Chapter 6 home work 11 Telescopes Flashcards Preview

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Flashcards in Chapter 6 home work 11 Telescopes Deck (65)
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31

Which of the following best describes the development of astronomical telescopes over the past 65 years?

The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built.
Over the 65-year period, telescopes have gradually gotten bigger and more powerful.
Although there have been advances in cameras and computing power, telescopes themselves have not changed much in the last 65 years.
The only major change in telescope power has occurred because of our ability to launch telescopes into space rather than operating them only from the ground.

The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built.

32

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?

It is because radio telescopes are used in the daytime and visible light telescopes are used at night.
Radio telescopes are designed to collect sound rather than light.
Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.
Objects that emit radio waves are always much larger than objects that emit visible light, and therefore require larger telescopes.

Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.

33

Which of the following studies is best suited to astronomical observations that fall into the category called time monitoring?

Measuring the rotation rate of a distant star.
Studying how different planets differ in their surface compositions.
Determining the age of the solar system.
Studying how a star's brightness varies over a period of 3 years.

Studying how a star's brightness varies over a period of 3 years.

34

Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates?

Dry regions mean less rain and clouds, and mountaintops in dry regions may even allow some infrared observations.
Mountaintops far from cities are generally subject to less light pollution than locations nearer to cities.
Being on a high mountain top means being relatively high in the atmosphere, which tends to limit turbulence.
The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

35

The stars in our sky twinkle in brightness and color because of ______.

light pollution
turbulence in the Earth's atmosphere
rapid changes in the brightnesses and colors of stars caused by changes in their spectra
the bubbling and boiling of gases on the surfaces of stars

turbulence in the Earth's atmosphere

36

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?

Stars do not twinkle when observed from space.
It is closer to the stars.
It never has to close because of cloudy skies.
It can observe infrared and ultraviolet light, as well as visible light.

It is closer to the stars.

37

The Chandra X-ray Observatory must operate in space because:

X rays are too dangerous to be allowed on the ground.
It was built by NASA.
X rays do not penetrate Earth's atmosphere.
X-ray telescopes require the use of grazing incidence mirrors.

X rays do not penetrate Earth's atmosphere.

38

Which of the following telescopes benefits most from adaptive optics?

The Arecibo radio telescope in Puerto Rico
The Chandra X-ray Observatory
The Keck I telescope on Mauna Kea
The Hubble Space telescope

The Keck I telescope on Mauna Kea

39

Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.)

Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.
Observatory Y can detect dimmer stars and Observatory X reveals more detail in images.
Observatory Y both detects dimmer stars and reveals more detail in images.
Observatory X both detects dimmer stars and reveals more detail in images.
Both observatories have the same capabilities, but Observatory Y would be cheaper to build.

Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.

40

Why can't X-ray and gamma-ray telescopes use the same designs as visible-light telescopes?

X rays and gamma rays do not penetrate Earth's atmosphere.
X rays and gamma rays have so much energy that they cannot be reflected in the same way as visible light.
X rays and gamma rays are so intense that they would melt the glass in a visible-light telescope.
Visible-light telescopes can only reflect light that we see, not any other kind of light.

X rays and gamma rays have so much energy that they cannot be reflected in the same way as visible light.

41

How much greater is the light-collecting area of one of the 10-meter Keck telescopes than that of the 5-meter Hale telescope?

2
4
8
16

4

42

Suppose astronomers built a 60-meter telescope. How much greater would its light-collecting area be than that of the 10-meter Keck telescope?

36

43

What is the angular separation of the two stars? Give your answer in degrees.

θ = 2.4×10^−6 ∘

44

What is the angular separation of the two stars? Give your answer in arcseconds.

θ = 8.7×10^−3 ′′

45

Can the Hubble Space Telescope resolve the two stars?

yes
no

no

46

Listed following are the names and mirror diameters for six of the world’s greatest reflecting telescopes used to gather visible light. Rank the telescopes from left to right based on their light-collecting area from largest to smallest. For telescopes with more than one mirror, rank based on the combined light-collecting area of the mirrors.

Large binocular telescope with two 8.4 m mirrors
Keck 1 one 10 - m mirror
Hobby-Ebberly one 9.2-m mirror
Subaru one 8.3 m mirror
Gemini North one 8-m mirror
Magellan 2 one 6.5 m mirorr

Large binocular telescope with two 8.4 m mirrors
Keck 1 one 10 - m mirror
Hobby-Ebberly one 9.2-m mirror
Subaru one 8.3 m mirror
Gemini North one 8-m mirror
Magellan 2 one 6.5 m mirorr

47

Listed below are the names, spectral types (in parentheses), and approximate masses of several nearby main-sequence stars. Rank the stars based on the distances to their habitable zones (from the central star), from shortest to longest.

Barnard's Star (m4) 0.2 Msun
61 Cygni A (K5) 0.2 Msun
Alpha Centauri A (G2) 1 Msun
Siruis (A1) 2 Msun
Spica (B1) 11Msun

Barnard's Star (m4) 0.2 Msun
61 Cygni A (K5) 0.2 Msun
Alpha Centauri A (G2) 1 Msun
Siruis (A1) 2 Msun
Spica (B1) 11Msun

48

Consider again the same set of five stars. This time, rank the stars based on the size (width) of their habitable zones, from smallest to largest.
Barnard's Star (m4) 0.2 Msun
61 Cygni A (K5) 0.2 Msun
Alpha Centauri A (G2) 1 Msun
Siruis (A1) 2 Msun
Spica (B1) 11Msun

Barnard's Star (m4) 0.2 Msun
61 Cygni A (K5) 0.2 Msun
Alpha Centauri A (G2) 1 Msun
Siruis (A1) 2 Msun
Spica (B1) 11Msun

49

Imagine that each of the five stars is orbited by a terrestrial planet at a distance of 1 AU (Earth’s distance from the Sun). Rank the stars based on the planet’s expected surface temperature (not including any greenhouse effect), from lowest to highest.

Barnard's Star (m4) 0.2 Msun
61 Cygni A (K5) 0.2 Msun
Alpha Centauri A (G2) 1 Msun
Siruis (A1) 2 Msun
Spica (B1) 11Msun

Barnard's Star (m4) 0.2 Msun
61 Cygni A (K5) 0.2 Msun
Alpha Centauri A (G2) 1 Msun
Siruis (A1) 2 Msun
Spica (B1) 11Msun

50

The items below describe worlds or selected localities on worlds. Based on our current scientific understanding, match these items to the appropriate category below. - Likely to be habitable

Moon with atmosphere orbiting jovian planet 1 au from 1 msun Star
Underground on Mars
Subsurface ocean on Europa
Surface of mars
Surface of terrestrial plante 10 au from 0.5 Msun star
volcanoes on Io


Moon with atmosphere orbiting jovian planet 1 au from 1 msun Star
Underground on Mars
Subsurface ocean on Europa

51

The items below describe worlds or selected localities on worlds. Based on our current scientific understanding, match these items to the appropriate category below. - unlikely to be habitable

Moon with atmosphere orbiting jovian planet 1 au from 1 msun Star
Underground on Mars
Subsurface ocean on Europa
Surface of mars
Surface of terrestrial plante 10 au from 0.5 Msun star
volcanoes on Io

Surface of mars
Surface of terrestrial plante 10 au from 0.5 Msun star
volcanoes on Io

52

Which statement explains the observations that make it seem possible that Mars could have life underground?

We have detected water ice on Mars, and Mars still has some volcanic heat.
We have detected subsurface wells of liquid water in equatorial regions of Mars.
We have found surface liquid water on Mars, so it should also have water underground.
Mars is located within the Sun's habitable zone.

We have detected water ice on Mars, and Mars still has some volcanic heat.

53

In Part A you found that the terrestrial planet 10 AU from a 0.5MSun star is unlikely to be habitable. Could this planet be habitable if it were in a different orbit around its star?

Yes, if it were 1 AU from its star.
Yes, but it would have to be less than 0.5 AU from its star.
Yes, if it had an eccentric orbit that sometimes brought it within 0.01 AU of its star.
No, because its star is too small to have a habitable planet.

Yes, but it would have to be less than 0.5 AU from its star.

54

As the mass of the central star increases, the distance to the habitable zone __________ and the size (width) of the habitable zone __________.
Select from the choices in the format first blank / second blank.

decreases / increases
decreases / decreases
increases / decreases
increases / increases

increases / increases

55

Suppose that our Sun was cool enough to include Mercury in its habitable zone. Which of the following would be true in that case?

Only Mercury would be in the Sun's habitable zone.
Mercury and Venus would be in the Sun’s habitable zone, but Earth and Mars would not.
Mercury, Venus, and Earth would be in the Sun’s habitable zone, but Mars would not.
All the terrestrial planets would be in the Sun's habitable zone.

Only Mercury would be in the Sun's habitable zone.

56

Scientists think it is very unlikely that complex and large forms of life could evolve on planets that orbit stars that are much more massive than the Sun. Why?

The habitable zone of a massive star is too far from the star to allow for the evolution of complex life
The expected lifetime of a massive star is too short to allow for the evolution of complex life
The habitable zone of a massive star covers too wide a range of distances from the star to allow for the evolution of complex life

The expected lifetime of a massive star is too short to allow for the evolution of complex life

57

Which of the following best describes what we mean by a habitable world?

a planet or moon that could support life, if any life happened to be on it
a planet or moon on which humans could survive if we happened to go there
a planet or moon with life
a planet or moon that lies within its star's habitable zone

a planet or moon that could support life, if any life happened to be on it

58

Which of the following places is not generally considered a potential home for life in our solar system?

Titan
Europa
Jupiter's atmosphere
Mars

Jupiter's atmosphere

59

The Sun's habitable zone _________.

consists only of Earth, since Earth is the only planet known to be inhabited
extends from the orbit of Earth to the orbit of Jupiter
extends from some place a little beyond the orbit of Venus to some place near the orbit of Mars
extends from just beyond the orbit of Mercury to just beyond Earth's orbit

extends from some place a little beyond the orbit of Venus to some place near the orbit of Mars

60

Why don't we expect to find life on planets orbiting high-mass stars?

The lifetime of a high-mass star is too short.
The high-mass stars emit too much ultraviolet radiation.
The stars are too hot to allow for life.
Planets cannot have stable orbits around high-mass stars.

The lifetime of a high-mass star is too short.