Question 12 pts
- You Discover a New Planet! (8 points)
You are using a telescope to discover new planets using the transit technique. You found one! You call it “planet b”.
Here is your observed transit light curve:
(note: if the image does not appear, right click to download and view)
- (2 points) Based on the transit light curve, what is the orbital periodof planet b (in days)?
Question 22 pts
- (2 point) What is the transit depth(in percent)?
Question 32 pts
- What planet property can we use the transit depth to measure?
Group of answer choices
Mass
Radius
Orbital period
Temperature
Semi-major axis
Question 42 pts
- (2 points) Your planet is orbiting a star like the Sun. If it were orbiting a larger star (with the same brightness as seen from Earth), would it be easier, harder, or about the same difficulty to observe the transit?
Group of answer choices
Easier
Harder
The same difficulty
Question 53 pts
- Radial Velocity Planets (10 points)
Your friend shows you the following radial velocity curves:
- (1 point each) What’s the estimated orbital periodof each planet?
Planet A: days
Planet B: days
Planet C: days
Question 62 pts
- (2 points) List the planets in order of increasing radial velocity amplitude:
Group of answer choices
A, B, C
A, C, B
B, A, C
B, C, A
C, A, B
C, B, A
Question 72 pts
- (2 points) Which radial velocity curve shows a more massive planet, A or C? (assume they orbit the same kind of star).
Group of answer choices
A
C
they have the same mass
it’s impossible to tell from the radial velocity curve alone
Question 82 pts
- Measuring Planet Properties (14 points)
You measure the masses, radii, and semimajor axes of 6 new planets:
Planet b: M=10 MEarth, R=2 Earth a=0.01 AU
Planet c: M=5 MEarth, R=1.6 REarth a=0.04 AU
Planet d: M=1 MEarth, R=1 Earth a=0.06 AU
Planet e: M=5 MEarth R=4 REarth a=0.09 AU
Planet f: M=17 MEarth R=2.2 REarth a=0.11 AU
Planet g: M=17 MEarth, R=4 REarth a=1 AU
- (2 points) Which of your planets is located at each point?
Group of answer choices
b
[ Choose ] S P Q U R T
c
[ Choose ] S P Q U R T
d
[ Choose ] S P Q U R T
e
[ Choose ] S P Q U R T
f
[ Choose ] S P Q U R T
g
[ Choose ] S P Q U R T
Question 92 pts
For the following questions you must select all correct answers to get credit.
- (2 points) Which planet(s) are likely to have rocky surfaces?
Group of answer choices
b
c
d
e
f
g
Question 102 pts
- (2 points) These planets all orbit the same star, with a radius of 0.3 Rsun, a mass of 0.2 Msun, and a temperature of 3000 K. You calculate that the habitable zone around this star is between 0.05 and 0.12 AU. Which planets are in the habitable zone?
Group of answer choices
b
c
d
e
f
g
You measure the eclipse depth to determine surface temperatures and find:
- b: 700 K
- c: 900 K
- 290 K
- 320 K
- f: 300 K
- g: 100 K
And you measure the spectra of your planets to detect molecules in their atmospheres and find:
- b: None!
- c: carbon dioxide
- None!
- methane, water vapor
- f: oxygen, methane, carbon dioxide, water vapor
- g: methane
Use this information, along with your previous answers, to answer the following 4 questions:
Question 112 pts
- (2 points) Which planet(s) likely lost its(their) atmosphere(s)?
Group of answer choices
b
c
d
e
f
g
Question 122 pts
- (2 points) Which planet(s) experienced a runaway greenhouse effect?
Group of answer choices
b
c
d
e
f
g
Question 132 pts
- (2 points) Which planet(s) likely have surface liquid water?
Group of answer choices
b
c
d
e
f
g
Question 142 pts
- (2 points) Which planet(s) have signs of life?
Group of answer choices
b
c
d
e
f
g
Question 152 pts
- Life Outside the Solar System (12 points)
- (2 points) The most massive stars live only 500,000 yrs while the smallest stars can live for 600 billion years. How does stellar lifetime affect the type of life (e.g., microbes, complex life, intelligent civilizations) likely to form?
12pt
Paragraph
Question 162 pts
- (2 points) List twoways that we can detect signs of biological life on an exoplanet.
12pt
Paragraph
Question 172 pts
- (2 points) Briefly describe the Fermi paradox:
12pt
Paragraph
Question 182 pts
- (4 points) List twopossible solutions to the Fermi paradox, including how this idea solves the paradox and the implications of this solution for humanity.
Solution 1 (2 points):
12pt
Paragraph
Question 192 pts
Solution 2 (2 points):
12pt
Paragraph
Question 202 pts
Many of the extrasolar planets that have been directly imaged to date are
Group of answer choices
- A) very large, and at great distances from their parent star
- B) small and at great distances from their parent star
- C) small and close to their parent star
- D) very large and close to their parent star
Question 212 pts
The results of statistical studies of the exoplanet systems discovered to date suggest that
Group of answer choices
- A) planets are common
- B) small planets outnumber large planets by a significant margin
- C) Earth-size planets are very common
- D) all of the above
- E) A and C
Question 222 pts
When we directly image a planet for several years, from the set of photographs we are able to measure the
Group of answer choices
- A) planet’s radius
- B) planet’s orbit
- C) planet’s temperature
- D) all of the above
- E) B and C
Question 232 pts
The average density of a planet can be obtained from
Group of answer choices
- A) the radial velocity method only
- B) a combination of the radial velocity and transit methods
- C) the transit method only
- D) a combination of the imaging and radial velocity methods
Question 242 pts
You observe a Jupiter-sized planet (R~70,000 km) transit a Sun-like star (R~700,000 km). What is the transit depth?
Hint: transit depth = (Rp/Rs)2
Group of answer choices
- A) 10%
- B) 1%
- C) 0.1%
- D) 0.01%
Question 252 pts
Drake equation: Number of civilizations = NHP×flife×fciv×fnowNHP×flife×fciv×fnow
Which of the following factors in the simplified Drake equation is best known?
Group of answer choices
- A) N_HP, the number of habitable planets in our galaxy
- B) f_civ, fraction of life-bearing planets where intelligent civilizations have arisen at any time
- C) f_now, fraction of civilization-bearing planets that have intelligent civilizations on them now
- D) f_life, fraction of life-bearing habitable planets
Question 262 pts
Drake equation: Number of civilizations = NHP×flife×fciv×fnowNHP×flife×fciv×fnow
In the simplified Drake equation, the total number of life-bearing planets in our galaxy is given by
Group of answer choices
- A) N_HP
- B) f_life
- C) N_HP x f_life
- D) N_HP / f_life
Question 272 pts
Drake equation: Number of civilizations = NHP×flife×fciv×fnowNHP×flife×fciv×fnow
In the simplified Drake equation, a value of flifeflife = 1 would imply that
Group of answer choices
- A) there is one other habitable planet in the galaxy
- B) all habitable planets in the galaxy develop life
- C) there is one other habitable planet in the galaxy with life on it now
- D) all habitable planets in the galaxy have life on them now
Question 282 pts
Drake equation: Number of civilizations = NHP×flife×fciv×fnowNHP×flife×fciv×fnow
Suppose that there are 10 billion (10,000,000,000) habitable planets in our galaxy, that 1 in 5 habitable planets has life, that 1 in 1000 planets with life has at some point had an intelligent civilization, and that 1 in 1000 civilizations that have ever existed is in existence now. How many civilizations would exist at present?
Group of answer choices
- A) 200,000
- B) 2,000
- C) 20,000
- D) 20,000,000
Question 292 pts
If the communication lifetime of civilizations in our galaxy is 100 million years and our galaxy is 13 billion years old, what is the chance of us detecting another intelligent civilization now (i.e., what is fnowfnow)?
Group of answer choices
- A) 1 in 1,300,000
- B) 1 in 13
- C) 1 in 1300
- D) 1 in 130
Question 302 pts
A dinosaur like a Brontosaurus with a small head and a large body would be expected to have an Encephalization Quotient (EQ) of
Group of answer choices
- A) exactly 1
- B) less than 1 but greater than zero
- C) zero
- D) greater than 1
Question 312 pts
Intelligence may be subject to convergent evolution because it
Group of answer choices
- A) is inevitable
- B) is a fundamental characteristic of life
- C) has survival value
- D) is required for survival
Question 322 pts
The 1420 MHz (21 cm) radio line generated by neutral hydrogen atoms is a good choice for interstellar communications because
Group of answer choices
- A) it is the easiest radio frequency to generate
- B) it is the only radio frequency that is not blocked by interstellar matter
- C) all intelligent civilizations should be aware of its universal significance and would probably also think of sending and receiving signals at this frequency
- D) it is the only frequency to which radio telescopes can be tuned
Question 332 pts
Which of the following kinds of signal do we currently have the best chance of detecting with currently technology?
Group of answer choices
- A) a signal used for communication between a civilization’s home world and another star system
- B) a signal used for communication between a civilization’s home world and another planet in its own planetary system
- C) an intentional signal beacon
- D) a signal used for local communication in the world where the intelligent beings exist
Question 342 pts
According to SETI scientists, any reply to a detected SETI signal should
Group of answer choices
- A) be decided upon by the group of scientists who first detected the signal
- B) be decided upon by the government of the country who first detected the signal
- C) be sent immediately as a signal is received
- D) represent a consensus of the Earth’s population
Question 352 pts
On the basis of the scientific method, which of the following would be considered conclusive evidence that we are being visited by aliens?
Group of answer choices
- A) an eyewitness account
- B) none of these would be conclusive
- C) claims of alien abduction made under hypnosis
- D) a photograph
Question 362 pts
Which of the following is a difficulty associated with interstellar travel?
Group of answer choices
- A) all three are difficulties
- B) the speed of light being the fastest possible speed we can travel
- C) the enormous amount of energy required to accelerate any ship to high speed
- D) the huge distances between the stars
Question 372 pts
Which type of spacecraft does NOT need to carry any fuel to accelerate?
Group of answer choices
- A) nuclear rockets
- B) interstellar arks
- C) solar sails
- D) chemical rockets
Question 382 pts
The ultimate speed of a solar-sail-propelled spacecraft is most limited by the
Group of answer choices
- A) low energy photons that the Sun produces
- B) gravitational force of the Sun
- C) fact that the intensity of sunlight falls off rapidly with distance
- D) type of material the sail is made from
Question 392 pts
Bert and Ernie are two friends of the same age. Bert visits a nearby star system on a spaceship that travels close to the speed of light while Ernie stays at home. Which of the following will be true on Bert’s return to Earth?
Group of answer choices
- A) Ernie will be younger than Bert
- B) Ernie will be older than Bert
- C) Bert and Ernie will still be the same age
- D) Ernie will not have been born
Question 402 pts
Which of the following types of propulsion could allow us to reach nearby stars within a human lifetime?
Group of answer choices
- A) chemical rockets
- B) nuclear-powered rockets
- C) solar/laser sails
- D) All of the above
- E) B and C
Question 412 pts
Given how many times intelligent civilizations could have appeared over the universe’s history, it is most likely that if other civilizations exist, they will
Group of answer choices
- A) be slightly less advanced than us
- B) be much less advanced than us
- C) have about the same level of technology as us
- D) be much more advanced than us
Question 422 pts
Habitable zones
Group of answer choices
- A) are at the same distance around all stars, around 1 AU
- B) are farther away from cooler stars and closer to hotter stars
- C) are farther away from hotter stars and closer to cooler stars
- D) move closer to stars over their lifetimes as they burn hydrogen
Question 432 pts
A tidally locked planet
Group of answer choices
- A) rotates at the same rate as it orbits the star
- B) has a permanent dayside and permanent nightside
- C) always has a subsurface oceans due to tides
- D) All of the above
- E) A and B
Question 442 pts
Life around an M dwarf
Group of answer choices
- A) would likely photosynthesize using chlorophyll to get energy from both blue and red light
- B) would likely get energy from redder wavelengths of light than Earth life
- C) would likely get energy from bluer wavelengths of light than Earth life
- D) would definitely be purple
- E) all of the above
Question 452 pts
Life around a binary star
Group of answer choices
- A) is impossible because planets never form around binary stars
- B) is much more likely than life around a single star because there is twice as much energy available
- C) is possible but only if the planet orbits both stars
- D) is possible but only if the planet orbits one of the stars
- E) is possible if the planet’s climate is stable for long periods of time
Question 462 pts
If we detect oxygen in an exoplanet’s atmosphere,
Group of answer choices
- A) we should look for other molecules that wouldn’t exist without life
- B) there must be life on the planet’s surface
- C) the planet must have an ocean
- D) all of the above
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