How can the light that reaches earth from a star be used to estimate it's temperature?

Question

How can the light that reaches earth from a star be used to estimate it's temperature?

Answer 1

In simple terms, they use a machine that measures tiny particles, and however many there are determines its temperature.

Answer 2

For a blackbody, Wien's Displacement Law allows you to directly calculate the temperature of a blackbody based on the wavelength of the peak of its spectral emission.

Answer 3

Actually it's a luttle more complicated that the others suggest.

We can use the color to estimate the temperature, but it is a very rough estimate: blue star is very hot(30000K), white star is hot (10000K), yellow star is average (6000K), red star is cool (3000K), and this is based on blackbody radiation, but...

By taking a spectrum, we can see which atoms, ions, molecules are absorbing light as it passes thru the stars atmosphere. At 10,000 K there should be strong absorption lines at atomic hydrogen, hotter stars show absorption by helium, cool stars show absorption by molecules and so on. Because there are always several things absorbing, it can be calibrated wuite accurately...

Answer 4

I command Jove, master of the sky, to brandish me with a spectrometer!

The Gods have been informed

Answer 5

The wavelength of light will determine its temperature.  When something heats up, it will eventually become glowing red.  As it gets hotter, the wavelenth of the light it radiates will shorten and increase in energy.  It will become white hot, then blue.  White dwarf stars are actually so hot that they radiate mostly in the untraviolet.