ch 1 review questions

Identify the FALSE statement. The planets formed out of a flattened disk of gas evolving around a central mass. A stellar wind consists of the debris that is exploded out of a star as it "dies." To an astronomer, dust is solid rocky or metallic soot-sized particles formed from cooled refractory materials. Planetesimals that were larger than 1 km gravitationally pulled in all surrounding dust, ice, and smaller planetesimals to become protoplanets. The center material of our Solar System's protoplanetary disk developed into the Sun, while the series of surrounding dust, gas, and ice rings became planets.

A stellar wind consists of the debris that is exploded out of a star as it "dies." A stellar wind is a stream of atoms emitted from a star during its lifetime. (Section refs: 1.5, p. 27)

Identify the FALSE statement: A fifth-generation star would have a greater proportion of heavier elements than a second-generation star. The elements of any person's body were once star matter; therefore we are all literally made of stardust. Our Universe is so old there are no first-generation stars left in it. Dense regions of a nebula pull in surrounding material and therefore grow in mass and density and rotate faster. An accretionary disk eventually grows hot and massive enough to become a protostar, then a star.

Our Universe is so old there are no first-generation stars left in it. (Because stars live for varied periods of time, the Universe always contains many different generations of stars)

Identify the FALSE statement. Stars: create elements by fusing the nuclei of small atoms into the nuclei of larger atoms. have limited amounts of fuel and therefore don't exist forever. all explode cataclysmically when they die and contribute their matter to future star generations. that are the size of our Sun will burn for about 10 billion years. begin as protostars, which fire up when they collapse and become denser and hotter.

all explode cataclysmically when they die and contribute their matter to future star generations. (Only massive stars become supernovas)

Identify the FALSE statement. Asteroids:

are all irregular in shape, not spherical

The heavier elements on Earth (those with atomic numbers greater than 5): were in existence at the moment of the big bang. were formed immediately after the big bang. are formed by stellar nucleosynthesis during the life cycles of existing stars. are constantly being created by fusion in our Sun and blown here by the solar wind. All of the above are true statements.

are formed by stellar nucleosynthesis during the life cycles of existing stars. There was no matter during the first instant, only energy. Heavier elements came later, after small atoms were present to be processed into bigger elements. (Section refs: 1.5, p. 27)

Our Solar System: is centrally positioned in the Milky Way galaxy. formed 10 billion years ago. has a massive, first-generation star at its center. completes one rotation around the center of the Milky Way every 250 million years. All of the above are true.

completes one rotation around the center of the Milky Way every 250 million years. (Our Solar System lies near the outer edge of the Milky Way, it formed less than 5 billion years ago, and our Sun is a third- or fourth-generation star.)

Identify the FALSE statement. Cosmology: is the study of the structure and evolution of the Universe. has ancient beginnings in many cultures. was dominated by the geocentric model for centuries. became more scientific and modern with the work of Renaissance thinkers like Copernicus, Kepler, Galileo, and Newton. currently advocates the heliocentric model, which states that the Sun, not the Earth, is the center of the Universe.

currently advocates the heliocentric model, which states that the Sun, not the Earth, is the center of the Universe. Earth and all other planets of our Solar System orbit the Sun; the entire Universe is not Sun-centered. (Section refs: 1.1, p. 15)

Our solar system

formed about 4.6 Billion years ago

The __ concept placed the sun as the center of the universe, with Earth and other planets revolving around it. The __ concept placed Earth at the center of the Universe, with the sun and other planets revolving around it

heliocentric, geocentric

The earliest nebulae to form in the universe were made almost entirely of

hydrogen and helium

Fusion reactions happen at a slower rate

in smaller stars than in bigger ones

Identify the FALSE statement. The big bang: occurred more than 13 billion years ago. cataclysmically exploded matter outward. began with all matter and energy concentrated in an infinitesimally small point. theory states that at the instant of explosion, everything had so much thermal energy even the smallest atomic pieces couldn't exist. is the explanation for how our Solar System developed.

is the explanation for how our Solar System developed The big bang theory is the explanation for how our Universe began. (Section refs: 1.3, p. 25)

Identify the FALSE statement. You could summarize our Solar System's development by saying: it formed solely from atoms generated by the big bang. its formation began as gravity pulled material into a bulbous disc. the central ball of the bulbous disc developed into the Sun. outlying material of the disc condensed into planetesimals. planetesimals coalesced to form the planets.

it formed solely from atoms generated by the big bang. Solar System material also came from atoms produced over billions of years in previously existing stars. (Section refs: 1.5, p. 27)

Imagine yourself in a universe that is exhibiting a blue shift. This must mean: it's expanding much faster than our Universe. it's expanding, but in a jerky fashion. it's collapsing. it's in a steady state, neither expanding nor collapsing. there's no such thing as a blue shift of light waves.

it's collapsing. When a light source moves toward you, it becomes blue as it shifts to a higher frequency; receding light shifts to red, a lower frequency. (Section refs: 1.3, p. 24)

Earth is round because: erosion over time has worn down the jagged edges of its planetesimals. its interior rock is warm enough to flow slowly in response to gravity. solar wind has shaped it. the gravitational tug of the Moon has worn down the jagged edges. the gravitational tug of the Sun has worn down the jagged edges.

its interior rock is warm enough to flow slowly in response to gravity. A sphere is a shape that permits the force of gravity to be the same at all points on its surface. (Section refs: 1.5, p. 29)

Select the FALSE statement. The Doppler effect: occurs when the frequency of sound waves received is greater if the wave source is moving toward you than if it's moving away. occurs when the pitch of a sound will get higher if the source is receding. is relevant to sound but can also be applied to the behavior of light waves. is the basic explanation for the red shift of our Universe. is evidence for the belief in an expanding Universe.

occurs when the pitch of a sound will get higher if the source is receding The Doppler effect states that the pitch will get lower as the source recedes. (Section refs: 1.3, p. 24)

Identify the FALSE statement. Asteroids: are rocky or metallic bodies, meters to kilometers in diameter. orbit in a belt between Jupiter and Saturn. probably didn't accrete into a planet because Jupiter's gravity interfered. are irregular in shape, not spherical. number in the millions.

orbit in a belt between Jupiter and Saturn. (they actually orbit between Mars and Jupiter)

Identify the FALSE statement. Stellar nucleosynthesis: is the term for the process by which stars create the heavier elements. means stars use their small atoms to produce larger atoms. is a normal process that happens during the life cycle of stars. reactions vary and are dependent on the mass of the star. produces elements up to atomic number 26 (iron) in low-mass stars like our Sun.

produces elements up to atomic number 26 (iron) in low-mass stars like our Sun. Low-mass stars can produce elements only up to atomic number 6 (carbon). They don't have high enough temperatures to cause larger nuclei to collide and attach. (Section refs: 1.5, p. 27)

Identify the TRUE statement. Stellar nucleosynthesis:

reactions vary and are dependent on the mass of the star

Distant galaxies display a __ shift. This observation was the basis for the realization that __

red shift, the universe is expanding

Strong evidence that the universe is expanding comes from the fact that the light emitted from distant galaxies appears to be:

red-shifted

The expanding Universe theory: contends that galaxies are moving away from Earth and from each other at fantastic speed. is supported by the fact that all galaxies exhibit a red shift. raises the question of when the expansion began. resulted in the formulation of the big bang theory. All of the above are true.

All of the above are true.

True or False: Stars are evenly distributed throughout the Universe.

False (Gravity pulls stars together to form giant systems called galaxies, which are separated by immense expanses of empty space)

True or False: Our Sun is a first-generation star.

False (Our Sun is less than 5 billion years old and is likely a third- or fourth-generation star.)

True or False: Fusion reactions happen at a slower rate in bigger stars than in smaller ones.

False Large stars, because of their greater mass, become denser and therefore hotter than small stars; fusion reactions are accelerated, and the large stars burn out faster. (Section refs: 1.4, p. 26)

True or false: Pluto, discovered in 1930, was "demoted" to "dwarf planet" status in 2006 simply because it is much smaller than the other planets.

False Pluto is smaller than the others and was demoted, but for many reasons. It has a different composition and plane of orbit than the others and is more similar to Kuiper Belt objects discovered in the 1990s than it is to other planets. Read more in Box 1.3, Discovering Planets.

True or False: The element carbon, so important to life, was formed in the earliest nebulae of the Universe and thus became a component of all protostars.

False The earliest nebulae consisted entirely of the smallest atoms, mainly hydrogen and helium. Carbon production required the temperatures and subsequent particle velocities of stellar nucleosynthesis of at least first-generation stars. (Section refs: 1.5, p. 27)

True or False: To avoid confusion, cosmologists use the term ice to mean only frozen water; other frozen gases are called plasma.

False (Ice refers to water and to any frozen volatile, including hydrogen, helium, methane, ammonia, and carbon monoxide.)

True or False: The naked eye can see slightly more than 2,000 light years away; powerful telescopes see 13 million light years away.

False (The naked eye can see nearly 3 million light years distant; powerful telescopes see 13 billion light years away)

True or false: Mars, Jupiter, Saturn, and Venus are the Jovian planets.

False (Jupiter, Saturn, Uranus, and Neptune are the Jovian planets; Mercury, Venus, Earth, and Mars are the terrestrial planets.)

True or False: The Sun is roughly 6 trillion miles (1 light year) away from Earth.

False (The Sun is 93 million miles (about 8.3 light minutes) from Earth.)

True or false: In the early Universe the only two elements in existence were carbon and hydrogen.

False (The early Universe consisted entirely of the smallest atoms, principally hydrogen and helium, with traces of lithium, beryllium, and boron.)

Identify the TRUE statement. The composition of the Jovian planets is mainly gas and "ice." The terrestrial planets consist mainly of "ice." The Sun accounts for almost 50% of the Solar System's mass. The only two planets with moons are Earth and Jupiter. Our Sun is the only star we know of that has planets associated with it.

The composition of the Jovian planets is mainly gas and "ice." The Jovian (gas/giant) planets consist mainly of "ice" (frozen volatiles). Contrary to answer B, the terrestrial planets consist mainly of cooled refractory materials (rock or metal). Contrary to answer C, the Sun comprises 99.8% of all mass of the Solar System. Contrary to answer D, most planets have moons. Contrary to answer E, scientists have observed dozens of stars with planetary systems. (Section refs: 1.2, p. 17)

True or False: If the star Alpha Centauri, 4.3 light years distant from the Earth, were to explode this instant, we would not be aware of this event until 4.3 years from now.

True By the definition of light year, the light we see from Alpha Centauri left the star 4.3 years ago, so we are looking at the past; to see what is happening on Alpha Centauri now, we must wait 4.3 years. (Section refs: 1.2, p. 21)

True or false: Because of Earth's rotation, a swinging pendulum rotates about a vertical axis once every twenty-four hours.

True French physicist Leon Foucault demonstrated that Earth rotates on its axis once every twenty-four hours using a pendulum in the mid-1800s. (Section refs: Box 1.1, p. 16)

True or False The contemporary explanation of the big bang states that early profound changes happened incredibly fast, sometimes in fractions of a second, at multibillion-degree temperatures.

True Observations of the Universe and calculations suggest this scenario, which is so far removed from human experience it is hard to comprehend. (Section refs: 1.4, p 26)

True or false: Very large atoms, with atomic numbers greater than iron, generally form in a high-mass star and are disbursed by its "death" as a supernova explosion.

True Only high mass-stars consist of atoms large enough to combine and produce very large atoms, and they are the only stars to supernova at their "deaths." (Section refs: 1.5, p. 27)

True or false: Modern telescopes have allowed us to see 13 billion years back into the past.

True The edge of the visible Universe is about 13 billion light years distant; this means that light traveling to Earth from the edge of the Universe began its journey over 9 billion years before Earth even existed. (Section refs: 1.2, p. 21)

True or false: The solar wind blew light, gaseous elements out of the inner Solar System.

True The solar wind left the inner planets (Mercury, Venus, Earth, and Mars) relatively free of light, gaseous elements such as hydrogen and helium. (Section refs: 1.5, p. 29)

Identify the FALSE statement: The big bang theory states that: initial changes happened within minutes and later changes occurred over millions of years. the temperature had to fall below one billion degrees to allow atoms to form. the process of atom creation, termed big bang nucleosynthesis, produced all known natural elements. as the Universe cooled, atoms and molecules accumulated in patchy clouds of gas called nebulae. nebulae condensed and heated to become spinning accretion disks, then protostars, then stars.

the process of atom creation, termed big bang nucleosynthesis, produced all known natural elements. Only small atoms like helium, lithium, beryllium, and boron were formed. Larger atoms developed in later generation stars and in supernova explosions. (Section refs: 1.4, p. 26)

Our Moon: was formed by the collision of Earth with a Mars-sized protoplanet. was a separate small planet before it was captured by Earth's gravity. is 93 million miles away from Earth. is 4.3 light years away from Earth. has a composition similar to Earth's core.

was formed by the collision of Earth with a Mars-sized protoplanet. Contrary to answer C, the Moon is 237,000 miles away from Earth; it is the Sun that is 93 million miles away from Earth. Contrary to answer D, Alpha Centauri is 4.3 light years away. Contrary to answer E, Moon composition is similar to Earth's mantle. (Section refs: 1.5, p. 29)

Identify the FALSE statement. Differentiation of large planetesimals and protoplanets

was inhibited by the presence of radioactive elements because their decay absorbs heat from the surroundings

Identify the FALSE statement. Differentiation of large planetesimals and protoplanets: is the process by which these bodies develop internal layering. began with heating up component materials within these bodies. was caused by heat created by the transformation of kinetic energy from collisions into thermal energy. was inhibited if radioactive elements were present because their decay required heat input from the surroundings. resulted in a central ball of iron alloy (the core) and an outer shell of lighter rocky materials (the mantle.)

was inhibited if radioactive elements were present because their decay required heat input from the surroundings. Radioactive decay releases energy; it doesn't require the input of energy. (Section refs: 1.5, p. 28)