## 20120605

### Astronomy final exam question: could a super-Earth support life?

Astronomy 210 Final Exam, spring semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
[20 points.] An astronomy question on an online discussion board(*) was asked and answered:
P-d...: Could a [planet more massive than Earth around another sun-like star] support life...? Would [it]...be too hot, or too cold, or could [it] have moderate temperatures?
Quadrillian: ...A giant rocky planet could easily exist outside the orbit of Mars and...be habitable [with moderate temperatures.]
Discuss why this answer is correct, and how you know this. Explain using the properties of greenhouse gases and geological activity.

• p = 20/20:
Correct. Being farther from the sun, (a) this planet would receive less radiation for a greenhouse effect, but (b) a massive enough terrestrial planet would outgas and retain an atmosphere sufficiently thick enough for a greenhouse effect and moderate temperatures.
• r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. One of two points (a)-(b) correct, other is problematic/incomplete.
• t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Both points (a)-(b) problematic/incomplete, or one point correct while other is missing.
• v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least understands factors that contribute to atmosphere density and greenhouse effect.
• x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. Discusses factors other than relevant to the greenhouse effect.
• y = 2/20:
Irrelevant discussion/effectively blank.
• z = 0/20:
Blank.
Section 30674
Exam code: finalN34r
p: 7 students
r: 0 students
t: 13 students
v: 5 students
x: 4 students
y: 1 student
z: 0 students

A sample "p" response (from student 5213):
Another sample "p" response (from student 0401):

[Version 2]
[20 points.] An astronomy question on an online discussion board(*) was asked and answered:
P-d...: Could a [planet more massive than Earth around another sun-like star] support life...? Would [it]...be too hot, or too cold, or could [it] have moderate temperatures?
Quadrillian: The larger the planet[,] the further away from [its] star it needs to be in order to [be] at least be potentially habitable... If closer, it would have to be much smaller in order to prevent a runaway greenhouse effect.
Discuss why this answer is correct, and how you know this. Explain using the properties of greenhouse gases and geological activity.

• p = 20/20:
Correct. Being farther from the sun, (a) this planet would receive less radiation for a greenhouse effect, but (b) a massive enough terrestrial planet would outgas and retain an atmosphere sufficiently thick enough for a greenhouse effect and moderate temperatures.
• r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. One of two points (a)-(b) correct, other is problematic/incomplete.
• t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Both points (a)-(b) problematic/incomplete, or one point correct while other is missing.
• v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least understands factors that contribute to atmosphere density and greenhouse effect.
• x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. Discusses factors other than relevant to the greenhouse effect.
• y = 2/20:
Irrelevant discussion/effectively blank.
• z = 0/20:
Blank.
Section 30676
Exam code: final5t4R
p: 10 students
r: 0 students
t: 8 students
v: 8 students
x: 3 students
y: 3 students
z: 0 students

A sample "p" response (from student 1436):
A sample "y" response (from student 8856):