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eyad-996
- 18
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I'm having the hardest time understanding Black bodies. I have a lot of questions about them so I can't write all of them, instead I'll just start with : Why are stars considered black bodies?
eyad-996 said:I'm having the hardest time understanding Black bodies. I have a lot of questions about them so I can't write all of them, instead I'll just start with : Why are stars considered black bodies?
dauto said:That doesn't mean they will be black because black bodies produce their own radiation according with the black body radiation formula which depends on the temperature of the black body.
eyad-996 said:So the radiation they emit is not within the visible spectrum, correct?
On whatis.techtarget.com
They defined a Black body as " a theoretically ideal radiator and absorber ".
Doesn't that contradict with what you said about black bodies not reflecting any radiation back?
In other words, how does reflection differ from radiation?
eyad-996 said:So the radiation they emit is not within the visible spectrum, correct?
On whatis.techtarget.com
They defined a Black body as " a theoretically ideal radiator and absorber ".
Doesn't that contradict with what you said about black bodies not reflecting any radiation back?
In other words, how does reflection differ from radiation?
berkeman said:From your reading, what is the equation for the emission spectra from a black body?
eyad-996 said:To determine the peak of an emission spectrum (I think I phrased that right!) You use Wien's Displacement Law :
Peak λ * T = b
where T is the absolute temperature of the Black body, and b is around 2.9*10^-3
eyad-996 said:So let me get this straight, a Black body absorbs the radiation of a certain spectrum and then re-emits it in a different spectrum with a different peak wavelength?
eyad-996 said:I keep picturing a star every time I talk about Black bodies, how wrong is that?
dauto said:Yes, that's right.
eyad-996 said:Well then where/when did this 'conversion' happen?
A black body is an idealized object that absorbs all radiation that falls on it, without reflecting or transmitting any of it. It also emits radiation at all wavelengths according to its temperature, making it appear completely black.
Stars are considered black bodies because they emit radiation at all wavelengths according to their temperature, just like a black body. Additionally, they absorb most of the radiation that falls on them, making them appear black in space.
The intense pressure and temperature at the core of a star cause nuclear fusion reactions, which release energy in the form of radiation. This radiation is emitted from the star's surface and is what makes stars visible to us.
No, not all stars are the same temperature. The temperature of a star depends on its size, mass, and stage in its life cycle. For example, smaller stars tend to be cooler, while larger stars are hotter.
Black bodies play a crucial role in astronomy as they help scientists understand the behavior of radiation and the properties of objects in space. By studying the radiation emitted from stars, astronomers can determine their temperature, composition, and other characteristics.