Questions and Answers
Rank the following items according to their size (diameter) from largest to smallest:
Universe = Largest Local Supercluster = Second Largest Local Group = Third Largest Milky Way Galaxy = Fourth Largest Solar System = Fifth Largest Sun = Sixth Largest Jupiter = Seventh Largest Earth = Smallest
Rank the following items that describe distances from longest distance (top) to shortest distance (bottom):
Distance from Milky Way Galaxy to the Andromeda Galaxy = Longest Distance from the Sun to the center of the Milky Way Galaxy = Second Longest Distance from Earth to Alpha Centauri = Third Longest One light year = Fourth Longest Distance across our solar system (to Neptune) = Fifth Longest Average distance from Earth to the Sun, one astronomical unit = Shortest
According to current scientific estimates, when did the Big Bang occur?
about 14 billion years ago
On the Cosmic Calendar, about when did Earth form?
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On the Cosmic Calendar, about when did life arise on Earth?
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On the Cosmic Calendar, about when did early humans first walk on Earth?
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An astronomical unit is?
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The star Betelgeuse is about 600 light-years away. If it explodes tonight, we won't know about it until?
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Could we see a galaxy that is 50 billion light-years away?
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Which of the following correctly lists our 'cosmic address' from small to large?
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If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then?
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The total number of stars in the observable universe is roughly equivalent to:
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If stars existed but galaxies did not, we would not exist because we are made of material that required recycling in galaxies.
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The age of our solar system is about?
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When we say the universe is expanding, we mean that?
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The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that?
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In San Diego, California, where does the north celestial pole appear in your sky?
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Two stars that are in the same constellation may actually be very far away from each other.
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The North Celestial Pole is 35 degrees above your northern horizon. This tells you that you are at?
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Beijing and Philadelphia have about the same latitude but very different longitudes. Therefore, tonight's night sky in these two places?
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In winter, Earth's axis points toward the star Polaris. In spring?
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When it is summer in Australia, the season in the United States is winter.
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If the Sun rises precisely due east, it must be the day of either the spring or fall equinox.
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The fact that we always see the same face of the Moon tells us that?
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A week after a full moon, the Moon's phase is?
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If there is going to be a total lunar eclipse tonight, then you know that?
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When we see Saturn going through a period of apparent retrograde motion, it means?
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Based on what you have learned from your rankings in Parts A and B, which statement best describes how variation in the Earth-Sun distance affects the seasons?
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What is the cause of the seasons?
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In the Greek geocentric model, the retrograde motion of a planet occurs when?
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Which of the following was not a major advantage of Copernicus's Sun-centered model over the Ptolemaic model?
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When we say that a planet has a highly eccentric orbit, we mean that?
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Earth is closer to the Sun in January than in July. Therefore, according to Kepler's second law, Earth travels fast in its orbit around the Sun in January than in July.
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According to Kepler's third law:
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Tycho Brahe's contribution to astronomy included:
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Galileo's contribution to astronomy included:
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Newton's First Law of Motion:
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Newton's Second Law of Motion:
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Newton's Third Law of Motion states:
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Conservation of angular momentum is expressed as:
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Identify the basic types of energy:
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Thermal energy vs temperature:
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Application of Gravitational Potential Energy in Astronomy:
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The Universal Law of Gravitation is expressed as:
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Newton's version of Kepler's Third Law states:
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How does gravity cause tides?
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As shown in the video, Earth has two tidal bulges at all times. Approximately where are these bulges located?
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Most people are familiar with the rise and fall of ocean tides. Do tides also affect land?
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Any particular location on Earth experiences?
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One tidal bulge faces toward the Moon because that is where the gravitational attraction between Earth and the Moon is strongest. Why is there also a second tidal bulge?
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Compared to red light, blue light has?
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Why is a sunflower yellow?
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Radio waves are?
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Compared to an atom as a whole, an atomic nucleus is?
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The set of spectral lines that we see in a star's spectrum depends on the star's?
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A star whose spectrum peaks in the infrared is?
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If a spectral line appears at a wavelength of 321 nm in the laboratory but at 328 nm in the spectrum of a distant object, we say that the object's spectrum is?
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How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?
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The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is?
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What does the wavelength of the peak labeled 6 tell us about Mars?
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Which properties can we infer simply by looking at the spectrum of a star or of a planet's atmosphere?
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For an object's radial speed (toward or away from us) to be measured with a Doppler shift, what must we be able to see in the object's spectrum?
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Remember that the Doppler shift measures motion only toward or away from you. What does this imply about the true speed of an object?
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Study Notes
Size Comparison in the Universe
- Largest to smallest: Universe, Local Supercluster, Local Group, Milky Way Galaxy, Solar System, Sun, Jupiter, Earth.
Distance Rankings
- Longest to shortest distances: Milky Way to Andromeda Galaxy, Sun to Milky Way center, Earth to Alpha Centauri, one light year, solar system distance to Neptune, one astronomical unit (average distance from Earth to the Sun).
Big Bang Timeline
- The Big Bang occurred approximately 14 billion years ago.
Cosmic Calendar Insights
- Earth formed in early September on the Cosmic calendar.
- Life arose on Earth also in September on the Cosmic calendar.
- Early humans first walked on Earth just hours before midnight on December 31.
Astronomical Unit Definition
- An astronomical unit (AU) is defined as Earth's average distance from the Sun.
Betelgeuse and Distance
- Betelgeuse is 600 light-years away; its explosion would not be known until 600 years later.
Observable Universe Limits
- A galaxy 50 billion light-years away cannot be seen, as it exceeds the observable universe boundaries.
Cosmic Address
- Cosmic address from small to large: Earth, Solar System, Milky Way Galaxy, Local Group, Local Supercluster, Universe.
Scale of Solar System
- If the solar system is scaled for walking to Pluto in minutes, planets would be marble-sized, with nearest stars thousands of miles away.
Stars in the Universe
- The observable universe contains roughly the same number of stars as grains of sand on all Earth’s beaches.
Recycling of Stars
- Existence of stars is essential for the recycling of material required for our existence within galaxies.
Solar System Age
- The solar system is about one-third the age of the universe.
Universe Expansion
- The universe is expanding, with the average distance between galaxies increasing over time.
- Nearly all galaxies moving away supports the conclusion that the universe is expanding.
Celestial Navigation
- In San Diego, the north celestial pole is 32 degrees above the northern horizon.
- Two stars in the same constellation can be far apart in space.
Latitude and Longitude Implications
- North celestial pole altitude indicates latitude: 35 degrees North.
- Beijing and Philadelphia share similar latitudes but differ in longitudes; their night skies will appear similar.
Seasonal Changes and Earth's Axis
- Earth's axis points toward Polaris during winter and spring.
- Summer in Australia corresponds to winter in the United States.
Equinox Indicator
- Sunrise due east indicates either the spring or fall equinox.
Moon Phases and Eclipses
- The Moon's rotation period aligns with its orbital period, causing us to always see the same face.
- A week after full moon, the Moon is in its third quarter.
- A total lunar eclipse occurs during the full moon phase.
Planetary Motion
- Apparent retrograde motion in Saturn occurs when Earth passes it in orbit.
Earth-Sun Distance and Seasons
- The variation in Earth-Sun distance has minimal effect on seasonal changes.
- Seasons are primarily caused by the tilt of Earth's axis.
Retrograde Motion in Geocentric Model
- Retrograde motion in the Greek geocentric model occurs when a planet appears to move backward in its orbit around Earth.
Kepler's Laws
- Copernicus's model improved, but did not significantly improve predictions of planetary positions compared to the Ptolemaic model.
- A planet with a highly eccentric orbit varies in distance to the Sun.
- Earth travels faster around the Sun in January than in July because it is closer in that month.
Tycho Brahe and Galileo's Contributions
- Tycho Brahe collected data that facilitated Kepler's laws of planetary motion.
- Galileo observed and experimented, countering objections to the Sun-centered model.
Newton’s Laws of Motion
- First Law: Objects maintain constant velocity unless acted upon by a net force.
- Second Law: Force equals mass times acceleration (F = ma).
- Third Law: Every action has an equal and opposite reaction.
Angular Momentum and Energy Types
- Conservation of angular momentum is represented as mvr.
- Basic energy types include kinetic energy, radiative energy, and potential energy.
Understanding Temperature and Thermal Energy
- Thermal energy is the total kinetic energy of particles; temperature is the average kinetic energy.
Gravitational Potential Energy in Astronomy
- A large gas cloud possesses more gravitational potential energy when spread out than when contracted.
Universal Law of Gravitation
- The gravitational force formula: Fg = GM1M2/d^2.
Newton’s Third Law Application
- From Kepler's third law, a small object's orbital period and radius can determine the mass of a larger object.
Tides and Gravitational Effects
- Tides result from Earth being stretched due to the Moon's gravitational pull.
- Earth experiences two tidal bulges: one facing the Moon and one opposite.
Tides Affecting Land
- Tides also slightly affect land, though the changes are minimal compared to ocean tides.
Tidal Experience
- Each location on Earth experiences two high tides and two low tides daily.
- The second tidal bulge forms because of varying gravitational pull with distance from the Moon.
Light Properties
- Blue light has higher frequency, energy, and shorter wavelength compared to red light.
- The visible spectrum of a star or planet indicates its chemical composition and temperature.
- Radio waves are a form of light.
Atomic Structures
- Atomic nuclei are tiny but contain most of an atom's mass.
Spectral Lines and Redshift
- Spectral lines reveal a star's chemical composition, and redshift indicates motion away from the observer.
Telescope Light-Collecting Power
- A 6-meter telescope has four times the light-collecting area compared to a 3-meter telescope.
Hubble Space Telescope Advantage
- The Hubble Space Telescope obtains higher-resolution images due to its position above Earth's atmosphere.
Spectra and Temperature
- The peak wavelength of a spectrum indicates surface temperature, such as that of Mars.
Doppler Shift Basics
- The Doppler shift measures radial motion; actual speed, including across-line-of-sight motion, is often greater than reported by the shift.
- The presence of absorption or emission lines in a spectrum is crucial for measuring an object's radial speed.
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Description
Explore the vastness of the universe with this quiz that covers size comparisons, distance rankings, and cosmic events. Learn about the scale of celestial objects from the universe down to Earth, and discover intriguing facts about the Big Bang and astronomical units. Test your knowledge on how these elements shape our understanding of space.