Solar System Formation
What is the solar nebular theory?
The theory that the solar system formed from a large cloud of gas and dust that collapsed and eventually formed the Sun, planets, and other objects.
What shape does Kepler’s First Law state that planetary orbits have?
An ellipse
What primarily causes Earth’s ocean tides?
The gravitational pull of the Moon and the Sun, with the Moon having the greater effect.
What causes the different phases of the Moon as viewed from Earth?
As the Moon revolves around Earth, we see different portions of its sunlit half.
What are the four terrestrial planets?
Mercury, Venus, Earth, and Mars
What force caused the solar nebula to collapse and come together?
gravity
According to Kepler’s Second Law, when does a planet move fastest in its orbit?
When it is closest to the Sun.
What is the difference between a spring tide and a neap tide?
Spring tides have a greater tidal range, while neap tides have a smaller tidal range.
Approximately how long does it take the Moon to complete one cycle of phases?
About 29.5 days.
What is one major difference between terrestrial planets and gas/ice giants?
Terrestrial planets are smaller and rocky, while gas/ice giants are much larger and composed primarily of gases and/or ices.
-Distance
-Temperature
Describe what happened to the solar nebula as it collapsed and began to rotate.
It became smaller, denser, and flattened into a rotating disk, with most material moving toward the center.
Explain what Kepler’s Second Law tells us about the speed of a planet as its distance from the Sun changes.
A planet moves faster when it is closer to the Sun and slower when it is farther away.
During which two Moon phases do spring tides occur, and why?
New Moon and Full Moon. The Sun, Earth, and Moon are approximately aligned, causing their gravitational effects to work together.
If the Moon is positioned between Earth and the Sun, what phase would an observer on Earth see? Explain why.
New Moon. The illuminated side faces mostly toward the Sun, while the side facing Earth is mostly unilluminated.
Why are the terrestrial planets located closer to the Sun than the gas giants?
The inner solar system was hotter, so only materials with higher melting/condensation temperatures, such as rock and metal, could form planets there.
Explain how accretion contributed to the formation of planets.
Small particles collided and stuck together, gradually forming larger objects that eventually became planets.
Planet A takes 2 years to orbit the Sun, while Planet B takes 8 years. Which planet has the greater average distance from the Sun? Explain how you know.
Planet B. According to Kepler’s Third Law, planets with longer orbital periods have larger average orbital distances.
Explain why neap tides have a smaller difference between high and low tide than spring tides.
During first and third quarter Moon, the Sun and Moon are positioned approximately at right angles relative to Earth, so their gravitational effects partially counteract each other.
A student observes a full Moon. Describe the relative positions of the Sun, Earth, and Moon.
Earth is approximately between the Sun and Moon, with the Moon opposite the Sun from Earth’s perspective.
Compare the orbital periods of an inner planet and an outer planet. What general pattern would you expect, and why?
Outer planets have longer orbital periods because they travel along larger orbits and are farther from the Sun.
A model of the early solar system shows that temperatures were much hotter near the center of the nebula and cooler farther away. Use the model to explain why the inner planets became mostly rocky while the outer planets became much larger and richer in gases and ices.
The inner solar system was too hot for many gases and ices to condense, so rock and metal remained and formed the terrestrial planets. Farther from the Sun, temperatures were cooler, allowing ices and gases to accumulate, producing larger planets.
A planet’s distance from the Sun changes as it travels along its elliptical orbit. Predict how its orbital speed changes throughout the orbit and explain your prediction using Kepler’s laws.
The planet speeds up as it approaches the Sun and slows down as it moves farther away. This applies Kepler’s Second Law. Its elliptical orbit means its distance from the Sun changes.
A coastal community experiences an unusually large difference between high and low tide. Describe the positions of the Sun, Earth, and Moon that would most likely produce this observation and explain why those positions create larger tides.
The Sun, Earth, and Moon are approximately aligned, producing a spring tide. The gravitational pulls of the Sun and Moon reinforce one another, producing a larger tidal range.
A student records the Moon’s phases over several weeks and notices a repeating pattern. Explain how the Moon’s revolution around Earth produces this repeating pattern.
As the Moon revolves around Earth, its position relative to the Sun and Earth changes. This changes how much of its illuminated side we can see, creating the repeating sequence of Moon phases.
Scientists discover a newly identified planet with a long orbital period and a large average distance from its star. Based on patterns in our solar system, what characteristics would you predict this planet might have? Explain your reasoning.
It would likely be a large planet, potentially a gas or ice giant. Its greater distance and long orbital period are consistent with the outer planets in our solar system.