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geo > chapter 18 Review > Flashcards

chapter 18 Review Flashcards

1
Q

The ________ is the totality of all matter, energy, and space.

A

Universe

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2
Q

the huge imaginary sphere of the sky on which all the stars seem to be located is the __________

A

celestial sphere

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3
Q

A ________ is the distance (3.26 ly) to an object with a parallax of 1 arc second.

A

parsec

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4
Q

The layer of the sun that we see is the ________

A

photosphere

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5
Q

_____________ is a measure of the brightness of a star as seen from earth.

A

Apparent magnitude

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6
Q

________ is a measure of the brightness of a star if I we seen from a standard distance of 10 pc (32.6 ly).

A
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7
Q

The band of stars from the upper left to the lower right in above plot that most stars fall into is the ____________.

A

main sequence

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8
Q

The relatively cool bright stars with diameters 10-100 times that of the sun are the __________

A

red giants

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9
Q

________ are cool denser clouds of interstellar gas and dust

A

nebula

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10
Q

The shell of gas ejected from an old low mass stairs a __________

A

planetary nebula

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11
Q

A white dwarf star that suddenly increases dramatically in brightness for a brief period of time is a ____________

A

nova

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12
Q

when a star explodes it is a ___________

A

super nova

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13
Q

All elements heavier than _______ are made in _______ explosions.

A

iron, supernova

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14
Q

A _______ is The extremely dense remnant of a high mass star that is made of neutrons

A

neutron star

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15
Q

A rapidly rotating that appears to pulse on and off is called a __________

A

pulstar

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16
Q

A large gravitationally bound collection of stars and gas is a _________

A

galaxy

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17
Q

Galaxies come in 3 types

A

elliptical
spiral
irregular

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18
Q

The additional mass required the keep galaxies gravitationally bound that we cannot see is called ________.

A

black matter

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19
Q

The study of the structure and history of the the entire universe is

A

cosmology

20
Q

Hubble’s law say the further away a galaxy is the _________ it is travelling away from us

A

faster

21
Q

The force accelerating the expansion of the universe is called

A

energy

22
Q

The universe is expanding because the __________ itself is expanding.

A

space

23
Q

The _______Theory of the beginning of the universe states that the known universe was smaller, hotter, and denser in the past, and that it began rapidly expanding 13.8 billion years ago.

A

Big Bang

24
Q

What is the point on the celestial sphere representing the extension of the axis of Earth’s North Pole?

A

North celestial pole

25
Q

What is the name of the path on the sky that the Sun appears to follow as it moves among the stars?

A

the ecliptic

26
Q

Define the term cosmology.

A

The branch of astronomy that is the study of the structure and evolution of the universe.

27
Q

Which is the larger unit of distance, the light-year or the parsec?

A

the parsec

28
Q

Why are sunspots darker than the regions of the Sun around them?

A

They are cooler than the surrounding material.

29
Q

Where in the Sun does fusion of hydrogen occur?

A

only in the core

30
Q

What is the approximate temperature (in K) of the Sun at its surface?

A

6,000 K

31
Q

A relatively cool star is what color?

A

red

32
Q

Which star is closest to the Sun?

A

Proxima Centauri

33
Q

A white dwarf has about the same diameter as which of the following?
the Earth
Texas
the Sun
Jupiter

A

the Earth

34
Q

How big will the Sun become as a red giant star?

A

It will engulf the orbits of Mercury, Venus and possibly the Earth.

35
Q

Define the term nucleosynthesis.

A

the creation of nuclei inside stars

36
Q

Describe how the mass of a star plays a role in the lifetime of a star.

A

The more massive the star, the shorter the lifetime.

37
Q

What is the fundamental quantity of a star that indicates its ultimate fate?

A

Mass

38
Q

What event is believed to create elements heavier than iron?

A

a supernova explosion

39
Q

What is dark matter?

A

unknown exotic matter

40
Q

How much of the universe appears to be normal ordinary matter?

A

5%

41
Q

What is the cosmic background radiation?

A

the light-energy remnants of the explosion in which the universe was born

42
Q

What key observation led Hubble to conclude that the universe is expanding?

A

the redshift of light from distant galaxies

43
Q

What is the galaxy classification of the Milky Way galaxy?

A

barred spiral galaxy

44
Q

What is a quasar?

A

The core of a young very active galaxy observed when the universe was very young.

45
Q

The Milky Way is classified as what kind of galaxy?

A

spiral

46
Q

Black holes appear black for what basic reason?

A

Light cannot escape them.

geo (4 decks)

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