Essay Topics

University of Minnesota

Department of Astronomy

Essay 3 (Due 15 April): Sun-Earth Connection

The nearest star, the Sun, is the source of insolation that warms the Earth, as well as high energy particles (e.g., protons, alpha particles, electrons, and neutrinos) that stream into the interplanetary space of our Solar System. We often assume that the Sun is a quiescent object. However, during periods of violent activity, the Sun releases large numbers particles with very high energies (giving rise to space weather) causing a number of interesting environmental interactions and planet-wide responses from our terrestrial biosphere -- some severe.
In your essay, discuss in your own words:

1. What is a coronal mass ejection event (CME) , where does this phenomena originate, and what environmental impacts on the our biosphere result. (Identify and describe at least one phenomena.)

2. Describe the origin of Earth's magnetic field, how it interacts with Sun induced space weather, and whether or not our magnetic field is "stable" (both in polarity and strength).

3. How your own personal or daily habits might be affected by the variations in the "solar wind."

Suggested References:
http://www.sec.noaa.gov/info/SolarEffects.html
http://www.sec.noaa.gov/Curric_7-12/Chapter_4.pdf
http://space.au.af.mil/primer/space_environment.pdf
http://www.spacetoday.org/SolSys/Sun/SolarIndicesFAQ.html
http://www.sec.noaa.gov/NOAAscales/index.html
http://www.sec.noaa.gov/Education/index.html
http://www.sec.noaa.gov/info/Navigation.pdf
http://www.sec.noaa.gov/info/SolarMax.pdf
http://www.sec.noaa.gov/info/Radio.pdf
http://www.sec.noaa.gov/info/Satellite.pdf


AND:
The Reference Room in the Walter Library (rm. 206) has a specially selected set of books addressing the topics of this essay. The books are kept on reserve for this course. Look for the bright red sign "Ast1001/1005/1011H" to your left, as you enter rm. 206.

Essay 2 (Due 11 March): Cosmic Impacts

The effects of impacts over the last few billion years is evident throughout the solar system. We have seen craters on Mercury, the Moon, Mars, and the various moons of the outer planets; there is, of course, among other known craters here on Earth, the Meteor Crater in Arizona.

Events have also shown that impacts within the solar system have occurred on human timescales. For example, the Tunguska explosion in Siberia occurred in 1908, and the collision of the remnants of the Comet Shoemaker-Levy with Jupiter was observed by a wide array of telescopes in 1994.

An impact on our planet at current epochs would clearly be a catastrophic event with expected wide-ranging effects on human, plant, and animal life; and on weather and climate change. While the chances may be remote, the evidence above states that the chances are still real.

For your essay, discuss in your own words your answers to all of the following questions; be sure to support your arguments or viewpoints with multiple references.

1. What is the current scientific explanation for the mass extinction here on Earth at the end of the Cretaceous period 65 million years ago? What evidence do we have that this event was caused by an asteroid?

2. What would the effects be if a 1-km sized rock from the solar system were to land and impact the middle of the Pacific Ocean? Would the effects be any different if the object were to land in the middle of a continental landmass?

3. How can we prevent asteroids and comets from hitting the earth? What scientifically feasible methods to monitor and to destroy these kinds of objects have been proposed? Are these preventative measures affordable and within the means of nations' economies?

Suggested references:

Essay 1 (Due February 11): Are We altering the Climate of the Earth?

Recent measurements have led to speculation that the earth's weather is steadily warming and that the ozone layer in the upper atmosphere is being depleted. Both trends could have catastrophic effects on plant and animal file if the change over time is large enough. There has been much argument in the scientific and political communities about whether these effects are real and, if so, whether they are natural consequences of the evolution of the earth or are induced by man-made polutants released into the atmosphere. Based on the existing data related to this issue as you understand them from your research, write an editorial essay summarizing your point view about whether or not there is anything that society could or should be doing about warming and ozone depletion. In your essay, consider the following questions:


1) What are the possible factors that could explain the observations? Support your answer with reasoning and by trying to assess the veracity of the sources you consult.

2) What mechanisms are there for climatological warming and ozone depletion? How could our knowledge of technology be used to reverse these trends?

3) Discuss the runaway greenhouse affect on Venus and why it is an important example to consider when thinking about the Earth's atmosphere.

4) How might climatological warming and ozone depletion affect life? How much change will endanger life on earth?

Feel free to explore other related areas of this problem. You are also encouraged to think through these problems yourself and come up with your own well-reasoned ideas. This is by no means a closed question in science, and opinions in the scientific community are greatly varied and divided.

Possible References: