From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers (nm). the spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nm. what can we conclude? from laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers (nm). the spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nm. what can we conclude?
a. the star is getting hotter.
b. the "star" actually is a planet.
c. the star is moving away from us.
d. the star is moving toward us.
e. the star is getting colder.