By Jonny Lupsha, Current Events Writer
Nuclear fusion occurs when smaller atoms combine into bigger elements. For a century, scientists have struggled to make it—and its energy—a clean, safe reality on Earth. Two powerful new magnets just made nuclear fusion draw closer.
One method of achieving nuclear fusion—which has powered the Sun for five billion years—involves turning hydrogen into a plasma by using incredible amounts of heat and pressure. Superconducting magnets aid in this process, and two separate teams of scientists have simultaneously made announcements that signal major advancements in the century-old dilemma of nuclear fusion.
Scientists at the Massachusetts Institute of Technology announced a successful test of the world’s strongest, high-temperature superconducting magnet. Meanwhile, scientists working with the International Thermonuclear Experiment Reactor (the ITER project) have received partial delivery of a magnet said to be so strong it could lift an aircraft carrier.
What is nuclear fusion and how did we discover it? In his video series Chemistry and Our Universe: How It All Works, Dr. Ron B. Davis, Jr., Associate Teaching Professor of Chemistry at Georgetown University, explained our history with nuclear fusion.
Defining Nuclear Fusion
“If heavier elements tend to break down to lower their energy, smaller ones like hydrogen and helium should have a tendency to want to come together to create larger elements in the same quest,” Dr. Davis said. “Chemists call this process nuclear fusion.
“Fusion reactions are the alter ego of fission reactions; they involve the building up of larger nuclei from smaller ones.”
The trick, he said, is getting the atoms to combine, since there’s a natural repulsion due to the charges of their nuclei. Pushing them together requires force. Stars are the only place in nature with high enough temperatures and pressures to induce nuclear fusion. The simplest and most powerful fusion of all is that of hydrogen atoms to make helium. Dr. Davis said that this reaction has powered the Sun for five billion years and will likely power it for another five billion.
Staring at the Sun
Understanding nuclear fusion has taken more than a century. Even in the 1900s, scientists debated over the current age and life span of the universe, the Sun, and Earth itself.
“One of the burning questions was the life span of the Sun,” Dr. Davis said. “Radiometric dating of Earth rocks had put the age of the solar system at about five billion years, but possibly an even more important question than ‘How old is our home?’ would be ‘How much longer will it last?'”
In the late 1800s, an English astronomer named William Huggins proposed that supernovas, a fascinating astronomical phenomenon, were the death of stars similar to the Sun. Those who believed him had to face the dreaded notion that if stars could die, ours could too.
“French astronomer Pierre Jansen had only recently observed the line spectrum of helium in the Sun’s corona during an 1868 solar eclipse, revealing that the awesome heat and light generated from our star was released primarily due to the fusion of hydrogen into helium,” Dr. Davis said.
Finally, British astronomer Arthur Stanley Eddington, who lived from 1882 to 1944, decided to take on the task of determining how much fuel is left in the Sun’s energy tank, so to speak. He concluded that it would continue to burn for another billion years. However, since then, other scientists have discovered that the amount of fusible hydrogen in the Sun implies that it should burn for five billion more years, using just a tiny fraction of its mass in the conversion from hydrogen to helium.
This incredible power and its discovery have led to our endeavors in nuclear fusion—endeavors which are now one step closer to coming to fruition.