chapter 9

how are small bodies in the solar system primarily classified

by their size and composition

which of the following is a dwarf planet: ceres, ganymede, titan

ceres

what characteristic is used to differentiate between asteroids and comets

presence of a tail when near the sun

what are asteroids primarily composed of

rock and metal

what do meteorites tell us about asteroids

they provide information about the early solar system

why is there an asteroid belt between mars and juputer

gravitational influences from jupiter prevented planet formation

why do comets grow tails when they approach the sun

the heat from the sun causes sublimation of ice into gas

where do most comets originate from

the kuiper belt and oort cloud

what is a distinguishing feature of a comet’s nucleus

it is composed of mostly ice mixed with dust and rock

what is pluto primarily composed of

ice and rock

what characteristic distinguishes kuiper belt objects from asteroids in the asteroid belt

kuiper belt objects are farther away from the sun

which dwarf planet is located in the kuiper belt: eris, vesta, phobos

eris

did an impact kill the dinosaurs

yes, an asteroid impact is believed to have caused their extinction

how great is the impact risk today from small bodies like asteroids or comets

the risk exists but is relatively low due to monitoring efforts

how do jovian planets affect impact rates on earth

their gravity can redirect comets towards or away from earth

what is the primary difference between asteroids and comets

asteroids are rocky, while comets are ice-rich

which of the following best describes a dwarf planet

a small body that is large enough to be round and orbits the sun

what characteristic led to pluto being classified as a dwarf planet

its ice-rich composition and small size

where are most asteroids found in our solar system

between mars and jupiter in the asteroid belt

what was the first asteroid discovered

ceres

why were asteroids initially called “minor planets”

because they were recognized as being much smaller than other planets

where do most comet in our solar system reside

in the kuiper belt and oort cloud beyond neptune

what causes some comets to develop tails

their icy composition melting as they approach the sun

which comet is known for its 76-year orbit around the sun

halley’s comet

which object discovered in 2005 reignited debates about what constitutes a planet

eris

what common feature of objects classified as dwarf planets

they are large enough to be round but not large enough to be clear in their orbital path of other debris

which of these objects is NOT classified as a dwarf planet: ceres, haumea, vesta

vesta

what is a meteor technically defined as

a flash of light caused by a particle entering earth’s atmosphere at high speed

where do most meteorites originate from

the asteroid belt

what distinguishes a meteorite from a meteor

a meteorite reaches earth’s surface, while a meteor is just a flash of light in the atmosphere

what makes asteroids scientifically important

they provide clues to the solar system’s birth

what is the largest asteroid by mass in our solar system

ceres

why do small asteroids have diverse shapes

their gravity is too weak to reshape them into spheres

what suggests that water ice makes up a significant fraction of ceres’ composition

its low density and location in the outer part of the asteroid belt

what was one surprising discovery about ceres made by the dawn spacecraft

it has bright spots made of salts and other reflective minerals

how do scientists believe vesta acquired its irregular shape

due to an impact that gouged out a huge crater near its south pole

what distinguishes primitive meteorites from processed meteorites

primitive meteorites are remnants from when solid material first condensed from the solar nebula

what do processed meteorites tell us about their parent asteroids

they underwent differentiation into core-mantle-crust structures

why are some processed meteorites metal-rich

they are fragments of the cores of shattered asteroids

where is the asteroid belt located in our solar system

between mars and jupiter

how do orbital resonances with jupiter affect asteroids in the asteroid belt

they nudge asteroids out of certain orbits, creating gaps

why didn’t a full-fledged planet form in the region of the asteroid belt

jupiter’s gravitational influence disrupted planetesimal orbits, preventing accretion into a planet

what primarily causes a comet to develop a tail as it approaches the sun

the vaporization of ices into gas and dust due to the sun’s heat

what is the nucleus of a comet

the solid, frozen center of a comet

which type of tail is formed by ionized gas pushed away by the solar wind

plasma tail

what happens to a comet after it loops around the sun and begins to head back outward

vaporization declines, the coma dissipates, and the tails disappear

which mission provided a wealth of information on comet 67P/churyumov-gerasimenko

european space agency’s rosetta mission

what causes meteor showers on earth

particles ejected from comets that earth crosses in its orbit

why do meteor showers appear to radiate from a particular direction in the sky

due to earth’s motion through space, similar to how snow appears to comes from one direction when driving a car

when are meteor showers best observed

in the predawn sky, when part of the sky faces in the direction of the earth’s motion

where do most comets that visit the inner solar system originate from

the oort cloud and kuiper belt in the distant outer solar system

how did comets end up in regions like the oort cloud and the kuiper belt

they were flung outward by gravitational encounters with jovian planets or remained near neptune’s orbit after formation

what is unique about oort cloud comets compared to the kuiper belt comets

oort cloud comets have random elliptical orbits extending far beyond planetary orbits, while kuiper belt comets have more circular orbits near neptune’s orbit

how does gravity influence oort cloud comets differently than kuiper belt comets

gravity from nearby stars can nudge oort cloud comets, altering their paths significantly, while kuiper belt comets remain relatively less stable due to less gravitational influence

what was significant about nasa’s stardust mission regarding comet research

it captured dust particles from the comet wild 2 and returned them to earth for study

what did spectroscopy reveal about comet temple 1 during nasa’s deep impact mission

the comet contained many complex carbon compounds

what discoveries did rosetta’s philae lander make about comet 67P/churyumov-gerasimenko’s surface composition

it found that virtually no ice was exposed at the surface; instead, ice was hidden under a substantial crust of dusty materi

why are small comets often described as “dirty snowballs”

because they are chunks of ice mixed with rocky dust and complex chemicals

how long can comet tails extend in length

hundreds of millions of kilometers

what happens when sand-to-pebble-size particles ejected by a comet enter earth’s atmosphere

they make surrounding air glow with heat, creating meteors visible as brief flashes

how long does it take for pluto to complete one orbit around the sun

248 years

what is unique about pluto’s orbit compared to the eight planets

it is more elliptical and inclined to the ecliptic plane

what prevents pluto from colliding with neptune despite their intersecting orbits

neptune orbits the sun precisely 3 times for every 2 pluto orbits

which of pluto’s moons is the largest

charon

how does charon compare in size and mass to pluto

charon has more than half the diameter and about one-eighth the mass of pluto

what likely caused the formation of charon and pluto’s smaller moons

a giant impact similar to that which formed earth’s moon

what is the average surface temperature on pluto

40 K

what gases are found in pluto’s thin atmosphere

nitrogen, methane, and carbon monoxide

what event in 1994 provided direct proof that large impacts still occur in the solar system

the collision of comet shoemaker-levy 9 with jupiter

what was the energy equivalent of each nucleus of comet shoemaker-levy 9 when it impacted jupiter

a million hydrogen bombs

what evidence suggests that a major impact coincided with the extinction of the dinosaurs

a layer of iridium-rich sediments and a 65-million-year-old crater are key evidence of a major impact

which location was identified as the impact site that likely caused the extinction of the dinosaurs

mexico

what were some of the longer-term effects of the impact that killed the dinosaurs

global winter, halted photosynthesis, and acid rain

what was significant about the tunguska event in 1908

it released energy equivalent to several atomic bombs

what happened during the chelyabinsk event in 2013

an asteroid exploded in midair, injuring over a thousand people mostly due to shattered glass

how often do objects a few meters across enter earth’s atmosphere

every week or so

why is it difficult to predict and prevent potentially damaging impacts from asteroids or comets

current technology may not be sufficient to demolish or divert an incoming asteroid

how have jovian planets like jupiter influenced cosmic collisions in our solar system

by shaping the orbits of asteroids and comets, leading some towards earth

what might have been different if jupiter did not exist in our solar system

the threat from asteroids might be smaller but the threat from comets might be. greater

which jovian planet is primarily responsible for creating the oort cloud by ejecting icy planetesimals

jupiter

what is the primary difference between an asteroid and a comet

asteroids are rocky, comets are ice-rich

what do we call a small piece of rock that survives its passage through earth’s atmosphere and reaches the ground

meteorite

what can be classified as a dwarf planet

both rocky and ice-rich bodies that are large enough to be round

what characteristic is more common in asteroids located farther from the sun

more carbon compounds and water

what do primitive meteorites tell us about the early solar system

they provide information about the material that accreted to form asteroids and planets

why does the asteroid belt exist between mars and jupiter

it is a region where planetesimals were never able to form planets due to orbital resonances

what causes a comet to develop tails as it approaches the sun

the vaporization of ice into gas, forming a coma and tails

where do kuiper belt comets originate from

beyond neptune, in the region where they formed

how are oort cloud comets believed to have reached their current locations

by being flung out by gravitational encounters with jovian planets

what is unique about pluto’s orbit in relation to neptune

pluto’s orbit is in resonance with neptune, preventing collisions despite sometimes coming closer to the sun

what evidence suggests that some kuiper belt objects may be geologically active like pluto

observations of neptune’s moon triton, which likely formed in the kuiper belt

how was pluto’s large moon charon likely formed

from a giant impact event

what evidence supports the theory that an impact coincided with the mass extinction of dinosaurs

sediments containing iridium and an impact crater near mexico from around 65million years ago

how often might impacts like the tunguska event occur on earth

every couple of hundred years

how do jovian planets influence impact rates on earth

through their gravitational influences, which shape asteroid belts and occasionally send objects towards earth