If you are good at Earth Science, please open this?

H

heather

New member
I need help on these two questions...I am completely lost. I don't understand this topic at all. I appreciate anyone who helps me! Thanks =)

1) Explain how the spectrum of the light from a distant star can be used to determine the direction of the star's motion.

2) How is the spectrum from a gas tube different from the spectrum of light from the sun?
 
(1) The spectrum of light used to determine direction is called redshift. Redshift occurs when electromagnetic radiation—usually visible light—emitted or reflected by an object is shifted towards the less energetic ("red") end of the electromagnetic spectrum due to the Doppler effect or other gravitationally-induced effects. More generally, redshift is defined as an increase in the wavelength of electromagnetic radiation received by a detector compared with the wavelength emitted by the source. This increase in wavelength corresponds to a drop in the frequency of the electromagnetic radiation. Conversely, a decrease in wavelength is called blue shift. You can tell distance and direction.

(2) The spectrum of light being emitted from a gas tub is narrow (and so it appears "green" etc.), whereas that from the sun covers the entire visible spectrum (and appears "white").
 
Back
Top