would become more extreme: hotter summers, colder winters, larger climate shifts
Describe how the Moon’s phase relates to its position relative to Earth and Sun (give two examples).
Example: New moon = Moon between Sun and Earth (near side dark); Full moon = Earth between Sun and Moon (near side lit).
Describe one compositional difference between planets and stars.
Planets are not self-luminous and are made of rock/gas; stars produce energy by nuclear fusion and emit light.
Given two stars with the same apparent magnitude, what additional information do astronomers need to determine which has greater luminosity?
Distance to each star (so you can convert apparent magnitude to luminosity)
Explain how orbital speed relates to distance from the Sun using an example planet closer vs. farther from the Sun.
Think about the lab we did!
Closer planets (e.g., Mercury) orbit faster; farther planets (e.g., Neptune) orbit slower (Kepler’s laws).
Explain how Earth's tilt and orbit combine so that when the Northern Hemisphere has longer days, the Southern Hemisphere has shorter days.
When the Northern Hemisphere tilts toward the Sun it receives more direct light and longer days; the Southern Hemisphere tilts away, receiving less direct light and shorter days.
Compare and contrast spring tides and neap tides including Moon–Sun alignment
Spring tides: Sun–Moon–Earth aligned → higher high tides and lower low tides. Neap tides: Sun–Moon at right angle → smaller tidal range.
You observe a faint object that moves noticeably against the background stars from night to night. Explain why this observation suggests the object is inside our Solar System rather than a distant star or galaxy
Because objects in our Solar System orbit the Sun and are relatively close, they change position noticeably against the background stars over days or weeks.
Explain how a star's temperature, size, and luminosity are related on the Hertzsprung–Russell diagram (briefly describe one typical relationship).
On the H–R diagram, hotter stars tend to be more luminous; for main-sequence stars, greater temperature correlates with greater luminosity and typically larger size.
Two planets have the same radius, but one is much larger in mass than the other. Compare the surface gravity on these two planets and explain why it differs
Mass depends on distance and mass, so the heavier planet has higher gravity