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73 terms

Science: Astronomy

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electromagnetic radiation
any energy that travels in waves, travels through space at 300,000 kilometers per second
speed of light
300,000 kilometers per second
wavelength
the distance between the crest of one wave to the next wave
frequency
the number of waves that pass by a point in a second
electromagnetic spectrum
the range of detectable electromagnetic radiation
Visible spectrum
includes what we can detect with our naked eye
spectroscopy
the study of the spectra of stars by analyzing the spectral properties of the light they give off
continuous spectra
the complete spectra is visible with the same brightness of wavelength
bright line spectra
a characteristic "signature" for each element is given by the bright lines. Created by a glowing gas of an element
dark line spectra
dark lines in a spectra created when wavelengths are absorbed by cooler gases within the star
spectroscope
an instrument used to analyze the spectra of light sources
big bang
the currently accepted theory that the universe began in a massive exlosion over 14 billion years ago and has been expanding outwards ever since
doppler effect
the phenomena causedby waves being compressed or shortened when objects are moving towards a stationary object and stretched out when an object is moving away from a stationary object
red shift
commonly cited as evidence of the big bang theory. all distant objects display a shift into the red (long) end of the spectrum indicating the object is moving towards earth.
star evolution
stars form and exhaust themselves in the known sequence that follows
nebula
clouds of gas and dust in space possibly formed from debris of a former star
protostar
a force from outside begins to coalesce the gas into a star
stable state
as contradiction continues the star becomes better and brighter and begins to burn under its own power (nuclear fusion). It remains in this state until the fuel is expended
H-R diagram
a diagram of the sequence that normal size stars go through in their development
red giant
when a star loses stability its core contracts and its outer atmosphere swells to many times its diameter and it forms a _______.
white dwarf
when most of the fuel is gone the star can no longer burn and it shrinks. Finally becomes a cold metallic mass called a black dwarf
high density stars
stars 3x the mass of our sun or greater
supernova
the massive, violent explosion at the end of some stars lifespan, happens in a brilliant flash
pulsar
a rapidly rotating star that emits both light and radio waves
neutron star
the massive core left behind after supernova
black hole
an object with gravitation so intense that light cannot escape it.
galaxies
all of these objects rotate around a central disk which may contain a black hole
spiral galaxies
about a third of the galaxies are this type with spiral arms rotating around a central disk.
elliptical galaxies
smaller galaxies that are elliptical or oval shaped. Compromise 60% of galaxies
irregular galaxies
rare or unusual shaped galaxies, usually of young stars
sun
an average star about 100x the earths diameter
core
the region of the sun where the nuclear reaction occurs
radiative zone
zone outside the core extremely high energy radiation and heat flow outwards
convective zone
where hot ionized gases circulate transferring heat energy outwards
photosphere
the surface of the sun where solar energy streams out into space
chromosphere
the sun's atmosphere consisting of swirling super heated gases
corona
the halo around the sun reaching outward millions of kilometers
sunspots
dark patches on the sun caused by magnetic storms that occur on an 11 year cycle. They occur in pairs on opposite ends of the solar equator
solar flares
bursts of light from the suns surface
solar prominences
solar materials streaming into space and back to the suns surface
auroras
high energy particles travel down the earths magnetic field and energize particles in our atmosphere
revolution
the time neccessary for a planet to make one complete orbit of the sun
24 hours
the time neccessary for a planet to make one complete rotation on its axis
planetary laws
all planets orbit the sun in elliptical orbits
aphelion
the most distant point from the sun in a planets orbit
perihelion
the closest point from the sun in a planets orbit
equal areas law
planets sweep out on equal areas in equal times of their orbit
moon
earth's only natural satellite. Responsible for a variety of effects on earth
perigee
the closest point of the moons elliptical orbit around the earth
apogee
the most distant point of the moons elliptical orbit around the earth
craters
impact features on the lunar surface
tycho
the moons largest crater
maria
lunar plains that were named after seas. they are thought to be of volcanic origin
phases
daily changes in the moons appearance due to reflected light and the moons orbital position
eclipse
caused by shadows each shadow has two parts the umbra (total shadow) and penumbra (partial shadow)
lunar eclipse
when the moon passes into the earths umbra or penumbra
solar eclipse
when the moons umbra reaches the earth
tides
attractions of the moons gravity on the oceans causes two of these per day
spring tide
when the effect of the sun and moon act together to form unusually high and low tides
neap tides
when the effect of the sun and the moon are 90 degrees off for unusually low tides. Happens 1st and last quarter
seasons
the earth experiences ________ due to the axial tilt (23.5 degrees) and our revolution around the sun
rotation
the earths spinning on its axis causes night and day
revolution
the earth revolves around the sun every 365.25 days causing seasonal variations
eqinoxes
this occurs on March 21st (spring) and september 21st (autumn) this is the point at which day and night hours are equal
solstices
they occur on June 21st (summer) and December 21st (winter) those are the longest and shortest days of the year respectively. They are opposite in the southern hemisphere
Tropic of Cancer
23.5 degrees N lat. which is the most northen point where the suns rays are dirctly overhead.
Tropic of Capricorn
23.5 degrees S lat. most southern point where the suns rays are directly overhead
Arctic and Antarctic Circle
66.5 degrees N and S the point beyond which there is total darkness/daylight on the longest/shortest days of the year
Sputnik
the first satellite launched by the Russians in 1957. It accelerated the race for space in 1957. ( a dog was aboard)
Mercury
the 1st american spacecraft to carry an astronaut
John Glenn
the first astronaut to orbit the earth in the Mercury 6 (1963)
Gemini
Missions designed for 2 astronauts (1965-1967). The first docking of 2 spacecraft
Apollo
these missions carried 3 astronauts. Apollo 11 landed on the moon in 1969 (Neil Armstrong). Rocks were brought back from the moon and monitors were left behind. Shuttle missions have deployed hundreds of times since 1969.