Cosmology Vocabulary

Vocabulary Words

• Terrestrial Planets

• The Sun

• Gravity

• Galaxy

• Lightyear

• Axis

• Comets

• Kuiper Belt

• Oort Cloud

• Meteors

•AU

•Nebula

• Solar System

• Cosmology

• Universe

• Coalescence

• Jovian Planets

• Asteroids

• Dwarf Planets

• Orbit

• Planetesimal

Cosmology

• The study of the origin,

properties, process, and the

evolution of the universe

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Universe

• the totality of everything that

exists

• including planets, stars,

galaxies, and all matter and

energy.

• Estimated at 14.5 billion years

old.

Lightyear

• the distance that light travels in

a vacuum in one year.

• Our galaxy is 100,000 light

years wide.

• Proxima Centauri is the closest

star to our Sun at 4.2 light years

away.

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Galaxy

• a collection of star systems.

• Our is The Milky Way

Solar System

• The sun & all of the planets &

other bodies that travel around

it.

• ~4.6 billion years old

• • ~1.25 light years

• wide

Gravity

• the force of attraction between

all masses in the universe

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The Sun

• the star at the center of

the Solar System.

• Accounts for about

99.86% of the total

mass of the Solar System

• Classified as yellow dwarf star

Sun

• the star at the center of

• our Solar System.

• • Accounts for about

• 99.86% of the total mass of our

Solar System

• Contains mostly hydrogen and

helium

Terrestrial Planets

•Terra =“earth like” • inner, rocky, denser, smaller

Mercury VenusEarthMars

Jovian Planets

outer, balls of gas, larger, rings,

less dense

• “gas giants” and “ice giants”

Jupiter

Saturn

Uranus

Neptune

Asteroids

• A small orbiting object that does not have

characteristics of a planet, moon, or move

like a comet.

• • Most are found between Mars and

Jupiter

• • usually rocky or metallic.

• Billions burn up in Earth’s atmosphere

daily

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Comets

• a small orbiting object that when

close enough to the Sun,

displays a tail

• • composed of loose collections

of ice, dust, and small rocky

particles.

• • “dirty snowballs”

Meteoroids/Meteors/Meteorites

• a small object, considerably

smaller than an asteroid or

comet.

• Most are fragments from comets

or asteroids and varies in

composition.

• Varies in composition.

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Dwarf Planet

• it is a planetary-mass object but

does not follow a single

gravitation orbit. Significantly

smaller than most other planets.

• Eris & Pluto

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Kuiper Belt

• region beyond Neptune where

small remnants of the solar

system orbit.

• Like the Asteroid belt but icy

instead of rocky

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Orbit

• gravitationally curved path of an

object around a point in space

• example the orbit

of a planet around

• center of a star

• system, typically

• elliptical.

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Oort Cloud

• Small dust particles

• outer limits of our Solar System

consisting of comets.

• defines the boundary of the

Sun's gravitational limits

Axis

• the angle/tilt between its

equatorial plane and orbital

plane.

Astronomical Unit

• is a unit of length, roughly the distance

from the Earth to the Sun.

• The astronomical unit is used primarily as

a convenient yardstick for measuring

distances within the Solar System.

Coalescence

•the process by which two or

more particles merge during

contact to form a single

daughter particle.

•For example, it is seen in the

formation of raindrops as well

as planetary and star formation.

Coalescence

•the process by which two or more particles merge

during contact to form a single daughter particle.

•For example, it is seen in the formation of

raindrops as well as planetary and star formation.

Nebula

•Latin for “cloud”

•a large cloud of gas and

dust

•are often star-forming

regions,

Planetismals

•“pre-planet”

•Large masses found in a solar

system that are becoming planets.

•Our planets were planetismals

before they were planets.