EARTH SYSTEM SCIENCE

WRITING ASSIGNMENT #7a - HERE COMES THE SUN

Your assignment this week is learn a little about our very own star, the Sun. To do so, we will create an animation illustrating the dynamics nature of the Sun utilizing imagery obtained from NASA's Solar and Heliospheric Observatory (SOHO).

YOUR ASSIGNMENT FOR THIS WEEK:

Here's what to do:

1. Go to the SOHO site by clicking the button at the bottom of the page.

2. From the SOHO Home Page, click on the "DATA - Archive" link on the left side of the page.

3. Once on the SOHO Data page, click on the link for Near Real Time images. This will take you to a page where archival images of the Sun are available from a variety of sensors on the SOHO space platform. We are interested in acquiring images from the MDI Continuum instrument. Locate the links for these images, and click on the link for 256 x 256 images. Scroll to the bottom of the page and follow the link for List of all individual images.

4. The List of all individual images contains imagery acquired during the last year of operation of SOHO. I want each of you to copy and insert images for any two-week interval on this list (i.e. download all images for any 14-day period in the archive). Once you have downloaded these images, import them to Movie Maker as we have done before and create an animation showing changes in the Sun's surface during this interval. A particularly active episode occurred during the last two weeks of October and the first week of November in 2003.

5. Once you have created your movie, save both the "project" file and the "movie" on your computer. Recall that the "movie" file defaults to a directory called "My Videos" of our computers. This is a reasonable place to store your work. To complete your assignment, provide written responses to the questions below:

QUESTIONS TO ANSWER:

1. When was the SOHO satellite launched and what is happening with it at the present time? Note that a number of data sets have the phrases "CCD Bakeout" or :SOHO Telemtry Keyhole" labled on the index pages. What do these terms mean?

2. The images we are using are from the MDI instrument onboard SOHO. What does the acronym MDI stand for, and what does this instrument do? What do the images from this instrument show?

3. What are the black areas observed on the surface of the Sun with the MDI sensor? How do these areas form?

4. Use the Internet to acquire data on the size of the Sun (diameter and circumference). Using your images and animation, estimate the time it takes for the Sun to rotate once on its axis. How long is this? How fast (km per hour) do the black areas appear to be moving across the screen?

5. On the SOHO website or elsewhere, locate information about Coronal Mass Ejections (CMEs). What is a CME? What effects do CMEs have on Earth? Have CMEs ever caused any damage on the Earth's surface? If so, when did this occur and what were the observed effects?

SOLAR AND HELIOSPHERIC OBSERVATORY