Planets & Habitable Zone

Answer each of the following questions drawing your arguments and evidence from the resources we have used in this class. This is open notes/internet/textbook, but we expect that you will do your own work, and that you will not communicate or collaborate in any way with other students on this. All your responses must be in your own words and represent your own individual work. If you do use information from outside resources we expect you to provide sufficient citation (links, authors, titles, etc.) so that we can easily check those sources. The textbook and the lectures generally qualify as ‘common knowledge’ and do not need to be cited, but you may not copy text from those sources directly — your words must be your own.

Do not copy the questions themselves into your responses, as it tends to tag your submission as plagiarized.

1. (2 points) Based on studies of planetary systems around other stars, which of the following statements are currently believed to be true about how common or rare it is for stars to have planets in orbit around them? (You may simply type your answer as “A”, “B”, “C”, or “D” — and please note there is only one correct answer; see the May 29 Zoom Lecture in the Week 9 materials for guidance.):

A) Planets in general are believed to exist around less than half of all stars.

B) Giant planets like Jupiter are extremely common, but terrestrial (“Earthlike”) planets are extremely rare.

C) Planets are believed to exist around most, if not all stars, and terrestrial (“Earthlike”) planets are not especially rare.

D) Planets around other stars are too hard to detect with current technology, and so we are very uncertain how common or rare it is for stars to have planets in orbit around them.

2. (2 points) Popular news sources often talk about planets around other stars, and often state whether or not a planet is in the “habitable zone” of the star it orbits. What does the phrase “habitable zone” mean in the context of planets around other stars? (You may simply type your answer as “A”, “B”, “C”, or “D” — and please note there is only one correct answer; see the May 29 Zoom Lecture in the Week 9 materials for guidance.)

A) The region around a star where observational evidence has clearly shown that life exists.

B) The region around a star where water could potentially remain liquid on the surface of an Earth-sized world.

C) The region around a star where observational evidence has shown clearly that water exists.

D) The region around a star where x-ray and ultraviolet radiation would not destroy life on the surface of a planet.

3. (6 points) In a paragraph or two, briefly describe Fermi’s Paradox, and offer at least one scientifically plausible solution to it (PLEASE NOTE: the rubric for this short answer question has changed for this week — any thoughtful and plausible answer will be given full credit; see the June 3rd Zoom Lecture in the Week 9 materials for more guidance.)

Rubric