How are we able to determine the composition of our orbiting planets?
Asked by: J.J. Yrue
Essentially we look at the light being reflected
from the planet. This is called spectroscopy
and it involves looking at the wavelengths of all
the photons that are coming from the planet. Each
element emits light at a characteristic wavelength
that can be determined in a lab here on earth.
so we just match up the wavelengths of incoming
light with the wavelengths we know, and then
determine the composition of the planet, and its
relative quantity of each element.
Answered by: Mike Perkins, Physics/Astronomy Major, Penn State
'Strange is our situation here upon the earth. Each of us comes for a short visit, not knowing why, yet sometimes seeming to divine a purpose.'