Astronomy Chapter 1 & 2 Flashcards

Questions and Answers

What do modern astronomers mean by a constellation?

A constellation is a group of stars related through an ancient story.

A constellation is any random grouping of stars in the sky.

A constellation is a region in the sky as seen from Earth. (correct)

A constellation is a group of stars that are all located in about the same place in space.

Why do the patterns of the stars in our sky look the same from year to year?

Although these stars move quite fast as they orbit around the Milky Way Galaxy, they all move together so they don't change their relative positions.

These stars are not moving.

Although these stars are moving, they move so slowly—typically about the speed of a snail—that their motion is not noticeable.

Although these stars move quite fast by human standards, they are so far away that it would take thousands of years for their motion to be noticeable to the eye. (correct)

If you had a very fast spaceship, you could travel to the celestial sphere in about a month.

This statement doesn't make sense because the celestial sphere is a concept and not a physical object. (correct)

Yes, but once such a spacecraft crosses the celestial sphere it can never return.

Yes, and the NASA Voyager spacecraft has already done so.

No, the celestial sphere moves away from us at the speed of light so we can never catch up with it.

Which of the following statements about the celestial equator is true at all latitudes?

It represents an extension of Earth's equator onto the celestial sphere. Signup and view all the answers

The point directly over your head is called:

The zenith. Signup and view all the answers

You are standing on Earth's equator. Which way is Polaris, the North Star?

On the northern horizon. Signup and view all the answers

As seen from North America, stars near Polaris in the sky:

Never set. Signup and view all the answers

Suppose you use the Southern Cross to determine that the south celestial pole appears 40° above your horizon. Then you must be located at:

Latitude 40° south. Signup and view all the answers

The constellation Orion is visible on winter evenings but not summer evenings because of:

The location of Earth in its orbit. Signup and view all the answers

Which of the following is the reason for the solar day being longer than a sidereal day?

The combined effect of the rotation of Earth and its orbit about the Sun. Signup and view all the answers

Which of the following best describes why we have seasons on Earth?

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

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

The axis also points towards Polaris. Signup and view all the answers

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

Third quarter. Signup and view all the answers

At approximately what time would a third quarter moon rise?

Midnight. 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

Each part below describes how a given astronomical phenomenon is related to a time period. Which one is incorrect?

Earth's cycle of axis precession takes about a month. Signup and view all the answers

Which of the following is smallest?

Size of a typical planet. Signup and view all the answers

Imagine that we put a raisin cake into the oven, with each raisin separated from the others by 1 cm. An hour later, we take it out and the distances between raisins are 3 cm. If you lived in one of the raisins and watched the other raisins as the cake expanded, which of the following would you conclude?

More distant raisins would be moving away from you faster. 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

What do we mean by the Big Bang?

The event that marked the beginning of the expansion of the universe. Signup and view all the answers

When we say that we are made of 'star stuff', we mean that:

Nearly every atom from which we are made was once inside of a star. Signup and view all the answers

What is the Sun mainly made of?

Hydrogen and helium. Signup and view all the answers

A moon is a(n):

Object orbiting a planet. Signup and view all the answers

Which of the following objects is not considered a 'dwarf planet'?

Mercury. Signup and view all the answers

Which of the following lists the planets correctly from closest to farthest from the Sun?

Mercury, Venus, Earth, Mars. Signup and view all the answers

Which of the following statements does not use the term light-year in an appropriate way?

It will take me light-years to complete this homework assignment. Signup and view all the answers

The movement of one object around its own axis is called:

Rotation. Signup and view all the answers

Suppose we imagine the Sun to be about the size of a grapefruit. How big an area would the orbits of the eight planets of the Solar System cover?

The size of a typical campus. Signup and view all the answers

On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did Kepler and Galileo first discover that we live on a planet in a solar system?

1 second ago. Signup and view all the answers

Suppose we look at a photograph of many galaxies. Assuming that all galaxies formed at about the same time, which galaxy in the picture is seen in the earliest (youngest) stage?

The one that is farthest away. Signup and view all the answers

Which of the following best describes what we mean by the universe?

The sum total of all matter and energy. Signup and view all the answers

How long does it take Earth to complete one rotation on its axis?

One day. Signup and view all the answers

Study Notes

Constellations and Celestial Observations

A constellation represents a region in the sky as observed from Earth.
Despite their rapid movement, stars maintain consistent patterns due to vast distances, making noticeable motion over human timescales impossible.
The celestial sphere is a conceptual model, not a physical location, hence cannot be traveled to.
The celestial equator extends Earth's equator onto the celestial sphere, present at all latitudes.

Key Astronomical Terms

The zenith is the point directly overhead for an observer.
Polaris, or the North Star, is located on the northern horizon when at Earth's equator.
Stars near Polaris never set in North America and are visible throughout the night.

Understanding Earth’s Motion and Seasons

A celestial pole’s position indicates geographical latitude; a south celestial pole at 40° above the horizon indicates a location at latitude 40° south.
Orion's visibility varies seasonally due to Earth's orbital position around the Sun.
The solar day is longer than a sidereal day due to Earth’s axial rotation and orbit around the Sun.

Earth’s Axis and Lunar Phases

Earth’s axis consistently points towards Polaris across seasons.
A week after a full moon, the moon phase is the third quarter, which rises around midnight.
A total lunar eclipse occurs only during the full moon phase.

Cycles of Time and Astronomical Measurements

Earth's rotation establishes a day, while the Moon's phases cycle over a month.
The axial precession cycle takes about 26,000 years, not a month.
A typical planet is the smallest compared to astronomical units (AU) and other celestial objects.

Cosmic Understanding and Universe Structure

More distant galaxies move away from us faster, indicating an expanding Universe.
The Big Bang marks the beginning of the Universe, not just our solar system.
Human atoms originated from stars, highlighting our connection to cosmic material.

Solar System and Celestial Bodies

The Sun's composition is primarily hydrogen and helium.
Moons are defined as objects orbiting planets.
Mercury is not classified as a dwarf planet.

Planetary Motion and Galactic Observation

The order of planets from the Sun is Mercury, Venus, Earth, Mars.
A light-year describes astronomical distances; it is misused when referring to time.
Rotation refers to an object's movement around its axis, while revolution pertains to its orbit around another object.

Metaphorical Cosmic Scales and Historical Context

If the Sun were the size of a grapefruit, the area of the planets' orbits would cover the size of a typical campus.
Key discoveries in astronomy, such as the heliocentric model, occurred just a second ago on a cosmic calendar.
Distant galaxies observed today are in earlier stages of their development, as light takes time to travel.

Universe Definition

The universe encompasses all matter and energy, not just galaxies or stars.

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Description

Test your knowledge of fundamental concepts in astronomy with these flashcards covering chapters 1 and 2. Each card features key definitions and questions that will challenge your understanding of constellations and other celestial phenomena.