3 ms·
Been a while since chem & physics class for me as well. How are these estimations calculated, and to what certainty? Surely, these are calculations only from t
by jonalmeida 12y ago
Been a while since chem & physics class for me as well.
How are these estimations calculated, and to what certainty? Surely, these are calculations only from the observable universe?
- ars 12y agoI'm not sure how they know, but see here: https://en.wikipedia.org/wiki/Stellar_nucleosynthesis https://en.wikipedia.org/wiki/Stellar_nucleosynthesis for the reason for the quantities.
- bsurmanski 12y agoI'm not a scientist, but I imagine that they would use the emission spectrum[0] of the various elements. Perhaps they could sample the spectrum of all of the stars and that might give a reasonable approximation. [0] http://en.wikipedia.org/wiki/Emission_spectrum http://en.wikipedia.org/wiki/Emission_spectrum
- mjfl 12y agoThey do it using spectral analysis. Different elements have different absorption bands of light. You can look at a graph of light from a star, with intensity of light on the y-axis and frequency/wavelength (color) on the x-axis and that tells you quite a bit about the composition of the star.
- ars 12y agoThat only tells you the composition of the surface of the star. The heavier elements will be deeper. I suspect there is mathematical modeling. Interstellar dust might provide the spectrum instead of stars, although that really only tells us the composition of the milky way.
- mjfl 12y agoWell, in order to find the composition of interstellar dust, they will use spectral analysis as well...