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Episode 8 "Sisters of the Sun"
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4/28/2014 at 12:43:48 AM GMT
Posts: 142
Episode 8 "Sisters of the Sun"
This topic is devoted to episode 8 of Cosmos: A Spacetime Odyssey

Last edited Sunday, May 11, 2014
4/28/2014 at 2:13:54 AM GMT
Posts: 142
Another great story! Most of the science was pretty well known, but the history was new to me and very interesting. What a great tribute to some of the pioneering women in astronomy. I really like the way Tyson is bringing to light some of the great contributors in science who are not as well-known but should be.

4/28/2014 at 11:45:22 AM GMT
Posts: 41
I did learn of hypernovas, a term I was not familiar with.  This related about Betelgeus is interesting.

The Cecilia Payne story was also interesting -- how new ideas are accepted slowly in science.  I expect that has parallels for science/faith issues.  I understand part of this story was that fact that she was a women in a predominantly man's world at the time.  But, there are many other stories like that.

4/29/2014 at 1:48:35 PM GMT
Posts: 53
It indeed was a nice touch to see women in science honored. The show's historical accuracy was better than I expected. Even the glass plates of spectra were very close to what Anne Jump Canon worked with in classifying well over 200,000 spectra. She was incredible. The stellar classification story goes deeper, of course, as others had tried to develop one. Father Secchi (Rome) was the earliest pioneer at this with 5 types of star classes, classifying about 10,000 spectra.

It was the technological improvement of dry photography that allowed for the advancement of stellar work, especially spectra analysis. Father Secchi eagerly acquired the latest and greatest instrument, which he mounted on his telescope and began his work.

Of course, back then it was all black and white imaging. This is where some of the beans fell through the grill and we still have some errors in stellar colors today. The show is very colorful for effect, but many of the colors used for stars aren't correct. For instance, red stars are called red because they have the coolest surface temperatures, but they usually appear far more reddish orange or orange, than red. This is because stars have spectral energy distributions that closely match blackbodies, so that there is a well known distribution of all the colors of the visible spectrum for all stars. The coolest strars are certainly strong in the red end, but they still radiate much orange, yellow, green, and even some blue. This causes us to see more of an orange color for even the reddest star. [Carbon stars may be an exception to this., and variations in human eyes can make orange for me look more red for another.] The blue stars have this same circumstance but even more so. A saturated blue color star would require a surface temperature of about 15 million K, which happens to be our Sun's core temperature, so it would appear blue (if proper attenuation is used to view it somehow).

For this same reason, the claim that their triple star system including a "blue" star and a "red" star might produce a blue sky and a red sky are unlikely. A red star emits a fair amount of the rest of the colors and the inverse 4th scattering effect would make the sky some color other than red.

Accurately determining "true" color for celestial objects is not critical to astronomy, admittedly. As usual, I am more concerned with the lack of an explicit explanation of what science is. In this episode, all that I heard in this area was that "the only thing that counts is the evidence and the logic." Ug.

I was also surprised that they did not make much of an effort to demonstrate graphically the awesome differences in star sizes. This is a popular area of interest and one that graphics can do a great job.

Last edited Tuesday, April 29, 2014