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Life on Europa? |
Given information about life living under extreme conditions on Earth and the evidence for a liquid ocean on Europa, the students will summarize their position in the "Life on Europa" debate and judge whether or not further exploration is warranted.
This is a web-research activity. Your first goal is to find and read enough information to be able to present, in a few paragraphs, the arguments for and against the possibility of primitive life in the liquid oceans underlying Europa's icy surface. Your second goal is to judge whether or not we should be funding future probes to Europa.
Because this is an essay and not a lab, some initial guidance is definitely warranted. First, because we are looking for life that can live under hostile and exceptional conditions, we need to formally define some terms. As you review the following "definitions," be sure to read the supporting links for needed information.
The term exobiology means is the study of life beyond the Earth. But since there's no known life beyond the Earth people say its a subject with no subject matter. It refers to the search for life elsewhere, Mars, the satellites of Jupiter and in other solar systems. It is also used to describe studies of the origin of life on Earth, that is, the study of pre-biotic Earth and what chemical reactions might have taken place as the setting for life's origin. From An interview with exobiology pioneer, Dr. Stanley L. Miller, UCSD
Life on Earth is remarkably adaptable. Organisms are able to survive under conditions previously thought impossible. Specific examples of extreme environments that harbor life are sea ice, sub-seafloor hydrothermal systems, and subterranean basalt. From University of Washington astrobiology research pages.
This is a term you will be coming across frequently in your reading. "Archaeans don't look that different from most bacteria under the microscope; since most of them are extremely difficult to culture, their unique place among living organisms long went unrecognized. However, biochemically and genetically, they are as different from bacteria as you are. Although many books and articles refer to them as 'Archaebacteria,' they aren't bacteria - they're archaea."
Archaeans include inhabitants of some of the most extreme environments on the planet. For further information, see Introduction to the Archaea from UC Berkeley.
Type up your responses for the following topics. Your essay should be in narrative form, having good paper structure, and not simply rote answering of the questions. Put in a good opening paragraph that will let the reader know what is to follow. You do not need to go into great detail in any of the areas, but you must show you have read the material and are "qualified" to enter into the scientific debate. Nicely constructed two-three paragraphs for each should do. Be sure to bring in information from the above readings and what you have learned during this quarter.
Start by describing the evidence suggesting Europa may have a subsurface ocean of liquid water. Besides your text, check out Cracks Best Evidence Yet for Europan Ocean.
Summarize the arguments supporting the likelihood of life on Europa. See Could Life Exist Near Europa's Surface? from Space Views.
We may wish for little phosphorescent aliens with swollen heads, big eyes, and long limbs, but we probably aren't going to get them. What are the arguments against complex life on Europa? See Complex Europan Life Unlikely from Space Views.
The above two articles give some ideas about how to answer some of our questions. Describe two space programs, present or future, for the exploration of Europa. Additional information can be had at NASA's Europa Orbiter mission.
Should we go there? Here is an article about possible contamination by life hitch-hiking on Earth probes. Summarize a couple of NASA's concerns.
Give your overall evaluation of the "Possible Life on Europa," and judge whether or not funds should be spent on sending probes to Europa in the future. That is, enter into this debate on a preliminary basis. You may take any approach or stance of your choosing. Points awarded for a convincing argument, for evidence of having carefully considered the alternatives, for bringing in knowledge gained from the past weeks spent in Astronomy 150u.
| The total essay should be about 2-3 pages long (12 pt, space-and-a-half, 1" margins -- or single spaced with double spaces between paragraphs). Your essay will be graded upon the clarity of your writing, indication that you have reviewed the material, and overall good writing techniques. |
So, now you want to become an astrobiologist. You can, you know. Study hard and then apply to become a graduate student in the first astrobiology PhD program in the States. Check out the University of Washington Astrobiology Program, a cross-disciplinary study in the possibility of life beyond Earth.
A different approach to the debate of liquid water and life on Europa
Extremophiles Scientific American, April 1997.
Some very serious considerations about
Preventing the Forward Contamination of Europa
from The National Academies.