Comets & Asteroids Flashcards
Largest object in the Asteroid Belt?
Ceres (named for the Roman goddess of grain).
Where is the asteroid belt located?
Between the orbits of Mars and Jupiter
How wide is the asteroid belt?
Roughly 140 million miles wide
How many asteroids are estimated to be in the asteroid belt?
Millions of asteroids
What is the largest object in the asteroid belt?
Ceres
What is the diameter of Ceres?
About 590 miles (940 km)
Name three other large asteroids in the belt besides Ceres.
- Vesta
- Pallas
- Hygiea
What percentage of the asteroid belt’s total mass does Ceres make up?
About 40%
What is the total mass of the asteroid belt compared to the Moon?
Less than 4% of the Moon’s mass
What caused the formation of the asteroid belt?
Remnants of the early solar system that never coalesced into a planet due to Jupiter’s gravitational influence
What are asteroids primarily composed of?
- Rock
- Metal
- Ice
What are the three main types of asteroids?
- C-type (carbonaceous)
- S-type (silicaceous)
- M-type (metallic)
What type of orbits do most asteroids have?
Elliptical orbits
What are Kirkwood Gaps?
Regions within the belt with fewer asteroids caused by Jupiter’s gravitational resonance
What are Trojan asteroids?
Asteroids that share orbits with larger planets like Jupiter
Who discovered the first asteroid and what was its name?
Giuseppe Piazzi discovered Ceres in 1801
Which NASA spacecraft explored Vesta and Ceres?
Dawn spacecraft
What happens when asteroids collide in the belt?
They create smaller fragments and dust
What are asteroid families?
Groups of asteroids with similar orbits believed to have originated from the same parent body
What is the risk of collision for spacecraft passing through the asteroid belt?
Extremely low due to the spread-out nature of the asteroids
What role does the asteroid belt play in understanding planet formation?
It offers clues about the conditions of the early solar system and why a planet didn’t form there
What is a comet primarily composed of?
A comet is primarily composed of ice, dust, and rocky material.
Fill in the blank: The nucleus of a comet is typically made up of ______.
ice and dust
What are the two main parts of a comet’s structure?
The nucleus and the coma.
What phenomenon causes a comet’s tail to form?
Solar radiation and solar wind cause the tail to form.
Multiple Choice: What is the name of the region where most comets originate?
Oort Cloud
What is the difference between a short-period comet and a long-period comet?
Short-period comets have orbits that take less than 200 years, while long-period comets have orbits that take more than 200 years.
True or False: Comets can be seen with the naked eye.
True
What is the term for the bright halo of gas and dust that surrounds a comet’s nucleus?
Coma
Fill in the blank: The tail of a comet always points ______ from the Sun.
away
What are the two types of tails that comets can have?
Ion tail and dust tail.
Multiple Choice: Which comet is known for its periodic appearance every 76 years?
Halley’s Comet
What is a comet’s orbital path typically shaped like?
An elongated ellipse.
What is the primary reason comets are considered important for scientific study?
They are believed to contain primitive materials from the early solar system.
From which two regions in the outer solar system do most comets originate?
Kuiper Belt and Oort Cloud
These regions are significant sources of comets due to their vast populations of icy bodies.
What are the three main parts of a comet?
- Nucleus
- Coma
- Tail
Each part plays a crucial role in the comet’s structure and behavior as it approaches the Sun.
What is the nucleus of a comet?
The solid, central core
The nucleus is composed of ice, dust, and rocky material.
What is the coma of a comet?
The cloud of gas and dust surrounding the nucleus when the comet is near the Sun
The coma can grow significantly as the comet approaches the Sun, becoming visible from Earth.
What forms the tail of a comet?
Gas and dust pushed away from the nucleus by solar radiation
The tail can extend millions of kilometers and is often visible from Earth.
How many tails do comets typically have?
Two tails
These tails are the ion tail and dust tail, which differ in composition and behavior.
What is the ion tail of a comet made of?
Charged particles pushed by the solar wind
The ion tail always points directly away from the Sun due to the influence of solar wind.
What characterizes the dust tail of a comet?
Made of larger particles, which are pushed more slowly and curve behind the comet
The dust tail appears more diffuse and less straight than the ion tail.
Describe the orbits of comets.
Highly elliptical orbits
These orbits take comets from the outer solar system to close proximity to the Sun.
How often is Halley’s Comet visible from Earth?
Every 76 years
Halley’s Comet was last seen in 1986, and it will next be visible in 2061.
What is notable about Comet NEOWISE?
A bright comet visible in 2020
It gained significant attention due to its brightness and visibility to the naked eye.
What is Comet Hale-Bopp known for?
Its brightness and long visibility in 1997
Hale-Bopp was one of the brightest comets of the late 20th century.
What NASA mission successfully landed the Philae probe on Comet 67P/Churyumov-Gerasimenko in 2014?
NASA’s ROSETTA mission successfully landed the Philae probe on Comet 67P/Churyumov-Gerasimenko in 2014.
What is the Kuiper Belt?
A region of the Solar System beyond the orbit of Neptune, populated with small icy bodies.
Which of the following objects is primarily found in the Kuiper Belt? a) Asteroids b) Comets c) Dwarf planets
c) Dwarf planets
Fill in the blank: The Kuiper Belt extends from about _______ to _______ astronomical units (AU) from the Sun.
30 to 55
Name one well-known dwarf planet located in the Kuiper Belt.
Pluto
What is the primary composition of objects in the Kuiper Belt?
Icy and rocky materials
True or False: The Kuiper Belt is home to more than 100,000 known objects.
True
What is the significance of the Kuiper Belt in understanding the Solar System’s formation?
It provides clues about the early Solar System and the formation of planets.
Multiple Choice: Which spacecraft was the first to visit a Kuiper Belt object? a) Voyager 1 b) New Horizons c) Cassini
b) New Horizons
What is the term for the boundary that separates the Kuiper Belt from the interstellar space?
Heliosphere
What is the Oort Cloud?
The Oort Cloud is a theoretical cloud of icy bodies that is believed to surround the solar system.
What is the estimated distance of the Oort Cloud from the Sun?
The Oort Cloud is estimated to be between 2,000 and 100,000 astronomical units (AU) from the Sun.
Fill in the blank: The Oort Cloud is thought to be the source of _______.
long-period comets.
Who proposed the existence of the Oort Cloud?
Jan Oort proposed the existence of the Oort Cloud in 1950.
Multiple Choice: Which of the following best describes the Oort Cloud?
A spherical shell of icy objects surrounding the solar system.
What are the two regions of the Oort Cloud called?
The inner Oort Cloud and the outer Oort Cloud.
What is the primary composition of objects in the Oort Cloud?
Ices, such as water, ammonia, and methane.
Fill in the blank: The Oort Cloud is thought to be a remnant of the _______ of the solar system.
formation.
What role does the Oort Cloud play in the solar system?
It serves as a reservoir for long-period comets.
What is the significance of the Oort Cloud in relation to comet origins?
It is believed to be the source of long-period comets that enter the inner solar system.
What is the estimated thickness of the Oort Cloud?
It is estimated to be about 1000 AU thick.
What is the size comparison between the Kuiper Belt and the asteroid belt?
The Kuiper Belt is about 20 times wider and up to 200 times more massive than the asteroid belt.
This significant difference highlights the vastness of the Kuiper Belt in the solar system.
Name three dwarf planets found in the Kuiper Belt.
Pluto, Haumea, Makemake
These dwarf planets are some of the largest objects within the Kuiper Belt.
What type of comets originate from the Kuiper Belt?
Short-period comets
These comets take less than 200 years to complete an orbit around the Sun.
What are Kuiper Belt Objects (KBOs) primarily composed of?
Rock, ice, frozen gases like methane, ammonia, and water
This composition is indicative of the cold, distant environment of the Kuiper Belt.
What is the current classification of Pluto?
Dwarf planet
Pluto was reclassified from being considered the ninth planet in the solar system.
Who theorized the existence of the Kuiper Belt?
Gerard Kuiper and Kenneth Edgeworth
Their theories in the mid-20th century laid the groundwork for later discoveries.
What was the first confirmed Kuiper Belt Object (KBO) discovered?
1992 QB1
This discovery in 1992 marked the beginning of observational studies of the Kuiper Belt.
What spacecraft provided the first close-up study of a Kuiper Belt object?
NASA’s New Horizons spacecraft
In what year did New Horizons fly past Pluto?
2015
What was the second Kuiper Belt object visited by New Horizons?
Arrokoth
In what year did New Horizons visit Arrokoth?
2019
What is Pluto formally designated as?
134340 Pluto
Pluto was reclassified as a dwarf planet in 2006 due to its inability to clear the neighborhood of its orbit.
Who discovered Pluto and how did he find it?
Clyde Tombaugh; by comparing photographs of the same area of the sky to detect movement
Tombaugh was 24 years old at the time of discovery.
What significant feature on Pluto was named Tombaugh Regio?
A heart-shaped area in the southern hemisphere of Pluto
This region was one of the striking features observed by NASA’s New Horizons probe.
What is the Kuiper belt?
A disk of outer Solar System objects ranging from around 30–50 AU from the Sun
Pluto is part of the Kuiper belt.
What is the largest natural satellite of Pluto?
Charon
What is Halley’s Comet known for?
Short orbital period of about 75.5 years and visibility to the naked eye
Named after Edmond Halley, who predicted its return.
When did Halley’s Comet last return to the inner solar system?
1986
What meteor shower is associated with Halley’s Comet?
Orionid meteor shower
What makes Comet Hale–Bopp notable?
Longest continuous observational period of any comet at 18 months
It reached a peak magnitude of −1.8.
What significant event is associated with Comet Hale–Bopp in 1997?
Mass suicide of the Heaven’s Gate cult
What was the significance of Comet Shoemaker–Levy 9’s collision with Jupiter?
First opportunity to observe a collision between two major solar system objects
Observed in 1994, providing new insights into Jupiter’s atmosphere.
What was discovered about Jupiter’s atmosphere after the collision with Shoemaker–Levy 9?
Existence of sulfur and disruption patterns in its atmosphere
There was disappointment over the lack of evidence for theorized water clouds.
What is the orbital period of Comet 67P (Churyumov–Gerasimenko)?
About 6.5 years
What historic event occurred involving the Rosetta probe and Comet 67P?
Philae lander touched down on the comet’s surface
This was the first successful landing of a spacecraft on a comet.
What notable findings were made during the Rosetta probe’s mission to Comet 67P?
Contains three times the amount of deuterium found in Earth water and organic compounds
The comet is surrounded by diatomic oxygen.
What is Ceres formally designated as?
1 Ceres
Who discovered Ceres and when?
Giuseppe Piazzi in 1801
What is Ceres classified as within the solar system?
The only dwarf planet in the inner solar system
Reclassified as a dwarf planet in 2006.
What significant feature does Ceres have?
Ahuna Mons, a cryovolcano that erupts aqueous solutions
What is Vesta formally designated as?
4 Vesta
Who discovered Vesta and when?
Heinrich Olbers; details not specified
What notable feature does Vesta have?
Rheasilvia crater, an enormous impact crater
Its diameter is over 90% of Vesta’s diameter.
What are HED meteorites?
Meteorites classified as howardites, eucrites, or diogenites
They originated from Vesta.
What is Eris formally designated as?
136199 Eris
What is the orbital range of Eris from the Sun?
Between 38 and 97 AU
What was the significance of Eris’s discovery?
Prompted the 2006 IAU redefinition of the term ‘planet’
It caused strife within the astronomy community.
What is Theia hypothesized to have done?
Collided with Earth, contributing to the formation of the Moon
This is known as the ‘Giant Impact Hypothesis.’
What is the estimated size of Theia?
Around the size of Mars
What evidence supports the existence of Theia?
Shock heating in meteorites and chlorine isotopic differences between Earth and the Moon
These findings support the collision hypothesis.
What are the Large Low Shear Velocity Provinces?
Possible remnants of Theia found in Earth’s mantle
Proposed by scientists at Arizona State University.
