Podcast
Questions and Answers
The objects that are sometimes visible in the night sky with long tails are __________.
The objects that are sometimes visible in the night sky with long tails are __________.
comets
Leftover planetesimals that formed in the region of the solar system now occupied by the jovian planets are called _________.
Leftover planetesimals that formed in the region of the solar system now occupied by the jovian planets are called _________.
asteroids
Pieces of asteroids that have fallen to Earth are called ___________.
Pieces of asteroids that have fallen to Earth are called ___________.
meteorites
Leftover planetesimals that formed inside the frost line are known as ___________.
Leftover planetesimals that formed inside the frost line are known as ___________.
Ceres, Pluto, and Eris are all round in shape and classified as ________.
Ceres, Pluto, and Eris are all round in shape and classified as ________.
Meteor showers are associated with debris from ________.
Meteor showers are associated with debris from ________.
Why didn't a planet form in the region of the solar system now occupied by the asteroid belt?
Why didn't a planet form in the region of the solar system now occupied by the asteroid belt?
The biggest surprise from the New Horizons flyby of Pluto was learning that Pluto ________.
The biggest surprise from the New Horizons flyby of Pluto was learning that Pluto ________.
Rank these objects from left to right based on their distance from the Sun, from closest to farthest: a typical Oort cloud object, a typical asteroid in the asteroid belt, a typical Kuiper belt.
Rank these objects from left to right based on their distance from the Sun, from closest to farthest: a typical Oort cloud object, a typical asteroid in the asteroid belt, a typical Kuiper belt.
Rank these objects from left to right based on their orbital period around the Sun from shortest to longest: a typical Oort cloud object, a typical asteroid in the asteroid belt, a typical Kuiper belt.
Rank these objects from left to right based on their orbital period around the Sun from shortest to longest: a typical Oort cloud object, a typical asteroid in the asteroid belt, a typical Kuiper belt.
Rank these objects based on the distance from the Sun at which they are presumed to have formed, from nearest to farthest.
Rank these objects based on the distance from the Sun at which they are presumed to have formed, from nearest to farthest.
Rank the positions of the comet from left to right based on the expected size of its tail, from shortest to longest.
Rank the positions of the comet from left to right based on the expected size of its tail, from shortest to longest.
Match the following characteristics to comets, meteors, and asteroids.
Match the following characteristics to comets, meteors, and asteroids.
A comet entering the inner solar system from afar will __________.
A comet entering the inner solar system from afar will __________.
During the time that a comet passes through the inner solar system, the comet can appear quite bright because __________.
During the time that a comet passes through the inner solar system, the comet can appear quite bright because __________.
A comet's plasma tail always points directly away from the Sun because __________.
A comet's plasma tail always points directly away from the Sun because __________.
About a trillion comets are thought to be located far, far beyond Pluto in the ________.
About a trillion comets are thought to be located far, far beyond Pluto in the ________.
The bright spherical part of a comet observed when it is close to the Sun is the ______.
The bright spherical part of a comet observed when it is close to the Sun is the ______.
A comet's ____________ stretches directly away from the Sun.
A comet's ____________ stretches directly away from the Sun.
A comet's ________ is the frozen portion of a comet.
A comet's ________ is the frozen portion of a comet.
Particles ejected from a comet can cause a(n)_________on Earth.
Particles ejected from a comet can cause a(n)_________on Earth.
The__________extends from about beyond the orbit of Neptune to about twice the distance of Neptune from the Sun.
The__________extends from about beyond the orbit of Neptune to about twice the distance of Neptune from the Sun.
According to this graph, the minimum size of an object that could cause a mass extinction is a little less than ____.
According to this graph, the minimum size of an object that could cause a mass extinction is a little less than ____.
According to the graph, an object 10 kilometers across hits Earth __________.
According to the graph, an object 10 kilometers across hits Earth __________.
What is the probability that an object 100 meters in diameter will hit Earth during the coming year?
What is the probability that an object 100 meters in diameter will hit Earth during the coming year?
Based on this graph, which statement below most accurately describes the impacts we should expect on Earth during the coming year?
Based on this graph, which statement below most accurately describes the impacts we should expect on Earth during the coming year?
The impact of a 100-meter object will not cause 'widespread' devastation, but it could still kill millions of people if it struck a major city. In Part C, you found that the probability of such an impact in any single year is only 1 in 1000. Suppose we learn that it has already been 1200 years since the last such impact. What would that tell us?
The impact of a 100-meter object will not cause 'widespread' devastation, but it could still kill millions of people if it struck a major city. In Part C, you found that the probability of such an impact in any single year is only 1 in 1000. Suppose we learn that it has already been 1200 years since the last such impact. What would that tell us?
The asteroid belt lies between the orbits of:
The asteroid belt lies between the orbits of:
Jupiter nudges the asteroids through the influence of:
Jupiter nudges the asteroids through the influence of:
Can an asteroid be pure metal?
Can an asteroid be pure metal?
Did a large terrestrial planet ever form in the region of the asteroid belt?
Did a large terrestrial planet ever form in the region of the asteroid belt?
How big an object causes a typical shooting star?
How big an object causes a typical shooting star?
About how often does a 1-kilometer object strike the Earth?
About how often does a 1-kilometer object strike the Earth?
What would happen if a 1-kilometer object struck the Earth?
What would happen if a 1-kilometer object struck the Earth?
Which have the most elliptical and tilted orbits?
Which have the most elliptical and tilted orbits?
Which are thought to have formed farthest from the Sun?
Which are thought to have formed farthest from the Sun?
Choose the approximate time it would take for Earth to get 0.1% heavier at this rate.
Choose the approximate time it would take for Earth to get 0.1% heavier at this rate.
Is this mass accumulation significant for Earth as a planet?
Is this mass accumulation significant for Earth as a planet?
What does Pluto most resemble?
What does Pluto most resemble?
Which of the following statements about asteroids, Kuiper belt objects, and Oort cloud objects is true?
Which of the following statements about asteroids, Kuiper belt objects, and Oort cloud objects is true?
Estimate Comet Tempel 1's diameter, using the scale bar in (Figure 2). Express your answer to one significant figure and include the appropriate units.
Estimate Comet Tempel 1's diameter, using the scale bar in (Figure 2). Express your answer to one significant figure and include the appropriate units.
According to the graph in (Figure 1), how frequently do objects the size of Comet Tempel 1 strike Earth?
According to the graph in (Figure 1), how frequently do objects the size of Comet Tempel 1 strike Earth?
Consider an object twice the size of Comet Tempel 1. What kind of damage would this object cause if it hit our planet?
Consider an object twice the size of Comet Tempel 1. What kind of damage would this object cause if it hit our planet?
The Meteor Crater in Arizona is about 1.2 kilometers across. According to the graph, about how big was the object that made this crater?
The Meteor Crater in Arizona is about 1.2 kilometers across. According to the graph, about how big was the object that made this crater?
How often do objects big enough to create craters like the Meteor Crater impact Earth?
How often do objects big enough to create craters like the Meteor Crater impact Earth?
What is the significance of the impact described in this article?
What is the significance of the impact described in this article?
What does an asteroid impact probability of 99% mean?
What does an asteroid impact probability of 99% mean?
If Earth had no atmosphere, how would the asteroid's kinetic energy shortly before it impacted the surface compare to its kinetic energy when it was far away from Earth?
If Earth had no atmosphere, how would the asteroid's kinetic energy shortly before it impacted the surface compare to its kinetic energy when it was far away from Earth?
Where did the energy of impact come from?
Where did the energy of impact come from?
Which statement is NOT thought to be true of all comets in our solar system?
Which statement is NOT thought to be true of all comets in our solar system?
Which direction do a comet's dust and plasma tails point?
Which direction do a comet's dust and plasma tails point?
When a comet passes near the Sun, part of it takes on the appearance of a large, bright ball from which the tail extends. This part is called _________.
When a comet passes near the Sun, part of it takes on the appearance of a large, bright ball from which the tail extends. This part is called _________.
A rock found on Earth that crashed down from space is called _________.
A rock found on Earth that crashed down from space is called _________.
The asteroid belt is located _________.
The asteroid belt is located _________.
A typical meteor is created by a particle about the size of a _________.
A typical meteor is created by a particle about the size of a _________.
Among discovered meteorites, we have found some with all the following origins EXCEPT _________.
Among discovered meteorites, we have found some with all the following origins EXCEPT _________.
Study Notes
Celestial Objects
- Comets: Visible with long tails when near the Sun, forming a coma and subsequently a tail as they approach.
- Asteroids: Leftover planetesimals from the solar system's formation, primarily found between Mars and Jupiter in the asteroid belt.
- Dwarf Planets: Ceres, Pluto, and Eris are round and classified as dwarf planets.
- Meteorites: Solid debris of asteroids that fall to Earth, causing meteor showers when they enter the atmosphere.
Formation and Characteristics
- Objects closer to the Sun are primarily rocky, while those in the outer regions, like the Kuiper belt and Oort cloud, are more icy.
- The Oort cloud is believed to contain about a trillion comets, formed in the region of the jovian planets and later ejected to their current orbits.
- Orbital resonances with Jupiter disrupted the formation of planets in the region now occupied by the asteroid belt.
Comet Dynamics
- A comet’s tail varies in length based on its proximity to the Sun, being longer when close and shorter when distant.
- The plasma tail of a comet always points away from the Sun due to solar wind pressure.
- The coma is the bright spherical part of a comet comprising gas and dust.
Impact Events
- An object about 10 km in diameter can statistically cause mass extinction events.
- A 1 km object strikes Earth approximately every million years and can cause widespread devastation.
- Meteor impacts are more frequent for smaller objects, with those around 100 meters striking about every 100,000 years.
Astronomical Statistics
- A 100-meter asteroid can still kill millions if it impacts a populated area, despite a 1 in 1000 chance per year of such an event occurring.
- Predictions and models suggest future predictions remain stable despite time without recorded impacts, maintaining the likelihood as unchanged.
Properties of Meteorites and Asteroids
- Asteroids can be composed entirely of metal if formed from the core of a shattered body.
- The unique properties of Oort cloud comets include the most elliptical and tilted orbits, compared to asteroids and Kuiper belt objects, which orbit in a similar plane to the planets.
Effects of the Atmosphere on Impacts
- Without an atmosphere, a meteor’s kinetic energy increases significantly upon impact due to gravitational acceleration.
- Kinetic energy transformed into heat upon impact can result from atmospheric friction during entry.
General Knowledge
- Not all comets create tails; tails are visible only when comets approach the Sun.
- A typical meteor results from particles as small as a pea entering the Earth's atmosphere.
- The asteroid belt is situated specifically between the orbits of Mars and Jupiter.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on celestial objects in this Chapter 9 flashcard set from your astronomy course. Learn about asteroids, comets, dwarf planets, and meteorites and their significance in our solar system. Perfect for reviewing key terms and concepts before your exam.
