Honors Astronomy Ch 15 Solar System Debris

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What are the solar system’s minor bodies?
Asteroids, comets, Kiuper belt objects, and meteoroids
How many minor bodies are esrimred ro be undiscovered?
1 billion
What are asteroids?
Relatively small, rocky objects orbiting the sun
How do asteroids differ from planets?
Size and orbits
What is the difference in orbits between asteroids and planets?
Asteroids move on eccentric trajectories, while planets have nearly circular orbits
Few asteroids are larger than _______
300 km
What is the largest known asteroid?
1st person to discover an asteroid & what asteroid did he detect
Giuseppe Piazzi; Ceres
How many known asteroids are there?
More than 500,000
Where are the majority of asteroids found?
Between the orbits of Mars and jupiter
How are asteroids classified?
By spectroscopic properties
The darkest or least reflective type of asteroid is known as?
Carbonaceous or C type
What is the most reflective type of asteroid
S type
What is the most common type of asteroid?
C type
What are the three largest asteroids?
Ceres, Pallas, & Vesta
How many asteroids are more than 300 km across?
What probe provided the first close up views of asteroids?
Why is Vesta unique?
Despite its size, it appears to have undergone volcanism
What asteroid has a tiny moon?
What is the name of the moon orbiting Ida?
What are binary asteroids?
Asteroids orbiting each other as they encircle the sun
What are Apollo asteroids?
Earth crossing asteroids
Will Apollo asteroids eventually collide with earth?
How large are most earth crossing asteroids?
About 1 km in diameter
What are Trojan asteroids?
Asteroids orbiting Jupiter, discovered by Lagrange
What do comets appear as in the sky?
Faint, fuzzy, patches of light in the sky
A comet’s orbit is highly _______
How do comets shine?
Reflect sunlight
What is the nucleus of a comet?
Main solid body of a comet
How large is the nucleus?
Typically only a few km across
Do comics emit visible light on their own?
What is a coma?
Atmosphere of dust and gas that develops around the nucleus when it approaches the sun
What is sublimation?
Changing phase from solid to gas w/out becoming liquid first
A comet becomes ____ and ______ as it nears the sun
Larger and brighter
When is te comet’s tail most pronounced?
When its closest to the sun
How large can a coma get?
Up to 100,000 km in diameter
What two parts of the comet are visible from earth?
Coma and comet tAil
What two parts are comet tails broken into?
The ion tail & dust tail
Comet tails are directed away from the Sun because______
Solar wind directs it
When was Halley’s Comet discovered?
How long does it take for Halley’s Comet to orbit?
When can Halley’s Comet be traced back to?
240 bc
When is Halley’s Comet expected to come into view?
A comet’s mass _______ with time
How many comets have been visited by human satellites?
Comet orbits are _______
Highly elongated
What is the Oort Cloud?
Vast reservoir of cometary material completely surrounding the sun
Where are comets less than 200 yrs old thought to originate?
Kiuper belt
What is the generic term for any body orbiting beyond Neptune?
Who calculated where Pluto should be?
Perceval Lowell
Who actually discovered Pluto?
Clyde Tambaugh
When was Pluto discovered?
Pluto’ orbit is _______
Can Pluto be inside Neptune’s orbit?
What is Pluto’s orbital period?
248 yrs
What orbits Pluto?
List 3 objects that are comparable to pluto
Quaoar, makemake, haumea
What are the criteria that planets have to fulfill
1. Orbits the sun
2. Massive enough that it’s gravity caused its shape to be approximately spherical
3. “Cleared the neighborhood” around its orbit of other bodies
What criteria does Pluto not fulfill?
Pluto is not large enough to clear the neighborhood around it
Aka shooting stars
What is a meteor?
Sudden streak of light caused by friction between air molecules in Earth’s atmosphere & an incoming piece of interplanetary matter
How do you distinguish between a meteoroid & an asteroid?
Size: meteors are less than 100 m in diameter
Meteor showers are formed from________
Comet fragments that broke off when it neared the sun and then swarmed together
What type of meteoroids are typically not associated with meteor showers?
How often does a comet’s orbit pass earth?
Twice a year
What are thought to have created most cratering on planets?
Stray asteroids
Categories: Astronomy