Saturday, July 7, 2012

Sunday Stamps #78

This week, something a little bit different, a different kind of theme.  Anything, As long as it is YELLOW or partially yellow.  Why not?

This is the stamp from Taiwan that inspired me.  I just found these yellow flowers to be so happy and cheerful.

And here is another:

A stamp from Germany, showing the solar spectrum (the rainbow) and the dark absorption lines.  These were studied by Joseph von Fraunhofer  (6 March 1787 – 7 June 1826). 

According to Wikipedia, "In physics and optics, the Fraunhofer lines are a set of spectral lines named for the German physicist Joseph von Fraunhofer (1787–1826). The lines were originally observed as dark features (absorption lines) in the optical spectrum of the Sun. ... About 45 years later Kirchhoff and Bunsen noticed that several Fraunhofer lines coincide with characteristic emission lines identified in the spectra of heated elements.  It was correctly deduced that dark lines in the solar spectrum are caused by absorption by chemical elements in the Solar atmosphere."

Essentially, when there is a ball of hot gas (the Sun) giving off light, and then an area with cool (relatively) gases (hydrogen, oxygen, etc.) the cool gases absorb certain wavelengths of light.  This happens in the outer atmosphere in the Sun.  Lab experiments can help identify these elements.  For example, the thicker line in the red is associated with hydrogen, and the two lines very close together in the YELLOW are associated with sodium.

So we can conclude: these elements seen on earth are also in the Sun, and when these lines are seen in the spectra of other stars, we know these elements exist in other stars.  And the star spectra can be used in other research, too much to go into here.

What yellow stamps do you have today?

Theme next week:  It's Canada Day, US Independence Day, Bastille Day, and probably other national holidays.  Let's share Flag stamps or patriotic stamps, from your country or another country. 

Viridian


8 comments:

Bob Scotney said...

The Fraunhofer lines take me back a bit (over 50 years) to my university days. Like that stamp.

Aimee Dars said...

Love the flower and rainbow colors!

Sheila @ A Postcard a Day said...

Bob reminded me I hadn't left my link.

I particularly like the yellow flowers from Taiwan. As you say, very cheerful.

I didn't think I had any yellow stamps but when I started looking there were three.

Joy said...

The Fraunhofer lines make a great stamp and interesting physics.

www.dakotaboo.com said...

Lovely stamp ... I'm in again this week, and my yellow stamp is up.

♥FoodTripFriday♥ said...

Yes, Yellow is the official color of the Aquinos,even her son right now, our current president,is also using it.
Willa Of PostageJournal

Marcie said...

I can't believe I missed the Sunday stamps the second week in a row...the weekends just run away lately...

Helen said...

I loved this theme... I was sorry i didn't participate. I looked for a yellow stamp & realised that yellow is one of the less-used colours on stamps! Anyhow i did pick one out- i just ran out of time.
I really like the stamp illustrating the colour spectrum and the little science lesson on colour that went with it! Really interesting Viridian, thanks!

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