Homework #5 for Astronomy 122

This first question is embedded in Lecture D ( Detecting Planets around Nearby Stars ) of Module 5 under the interactive exercise link.

Make sure you complete this interactive exercise tutorial before you start working on this question. The point of this exercise is to not only let you duplicate the actual scientific measurement process but also to show that not all systems can be easily detected.

Detection requires an optimum combination of different kinds of observing parameters (and the different cases give you different combinations of these parameters)

1. Solve for the Jupiter mass and separation of the three planetary systems that you choose under the catalog called Four Sample Stars. Note that you are to solve for three different systems using three different combinations of detector parameters (Case I, II and III) as specified at the bottom of the interactive exercise page these means doing 9 separate simulations and report on whether or not a successful detection of a planetary "wobble" curve was achieved. In most cases, there will not be a successful detection and you need to think about and report on why that is the case.

Download this work sheet to record all of your results and submit as homework when done

Note that the worksheet will now prompt you for a login. This means that if you submit with worksheet at any time you can retrieve it and finish it at a later time through your login.

For each star, the worksheet contains lines to a) record the mass of the hypothetical planet, b) record the distance of the hypothetical planet and c) the most important part argue whether or not the data is good enough to even perform a credible fit - in many cases the data is not good enough and you need to look at it and explain why.

Note: submit the answers to the remaining questions via regular email to astr122@gmail.com

2. Explain about how various kinds of systematic variations in the Earth's orbit about the sun are thought to be the best explanation for periodic ice ages on the Earth.

3. In the last few years, scientists have discovered that the martian polar caps have more water ice in them and less frozen carbon dioxide than previously thought. Summarize some of the implications of this result in terms of our view of the geologic history of Mars.

4. In the class notes we make use of the Drake equation as providing a statistical estimate of the number of civilizations that might exist in our Galaxy and are capable of communication. Recently, however, some scientists have argued that the Drake equation is an inaccurate description. This new theory is known as the "Rare Earth Theory" (by Ward and Brownless). Do some research on this new theory and identify what the key components of this theory are that suggests planets like the Earth are much rarer than we think they are.