Astronomy Exam 2 Ch 7 + 14

closest to farthest from the sun in solar system

sun, mercury, venus, earth, mars, asteroid belt, jupiter, saturn, uranus, neptune, kupier belt, oort cloud

ceres

largest body in the asteroid belt

Dwarf planets in the Kupier Belt

Pluto, Eris, Haumea, and Makemake

terrestrial planets

mercury, venus earth, mars

giant planets

jupiter, saturn, uranus, and neptune

gas giants

jupiter and saturn, dominated by enormously large atmospheres

ice giants, atmospheres have many ices

Uranus and Neptune

ecliptic

Earth’s orbital plane

pluto

____ is not in the plane of the planets inclined to the ecliptic

differentiation

a system that has different properties at different locations

leftover planetismals

asteroids and comets

how are larger moons formed

the giant planets’ accretion disks

radioactive decay

after one half-life passes, half of the original parents atoms in the sample are left, the other half is composed of the radioactive decay products called daughter atoms

does the decay of radioactive elements cause any visible change in the appearance of rocks?

no

how the solar system formed

cloud of gas and dust collapses under gravity and rotation, becomes a disk surrounding a protostar due to angular momentum conservation

collapse is slowed ___ to the rotation axis, but not parallel to the rotation axis → forms ___

perpendicular, disk

accretion

growth by infall

as the protostar continues to accrete more material, small particles in the accretion _____ and ____

collide, stick

smaller particles get larger ____, thus larger _____, through collisions with larger particles

accelerations, speeds

when they reach diameters of 1 km, what are larger particles called

planetesimals

what leads to planets

planetesimals pulling particles onto itself by gravity

the temperature difference between the inner and outer disk causes a _________ of inner and outer planets

difference in the composition

only materials that ________ can condense and cause particles to grow

do not become gaseous at high temperatures

refractory

does not melt at high temperature

volatile

can melt or evaporate at moderate temperatures

primary atmosphere

planetesimals gathering gases from the proto-planetary disk

what type of planets cannot hold on to their primary atmosphere

low-mass planets

what planets produce a secondary atmosphere and how

low-mass planets emit gases from interiors

how does fusion start in the protostar

when the core of the protostar becomes hot and dense enough

when does a protostar become a star

when the core starts fusing hydrogen and helium