Exam 1 Flashcards
Which is the correct sequence of planets, based on increasing average radius of their orbits?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
The inner planets ______________________.
Have the same composition as the outer planets
Same size as the outer planets
Have an orbiting system of rings
Have several moons
Which statement is true for the outer planets of our solar system?
They are largely made of hydrogen and helium.
Water ice is __________________________.
most abundant on the moons
What sets the composition of the moons of the outer planets apart from the inner planets?
The moons of the outer planets generally have lower densities.
Which objects have orbits that take them the farthest from the Sun in our solar system?
Comets
Some comets have orbital periods of hundreds of thousands of years. The group of comets that occupies the outermost limits of the solar system is called the Oort cloud.
Which of the following objects is most like Earth in size and composition?
A. Mercury
B. Ida
C. Mars
D. Venus
Venus
What is a major difference between planets and stars?
A. Planets are much smaller in diameter than the stars around which they revolve.
B. Planets do not generate energy through nuclear fusion.
Planets have rings and systems of orbiting moons and some planets (the outer planets) lack solid surfaces.
What are the major differences between a moon and a planet?
A.Planets revolve around the Sun.
B. Moons revolve around a Sun-orbiting planet.
A few moons are actually bigger than Pluto and Mercury. By definition, moons (natural satellites) don’t orbit the Sun but instead revolve around another planetary body. Some asteroids even have moons.
Which of the following are the characteristics of the asteroid belt?
B. The asteroids mark the transition from the rocky terrestrial planets to the outer planets.
C. Some asteroids appear to be rocky; some seem covered with lava; others seem to be metallic; and yet others may have water ice.
D. Many meteorites that fall on Earth come from the asteroid belt.
According to our best modern day evidence, how long ago was the Big Bang?
About 14 billion years ago.
the most basic subatomic particles include which of the following? (Select all that apply.)
A. Protons B. Neutrons C. Isotopes D. Ions E. Electrons
A, B & E
How are elements heavier than iron produced?
During a supernova explosion
What is the principal method of light element (up to iron, atomic number 26) production?
nuclear fusion
The T-Tauri phase of a star’s history ______________________.
s typified by extreme fluctuations in energy and a strong magnetic field
Many supernovas are the result of _____________________.
collapse of a star with multiple burning shells
How will the Sun’s life probably end?
With the formation of a planetary nebula.
Which of the following are correct about red giant stars? (Select all that apply.)
A. Krypton, home to Superman, was a red giant.
B. They form as a star expands and the surface cools.
C. They are among the stars with the hottest surfaces.
D. They evolve from medium-sized stars.
They evolve from large stars.
Heavy elements like uranium and thorium form in their interiors.
B&D
Put the following stages in the evolution of a medium-sized star in the correct time order, placing the first stage on the top and the last stage on the bottom. Don’t use those that don’t apply to a medium-sized star.
Gas and Dust, Protostar, Main sequence star, red giant, planetary nebula
Which kind of stars have the longest lifetimes (~10 billion years)?
Medium-sized stars like our Sun.
A giant molecular cloud is best described by which statement?
It is a cool mass of gas and dust that can be light years across.
Which of the following is correct about the nebulas we see in the sky today? (Select all that apply.)
A. They formed during the “Big Bang.”
B. They are concentrations of interstellar gas and dust.
C. Many are the birth grounds of stars.
D. Some form when stars explode.
B, C, & D
A “star” that shines, but not as a result of nuclear reactions, is called a __________.
protostar
Condensation in the solar nebula and accretion of planets is thought to have occurred about how many years ago?
Ages from meteorites suggest condensation occurred 4.5 billion years ago.
Most of the mass of the solar nebula resided in materials which
did not condense to form solids.
What were the most common solids that condensed from the solar nebular gases?
They were water ice.
Examples of highly refractory materials are ____________________________.
. tungsten (W), osmium (Os), and zirconium (Zr)
Refractory elements are those that condense at high temperatures. Volatile elements condense at low temperatures.
Which list is made of very volatile materials?
helium (He), argon (Ar), ammonia (NH3), and methane (CH4)
Helium, argon, methane, and ammonia are very volatile elements and only condense at extremely cold temperatures.
Why are the inner planets depleted (poor) in volatile elements?
Their constituents condensed at high temperatures.
Which of the following is involved in collisional accretion?
The aggregation of planetesimals when they impact one another.
Which of the following are true about planetary accretion? (Select all that apply.)
A. As these particles accreted, the planets became hot as kinetic energy was converted to thermal energy.
B. The planets grew larger and larger via repeated impact.
C. The planets became internally differentiated to different degrees.
D. The particles that accreted to form the planets were in orbit around the Sun.
A, B, C & D
When did the planets form?
the planets formed about the same time as the Sun in a relatively short period of time only a few million years long.
Which of these is evidence for planetary accretion?
A. The heavily cratered surfaces of the Moon and other planetary bodies.
B. The absence of atmospheres on the Moon and Mercury
C. The rings of Saturn.
D. The abundance of water on Earth.
A. The heavily cratered surfaces of the Moon and other planetary bodies.
How did the giant outer planets obtain their thick atmospheres?
By collapse of nebular gas onto a protoplanet’s icy core
Large planetary bodies failed to accrete in some parts of the solar system and did not sweep their neighborhoods clear of debris. Select the two most prominent zones of this “debris.”
A. between Venus and Earth
B. between Mars and Jupiter
C. between Uranus and Neptune
D. beyond Neptune
B & D
Which of the following are characteristics of the orbits of the objects that accrete to make planets? (Select all that apply.)
A. Their orbits form a flattened disk shape.
B. Their orbits form a spherical zone centered on the star.
C. Their orbits define an elliptical zone tilted about 90° to the elliptic.
D. They orbit in the equatorial plane (ecliptic) of the star.
A & D
The spin axes of some planets are tilted relative to the plane in which most orbit. What could have caused this?
The impact of a large object late in the history of accretion changed the spin.
Think about the process of planetary accretion. Which statement best describes our current ideas about the rate of impact cratering in the inner solar system?
Initially, the rate declined smoothly, but there was a later episode of heavy bombardment followed by resumption of the decline.
Which of the following best describes the orbital evolution of the planets in our solar system according to the Nice Model?
A. The orbits of the planets have been more or less the way they are today for over 4.5 billion years.
B. The orbits of the inner planets were once much closer to the Sun than they are now and they have slowly moved outward by centripetal forces.
C. Earth, Mars, and Venus formed in the outer solar system, but they have slowly spiraled inward to their present orbits near the Sun.
D. The orbits of the outer planets changed significantly about 3.9 billion years ago as Uranus and Neptune moved outward from the Sun.
D
