poor prediction about the possibilities of science was made in 1835 by
the prominent French philosopher Auguste Comte. In his Cours de la
Philosophie Positive he wrote:
subject of stars, all investigations which are not ultimately reducible
to simple visual observations are ... necessarily denied to us. While
we can conceive of the possibility of determining their shapes, their
sizes, and their motions, we shall never be able by any means to study
their chemical composition or their mineralogical structure ... Our
knowledge concerning their gaseous envelopes is necessarily limited
to their existence, size ... and refractive power, we shall not at all
be able to determine their chemical composition or even their density...
I regard any notion concerning the true mean temperature of the various
stars as forever denied to us.
later, the physicist Gustav Kirchhoff discovered that the chemical composition
of a gas could be deduced from the spectrum of its light. This method
was later extended to astronomical bodies by astronomers using spectrographs
attached to telescopes.