Size Comparison and Distances in the Universe

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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?

in early September Signup and view all the answers

On the Cosmic Calendar, about when did life arise on Earth?

in September Signup and view all the answers

On the Cosmic Calendar, about when did early humans first walk on Earth?

just a few hours before midnight on December 31 Signup and view all the answers

An astronomical unit is?

Earth's average distance from the Sun Signup and view all the answers

The star Betelgeuse is about 600 light-years away. If it explodes tonight, we won't know about it until?

600 years from now Signup and view all the answers

Could we see a galaxy that is 50 billion light-years away?

False Signup and view all the answers

Which of the following correctly lists our 'cosmic address' from small to large?

Earth, Solar System, Milky Way Galaxy, Local Group, Local Supercluster, Universe Signup and view all the answers

If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then?

the planets would all be marble size or smaller and the nearest stars would be thousands of miles away Signup and view all the answers

The total number of stars in the observable universe is roughly equivalent to:

the number of grains of sand on all the beaches on Earth Signup and view all the answers

If stars existed but galaxies did not, we would not exist because we are made of material that required recycling in galaxies.

True Signup and view all the answers

The age of our solar system is about?

one third of the age of the universe Signup and view all the answers

When we say the universe is expanding, we mean that?

the average distance between galaxies is growing with time Signup and view all the answers

The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that?

the universe is expanding Signup and view all the answers

In San Diego, California, where does the north celestial pole appear in your sky?

at an altitude of 32 degrees in the direction due north Signup and view all the answers

Two stars that are in the same constellation may actually be very far away from each other.

True Signup and view all the answers

The North Celestial Pole is 35 degrees above your northern horizon. This tells you that you are at?

latitude 35 degrees North Signup and view all the answers

Beijing and Philadelphia have about the same latitude but very different longitudes. Therefore, tonight's night sky in these two places?

will look about the same Signup and view all the answers

In winter, Earth's axis points toward the star Polaris. In spring?

the axis also points toward Polaris Signup and view all the answers

When it is summer in Australia, the season in the United States is winter.

True Signup and view all the answers

If the Sun rises precisely due east, it must be the day of either the spring or fall equinox.

True Signup and view all the answers

The fact that we always see the same face of the Moon tells us that?

the Moon's rotation period is the same as its orbital period Signup and view all the answers

A week after a full moon, the Moon's phase is?

third quarter Signup and view all the answers

If there is going to be a total lunar eclipse tonight, then you know that?

the Moon's phase is full Signup and view all the answers

When we see Saturn going through a period of apparent retrograde motion, it means?

Earth is passing Saturn in its orbit, with both planets on the same side of the Sun Signup and view all the answers

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?

The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons Signup and view all the answers

What is the cause of the seasons?

the tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year Signup and view all the answers

In the Greek geocentric model, the retrograde motion of a planet occurs when?

a planet actually goes backward in its orbit around Earth Signup and view all the answers

Which of the following was not a major advantage of Copernicus's Sun-centered model over the Ptolemaic model?

False Signup and view all the answers

When we say that a planet has a highly eccentric orbit, we mean that?

in some parts of its orbit it is much closer to the Sun than in other parts Signup and view all the answers

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.

True Signup and view all the answers

According to Kepler's third law:

Jupiter orbits the Sun at a faster speed than Saturn Signup and view all the answers

Tycho Brahe's contribution to astronomy included:

collecting data that enabled Kepler to discover the laws of planetary motion Signup and view all the answers

Galileo's contribution to astronomy included:

making observations and conducting experiments that dispelled scientific objections to the Sun-centered model Signup and view all the answers

Newton's First Law of Motion:

an object moves at constant velocity unless a net force acts to change its speed or direction Signup and view all the answers

Newton's Second Law of Motion:

force = mass x acceleration Signup and view all the answers

Newton's Third Law of Motion states:

for every force, there is always an equal and opposite reaction force Signup and view all the answers

Conservation of angular momentum is expressed as:

mvr Signup and view all the answers

Identify the basic types of energy:

KE = Kinetic Energy Radiative = Energy in the form of electromagnetic radiation Potential = Stored Energy Signup and view all the answers

Thermal energy vs temperature:

Thermal energy is the collective kinetic energy of many particles, while temperature is the average kinetic energy of many particles, not the sum Signup and view all the answers

Application of Gravitational Potential Energy in Astronomy:

a huge gas cloud has more gravitational potential energy when spread out than when it contracts Signup and view all the answers

The Universal Law of Gravitation is expressed as:

Fg = GM1M2/d^2 Signup and view all the answers

Newton's version of Kepler's Third Law states:

if a small object orbits a larger one, and if you measure the small orbiting object's orbital period and average orbital radius, then you can calculate the mass of the large object Signup and view all the answers

How does gravity cause tides?

Earth gets stretched along the Earth-Moon line through gravity from the Moon Signup and view all the answers

As shown in the video, Earth has two tidal bulges at all times. Approximately where are these bulges located?

one faces the Moon and one faces opposite the Moon Signup and view all the answers

Most people are familiar with the rise and fall of ocean tides. Do tides also affect land?

Yes, though land rises and falls by a much smaller amount than the oceans Signup and view all the answers

Any particular location on Earth experiences?

two high tides and two low tides each day Signup and view all the answers

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?

the second tidal bulge arises because gravity weakens with distance, essentially stretching Earth along the Earth-Moon line Signup and view all the answers

Compared to red light, blue light has?

higher frequency and higher energy and shorter wavelength Signup and view all the answers

Why is a sunflower yellow?

it reflects yellow light Signup and view all the answers

Radio waves are?

a form of light Signup and view all the answers

Compared to an atom as a whole, an atomic nucleus is?

very tiny but has most of the mass Signup and view all the answers

The set of spectral lines that we see in a star's spectrum depends on the star's?

chemical composition Signup and view all the answers

A star whose spectrum peaks in the infrared is?

cooler than our Sun Signup and view all the answers

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?

redshifted Signup and view all the answers

How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?

The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is?

above Earth's atmosphere Signup and view all the answers

What does the wavelength of the peak labeled 6 tell us about Mars?

its surface temperature Signup and view all the answers

Which properties can we infer simply by looking at the spectrum of a star or of a planet's atmosphere?

chemical composition and temperature Signup and view all the answers

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?

either absorption or emission lines Signup and view all the answers

Remember that the Doppler shift measures motion only toward or away from you. What does this imply about the true speed of an object?

it is likely to be greater than the speed measured by the Doppler shift Signup and view all the answers

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.

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.

Size Comparison and Distances in the Universe

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Podcast

Questions and Answers

Rank the following items according to their size (diameter) from largest to smallest:

Rank the following items that describe distances from longest distance (top) to shortest distance (bottom):

According to current scientific estimates, when did the Big Bang occur?

On the Cosmic Calendar, about when did Earth form?

On the Cosmic Calendar, about when did life arise on Earth?

On the Cosmic Calendar, about when did early humans first walk on Earth?

An astronomical unit is?

The star Betelgeuse is about 600 light-years away. If it explodes tonight, we won't know about it until?

Could we see a galaxy that is 50 billion light-years away?

Which of the following correctly lists our 'cosmic address' from small to large?

If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then?

The total number of stars in the observable universe is roughly equivalent to:

If stars existed but galaxies did not, we would not exist because we are made of material that required recycling in galaxies.

The age of our solar system is about?

When we say the universe is expanding, we mean that?

The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that?

In San Diego, California, where does the north celestial pole appear in your sky?

Two stars that are in the same constellation may actually be very far away from each other.

The North Celestial Pole is 35 degrees above your northern horizon. This tells you that you are at?

Beijing and Philadelphia have about the same latitude but very different longitudes. Therefore, tonight's night sky in these two places?

In winter, Earth's axis points toward the star Polaris. In spring?

When it is summer in Australia, the season in the United States is winter.

If the Sun rises precisely due east, it must be the day of either the spring or fall equinox.

The fact that we always see the same face of the Moon tells us that?

A week after a full moon, the Moon's phase is?

If there is going to be a total lunar eclipse tonight, then you know that?

When we see Saturn going through a period of apparent retrograde motion, it means?

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?

What is the cause of the seasons?

In the Greek geocentric model, the retrograde motion of a planet occurs when?

Which of the following was not a major advantage of Copernicus's Sun-centered model over the Ptolemaic model?

When we say that a planet has a highly eccentric orbit, we mean that?

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.

According to Kepler's third law:

Tycho Brahe's contribution to astronomy included:

Galileo's contribution to astronomy included:

Newton's First Law of Motion:

Newton's Second Law of Motion:

Newton's Third Law of Motion states:

Conservation of angular momentum is expressed as:

Identify the basic types of energy:

Thermal energy vs temperature:

Application of Gravitational Potential Energy in Astronomy:

The Universal Law of Gravitation is expressed as:

Newton's version of Kepler's Third Law states:

How does gravity cause tides?

As shown in the video, Earth has two tidal bulges at all times. Approximately where are these bulges located?

Most people are familiar with the rise and fall of ocean tides. Do tides also affect land?

Any particular location on Earth experiences?

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?

Compared to red light, blue light has?

Why is a sunflower yellow?

Radio waves are?

Compared to an atom as a whole, an atomic nucleus is?

The set of spectral lines that we see in a star's spectrum depends on the star's?

A star whose spectrum peaks in the infrared is?

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?

How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?

The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is?

What does the wavelength of the peak labeled 6 tell us about Mars?

Which properties can we infer simply by looking at the spectrum of a star or of a planet's atmosphere?

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?

Remember that the Doppler shift measures motion only toward or away from you. What does this imply about the true speed of an object?

Study Notes

Size Comparison in the Universe

Distance Rankings

Big Bang Timeline

Cosmic Calendar Insights

Astronomical Unit Definition

Betelgeuse and Distance

Observable Universe Limits

Cosmic Address

Scale of Solar System

Stars in the Universe

Recycling of Stars

Solar System Age