VocabularySpectrograph – device that breaks up the incoming light into colors

and takes a picture of that spectrumGalaxy – a cluster of starsUniverse – space and everything in itLight year – distance light travels in one year (300,000km per sec. or

9.5 million million km per yr.)Parallax – the way an object appears to change depending on the place

from which you are viewing itApparent magnitude – brightness of a star as if viewing it from Earth Absolute magnitude – brightness of a star as if it were a standard

distance from Earth

Tools of Modern Astronomy

Reflecting Telescope

Radio Telescopes

CaliforniaArecibo

Observatories

Satellites

Spectrograph

Takes in light and breaks it down into a spectrum that the astronomer can use to determine the chemical composition andtemperature of a star. Each element absorbs light at differentwavelengths which appears as a black lineon a spectrum. Each chemical has a unique set of lines. The amount of energy each element absorbs depends on the temperature of the star. By comparing the spectrum of a star to the known spectrum at certain temperatures the astronomer can infer how hot the star is burning.

Lab 13 Flame TestQuestion: What can the color an element burns tell an astronomer about a star?Hypothesis:Materials: goggles apron Bunsen burner

tongs copper sulfate calcium chloridesodium chloride potassium chloride strontium chloridenichrome wire spectrograph

Procedure: 1. Observe all safety precautions while completing this lab. Lab aprons are to be worn at ALL times. Goggles will be worn by the person burning the chemical. When not looking through the spectrograph all others will wear goggles. 2. Be sure the nichrome wire is completely cleaned before burning the next chemical. Wash the wire under the faucet and then burn it in the flame making sure it clean. 3. Once the burner is lit, place the wire loop in chemical A. Then place the loop in the flame. Observe the color of the flame. Have one person in the group observe the colored flame through the spectrograph to see if they can see the lines produced by that chemical.

4. Record the color of the flame in the data table.5. Repeat step 3 for each chemical you have been given.6. Once all the chemicals have been burned you will then need to check on the board to determine which chemical is which based on

the color of the flame.

Results:

Conclusion:

Element Letter Color Name of Chemical

A    

B    

C    

D    

E    

Data Table

Measuring Stars Distance

Are billions of galaxies in the universeGalaxies are very far apart – most of the universe is empty

spaceOur galaxy is the Milky Way – closest galaxy to us is the

Andromeda GalaxyBecause of the great distances in space astronomers use

the unit of the light year to indicate distanceIn order to measure a stars distance use parallax by measuring star when Earth is on one side of the sun and then again 6 months later when Earth is on the other side of the sunThe amount the star appears to have moved is measured

and used to calculate the star’s distanceThis is only good for stars less than 1000 light years from

Earth

Classifying StarsUse size, temperature, and brightness to classify starsSize:

all appear to be the same in the night skycan be giant stars or supergiantothers may be white dwarfs or neutron stars these are smaller than our sun

Color and Temperature:color reveals temperaturecoolest stars look reddishsome can be white or blue-white which is the hottest

Brightness:is the amount of light given offdepends on size and temperatureabsolute magnitude is determined by apparent magnitude

and distance from Earth

Hertzsprung-Russell Diagram

Diagram used to plot temperature and

brightness of stars

When plotted - patterns formed

Compiled by Ejnar Hertzsprung from Denmark and Henry Norris Russell from the US

Lab 14 How Old Are The Jewels?

Vocabulary

Pulsar- pulsating radio sourceNebula – lg. amount of gas and dust spread out in a large

volumeProtostar – earliest stage of a star’s lifeWhite dwarf – blue-white core of a left over starSupernova – explosion of a giant or supergiant starNeutron star – star formed from material left from a supernovaBlack hole – left from a massive star, mass may be 5 times that of the sun packed in a space 30km in diameterQuasar – object very far and very brightBinary star – a 2 star systemEclipsing binary – system in which one star blocks the light from the second star

www.seasky.org

Quasars

Discovered in the 1960’sAre unusual – are very far

away, very brightAre thought to be distant

galaxies with a blackhole in the middle

news.bbc.co.uk

Star Systems

Can have double star system

Considered a binary starsystem

If one blocks light from another is called an eclipsing binary

An X-ray image of the Sirius star system located 8.6 light years from Earth.

chandra.harvard.edu

Can also have a triple star system

www.jpl.nasa.gov/.../newplanets/pia03521-250.jpg

Galaxies

www.windows.ucar.edu www.adg.us

Have spiral galaxies

This dwarf elliptical galaxy is is being ripped by tidal forces into long streams of stars that will eventually be merged into the Milky Way (more from IAC and Astronomy Picture of the Day).

Elliptical Galaxies

NGC 1569 is a dwarf irregular galaxy that gave birth to thousands of new stars about 25 million years ago.

stardate.org/.../galaxies/NGC-1569_220x220.jpg

Irregular Galaxies

History and FutureTo study future need to look at presentAre able to tell that only a few galaxies are moving toward ours,

others moving awayPresent theory believes was enormous explosion 10 to 13 billion

years ago – referred to as “Big Bang”Big Bang began formation of universe – everything began

forming at that timeAbout 5 billion yrs ago our solar system began to form –

matter was pulled into center by gravity to form sun when nuclear fusion began

Planets began to form from gas and dust – both inner and outer ones

Beyond Pluto is lg. cloud of ice and other substances – is likely source of comets

So, what happens next:

Have several theories – universe will keep expanding and objects will get farther

apart at some point the universe will begin coming back

together until everything is compacted back into a lg. mass similar to original

Many questions still unanswered

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