Chapter 4 Concepts:
Describe how electrons and photons interact to produce emission or absorption line, and explain the
resulting emission or absorption lines.
Explain how spectra can be used to determine the chemical composition of an astronomical source.
Classify the physical conditions in objects according to whether they produce a continuum,
absorption, or emission spectrum.
http://www.abc.net.au/science/articles/2010/10/07/3012690.htm
Spectroscopy — the use of light from a distant object to work out the object is made of….
https://en.wikipedia.org/wiki/Astronomical_spectroscopy
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure
the spectrum of electromagnetic radiation, including visible light and radio, which radiates from stars
and other hot celestial objects.
Identify the basic properties of light, contrasting its wavelike and particle like properties.
Describe the meaning of the wavelength and frequency of light and how they relate to its color.
http://www.uni.edu/morgans/astro/course/Notes/section1/new4.html
How do we describe light? What types of light are there? How are light, energy and radiation
related? How does light interact with matter? What are the rules that govern hot objects?
http://earthsky.org/space/what-is-the-electromagnetic-spectrum
What is the electromagnetic spectrum?
Describe in detail each part of the electromagnetic spectrum and how astronomers use it.
Bottom line: the electromagnetic spectrum describes all the wavelengths of light – both seen and
unseen. The shorter the wavelength, the more energetic the light. By using telescopes sensitive to
different wavelength ranges of the spectrum, astronomers get a glimpse into a wide variety of objects
and phenomena in the universe.
http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html
The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is energy that
travels and spreads out as it goes – the visible light that comes from a lamp in your house and the radio
waves that come from a radio station are two types of electromagnetic radiation. The other types of EM
radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, Xrays and gamma-rays.
http://space.about.com/od/astronomydictionary/g/What-Is-The-Doppler-Effect.htm
http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::800::600::/sites/dl/free/00725098
56/78778/Doppler_Nav.swf::Doppler%20Shift%20Interactive
Learn about the Doppler Effect
The Doppler Effect is a shift in the frequency or wavelength of radiation emitted from an object as it
moves with respect to an observer. It's named after Austrian physicist Christian Doppler who first
proposed it in 1842.
How does it work?
Describe the conditions that produce a Doppler shift.
http://www.astro.cornell.edu/academics/courses/astro201/wiens_law.htm
https://www.astro.umd.edu/resources/introastro/wien.html
http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::640::480::/sites/dl/free/00725098
56/220727/Blackbody_Nav.swf::Blackbody%20Radiation%20Interactive
Describe how and under what conditions the color of an object changes with temperature, and how
to use Wien’s law to calculate its temperature.
Wien's Law tells us that objects of different temperature emit spectra that peak at different
wavelengths.
According to Wien's Law for Blackbody Radiation:
The peak wavelength is inversely proportional to its temperature in Kelvin.
The concept of thermal radiation is related to the ideas of energy and temperature. The key principles
were discovered in 1898 by the German physicist Wilhelm Wien (pronounced Veen). Wien discovered
that all bodies constantly emit thermal radiation.
The amount and peak wavelength of the radiation depends on the temperature of the body, but not on
its composition.
The higher the temperature, the more radiation is emitted and the shorter (or bluer) the wavelength of
the bulk of the radiation.
The mathematical form of Wien's law identifies the dominant wavelength, or color, of light coming from
a body at a given temperature. It is surprisingly simple. Suppose we designate the temperature of the
body as T, given in Kelvins. The wavelength at which the maximum amount of radiation is emitted can
be called λ, given in meters.