Astronomy Test #2 and SG #2

EM spectrum
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Terms in this set (48)
EM spectrum
Complete spectrum of light wave lengths
Longest to shortest
Radio Infrared visible light x-rays gamma
How to unravel message in EM spectrum
1. Pass narrow beam of light through prism
2. Find brightness (Stars spectrum)
Longer wavelength light energy that can be sensed by a thermometer
Infrared
invisible short-wavelength light energy
Ultraviolet
Blackbody radiation
spectrum that is determined by the temperature alone. Temperature of object determines wavelength
Higher temperature=
Lower temperature=
Shorter wavelength
Longer wavelength
Emission spectrum
used to figure out what elements are in the gas we're heating. (bright lines against dark background)
absorption spectrum
lines that show information about the stars composition (Dark lines on a rainbow)
continuous spectrum
complete range of wavelengths without any spectral lines
Describe the information gleaned from starlight that has been separated by color.
Elements-composition of star
Name the three components to measuring radiationCollect and focus light Sort the radiation by wavelength Detect and record dataLight gathering powerGather and focus light from distant and dim objectsResolving powerResolve closely spaced features (depends on LGP)Bigger the diameter-aperatureMore LGP it hasReflecting telescope1. Use mirrors instead of lenses 2. Much lighter and less expensiveRefracting telescope1. Uses only glass lens for magnification 2. Most crisp image 3. Heavy and expensiveExplain why the largest telescopes are reflecting and not refractingserious limitation on how large the telescope's aperture can be because they require a large area of unsupported glassDiscuss the ways in which the atmosphere is not helpful to astronomy, and ways around itWeather Atmosphere Light Pollution going to dry climates away form light and not too cloudy will mean more accurate imagesDescribe how to apply trigonometric parallax-Create triangle with the sun right triangle with earth sun and star -try to find the parallax angle from sun to star, angle will be smaller if star is futher away -use a parsec to find distance from earth to starDiscuss problems related with applying Astronomy to AstrologyWithout knowing the type of light source, the apparent magnitude cannot tell you the distance. You need the apparent magnitude and absolute magnitude-luminosity to find the distance to the starOrder of stars by color from hottest to coolestOBAFGKMHow are stars classified1. Barcode (Absorbtion line spectrum) 2. Temperature (OBAFGKM)What are stars made ofHydroge, Helium small amount of carbon, nitrogen, oxygen and ironHow we know what stars are made ofDifferent elements show up more clearly depending upon temperatureRed Giant stars- White Dwarfs--upper right corner cool, very bright stars, huge -lower left corner hot, dim stars, smallDiscuss how stars are born and live out the majority of their lives-Raw materials collapse -Protostar begins to spin -Eventually, fusion of H into He begins 90% of their livesDescribe how clusters of stars allow us to better understand stellar evolution-Globular clusters tend to consist mainly of very ancient stars leave main sequence and become red giants3 types of star deaths-Low mass: White dwarf -Medium mass: Neutron star or pulsar -High mass: Black holeLow mass star death1. Red giant runs out of He 2. 2nd stage giant fusion ceases 3. Become planetary nebula 4. White dwarf to black dwarf 5. If in binary system become type 1 supernovaHigh mass star death1. Red giant continues to fuse heaver elements until Fe forms 2. Contraction causes Electrons to Enter nuclei 3. Neutrons take energy to the outer shell causing Type II supernova (Which can also lead to black hole) 4. Core is called neutron star if emits radiation then pulsardifference between type I and II supernova-Type II supernova form from the core-collapse of a massive star -Type I supernova form from the explosion of a white dwarf starLow mass star evolution1. Interstellar cloud 2. Main sequence star 3. Red giant 4. Planetary nebula 5. White dwarf 6. (if Binary system type 1 supernova)Medium-High mass star evolution1. Interstellar cloud 2. Main sequence star 3. Red giant 4. Type 2 supernova 5. Neutron star if medium 6. Black hole if highWhat evidence is used to 'see' black holes?When Matter near the black hole rubs together, it gives off x rays we can see. We can also see gravitational wavesExplain the relationship between the event horizon and escape velocityAt the event horizon, the escape velocity is equal to the speed of light, since not even light can escape need tachyonsDiscuss three pieces of evidence that support the theory of relativity1. gravitational lensing (Space time bends altering path) 2. Time Dilation (space time fabric stretched making time go by slower) 3. Fabric (Fabric tells matter how to move)Three attributes a theory most possesF I T S E V I D E N C E ? T E S TA B L E? FA L S I F I A B L E ?Describe the scientific definition of a theory and a hypothesis-A hypothesis is a reasonable guess based on what you know or observe. -A scientific theory consists of one or more hypotheses that have been supported with repeated testing.The theory of relativity says what about space and time?fabric-force of gravity is caused by the curvature of space and time.identify the 4 different galaxy types and the age range of stars each contains1. Elliptical Galaxies 2. Spiral Galaxies 3. Barred Spirals 4. Irregularsred-shift and how it is this related to recessional velocity of galaxies.If a light source is receding, the wavelength that we recieved is actually longer, redshiftedSpectroscopic Parallax1. measure the stars apparent magnitude 2. Identify spectral class 3. Use HR diagram to find luminosity 4. Compare apparent and absolute magnitude to determine distanceProvide and explain evidence that the universe is expanding1. Hubbles law 2. Red Shift 3. Big bang 4. lower temperatures less denseEvidence that supports big bangHubble's law The age of globular clusters Leftover heat seen in the whole universeDescribe what we can learn about the universe by running Hubble's law in reverseIt was very dense, hot, no matter existed,how we infer the age of the universe from this diagramif we run time backwards we can determine how long it took galaxies to reach their current positionscientific methodObserve look for patterns Imagine explanations Predict tell peoplehubbles law of expansion equationv=hd (speed at which galaxy is receding is distance multiplied by a value that tells how fast universe expanding)