Mindblown: a blog about philosophy.
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The Doppler Effect
Learning Objectives By the end of this section, you will be able to: The last two sections introduced you to many new concepts, and we hope that through those, you have seen one major idea emerge. Astronomers can learn about the elements in stars and galaxies by decoding the information in their spectral lines. There…
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Formation of Spectral Lines
Learning Objectives By the end of this section, you will be able to: We can use Bohr’s model of the atom to understand how spectral lines are formed. The concept of energy levels for the electron orbits in an atom leads naturally to an explanation of why atoms absorb or emit only specific energies or…
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The Structure of the Atom
Learning Objectives By the end of this section, you will be able to: The idea that matter is composed of tiny particles called atoms is at least 25 centuries old. It took until the twentieth century, however, for scientists to invent instruments that permitted them to probe inside an atom and find that it is…
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Spectroscopy in Astronomy
Learning Objectives By the end of this section, you will be able to: Electromagnetic radiation carries a lot of information about the nature of stars and other astronomical objects. To extract this information, however, astronomers must be able to study the amounts of energy we receive at different wavelengths of light in fine detail. Let’s…
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The Electromagnetic Spectrum
Learning Objectives By the end of this section, you will be able to: Objects in the universe send out an enormous range of electromagnetic radiation. Scientists call this range the electromagnetic spectrum, which they have divided into a number of categories. The spectrum is shown in Figure 5.6, with some information about the waves in each…
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The Behavior of Light
Learning Objectives By the end of this section, you will be able to: Coded into the light and other kinds of radiation that reach us from objects in the universe is a wide range of information about what those objects are like and how they work. If we can decipher this code and read the…
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Thinking Ahead
The nearest star is so far away that the fastest spacecraft humans have built would take almost 100,000 years to get there. Yet we very much want to know what material this neighbor star is composed of and how it differs from our own Sun. How can we learn about the chemical makeup of stars…
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Collaborative Group Activities
Collaborative Group Activities
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For Further Exploration
For Further Exploration Articles Bakich, M. “Your Twenty-Year Solar Eclipse Planner.” Astronomy (October 2008): 74. Describes the circumstances of upcoming total eclipses of the Sun. Coco, M. “Not Just Another Pretty Phase.” Astronomy (July 1994): 76. Moon phases explained. Espenak, F., & Anderson, J. “Get Ready for America’s Coast to Coast Experience.” Sky & Telescope (February 2016): 22. Gingerich, O. “Notes…
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Eclipses of the Sun and Moon
Learning Objectives By the end of this section, you will be able to: One of the coincidences of living on Earth at the present time is that the two most prominent astronomical objects, the Sun and the Moon, have nearly the same apparent size in the sky. Although the Sun is about 400 times larger in diameter than the Moon,…
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