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Chapter 24: Astrophysics

Created by: CK-12

Orion nebula

Credit: Courtesy of NASA/JPL-Caltech/STScI
Source: http://commons.wikimedia.org/wiki/File:Orion_Nebula_-_new_image_from_Hubble_%26_Spitzer_%28293693669%29.jpg
License: CC BY-NC 3.0

One of the most recognized constellations is Orion, with its three prominent belt stars and four stars in the trapezium. This constellation can be seen at night ascending in the east, visible from all parts of the globe. In November of 2012, an international team of astrophysicists announced the result of their work in computer modeling, which suggests that a famous nebula – or cloud – in Orion known as the Orion Nebula has a black hole at its heart, whose mass is some 200 times the mass of our sun.

Chapter Outline

Chapter Summary

Astronomy is a fantastically old science, and the accuracy of some historical observations is truly remarkable.

Stars function as immense fusion reactors, converting smaller into larger elements.  All stars initially convert hydrogen into helium, and the rate of conversion is dependent on the mass of the star.  As the hydrogen is exhausted, the increased density of star allows it to begin converting heavier elements, which releases exponentially more energy and causes the star to expand once more. Depending on the initial mass of the star, it will end its life after millions or billions of years as a white or brown dwarf, a neutron star, or a black hole.  The Hertzsprung-Russel diagram is an image depicting the relationships between star size, color, and surface temperature.

Image Attributions

  1. [1]^ Credit: Courtesy of NASA/JPL-Caltech/STScI; Source: http://commons.wikimedia.org/wiki/File:Orion_Nebula_-_new_image_from_Hubble_%26_Spitzer_%28293693669%29.jpg; License: CC BY-NC 3.0


Date Created:

Oct 11, 2013

Last Modified:

Sep 04, 2014
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