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161 Cards in this Set

  • Front
  • Back
How many of small terrestrial bodies orbit our sun?
T or F
More than once the appearance of comets altered the course of human history.
T or F
Asteroids or comets falling to the EArth have altered the course of biologicial evolution.
Why is the study of asteroids and comets so important to science?
They provide an important testing ground for our theories of how our solar system came to be.
T or F
Small bodies' compositions, locations, and numbers have changed over the years.
Their locations, compositions, and numbers have remained virtually UNCHANGED.
Approximately how long ago were the small bodies formed?
4.5 Billion years ago
T or F
Comets, asteroids and meteorites carry the history of our solar system in their locations, numbers, and compositions.
What are considered the "scraps" left over from the formation of our solar system?
Comets, meteroites, and asteroids
What does the word, COMET, come from?
Greek word for HAIR
How did comets get their name?
Comes from the long hairlike tails they display on the rare occasions when they come close enough to the Sun to be visible in our sky?
Where do comets have to be located in order for us to see them in our sky?
Close to our Sun
WHere does the word, ASTEROID,come from?
It means, STARLIKE,
How are asteroids starlike?
That's how they appear through a telescope.
Do asteroids ACT like stars?
WHat does the word, METEOR, mean?
a thing in the air.
List the other terms given to meteors
1. shooting star
2. falling star
What is the term given to the larger chunks of "fallen stars" that plunge through the atmostphere and hit the ground?
What is a FALLING star?
What is a FALLEN star?
What is the definition of an ASTEROID?
A rocky leftover planetesimal orbiting the Sun
What is the definition of a COMET?
An icy leftover planetesimal orbiting the Sun -- regardless of its size or whether or not it has a tail
What is the definition of a METEOR?
A flash of light in the sky caused by a particle entering the atmosphere, whether the particle comes from an asteroid or a comet.
What is the definition of a METEROITE?
Any piece of rock that fell to the ground from the sky, whether from an asteroid a comet, or even another planet.
T or F
Asteroids are virtually undetectable to the naked eye.
After how many centuries had the telescope been invented did it take before an asteroid was observed using a telescope?
200 years or 2 centuries
How long ago were asteroids discovered?
200 years ago?
How were asteroids discovered?
When astronomers were searching the "extra wide gap" between the orbits of Mars and Jupiter.
What 2 planets were astronomers studying when asteroids were discovered?
Mars and Jupiter
How long did it take to discover the first 10 asteroids?
50 years
Once an asteroid is discovered, how is it tagged?
1. assigned a number in order of its verification; and
2. the discoverer chooses a name subject to the approval of the INternational Astronomical Union
What organization approves the names of asteroids?
International Astronomical Union
From what source were the earliest asteroids named?
Mythological figures
From what source are the latest asteroids named?
The names of scientists, cartoon heroes, pets, and rock stars
What is the name of the largest asteroid discovered to date?
What is the radius of the largest asteroid, Ceres?
500 kilometers
What planet is Ceres nearly half the size of ?
What is the estimated number of asteroids larger than 1 kilometer?
Approx. 1,000 asteroids may be larger than 1 kilometer
If all the asteroids' masses could be added up, what is it estimated to be their total?
A mass less than 1,000 kilometers in radiuus, much smaller than any terrestrial planet
Where is the main "asteroid belt" located?
Between 2.2 and 3.3 AU from the sun
Describe the orbits of asteroids?
1.Disctictly eliptical
2.All orbit the sun
3. All orbit in the same direction as the planets
What is the average distance between asteroids?
Millions of kilometers
Where are probably the answers to why are asteroids concentrated in the asteroid belt, and why didn't a full-fledged planet form in this region?
Answers may lie with ORBITAL RESONANCES.
An orbital resonance occurs whenever one object orbital period is a simple ratio of another object's period. Ex. 1/2,1/4, or 5/3.
How do you determine orbital resonances?
Take Jupeter for example.
Jupiter's orbital period = 12 years.
If an asteroid's orbit @ the sun = 4 years, the asteroid's orbital resonance = 1/3.
If an asgteroids orbit @ the sun = 3 years, the asteroid's orbital resonance = 1/4.
T or F
There are asteroids that have exactly 1/2, 1/3, or 1/4 of Jupiters?
What name is given to the the asteroids that are "impacts waiting to happen?
Earth-approaching asteroids
Where are asteroids congregated that are considered to be in stable zones?
1. Along Jupiter's orbit 60 degrees ahead; and
2. Along Jupiter's orbit 60 degrees behind
What are Trojan asteroids?
Asteroids found in 2 regions: along Jupiter's orbit 60 degrees ahead and behind.
T or F
Trojan asteriods are unstabel.
They are stable.
Why are Trojan asteroids considered to be stable asteroids?
1. They have a differect type of orbital resonance than Jupiter.
2. Any asteroid that wanders away from one of the orbital zones, it is nudged back into the zone by Jupiter's gravity
T or F
Asteroids are not easily recognizable because they take a long taime to move noticeably relative to the stars.
Asteroids are easily recognizable because they take relative short times to be noticed.
How are asteroid's orbits determined?
Using Kepler's Laws
T or F
Spacecraft have studied a handful of asteroids close-up
Has a spacecraft ever landed on an asteroid?
Who said, "It is easier to believe that Yankee professors would lie than that stones would fall from heaven."?
Thomas Jefferson
What name is given to very bright metereors?
T or F
There are reliable accounts of human deaths from metereors.
T or F
A human was injured by a metereor.
not a direct hit but by a ricochet.
Could someone live through a direct hit by a meteorite?
Where do most meteorites fall?
Most into the ocean which covers 3/4 of the Earth's surface area.
What is the ultimate judge of a meteorite's authenticity?
Lab analysis.
What element's presence in a rock is almost always indicative of a meteorite?
Why is the presence of iridium almost always a confirmation of the authenticity of a meteorite?
Most of the earth's iridium sank to the core of the Earth and is absent from surface rocks.
Name the 2 main types of meteorites:
1. Primitive meteorites
2. Processed meteorites
Describe what are primitive meteorites:
1. Composed of random mix of flakes from the solar nebula
2. formed @ the same time as solar system-4.6 billions yrs. ago
3. noticeable fraction of pure metallic flakes mixed in the rocks
Why would pure metallic flakes be of significance in categorizing meteorites?
In primitive meteorites, this is sign. because it proves that they were formed @ the solar system because eg., iron in Earth rocks is chemically bound in minerals
What group of meteorites are the majority of meteorites found?
Describe processed meteorites?
undergone substantial change since the formation of solar system, radioactive dating shows the to be younger
Describe Primitive meteorites in terms of composition:
1. rocky or
2. carbon rich
Where do carbon rich primitive meteorites originate?
the outer portion of the asteroid belt, beyond 3 AU from the sun.
Where do non-carbon rich primitive meteorites originate?
the inner warmer part of the asteroid belt.
How do we know that carbon-rich primitive meteorites originate from the outer portion of the asteroid belt?
Carbon compounds condense only at the relative low temperatures that were found in the solar nebula beyond 3 AU from the Sun
Which type of meteorites' compositions appear similar to the cores, matle, or crusts of the terrestrial worlds?
Processed meteorites
Describe "differentiation" that took place with processed meteorites:
they are fragments of worlds that must have been heated to high enough temps to melt inside, allowing metals to sink to the center and rocks to rise to the surface
What is unique @ processed meteorites with basaltic compositions?
They come from lava flows that occurred on the surfaces of some larger asteroids during a time when they had active volcanism
Which meteorites offer an opportunity to study a dissected planet?
Processed meteorites
What are lunar meteorites?
Chips broken off the moon that were hurled into space that later impacted EArth
What are martian meteorites?
Chips broken off Mars that were hurled into space that later impacted Earth
Name the most famous comet?
Halley's Comet
How long is Halley's comet?
76 years
When was Halley's comet last seen?
1986 but unimpressively
When was Halley's Comet last view as spectactular?
When will Halley's Comet make it's next visit?
What is the term given to icy planetesimals from the outer solar system?
How are comets' composition described?
"dirty snowball", ices mixed with rockyt dust
T or F
Comets are completely frozen when far from the Sun.
Describe the comet's nucleus.
Dirty snowball
How large are comets?
A few kilometers across
What is the term given to the rapidly escaping dusty atmosphere of a comet?
Which direction is the tail of a comet pointing?
Away from the sun regardless of which way the comet is moving through its orbit.
T or F
In most cases, we actually see 2 tails of a comet.
Explain how it is we often see 2 tails of a comet.
1. one tail is made of ionized gas
2. another tail is is made of small solid particles
What is the term given to a comet's tail that is made of ionized gas?
plasma tail
What is the term given to a comet's tail that is made of small solid particles?
dust tail
Approx how large is Halley's comet's nuclei?
16 kilometers long and 8 kilometers wide
T or F
Halley's Comet's nucleus is lighter than charcoal.
It is darker than charcoal reflecting only 3% of the light that falls on it.
Where do most comets most of their lives?
in the frigid outer limits of our solar system
At what distance from the Sun does sublimation take place on a comet?
@ 5 AU from the sun
Describe sublimation for a comet:
@ 5 AU from the Sun, a noticealble atmosphere begins to escape the comet's weak gravity draggin dust particles that were mixed with the ice and forms a dusty coma.
When sublimation rate increases as the comet approaches the Sun and gases jet away from patches on the nucleus 2 hundreds of meters per second
What are the particles of a comet that are actually resonsible for a "meteor shower?
pebble-size particles that are not pushed away from the Sun, they form an invisible tail extending along the comet's orbit
When does sublimation decline?
When the comet loops @ the Sun and begins to head back outward
T or F
Active comets can live forever.
Active comets cannot live forever.
Does anyone know for sure what happens to a comet after the volatiles stop escaping?
What are the volatiles that occur on a comet?
Whenever a comet passes the Sun, it loses @ O.1%
Approx. how much of a comet is lost whenever it passes the Sun?
Approx. 1 meter
T or F
Most comet orbits do not fit a pattern.
T or F
Comet orbits can be pointed in any direction
How many comets is it guesses are contained in the OOrt cloud?
a trillion or 10 to the 12th power ( 12
Where is it thought that comets originate:
1. Oort cloud
2. Kuiper belt
T or F
We have discovered more comets originating from the Oort cloud than the Kuiper belt.
We have discovered more than 400 Kuiper belt comets and only a rare Oort cloud
T or F
The total mass of the Kuiper belt is greater than the asteroid belt.
How large is the largest Kuiper belt comet discovered so far?
200q KX76, 1,200 kilometers across and thus, larger than the asteroid Ceres
Who discovered Pluto
American, Clyde Tombaugh in 1930
T or F
Neptune was long predicted mathematically before it was actually discovered
How long is Pluto's orbit @ the Sun?
248 years.
T or F
Near perihelion, Pluto actually comes closer to the Sun than Neptune.
At aphelion, how far away from the Sun is Pluto?
50 AU from the Sun
T or F
The orbital resonance between Neptune and Pluto is stable.
What makes Pluto hard to study?
1. small size
2. great distance
Name Pluto's moon?
T or F
Pluto rotates backward relative to the majority of planets.
What is Charon's diameter in relation to Pluto's?
more than 1/2.
T or F
Some astronomers charge that Pluto and Charon qualify as a "double planet."?
As Pluto recedes from the Sun, what is happening to its atmosphere?
It is thinning, the atmospheric gases, primarily nitrogen, are refreezing onto its surface.
T or F
Pluto and Charon rotate synchronously with each other.
What caused Pluto and Charon to rotate synchronously.
Their mutual tidal pulls long ago.
Would Charon's location in Pluto's sky change?
No. The only change would be its phases.
Where does Pluto orbit?
In the vicinity of the Kuiper belt.
T or F
Pluto remains the largest known object in the solar system neer visited by spacecraft.
What is the status of Pluto today?????????????????????
Who are Gene and Carolyn Shoemaker?
Comet hunters
Who is David Levy
A comet hunter
What were the Shoemaker-Levy 9 impacts on Jupiter.
Based on calculations of a near miss of a comet and Jupiter that occurred in July 1992, they correctly predicted that a mulit-nuclei comet would impact into Jupiter in July 1994.
What was the SL9?
The Shoemaker-Levy 9 impacts into the surface of Jupiter in July 1994
How many nuclei were observed to impacted Jupiter during the SL9 in 1994?
22 nuclei were observed to have impacted Jupiter.
How long did it take for the 22 nuclei to impact onto to Jupiter's surface?
1 week.
How long did it take for Jupter impact scars on on its surface last?
Approx how many major meteor showers are observed on Earth?
What meteor shower did we observe in North Carolina in August 1995?
Perseids, and because of cloud cover over most of the US we were one of the very few locations in the US that had such a great view. We packed up you kids and went on the beach, had a campfire early in the evening and roasted marshamallows until the light show happened. You were all thrilled to watch the shooting lights all around us!
T or F
Most meteors are created by single pieces of comet dust, each no larger than a pea.
What is the frequency of meteors that occur worldwide everyday?
25,000,000 meteors everyday.
25 million
What comet does the annual Perseids shower originate from?
The Swift-Tuttle comet
What is probably the most famous meteor shower?
The Perseids
Where do meteor showers get their names?
From the constellation from which they appear to radiate.
Where do the Perseids get their name?
They appear to radiate from the constellation Perseus
When is the best time to view meteors?
Predawn sky.
What is the name of the "comet" for the Geminaid meteor shower?
T or F
We have never seen a coma or tail associated with Phaethon.
What is Phaethon's classification?
It is now considered to an asteroid.
How old is the famous Meteor Crater in Arizona?
50,000 yrs. ago.
How large is it estimated that the meteor that hit Meteor Crater in Arizona was?
50 meters
Who discovered the possibility of a terrestrial impact 65 million years ago may have wiped out the dinosaurs?
Father/son team, italians Luis and Walter Alvarez
T or F
It is estimated that 99% of all living things were killed by the impact that is thought to have impacted the earth 65 million years ago.
What percentage of the all species living on Earth are thought to have wiped out following the impact 65 million years ago?
75% of all species.
What element is found in the sediment associated with the impact that occurredc 65million years ago?
What is the calculated size thought to be of the object that impacted the Earth 65 million years ago?
10 kilometers across
Where is it believed is the location of the impact that occurred 65 million years that caused 75% of all living species to become extinct?
Off of Mexico's Yucatan Penninsula, which id 200 kilometers, close to what is expected for a 10kilometer impactor.
What was the Tunguska Event?
In 1908, it is beleived that a weka stony meteorite 30 meters across exploeded in the air before reaching the surface. Located in Siberia, entire forests were flattened and set on fire, and air blasts knoked over peole, tents, and furniture up to 200 kilometers away.
What prevented scientists from studying the Tunguska Event for nearly 20 years after it occurred?
1. Remoteness of the region
2. politics of the time (Rioting and Russian Revolution, WWI, etc.
What is the largest known Earth-approaching asteroid?
How large is Eros?
40 kilometersk