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Social Welfare > The Universe Final > Flashcards

The Universe Final Flashcards

0
Q

All stars are isolated

A

False

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1
Q

All stars last forever

A

False

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2
Q

Black holes are like huge vacuums in space, sucking everything in.

A

False

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3
Q

Parallax is the measurement of …

A

the apparent motion of a star over the time due to a change in perspective of the observer

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4
Q

Stars A and B have the same apparent brightness, but Star A is twice as far away as star B. Therefore Star A is __________ as luminous as star B.

A

four times

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5
Q

For two stars of unequal masses in a binary system, the mass lies…..

A

closer to the more massive star

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6
Q

For main sequence stars, the hottest stars are also the …..

A

most massive

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7
Q

The most massive start end all fusion with a core composed of….

A

iorn

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8
Q

If a stars core were to suddenly start making less energy than normal, the following chain of reactions would occur: the stars pressure would_____, which would cause the star to____, which would cause the temperature in the stars core to____, which would return the energy production rate to its normal level.

A

decrease, contact, increase

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9
Q

If the sun were replaced by a 1-solar-mass black hole, what would happen to its gravitational influence of the earth?

A

It would stay the same

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10
Q

Why are black holes said to be black?

A

The velocity needed to escape from a black hole is greater than the speed of light, so not even light can escape.

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11
Q

Is it possible to detect low-mass black holes?

A

yes, by detecting radiation being emitted by gas falling into a black hole.

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12
Q

What happens if the mass of a white dwarf is pushed above 1.44 solar masses?

A

It explodes as a Type la (thermonuclear) supernova

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13
Q

The fact that we find O and B stars in the disk of our galaxy but not the halo suggests that….

A

star formation still occurs in the disk, but not in the halo

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14
Q

If astronomers miscalculated earth distance from the center of the galaxy and we’re actually much farther out, how would that effect our calculation of the mass of the galaxy inside earths orbit?

A

it would be greater than calculated

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15
Q

Most of the matter in our galaxy is in the form of …

A

dark matter

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16
Q

What evidence do astronomer shave that a super massive black hole lies at the center of our galaxy?

A

all of the above

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17
Q

Seasons are caused by earth changing its distance from the sun as it orbits the sun

A

False

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18
Q

X-rays are a form of light, and because of this, will travel at the speed of light.

A

True

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19
Q

All stars are the same color

A

False

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20
Q

In modern science, skepticism is considered to be…

A

essential

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21
Q

The daily motion of the heavens results from the…

A

spin of the earth on its axis

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22
Q

Which of the following describes on reason that eh Northern and the Southern hemispheres have different seasons

A

during a day of the year when the sun is high in the sky the northern hemisphere it will be low in the sky in the Southern Hemisphere

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23
Q

Some telescopes are placed in space above earths atmosphere primarily for which of the following reasons

A

the light from stars can be blocked by the earths atmosphere

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24
Q

The graph on the right shows the black body spect of three different stars. Which of the stars is at the highest temperature?

A

Star A

25
Q 
Scientific Notation-
one thousand
one million
one billion
one tenth
A

1000- 10^3
1 mill- 10^6
1bill- 10^9
1/10- 10^-1

26
Q

Star Q has more total energy output that Star Z. Star Z has a higher surface temperature than Star Q. This means that….

A

Star Q is larger than Star Z

27
Q

Which object would be at rest?

A

Object C

28
Q

Of the objects that are moving, which is moving at the fastest speed

A

Object A

29
Q

Two objects of different masses are pushed with the same amount of force. Which will accelerate more?

A

The lighter, less massive object

30
Q

Why should you never look directly into the sun

A

can cause blindness

31
Q

Energy from the sun allows life to exist on Earth. The source of the suns energy is:

A

Thermonuclear fusion reactions in which light nuclei combine to rom a heavier nucleus.

32
Q

Sunspots are cooler that he rest of the suns surface, sometimes by as much as 1500 degrees K. What would be the peak wavelength of radiation from the sunspot, when compared to that from the rest of the sun?

A

It would be longer

33
Q

Explain what is meant by the luminosity of the sun.

A

The suns luminosity is the amount of energy in each second

34
Q

Newton thought the universe was infinite because..

A

he reasoned that gravity would cause a finite universe to collapse

35
Q

In a infinite universe…

A

the night sky would be vary brights

36
Q

Olbers’s paradox arises when we attempt to answer the question…

A

Why is the sky dark at night

37
Q

In an expanding universe, the light of objects that are twice as far away will be….

A

stretched twice as much to redder colors

38
Q

Olbers’s paradox was resolved because the universe is

A

not infinitely old and is expanding

39
Q

Except for some quite nearby galaxies, we see all galaxies moving away from us, with more distant galaxies moving faster. What would an observer in a distant galaxy see?

A

the same thing we see- all distant galaxies moving away from, with more distant galaxies moving faster

40
Q

The light from more distant galaxies is more redshifted becasue

A

the photons have been traveling through expanding space for a longer time

41
Q

Out observable Universe…

A

gets longer over time, as more light reaches us from more distant locations

42
Q

According to Big Bang Theory, we can not see past the….

A

cosmic light horizon defined by the finite age of the universe

43
Q

If you were to measure the peak wavelength of the spectrum of the CMB a few billion years ago, it would be…

A

shorter that today

44
Q

The temperature of the cosmic microwave background is 2.725k. At what point in the history of the universe did the radiation cool to this temperature?

A

380,000 yrs after the Big Bang began, when the universe became transparent and radiation was able to travel freely.

45
Q

The cosmic microwave background is

A

left over radiation from the Big Bang itself, greatly redshifted by the expansion of the universe

46
Q

Isotropy Problem and the flatness problem were both solved by the theory that

A

just after Big Bang the universe suddenly increased in size by a factor of 10^50

47
Q

If the universe is closed, then parallel lines….

A

eventually come together and intersect as they extend into space.

48
Q

If space is Hyperbolic then initially parallel light beams will subsequently

A

always diverge

49
Q

The key piece of evidence showing that the expansion of the universe is accelerating is that the….

A

most distant Type Ia supernovae are fainter than they would be if they expansion were not accelerating

50
Q

Our current understanding of the material in the universe is that it consists of matter and dark energy. What percentage of this is matter?

A

27%

51
Q

If the universe were expanding twice as fast, then the Hubble plot would be….

A

twice as steep as it is now

52
Q

The expansion of the universe

A

has been accelerating ever since Big Bang

53
Q

Describe a suns life cycle

A

The sun will not explode,

however the Outside cools while the inside heats up causing the sun to eventually puff out becoming a white dwarf

54
Q

If the astronomers miscalculated earths speed around cent of galaxy and we’er actually moving much slower, how would this affect our calculation of the mass of the galaxy inside the earth orbit?

A

Less than calcualted

55
Q

Stars farther out from center galaxy travel ____ distance over time and complete one rotation ______ we do.

A

the same, slower than

56
Q

Cepheid Variable

A

the more luminous the cepheid the long the pulsation period

57
Q

Spiral Galaxies

A

have spiral arms and large center bulges. The arms contain hot, young, blue stars - indicated ongoing star formation- little star formation in the center bulge.

58
Q

Barred Spiral Galaxy

A

spiral arms originate at the end of bar shape running though nucleus. categorized by size of central bulge

59
Q

Elliptical galaxies

A

elliptical shapes with no spiral arms, round and flat, no gas or dust- no star formations-

60
Q

Which of the rungs on the distance ladder depend on an accurate measurement of parallax?

A

all rungs of the ladder are completely dependent on an accurate understand of brightness and as determined by parallax

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