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

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
The Sun Shines Stoking the fires of the Sun Wednesday, December 22, 2010
Rigel A star with a bright but short future Monday, August 16, 2010
Moon and Aldebaran A star that's changing in a hurry Thursday, July 8, 2010
Moon and Spica The long beginning of a long journey Monday, May 24, 2010
Alkaid Getting a handle on the Big Dipper Sunday, May 9, 2010
Too Darn Hot Stars that can't stand the heat Thursday, April 1, 2010
Pyxis Pointing the way to the compass Saturday, March 6, 2010
Moon and Regulus The Moon and the lion's "regal" heart Saturday, February 27, 2010
Unicorn Stars Impressive stars for the unicorn Wednesday, February 24, 2010
Tin Heavy metal the slow way Thursday, January 21, 2010
Magnesium Ready for a dose of magnesium Wednesday, January 20, 2010
HD 19445 A "heavy" discovery from a faint star Tuesday, January 19, 2010
Delta Capricorni Sweeping past a busy star system Monday, December 7, 2009
The Crane A crane strides across the southern horizon Friday, December 4, 2009
Future Sun A glimpse of the Sun's future Tuesday, November 10, 2009
Gamma Cassiopeia Looking into the future of a giant Wednesday, November 4, 2009
Capella Twin stars that are getting old in a hurry Wednesday, October 14, 2009
Altair A signal from the recent past Tuesday, September 8, 2009
Vega A star with a bulging waistline Tuesday, August 18, 2009
Carbon Making a basic ingredient of life Wednesday, August 12, 2009
Helium Floating through the heart of the Sun Tuesday, August 11, 2009
Nucleosynthesis Mixing up a chemical stew Monday, August 10, 2009
Scorpius A family of stellar showoffs Monday, July 27, 2009
Venus, Mars, Aldebaran From one orange companion to another Monday, July 13, 2009
Izar A colorfully "tricky" pair of stars Wednesday, June 10, 2009
Arcturus Life around a giant star Saturday, May 23, 2009
Alpha Herculis Red-headed Hercules Sunday, April 19, 2009
Moon and Antares Peeling back the layers of a star Sunday, April 12, 2009
Moon and Regulus A famous star gets ready to shine Sunday, April 5, 2009
Sirius Turning up the heat Wednesday, January 7, 2009

Featured Images

Rings and bubbles from a dying star
Jumping Through Hoops Thursday, August 5, 2010
A Dose of Magnesium Wednesday, January 20, 2010
Star Power Monday, November 20, 2006


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