Nuclear Fusion

A reaction that involves two atomic nuclei merging to create the nucleus of a new atom. The reaction is accompanied by a tremendous release of energy. The Sun's energy, as with all stars, comes from nuclear fusion reactions that happen in its core. The reactions fuse hydrogen nuclei into helium nuclei. About 0.7 percent of the mass of the hydrogen is converted to energy, which makes the star shine.


Star Color and Energy Stars come in a variety of sizes and colors, but...
Aries, the Ram Aries, the ram, is a faint pattern marked by...

Radio Programs

R Sculptoris Stirring up a stellar bubble Friday, December 11, 2015
Moon and Jupiter From the Big Bang to a big planet Thursday, November 5, 2015
Planetary Nebulae A ghostly planetary doppelganger Tuesday, November 3, 2015
Confirmation Particles from the heart of the Sun Wednesday, October 28, 2015
Alpha Persei A young star ages in a hurry Friday, October 9, 2015
The First Stars Whipping up the first stars Thursday, July 16, 2015
Moon and Aldebaran Igniting the core of a star Saturday, July 11, 2015
Fred Hoyle Unlocking the secrets of the stars Wednesday, June 24, 2015
Vega A middle-aged star with a difference Saturday, June 6, 2015
Brighter Sun The Sun gets a lot brighter Tuesday, April 28, 2015
Solar Fusion The Sun shines on and on and on Monday, April 27, 2015
Iron Ironing out a heavy element Thursday, February 5, 2015
Moon and Aldebaran Making carbon and oxygen in a star Friday, November 7, 2014
Great Square The above-average stars of the Great Square Tuesday, September 9, 2014
Outcast Star A stellar outcast in the Big Dipper Tuesday, July 22, 2014
Moon and Aldebaran Changing a delicate balancing act Monday, July 21, 2014
Oxygen Breathing a creation of the stars Thursday, June 19, 2014
Making Nitrogen Breathing the “ash” of dead stars Monday, February 17, 2014
Z Machine II The power source of the stars Tuesday, February 4, 2014
Wezen Dumping chemicals into space Wednesday, January 29, 2014
Moon and Jupiter Heating up a giant planet Wednesday, December 18, 2013
Capella A pair of bright, “puffy” stars Tuesday, November 19, 2013
Moon and Aldebaran The beginning of the end Thursday, July 4, 2013
Colorful Arcturus Adding some color to a bright star Sunday, June 23, 2013
Gamma-2 Velorum A star exposes its inner workings Friday, April 5, 2013
Polaris II The un-steady beat of the North Star Wednesday, February 20, 2013
Moon and Antares Building a stellar onion Saturday, July 28, 2012
The Sun II The long trip before the journey begins Tuesday, December 18, 2012
The Sun Powering up the Sun Monday, December 17, 2012
Triangulum Aging stars in the triangle Saturday, November 3, 2012
Unproductive Sun Outshining the Sun — sort of Monday, June 18, 2012
Capella A quick exit for a “heavy” star Friday, April 27, 2012
Star in a Bottle Making a bottleful of starstuff Friday, April 13, 2012
Supernova 1987A Blasting a giant star to bits Tuesday, February 21, 2012
White Dwarfs Squeezing the heart of a dead star Wednesday, February 1, 2012
Betelgeuse A superstar among supergiants Thursday, December 1, 2011
Alpha Persei A young but aging star Saturday, October 8, 2011
Pollux Forging the element of life Sunday, May 15, 2011
Gienah A young-but-old star Saturday, April 2, 2011
Denebola Shining through the moonlight Friday, March 18, 2011
Stellar Factory Forging elements in a stellar factory Tuesday, February 15, 2011

Featured Images

Abell 78, a planetary nebula
Last Round Tuesday, July 28, 2015
Rings and bubbles from a dying star
Jumping Through Hoops Thursday, August 5, 2010
A Dose of Magnesium Wednesday, January 20, 2010


©2015 The University of Texas McDonald Observatory