User talk:C. Trifle

From Wikipedia, the free encyclopedia

Motto for the "first order Stirling" research: Parmenides For never shall this prevail, that things that are not are.

So there must be a thing there. --C. Trifle 00:25, 10 November 2006 (UTC)

[edit] Edits to Planck's law of black body radiation

Several of us have noticed that you have greatly expanded the discussion on something about Stirling's approximation for the blackbody function. A lot of people are concerned about the section, and the article is now being discussed at Wikipedia Talk:WikiProject Physics. Before you make additional edits to the article, could you please discuss the article with other people at WikiProject Physics first? Dr. Submillimeter 13:53, 10 January 2007 (UTC)

[edit] Apology

Hi there, I wanted to apologize for my rather rude comments in the discussion on the WikiProject Physics Talk page. I'm going on wiki-break for a while till I calm down. Again, sorry. :) HEL 02:38, 12 January 2007 (UTC)

[edit] Leviathan cube?

Hi there! I've never heard of the Leviathan cube, so I don't think I could contribute anything helpful. Also, I couldn't find your comment on the WikiProject Physics page to which you referred on my talk page.... HEL 21:49, 22 January 2007 (UTC)

Oh, I see. The radiation inside the cube is just thermal radiation continually emitted and reabsorbed by the walls of the cube, which are sitting at some temperature T. The electromagnetic radiation inside is in thermal equilibrium with the walls. If you were setting up a blackbody cavity in the lab, you'd heat up the walls of the box/oven to some temperature and then wait a bit for everything to come into thermal equilibrium. By radiating off a bit of their energy into the inside of the cavity, the walls do cool off a little. The radiation that comes out of the small hole (which is used to measure the blackbody spectrum: it's hard to sit inside an oven) does transfer some energy away from the blackbody; if you wait then the whole system will start to cool off. Does that answer your concern?

I guess the thing to keep in mind is that the main purpose of the "cavity" blackbody is to get the radiation inside to be in thermal equilibrium with the (uniform-temperature) walls, by being repeatedly absorbed and re-radiated. That is what makes it a more nearly perfect blackbody. Something like the sun, or a hot electric stove element, does not produce a perfect blackbody spectrum because its natural ability to radiate is not the same at all wavelengths. (I'm not sure I'm explaining this very well...) The cosmic microwave background radiation has the most perfect blackbody spectrum of any system we've ever measured, because the radiation was in very good thermal equilibrium with the matter at the time it was released. HEL 13:13, 8 February 2007 (UTC)

Hi there! There seems to already be a nice introductory explanation of the blackbody "cavity," etc on the Black body page. I added a small comment on the top of Planck's law of black body radiation saying "For a general introduction, see black body." Hopefully that will cover the issue... HEL 22:20, 8 February 2007 (UTC)