Astro 2

1.

1 point

How long does a radar signal take to travel from Earth to Venus and back when Venus is at its closest point to Earth?

140 seconds

280 seconds

8 minutes 40 seconds

radar signal cannot travel in vacuum

2.

1 point

The Heliocentric model assumes

Sun is the center of the solar system

Earth is the center of the solar system

the stars move on the celestial sphere

Earth’s axis wobbles over 26,000 years

3.

1 point

What is the escape speed on Mercury, in km/s?

1.67

3.18

3.5

4.2

4.

1 point

The extent to which Mars’ orbit differs from a perfect circle is called its:

aphelion

perihelion

focus

eccentricity

5.

1 point

In light of modern solar system theory, why do the orbits of the planets all lie in the same plane?

The Sun's gravity forced them into these orbits.

The angular momentum of the solar system was kept to a minimum this way.

The early solar nebula flattened into a disk.

This happened purely by chance.

6.

1 point

The accelerations due to gravity at Earth’s surface is 9.80 m/s2. What is the acceleration at the altitude of 1000 km? Take Earth’s radius as 6400 km and mass as 5.97 × 1041 kg.

9.42 m/s2

7.27 m/s2

1.48m/s2

it is the same everywhere

7.

1 point

What was the orbital speed of Apollo 11 command module, orbiting 10 km above the lunar surface? Take Moon’s radius as 1748 km and mass as 7.348 × 1022 kg.

1.7 hours

6600 m/s

1670 m/s

11.2 m/s

8.

1 point

What is the mean density of Mercury, in kg/m3, given that its radius is about 2440 kilometres and its mass is roughly 3.3·1023 kg?

5430

5520

1760

660

9.

1 point

An asteroid has a perihelion distance of 2.0 A.U. and an aphelion distance of 4.0 A.U. Calculate its eccentricity.

0.02

0.09

0.67

0.81

10.

1 point

The asteroid Icarus has a perihelion distance of 0.2 AU and an orbital eccentricity of 0.7. What is Icarus’s aphelion distance from the Sun?

0.4 AU

0.9 AU

1.1 AU

1.3 AU

11.

1 point

What is Venus' mean orbital speed, in km/s?

47.87

29.79

32.14

35.02

12.

1 point

What happens when a solar nebula contracts?

It flattens out.

It spins faster.

It heats up

All of the above.

13.

1 point

Which of the following have not yet been visited (fly-by or orbit) by a space probe?

Mercury

Venus

Neptune

Pluto

14.

1 point

The wavelengths of the emission lines produced by an element

depend on its temperature.

depend on its density

are identical to its absorption lines.

are different than its absorption lines.

15.

1 point

Both Jupiter and Saturn

have liquid metallic hydrogen in their interiors.

haverings

rotate very rapidly.

all of the above.

16.

1 point

Two same-size stars have temperatures of 4000K and 5000K, respectively. Decide which one radiates more energy. By what factor, approximately, does its emission exceed the emission of the other star?

emissions are identical

2.4

5.1

12

17.

1 point

When strong solar winds are displaced poleward by our magnetic fields, we get:

the Van Allen radiation belts.

intense auroral displays.

sunspots.

hurricanes in the tropics.

18.

1 point

Which statement about the rotations of the Moon and Mercury is FALSE?

Our Moon is in a 1:1 synch with the Earth, keeping the same side toward us.

Mercury is in the 3:2 synch with the Sun, with the same side Sunward at perihelion.

Like our Moon, Mercury does not rotate at all, keeping the same side facing the Sun.

On Mercury, three days exactly equal two years.

19.

1 point

Compared to the density of water, our Earth averages about:

the same density, similar to Saturn.

3 times denser, much like our Moon.

5 times denser, like the Mercury and Venus.

10 times denser, due to our core of iron and nickel.

20.

1 point

Extrasolar planets the size of Earth have NOT been seen yet with current techniques because

small planets probably don’t exist

the large planets nearby have swept them up.

Earth-like planets take time to form

large planets orbiting near to their stars are more easily detected.

21.

1 point

The Oort Cloud is thought to be:

The cloud of gas and dust from which our solar system formed.

A cloud of debris that occasionally encounters the Earth, causing a meteor shower.

A cloud of comets surrounding the solar system.

A cloud of asteroids moving between the orbits of Mars and Jupiter.

22.

1 point

What are constellations?

groups of galaxies gravitationally bound and close together in the sky

groups of stars making an apparent pattern in the celestial sphere

groups of stars gravitationally bound and appearing close together in the sky

ancient story boards, useless to modern astronomers

23.

1 point

How do the atmospheres of the Moon and Mercury compare?

Mercuryʹs is much denser, like Venus, with much carbon dioxide.

The cooler Moon retains a thicker nitrogen atmosphere.

As no spacecraft has yet landed there, no information exists about Mercuryʹs.

Neither body has a permanent true atmosphere.

24.

1 point

Why are most large telescopes reflectors, not refractors?

Large lenses deform under their own weight, but mirrors can be supported.

Large mirrors need only one optical surface.

Reflectors do not suffer from chromatic aberration like refractors do.

All of the above are correct.

25.

1 point

Which of the four inner solar system planets has the largest satellite (moon)?

Earth

Mercury

Venus

Mars

26.

1 point

Growth of an object by the accumulation of matter is called

Lagrangian process

planetary formation

assembly

accretion

27.

1 point

Mega means

×10^9

×10^-9

×10^-3

×10^6

28.

1 point

What is emitted from an atom when one of its electrons makes a transition from a higher energy state to a lower energy state?

electron

photon

proton

neutron

29.

1 point

The semi-major axis of Venus’ orbit is 0.72 AU. What is its orbital period?

0.62 years

1.32years

1.88years

11.86 years

30.

1 point

You see that Rigel appears as a bright bluish star, while Betelgeuse appears as a bright reddish star. You can conclude that Rigel is ______ Betelgeuse.

hotter than

cooler than

more massive than

older than

31.

1 point

Why does Venus appear so bright to the eye?

The planet's cloud-cover is highly reflective, reflecting 60% of the sun's light.

It gets closer to us than any other planet does.

Venus is closer to the Sun, so gets more intense sunlight.

All of the above are correct.

32.

1 point

Resolution is improved by using

larger telescopes & longer wavelengths

larger telescopes & shorter wavelengths

infrared light

lower frequency light

33.

1 point

Suppose you can move at 50% of the speed of light. How long will it take you to reach a planet 10 pc from Earth?

65.2 years

15.32years

2 years 3 months

none of the above

34.

1 point

According to the nebula theory, which of the following statements is true?

The formation of planets is a rare event not observed much in our Galaxy.

The formation of planets requires a certain set of circumstances to occur while stars form.

The formation of planets occurs separately and well after their parent star has formed.

The formation of planets is a natural by-product of star formation.

35.

1 point

The average density of each planet in the solar system is determined by taking its mass and dividing that by its:

radius.

diameter.

surface area.

volume.

36.

1 point

Mercury is very hard to observe from Earth because

its elliptical orbit causes it to change speed unpredictably.

it always appears as only half lit from Earth.

it never gets more than 28 degrees from the Sun’s glare.

its barren surface reflects too little sunlight; it is almost invisible always.

37.

1 point

Most asteroids are found:

beyond the orbit of Neptune.

between the Earth and Sun.

between the orbits of Mars and Jupiter.

orbiting the jovian planets in captured, retrograde orbits.

38.

1 point

An asteroid has a perihelion distance of 2.0 A.U. and an aphelion distance of 4.0 A.U. Calculate its period, in years.

2.1

7.4

5.2

14.4

39.

1 point

The Doppler Effect is a phenomenon that allows one to measure an objectʹs:

temperature

radius

radial motion

tangential motion

40.

1 point

“Micro” means:

×10^3

×10^-3

×10^-6

×10^-9

41.

1 point

Europa is an interesting moon because:

It has a rich atmosphere that may resemble that of the early Earth.

Europa appears to be covered by an ocean of water that is frozen on top. The ocean might be suitable for supporting life.

It is the largest of the galilean moons and therefore the largest moon in the solar system.

All of the above.

42.

1 point

Kepler’s 1st law of planetary orbits states that

planets orbit the Sun

orbits are noncircular

orbits are elliptical in shape

all of the above

43.

1 point

A certain space-based telescope can achieve (diffraction-limited) angular resolution of 0.05" for red light (of wavelength 700 nm). What would its resolution be in the ultraviolet, at 140 nm?

0.022"

0.01"

0.14"

0.25"

44.

1 point

Rank the planets from left to right based on the amount of time it takes them to orbit the Sun, from longest to shortest.

Venus, Mars, Jupiter, Saturn, Neptune

Neptune, Saturn, Jupiter, Mars, Venus

Mars, Venus, Jupiter, Saturn, Neptune

Neptune, Jupiter, Saturn Mars, Venus

45.

1 point

On which of the following planets have scientists landed a space probe?

Only Mars

Only Venus

Mars and Venus

Mars, Venus and Mercury

46.

1 point

Almost all of our atmospheric gases lie in the:

ionosphere

stratosphere.

troposphere.

ozone layer.

47.

1 point

What is thought to be the cause of Io's volcanos?

Jupiter's magnetosphere

Jupiter's gravity.

Tidal stresses from both Jupiter and Europa.

Radioactive decay in Io's interior.

48.

1 point

What is the second-largest moon in our Solar System?

Titan

Ganymede

Callisto

Europa

49.

1 point

According to Kepler’s 2nd law, Jupiter will be travelling most slowly around the Sun when at:

aphelion

perihelion

focus

eccentricity

50.

1 point

The Greenhouse Effect works by trapping:

incoming ultraviolet radiation from the Sun.

outgoing ultraviolet radiation from the Earth.

incoming infrared radiation from the Sun.

outgoing infrared radiation from the Earth.