if stars appear to be like blackbodies, why are they not black?

Question

whats the answer to this question? (for my astronomy class)
if stars appear to be like blackbodies, why are they not black?

Answer 1

In physics, a black body is an object that absorbs all electromagnetic radiation that falls onto it. No radiation passes through it and none is reflected. It is this lack of both transmission and reflection to which the name refers. These properties make black bodies ideal sources of thermal radiation. That is, the amount and wavelength (color) of electromagnetic radiation they emit is directly related to their temperature. Black bodies below around 700 K (430 °C) produce very little radiation at visible wavelengths and appear black (hence the name). Black bodies above this temperature however, produce radiation at visible wavelengths starting at red, going through orange, yellow, and white before ending up at blue as the temperature increases.

Answer 2

In physics, a blackbody is a perfect radiator (and absorber) of electromagnetic energy. It will appear black only if it's cold. A hot blackbody will radiate energy in a spectral distribution, called a blackbody curve, that depends on temperature. The radiation from a star approximates that from a hot (~3000K to 30,000K) blackbody. All of this should be in your book.

Answer 3

Who said all stars were bright? Only the ones you can see are, but what about dead stars?

Anyway, "black body noise" encompases the entire elctromagnetic spectrumm while your eyes are only tuned to a very narrow slice. Black bodies are masses of matter that put out random noise at temperature above 0K at all frequencies with no apparent source. (the source is actually at the atomic level and the movement of charges in there). So while you may see combustion in the visible spectrum, there is blackbody noise radiated at frequencies you can't see/

By the way - the colour black indicates nothing is detected to your eye. Anything that isn't black means something is being detected.

Answer 4

Because that's not what blackbody means. If this is for your astronomy class, then look up 'blackbody' and find out. It's in your book (or on wikipedia).

Answer 5

A blackbody is something that reflects no radiation. A blackbody can emit radiation though, and if they emit enough, they will glow in the visible spectrum.

Answer 6

Black and white are the same thing, except white is brighter. The stars are white (black) with a certain color temperature, depending on the temperature of the surface of the star. It just means that the star emits a curve of wavelengths, instead of just one wavelength like a LASER does.