Phscs 127 Exam 1 Worksheet

Front 1

Arrange the following objects by their distance from the earth. Pleiades star cluster, Pluto, Saturn, the Pisces-Perseus supercluster of galaxies, the Andromedia galaxy, center of the Milky Way, Betelgeuse.

Back 1

Saturn
Pluto
Pleiades
Betelgeuse
Milky Way
Andromeda Galaxy
Pisces Perseus Supercluster

Front 2

We measure objects in the sky by their ________ size.

Back 2

Angular

Front 3

What is a distance measure determined by the parallax of a star which is the shifting of its position against the background sky every 6 months.

Back 3

Parsec

Front 4

One parsec is equal to ___ light years.

Back 4

3.26

Front 5

Which planets/stars from the worksheet can you measure using Parallax?

Back 5

Saturn, Betelgeuse, Pluto, Pleides. The rest are too far away.

Front 6

_____ pc is the greatest distance that can be resolved using parralax.

Back 6

1000 pc.

Front 7

All matter with a temperature above zero degrees on the Kelvin temperature scale gives off what?

Back 7

Radiation

Front 8

A dense, hot object, like the interior of a star, glows like a _________ —which is anything that absorbs all radiation that hits it and reradiates it back.

Back 8

Blackbody

Front 9

_________ is any perfect absorber of light will look black at room temperatures.

Back 9

Blackbody

Front 10

A glowing blackbody produces a __________ spectrum of electromagnetic radiation.

Back 10

continuous

Front 11

If radiation passes through a rarified gas cloud, then it will have ____________ created in it.

Back 11

Absorption lines

Front 12

When the gas re-radiates the subtracted light, it creates a(n) ____________ spectrum.

Back 12

emission line

Front 13

The absorption lines, continuous, and emission line spectrum are known as _________ laws.

Back 13

Kirchoff's laws

Front 14

What law says that the peak wavelength of the light from a blackbody multiplied by its temperature is equal to a what?

Back 14

Wien's Law and Constant.

Front 15

List the radiation type for each of the Objects: Gas spiraling into a black hole, A very hot star, A star like the Sun, A human being, An interstellar gas cloud, The universe as a whole.

Back 15

X-ray, UV Rays, Visible, IR, Far IR, Microwave.

Front 16

The __________ Law says that the TOTAL energy given off by every square centimeter of a blackbody is equal to a constant multiplied by the fourth power of the temperature.

Back 16

Stefan-Boltzman

Front 17

If an electron absorbs a photo what level would it be if it had absorbed the reddest of the Balmer series photons, hydrogen a.

Back 17

It moves AWAY from the Nucleus, UP from level 2 to level 3.

Front 18

If an electron sits on the third level, what does an electron do when it produces a Lyman series line.

Back 18

It progresses TOWARD the Nucleus, from the 3rd level to the 1st level.

Front 19

A technique of determining distance that is calibrated by parallax uses a relationship called what?

Back 19

The inverse square law

Front 20

Light dims as the square of the distance away from the source - what law is this?

Back 20

Inverse square law

Front 21

_________ are a logarithmic expression of brightness.

Back 21

Magnitudes

Front 22

A magnitude difference of 1 means that the brightness ratio is a factor of _____?

Back 22

2.512

Front 23

What element is 75% of the universe, what element is 23%?

Back 23

Hydrogen, Helium

Front 24

Which law says that If you double the temp, you cut the peak wavelength in half.

Back 24

Wien's Law

Front 25

Which law says if you double the temp, than there is 16x more energy coming off the surface of the large than the small

Back 25

Stephan Boltzman Law

Front 26

Apparent Magnitude, you give the brightest stars _ and the faintest stars 6

Back 26

1 bright, 6 faint

Front 27

The more negative the color index the more ____ it is.

Back 27

blue

Front 28

A blackbody gives off a rainbow light, missing no colors – this is called a

Back 28

continuous spectrum

Front 29

The light we receive from stars nearly always has pieces called _______ _____ missing from the spectrum

Back 29

Spectral Lines

Front 30

the study of magnitudes and colors and is best for studying lots of objects at once

Back 30

Photometry

Front 31

What is the detailed study of the entire spectrum and is best for chemical and motion analysis.

Back 31

Spectroscopy

Front 32

_ _ _ _ _ _ _ is a mnemonic used to remember the spectral sequance of stars arranged in order of temp.

Back 32

OBAFGKM

Front 33

A magnitude difference of 5 is exactly ___.

Back 33

100

Front 34

Originally the stars were classified by the strength of their hydrogen Balmer absorption lines, with the lines of type ___ being the strongest.

Back 34

A

Front 35

Later it was found that stars of type __ were the hottest and type __ were the coolest so the spectral type sequence was rearranged to be a temperature sequence.

Back 35

O and M

Front 36

The ____ ________ line is in the middle of the HR diagram.

Back 36

Main Sequence

Front 37

Where would you put giants, super-giants, and white dwarfs on an HR diagram?

Back 37

White dwarfs, bottom left
Super-giants, top right centerish (between F and G)
Giants - top right centerish.

Front 38

Giants and Supergiants only make up ___% of the population of all stars.

Back 38

1%

Front 39

most of the stars we see with our eyes in the night sky are what?

Back 39

luminous giants and supergiants

Front 40

By the inverse square law the hotter star can be the square root of 16 or 4 times fainter and yet appear....

Back 40

just as bright as the cooler star

Front 41

Most main sequence stars have about the same _________, so the hotter stars can all be seen to greater distances.

Back 41

diameter

Front 42

_____ gives us the shape of the blackbody curve.

Back 42

color

Front 43

The more negative the index the _____ the light.

Back 43

Bluer

Front 44

The bluer the light, the ______ the object.

Back 44

hotter

Front 45

What two things do we need to know in order to place it on an HR Diagram?

Back 45

Spectral type (color index) and Luminosity class.

Front 46

Knowing the ________ _________, we can measure the _________ _________ subtract the absolute magnitude from it, and use that to find the distance.

Back 46

absolute magnitude - apparent magnitude.

Front 47

___________ stars are the stars that are always visible in a particular location on the earth.

Back 47

Circumpolar

Front 48

Circumpolar stars in the north ____ be seen by observers in the south and vice versa.

Back 48

Can't

Front 49

The ___________ coordinate is divided into hours, minutes, and seconds. Its zero point is the ______ Equinox.

Back 49

Vernal Equinox.

Front 50

The greatest time value RA can have is __ hours.

Back 50

24

Front 51

The declination coordinate is divided into _______, minutes, seconds.

Back 51

DEGREES

Front 52

The declination coordinate zero line is the ________ equator.

Back 52

Celestial

Front 53

The greatest value that the dec coordinate is __ degrees.

Back 53

90

Front 54

Identify the times of the a) summer solstice; b) winter solstice; c) autumnal equinox; and d) vernal equinox. (North, South, East, West of the sun)

Back 54

North - Vernal Equinox
West - Summer Solstice
South - Autumnal Equinox
East - Winter Solstace

Starting top of counter clockwise - Spring/Summer/Fall/Winter

Front 55

Explain the Vernal Equinox and what it does on the celestial equator.

Back 55

Where the sun CROSSES or intersects the celestial equator going north - it does so on March 21st.

Front 56

Give two reasons why it is hot during the summer in the northern hemisphere.

Back 56

The sun's rays are more direct and The days are longer

Front 57

A Moon that is new and getting more illuminated every night, is in the ______ ________ portion of it's cycle.

Back 57

Waxing crescent

Front 58

When it passes the first quarter, it enters the ______ _______ portion.

Back 58

Waxing gibbous

Front 59

After it is full and begins to decrease in illumination, it is in the ______ _______ portion.

Back 59

Waning gibbous

Front 60

When the moon is in the third quarter it enters the ______ ________ portion.

Back 60

Waning Crescent

Front 61

A _____ or ________ day is defined as being the time interval between when the Sun is directly overhead and is exactly 24 hours.

Back 61

Solar or Synodic day

Front 62

A _________ day is defined as being the interval between times when a star is directly overhead and is about 23 hours 56 minutes.

Back 62

sidereal

Front 63

In a Sidereal day, if a star crosses the meridian at 8:00 PM one night, the next night it will cross the meridian at _____.

Back 63

7:56

Front 64

What is precession?

Back 64

Precession is the slow, regular “wobble” of the Earth’s axis with respect to the stars.

Front 65

What causes the north celestial pole to change position, going in a circle with a period of 26,000 yrs.

Back 65

Precession - the wobble of the earth's axis.

Front 66

The right ascension and declination coordinates for all stars change slightly every ____.

Back 66

Year

Front 67

In 13,000 years summer will still be in July and winter in January. However the ____ _____ __________ will change and in 13,000 years the current winter constellations will appear in July and the current summer constellations will appear in January.

Back 67

night time constellations

Front 68

When a full Moon sets in the west:

Back 68

At Sunrise

Front 69

when a 1st quarter moon is directly overhead

Back 69

At Sunset

Front 70

When a new Moon is directly overhead

Back 70

Noon

Front 71

When a 3rd Quarter Moon rises in the east

Back 71

Midnight

Front 72

Identify the a) new Moon; b) 1st quarter Moon; c) full Moon; and d) 3rd quarter Moon. Identify using North, South, East, West.

Back 72

North - 1st quarter
West - Full Moon
South - 3rd Quarter
East - New moon

Front 73

Is the dark side of the moon the same as the far side of the moon?

Back 73

(quick answer, no, not ALWAYS) The dark side is the side facing away from the sun. The far side is the side facing away from the Earth. As the Moon orbits the Earth the far side always remains the same but the dark side does not. It constantly changes with the lunar phases. At new moon the far side is illuminated and at full moon the far side is dark.

Front 74

If you lived on the moon would you see the earth rise and set or would it stay in the same place?

Back 74

Stay in the same place.

Front 75

A _____ eclipse occurs when the Moon passes into the Earth's shadow.

Back 75

Lunar

Front 76

There can be either a _______ eclipse if the Moon is not completely within the umbra of the Earth's shadow or a _____ eclipse if it is entirely obscured.

Back 76

Partial and Total

Front 77

Total and partial eclipses (lunar) only occur when the moon is at the _____ phase.

Back 77

Full

Front 78

A _____ eclipse occurs when the Earth passes into the Moon's shadow.

Back 78

Solar

Front 79

if the shadow umbra doesn't touch the surface of the Earth at all it is called an _______ eclipse. These occur only when the Moon is at the ___ phase.

Back 79

Annular and New phase

Front 80

The ____ of ______ which is the intersection of the plane of the Moon's orbit with the plane of the Earth's orbit, must be pointing at the _____ for an eclipse to occur.

Back 80

Line of Nodes and Sun

Front 81

The yearly path that the Sun traces on the celestial sphere is called the ______ because this is the only place where eclipses can occur.

Back 81

Ecliptic

Front 82

By measuring the length of the shadow and the height of the obelisk, and knowing the distance between Syene and Alexandria, Eratosthenes was able to derive the ____________ of the Earth using geometry.

Back 82

Circumference