Sun-Earth Connection Education Forum Podcasts
Transcript of Sun-Earth Day 2006 Podcast, Program 3
Welcome to the third in a series of NASA podcasts that will explore solar eclipses, and how humankind's fascination with the moon has been evident throughout history. These podcasts will connect you to the cultural history, math and science behind solar eclipses, and why we still find them so exciting to watch today.
My name is Troy Cline and in today's podcast you will hear an interview I recently conducted with Joe Davila. Joe is a NASA astronomer who has been working at the Goddard Space flight Center since 1982. He is primarily involved in Solar Physics and the study of our Sun's atmosphere. During his interview he talked about a very interesting and somewhat unique experiment he will be conducting during the upcoming total solar eclipse on march 29th!
My first question to Joe was in reference to the actual experiment he will be doing and the type of data he will be collecting.
Joe: "The total Totality part of the eclipse lasts for about four minutes. During that time, the bright disc of the Sun is covered and you're able to see the fainter corona around it. And the experiment that we're doing is a spectrograph, which takes pictures of the corona spreading the light into its different colors. Looking at the ratio of bands in these different colors, we're able to determine things like the electron temperature in the flow speed of the solar wind."
I was very curious to know if Joe had conducted this experiment before.
Joe: "This is actually the fourth time we've done this experiment. The first was in Turkey in 1999. The second was in 2001 in Zambia, and the third time was in South Africa in 2003. The first two times we were able to get spectra. The third time we were clouded out and so we were very anxious to get back and try this again."
At one point during our discussion Joe and talked about one of the most common questions people seem to ask about his experiment, "What are the reasons for using a ground based instrument as opposed to an instrument aboard a spacecraft?"
Joe: "The best place to observe the corona continuously is from space, and SOHO does that routinely now. But it's very expensive to develop new instruments in space and what we're doing with this eclipse instrument is developing a whole new concept of instrument that will lead to the next generation of space instruments. So from the ground we can test this instrument concept for a few thousand dollars where a space mission would cost hundreds of millions of dollars, and there is no instrument in space right now that can do what we're doing with this new instrument."
"Initially in Turkey, we found that the instrument design had too much scattered light in it. It was just light that doesn't really come from the corona but comes from somewhere else, and that contaminated our results, so we've redesigned the instrument. It seemed to have worked well in Africa, and so we're really trying to confirm those African measurements with this eclipse in Libya."
During this eclipse there will be many scientific teams sprinkled throughout the path of totality. Due to location and climate issues, Joe's team had to carefully pick an optimal viewing spot.
"Well, the Path of Totality of the eclipse is very long, but it's also very narrow. So you have a variety of positions you can choose on the Earth to observe the eclipse. What we try to do is maximize our chances of seeing something - that is minimize the chances of seeing clouds. And so we've chosen a place in the desert in southern Libya."
Given the amount of work going into the success of this experiment it is obvious that the data gathered on the 29th has significant scientific value. So I simply asked Joe the question, "Why is this data important?"
Joe: "Well, the information from this instrument is important for predicting what we call space weather, which is the environment in space around the Earth. Right now we're able to send out spacecraft that sample small regions of space, but not the entire domain. With this instrument, by taking images, we can remotely sense solar wind speed and temperature over huge vast areas. So this will be a large improvement . a huge improvement over what we're doing now."
Towards the end of the interview we had a chance to talk about experiences Joe has had during his eclipse travels. This particular story truly stands out!
Joe: "Well, when we were in South Africa for the eclipse in 2001, we had an extra day or two, so we decided that we would go to the witch doctor to get some prediction on the clouds for the eclipse. We went to a witch doctor, and we knew he was a witch doctor because he had a witch doctor certificate on the wall of his hut. And the witch doctor had us sit in a circle, and he shook a container of bones and nuts, and he would throw them on the ground and make his predictions."
"He predicted that the eclipse would be clear which it was, but he also predicted that one of our members of our team needed a wife. And so he developed a potion for this fellow. He gave him two potions, one was to attract women to him, and the other potion was to repel bad women so that he could find himself a really good wife. So he did eventually find a wife, and the witch doctor session cost us twenty bucks."
Sun Earth Day is a program sponsored by the NASA Sun-Earth Connection Education Forum at the Goddard Space Flight Center, and at the UC Berkeley Space Sciences Laboratory.
To find out more about the Sun Earth Day program and eclipses, visit our website at sunearthday.nasa.gov
This is Troy Cline signing off.
