Card Set Information
what is the universe composed of?
empty space, energy and matter
most of the universe is _________
whawt does matter in the universe include?
gas molecules, mainly hydrogen, and dust particles
some of this matter had come together to form______
stars, planets, moons, asteroids, meteoroids and comets
most of these objects can only be seen with a ___
telescope or other scientific instruments
spherical masses of hot gases that produce energy
why do stars look small?
because they are far away
what units do astronomers use to measure the distance of stars?
define a light year
the distance light travels in a year
Is our universe expanding?
most stars and galaxies of stars are moving ________
away from each other
how old is the sun estimated to be?
4.5 billion years old
what is the central and largest body of our solar system?
what si the nearest star to earth?
the sun is considered an _________ sized star
what color is the sun?
what are some features on the sun's surface?
eruptions called solar flares and sun spots
what are the brightest stars called?
what color are the coolest stars?
compared to a red dwarf, a white dwarf is ________
hotter and brighter
what is the sun classified as?
a main sequence star
light, heat, and ultraviolet radiation are types of _______produced be stars
what is the most common gaseous element found in stars?
solid bodies which move in definite paths around a central star
what keeps the planets in orbit around the sun?
what are the two types of planets in our solar system?
terrestrial and jovian
what are the inner planets called?
what are the outer planets called?
describe the inner planets
small dense and rocky
describe the outer planets
large gaseous and have low densities
what are the shapes of planets?
what is the name of the almost (but not quite) circular orbit planets and other objects take around the sun?
jovian planets have _____ moons than terrestrial planets
large irregular shaped rocks that orbit the sun
what is located between mars and jupiter?
masses of ice and embeded rock debris
what is the ice fromt eh comets made from?
water, ammonia, methane, and carbon dioxide.
whwat happens as a comet gets closer to the sun?
it will begin to warm and vaporize
as the comets melts it leaves behind a trail of ______
what does the rock debris from a comet become?
rock fragments in space that can be as big as a boulder or as small as dust
when meteoroids and asteroids hit moons or planets what does it form?
solid objects which orbit around planets
the phrase "dirty snowball could best describe a_______
what is the smallest planet?
what is the largest planet?
what planet has the longest revolution?
which planet had similar density as earth?
which planet has similar size as earth?
the moon is a ___________ of earth
what is the period of revolution and rotation?
27 1/3 days
why does the same side of the moon always face the earth?
because the rate of rotation and revolution is the same
why do we see the moon?
because it reflects light off the sun
what causes us to see the moons different phases?
the moons revolution around earth
what is the order of the planets?
mercury, venus, earth, mars, jupiter, saturn, uranus, neptune
what is the order of the moons phases?
new moon, waxing crescent, first quarter, waxing gibbous, full moon, wanning gibbous, last quarter, wanning crescent, new moon
what causes eclipses?
the interactive movements of the moon and earth relative to the sun
when do eclipses occur?
when the sun, moon and earth are exactly lined up
what is the order of the moon sun and earth during a solar eclipse?
the moon is in between the sun and earth (sun, moon, earth)
what is not visible during a solar eclipse?
why is the sun not visible during a solar eclipse?
because the moons shadow falls on earth
what is the order of the moon sun and earth during a lunar eclipse?
the earth is in between the sun and the moon (sun, earth, moon)
what is not visible during a lunar eclipse?
why is the moon not visible during a lunar eclipse?
because the earths shadows falls on the moon
cyclic pattern of water rising and falling along the ocean shoreline
what causes tides?
the gravitational pull of the moon and sun on the earths ocean
what has more effect on tides, the sun or the moon? why?
the moon because its closer