At the center of our solar system is an enormous nuclear generator. The Earth revolves around this massive body at an average distance of 93 million miles (149.6 million kilometers). It's a star we call the sun. The sun provides us with the energy necessary for life. But could scientists create a miniaturized version here on Earth?
It's not just possible -- it's already been done. If you think of a star as a nuclear fusion machine, mankind has duplicated the nature of stars on Earth. But this revelation has qualifiers. The examples of fusion here on Earth are on a small scale and last for just a few seconds at most.
To understand how scientists can make a star, it's necessary to learn what stars are made of and how fusion works. The sun is about 75 percent hydrogen and 24 percent helium. Heavier elements make up the final percent of the sun's mass. The core of the sun is intensely hot -- temperatures are greater than 15 million degrees Kelvin (nearly 27 million degrees Fahrenheit or just under 15 million degrees Celsius).
At these temperatures, the hydrogen atoms absorb so much energy that they fuse together. This isn't a trivial matter. The nucleus of a hydrogen atom is a single proton. To fuse two protons together requires enough energy to overcome electromagnetic force. That's because protons are positively charged. If you're familiar with magnets, you know that similar charges repel each other. But if you have enough energy to overcome this force, you can fuse the two nuclei into one.
What you're left with after this initial fusion is deuterium, an isotope of hydrogen. It's an atom with one proton and one neutron. Fusing deuterium with hydrogen creates helium-3. Fusing two helium-3 atoms together creates helium-4 and two hydrogen atoms. If you break all that down, it essentially means that four hydrogen atoms fuse to create a single helium-4 atom.
Here's where energy comes into play. A helium-4 atom has less mass than four hydrogen atoms collectively. So where does that extra mass go? It's converted into energy. And as Einstein's famous equation tells us, energy is equal to the mass of an object times the speed of light squared. That means the mass of the tiniest particle is equivalent to an enormous amount of energy.
So how can scientists create a star?
Creating enough energy to overcome electromagnetic force isn't easy but the United States managed to do it on Nov. 1, 1952. That's when Ivy Mike, the world's first hydrogen bomb, detonated on Elugelab Island. The bomb had two stages. The first stage was a fission bomb. Fission is the process of splitting a nucleus. It's the type of bomb the United States used on Nagasaki and Hiroshima to end World War II.
The fission bomb element of Ivy Mike was necessary to create the massive amount of energy required to overcome the electromagnetic force of hydrogen to fuse it into helium. Heat from the initial explosion transferred through the lead casing of the bomb to a flask containing liquid deuterium. A plutonium rod inside the flask acted as the ignition for the fusion reaction.
The resulting explosion was 10.4 megatons in size. It completely obliterated the island, leaving behind a crater 164 feet deep (nearly 50 meters) and 1.2 miles (1.9 kilometers) across [source: Brookings Institution]. For a brief moment, man had harnessed the power of the stars to create a weapon of immense power. The thermonuclear age had begun.
Laboratories around the world are now trying to find a way to harness fusion as an energy source. If they can find a way to create sustainable and controllable reactions, scientists could use fusion to provide massive amounts of power for millions of years. There's no shortage of fuel -- hydrogen is plentiful and the oceans have large amounts of deuterium in them.
But getting to the point where we can harness fusion for power is going to take years of research and billions of dollars in resources. The amount of power required to initiate fusion coupled with the intense heat created by the event make it difficult to build a facility capable of containing a reaction. Some scientists are looking at massive lasers as a way to ignite a fusion event. Others are exploring options with plasma -- the fourth state of matter. But no one has unlocked the secret just yet.
So, we can create a star on Earth -- at least for a short time. But it remains to be seen if we can sustain such a creation and harness its astounding energy.
Learn more about stars and energy by following the links on the next page.
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More Great Links
- Brookings Institution. "The 'Mike' test, November 1, 1952." 2010. (May 20, 2010) http://www.brookings.edu/projects/archive/nucweapons/mike.aspx
- Cox, Brian. "Can we make a star on Earth?" BBC Horizons. February 2009. (May 19, 2010) http://www.bbc.co.uk/programmes/b00hr6bk
- Cox, Brian. "How to build a star on Earth." BBC News. Feb. 16, 2009. (May 18, 2010) http://news.bbc.co.uk/2/hi/sci/tech/7891787.stm
- Gray, Richard. "Scientists plan to ignite tiny man-made star." Telegraph. Dec. 27, 2008. (May 18, 2010) http://www.telegraph.co.uk/science/science-news/3981697/Scientists-plan-to-ignite-tiny-man-made-star.html
- Los Alamos National Labs. "Helium." Dec. 15, 2003. (May 18, 2010) http://periodic.lanl.gov/elements/2.html
- Los Alamos National Labs. "Hydrogen." Dec. 15, 2003. (May 18, 2010) http://periodic.lanl.gov/elements/1.html
- NASA. "Sun." World Book at NASA. (May 18, 2010) http://www.nasa.gov/worldbook/sun_worldbook.html
- The Astrophysics Spectator. "Hydrogen Fusion." Oct. 6, 2004. (May 19, 2010) http://www.astrophysicsspectator.com/topics/stars/FusionHydrogen.html