Homework #6

Ch9Q38: Lesson for Life: Considering everything we’ve learned about the possible habitability of Jovian moons, make a list of what you think are the three most important lessons that apply to the search for life in other solar systems. Describe the importance of each lesson clearly, and conclude by summarizing how the study of Jovian moons as changed our perspective about life in the Universe.

     1.) Tidal Force can heat far away moons - When we search for life we initially look to planets that have an atmosphere and are in the "goldilocks zone" so that water can be liquid; however, the tidal forces evident in the relation Jovian Planets and there moons can mimic the same conditions for the temperate zone. Meaning we can find life in more places than previously expected.

     2.) Water is not the only liquid medium - Water is the liquid medium of our planet and therefore when in search for life we look for water as the liquid medium; however, methane and ethane, with there lower freezing temperatures, are liquid at much colder temperatures compared to space. This does mean chemical reactions are slower and the life would not be life as we know it, but it does mean that there are more places to search for life

     3.) Moons are very diverse - When we think of moons we look to our own moon as an example, a dead chunk of rock that could never support life as we know it, but moons can be very diverse as shown by Europa's and Ganymede's oceans.

Ch10Q48: Habitable Moons: As we’ll discuss in Chapter 11, some of the newly discovered exoplanets are Jupiter-like in size but are located at Earth-like distances from Sun-like stars. These planets are unlikely to be habitable themselves. Could they have moons with habitable surfaces? Explain.

     Yes, if they have an atmosphere and the combination of their current location and the tidal force is roughly equal to a planet lying in the temperate zone it would be habitable.

Ch11Q44: Explaining the Doppler Method: Explain how the Doppler method works in terms an elementary school child would understand. It may help to use an analogy to explain the difficulty of direct detection and the general phenomenon of the Doppler shift.

The Doppler Method is used by seeing how much a star wobbles back and forth. If it wobbles so much we can assume that a planet is tugging on it through gravity. Imagine a father swing a child around. The father moves back and forth as his son is pulling on him while in the air, even though the father is much bigger than the son.

Homework #6

CH9 Q41:

                If the oceans are made of water as we suspect then yes, we could definitely find some dissolved O2 in Europa’s ocean. As explained in the book, as high energy particles from the sun slam into water molecules on Europa they can cause chemical reactions which can alter the chemical composition creating oxygen in the oceans. Therefore, theoretically if we could transport fish from Earth to Europa they could potentially survive. It would have to be fish that can withstand extreme cold (which some can). Other forms of life that could survive on Europa would probably be more primitive forms of life that are single celled such as bacteria. We could find hypothetically aerobic and anaerobic forms of bacteria on Europa since there could be a presence of O2 on the moon. Multicellular organisms, although portrayed in the movie, more than probably do not exist on Europa if life does exist there.

CH10 Q50:

                The evidence that human activity can be summarized by the chart you (prof. Plavchan) presented in class. It showed the progression of natural occurrences on our Earth including volcanism, the El Nino effect, increased Sun activity and more, and how that has been predicted to effect temperature. Then CO2 increase in the atmosphere was presented which has been proven to have increased since the beginning of the industrial period on Earth. The effect of all the natural occurrences would have projected temperatures to have risen but only a degree or so more. This is not what actual temperature reading show. When the addition of the increase CO2 effect was added to the projections with the natural occurrences we see that the projections are accurate with the actual temperature increases being experienced on Earth concluding the deciding factor is CO2 increase in the atmosphere which has been shown to be caused by human activity. Simply put we need to limit our CO2 output throughout all mankind. This can be done following 2 ideas. The first is by creating a way in which to trap and/or chemically alter the CO2 emitted in the atmosphere. Underground basins have been given as a suggestion of a place to store the CO2. The second route is to limit and decrease the amount of CO2 emitted. This is tough because we as humans are becoming increasingly dependent on CO2 emitting fuel sources. Alternate avenues of energy are the solution for the train of thinking.

CH11 Q45:

                The transit method is a strategy in finding and identifying planets revolving around other stars than our sun. What we do is we take instruments that measure the light signature coming from other stars. The light that comes from a star is relatively constant. However, whenever a planet revolves in front of the star we see a dip in the light signature that we measure. This only works on planets that revolve in between its star and our visibility from Earth. If a planet’s revolution does not pass between its star and our visibility from Earth, we cannot use the transit method to find the planet. 

Homework #5

1. For a few of the most important past, present, or future robotic missions to the solar system, describe their targets, types, and mission highlights.
     Mars Opportunity Rover:
                                             -Target: Mars
                                             -Type: Rover
                                             -Highlights: Proved that at one point there was enough water to sustain                                                                      microbial life on mars

Voyager 1
                                             -Target: Jupiter, Saturn
                                             -Type: Flyby
                                             -Highlights: Launched during a special planetary lineup that only                                                           happens once every 176 years. Also, is carrying a time capsule of earth                                                 history
Europa Mission
                                              -Target: Europa
                                             -Type: Orbiter
                                             -Highlights: Has not launched yet but will study to see if Europa can                                                       support life
 2. What is the potential significance of atmospheric methane to the search for life on Mars? Are there other explanations for the methane?
     On Earth most Methane is accounted for by biological processes. However, it could just be that the Mars Rover experienced a local spike in methane that lay dormant under the martian surface.

 3. Describe the evidence for subsurface oceans on Ganymede and Callisto. What are the prospects for life on these worlds?
     Changing amounts of electrical currents beneath the surface of Callisto and Ganymede can point to a liquid ocean under their surfaces. If there was life on this world it would be very primordial due to the fact that chemical reactions are slower in colder climates.

HW #5

1. What happened to the gas that made up the much thicker atmosphere in the distant past, and what happened to the abundant water? What role did Mars’ small size play in these changes?

Most of the gas and water on Mars was stripped away due to solar ejections from our sun. Mars' small size and weak gravity meant that it didn't have enough gravitational pull to keep its atmoshpere from being stripped away.

2. What is synchronous rotation, and why is it so common among the Jovian moons? 

A synchronous rotation is when a moon's, or other body's, rotational speed matches it's orbit. The same of the moon would always face in towards its planet. Jovian planets are the largest in our solar system, and synchronous rotations occure with very massive objects that have a strong pull, making its moons fit into those todal forces. 

3.What are redox reactions? Give a couple of examples. 

Redox reactions, or reduction-oxidation reactions, are chemical reactions where electrons are transfered between atoms, a change in their oxidation state. Wood burning is an example of a redox reaction; carbon transfers electrons to the oxygen in the air. Combustion is a quick example, but this can occur over longer periods of time as well. The oxidation of iron, or rusting, is another example of a redox reaction where the electrons are transfered from the iron to the oxygen. 

HW #5

1. Briefly summarize the evidence from little over a century ago, both real and imagined that led to widespread belief in a Martian civilization.
   1. It was theorized that the surface of mars had canals that spanned the entire planet; someone even mapped the theorized canals from the polar ice caps interconnecting across the surface.
   2. Mars was approximately the same size as Earth and had about the same day length making people believe it was similar enough to host life as well.

 

1. Summarize the scientific pros and cons of sending humans to Mars. What other considerations are likely to play a role in decisions about such missions?
   1. Cons:
      1.  It is very dangerous!
      2. It would cost a lot more because we would have to provide life support vehicles as well as food and water and other things humans need to survive.
      3. For what we are looking for and the technology we have (if we were to compare cost to the benefit) it is much more efficient and safer to send robots to Mars for exploration right now.
   2. Pros:
      1. To infinity and beyond! It would be the greatest feat in human history going farther and exploring things we have never before.
      2. We could legitimately explore and experiment with Mars habitation and colonization.
      3. If life were to ever need to leave Earth we could have a tested plan for Mars.
      4. It would be easier to bring back and study Martian rocks if we were sending a manned mission.
          

3. Could Triton be habitable? Briefly discuss the possibility of finding habitable moons around Uranus or Neptune.
1. Yes. Although we as humans and astrobiologists have an understanding of what it takes to host and have life, we still cannot say with certainty that there is no life that can inhabit a moon like Triton. It might look completely foreign compared to life as we know it with different metabolite mechanisms and alternate sources of energy, but we cannot say it cannot happen.  So yes it could. If life were similar to ours it would have to be subsurface life closer to the hotter cores of the planet, and would most likely not be complex life forms but simple single celled organisms.
2. It is again a possibility life would have to be either quite different from how we know it here on Earth, or it would have to be insulated and protected by some feature of the moons. Again subsurface life would be most likely because of the intense low temperatures. I would said the possibility is there but the probability is low.