3 Astronomy Questions?

Question

1. Astronomers measure the light coming to Earth from a distant star. From this data they can derives several types of spectra. Explain how the astronomers might use one of these spectra to determine the temperature of the star's photosphere.

2. Describe the difference between emission-line spectra an absorption-line spectra. Using your knowledge of the structure of atom, describe how the interaction of light and atoms produce each type of spectrum.

3. Describe the best current model of the origin of the solar system.


Thanks!!!

Answer 1

The details can be found on Wikipedia.

In general:
1) the temperature of a body determines the amount of energy that is emitted at each frequency. The overall shape of the spectrum (the distribution of energy per color and the frequency of the peak emission) usually gives a pretty good idea of the temperature.

2) If the light comes from atoms (of the same element) having their electrons return to the ground state, then the photons emitted by these atoms will be of very particular frequencies. Thus, the light we receive will form an emission spectum (like the light we get from the sun's corona during a total eclipse of the sun). If the light is from a "blackbody", the spectrum should be continuous, unless there is some element between it and us: those atoms' electrons will absorb very precise frequencies from the overall light and what we get is what is left (a continuous spectrum minus absorption lines).

3) See Wikipedia at Solar System

Answer 2

1= D 2=C 3= D

Answer 3

1. Stars behave like blackbodies, and a blackbody's spectra reveals its temperature
http://en.wikipedia.org/wiki/Blackbody

2. Emission lines are where there is a presence of light, absorption lines are where there is an absence of light. So, in the first case, electrons drop in energy level, and emit a photon.
http://en.wikipedia.org/wiki/Emission_line

Answer 4

These sound like questions in a test. You won't learn simply by copying others' answers. You need to research and answer them yourself. That way you are actually learning, instead of parrotting.