science 9 ACS

87 terms by cthiessen

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is the science that studies the composition, position, and movements of all objects in space.


a scientist who studies astronomy


not science! It is a belief that the stars influence your life


a pattern of stars arranged as a mythical figure or animal


are parts of constellations. The big dipper is an asterism because it is only part of the constellation ursa major

circumpolar constellation

a constellation always in the night sky because it is around the pole


has the shortest day


has the longest day


rotates in the opposite direction on its side. their sun rises in the west and sets in the east


rotates opposite ( sun rises in the west and sets in the east)


its day is longer than its year. Their day is 243 earth days


shortest year


longest year


average diameter biggest planet


smallest planet


least amount of gravity


most amount of gravity


most amount of moons


hottest planet


has the most extreme temperatures


has no atmosphere


coldest planet


most dense


least dense


closest to the sun


has an atmosphere like a green house. (CO2). It is the brightest object in the sky


water planet only planet to have life


red planet


has famous moons-Io, Europa, Ganymede and Callisto


has great red spot-large hurricane. it also has a strong magnetic field


moon-titan (which is larger than mercury) has rings


very strong winds, a polar cap


described earth to be center of the universe


suggested sun is the center of the universe


has a large dark spot


the spinning of an object around an imaginary object


the number of hours fo daylight


constructed accurate telescopes
discovered moons and rings around planets, planets are musch closer than stars


earth is farthest away from the sun
(July 4


created laws of planetary motion
-elliptical orbits
-speed of orbit depends on distance
-farther planets have longer orbits


earth is closest to the sun (Jan 3)


the change in direction of the Earth's axis


when the sun is above and below the horizon an equal amount of time


the part of the sun that is visible during a complete solar ecllopse


the view that the earth is the center of the solar system

neap tides

weak tides

solar eclipse

the type of eclipse that occurs when it is sun, moon, earth

spring tide

very strong tides, very high and very low, when the sun,earth and moon are lined up


when the sun is at the highest and lowest positions in the sky

winter solstice

the day with the least hours of sunlight

summer solstice

the day with the most hours of sunlight


the motion of an object in a circular or elliptical path (a year)

retrograde motion

the apparent slowing, reversal and looping of a planet in its path across the sky

lunar eclipse

sun, earth , moon


the view that the sun is the center of the universe

celestial sphere

an imaginary rotating sphere upon which lie all the objects in the universe (p 567 B.C. science probe 9)

annular eclipse

a solar eclipse where the moon is further from the earth creating a ring of fire.


due to the tilt of the earth's axis


caused by the gravitational pull between the earth and the moon and the sun.

spring tides

when the sun, moon and earth are in a line, there a very high tides, due to the strong gravitational pull.

neap tides

weak tides, when the sun and moon are perpendicular to eachother with respect to the sun.


..smaller clumps of cooler matter, forced together by gravity, from the nebula.

outer planet

one of the four planets furthest from the sun, the gas giants, Jupiter, Saturn, Uranus and Neptune

gas giant

most of the planet is made up of gasses, the outer planets are all gas giants, Jupiter, Saturn, Uranus and Neptune.

Inner planet

The planets closest to the sun; Mercury, Venus, Earth, and Mars also known as the terrestrial planets

Terrestrial planet

one of the dense rocky planets nearest to the sun; Mercury, Venus, Earth, Mars

minor body

non-planetary matter, includes asteroids, meteors, and meteorites and comets


any of numerous small celestial bodies composed of rock and metal that move around the sun (mainly between the orbits of Mars and Jupiter)and are too small to be called planets


large meteors that reach the earth's surface and hit the surface


A STREAK OF LIGHT in the sky produced by the burning of a meteoroid in Earth's atmosphere, a falling star. It doesn't hit the ground.


frozen chunks of rocks and metalllic particles that orbit the sun in long elliptical paths

Big splash theory

The Current theory that explains the formation of the moon; it states that, approximately 4.5 billion years ago, the moon was formed as a result of an object approximately the size of mars colliding with earth, causing less dense portions to be blasted into space

rotating nebula theory

Theory of the formation of solar system which includes nebula -collapsingand sun forms, rotates and clumps form-protoplanets-planets p.381-382


He discovered the existence of other galaxies and determined that galaxies are moving away from us

red shift

a shift of the spectral lines to longer wavelengths. The greater the red shift, the faster the galaxy is moving away from us


a range of wavelengths,evident by bands of light, seen through a spectroscope. Each chemical element has its own spectrum. (color bands)


an instrument that splits and spreads out light into a spectrum.

big bang theory

the theory that all matter and energy in the universe was compressed into an extremely small volume that 13 billion to 15 billion years ago exploded and began expanding in all directions

light year

the distance light travels in one year


an apparent shift in the position of a star against the background of more distant non-moving stars.


a trigonometric method of determining the position of a fixed point from the angles to it from two fixed points a known distance apart (baseline)


the measurement between two fixed points, used in triangulation. Used to measure the distance of stars. The longest baseline used is the diameter of the earth's orbit.

nuclear fusion

hydrogen nuclei fuse to form helium nuclei.The reaction releases an enormous amount of energy

cepheid variable stars

are unstable big stars that are 1000x brighter than the sun and the pulse, they have predictable brightness and behavior, brighter=closer, dimmer=further, they are found in most galaxies and are used to determine distance

absolute magnitude

Amount of light a star actually gives off, recorded at a standard distance

apparent magnitude

How bright a star appears to be



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