Cold fusion

Some people thought they found a new way to make heat.

They used special water and a metal. This metal helped the water make extra heat. This could have made cheap power for everyone.

But many other scientists tried it. They could not make the extra heat. Because of this, most people do not believe it. A small group still studies it today. They hope to find the truth.

Scientists once thought they found a new way to make power. This idea is called cold fusion.

Normal fusion happens in stars. It needs millions of degrees to work. Cold fusion would happen at room temperature. In 1989, two men named Stanley Pons and Martin Fleischmann shared their news. They used a special setup. They used heavy water and a metal called palladium.

They used a process called electrolysis. This uses electricity to change water.

They said the setup made extra heat. This heat was more than the electricity they put in. They also found small bits of tritium and neutrons. These are signs of nuclear changes. Many people were excited. They hoped for cheap and clean energy.

But other scientists could not make the same heat. Many tests failed to work the same way. This led to many doubts. Most scientists now think the original results were wrong. A small group still studies it today. They sometimes call it low-energy nuclear reactions.

They hope to find the truth about these unusual effects.

Scientists have long wondered if we could create energy through nuclear fusion at low temperatures. This idea is known as cold fusion.

Usually, fusion happens in stars or inside hydrogen bombs. These processes require temperatures of millions of degrees to work. Cold fusion would be different because it would happen near room temperature. There is currently no accepted scientific model to explain how this could work. If it were real, it could provide a cheap and abundant source of energy.

To test this, researchers used a process called electrolysis. They placed a palladium electrode inside a container of heavy water. This container is called a calorimeter, which is a tool used to measure heat.

They applied electricity to the liquid for many weeks. During the experiments, the temperature would sometimes jump from 30 °C to 50 °C. This extra heat was more than the electricity they put into the system. They called this "excess heat." They also looked for signs like neutrons and tritium to prove fusion was happening.

Many people tried to find the history of this idea. In 1927, a Swedish scientist named John Tandberg reported fusing hydrogen into helium. He used an electrolytic cell with palladium electrodes just like later experiments. Later, in 1989, Martin Fleischmann and Stanley Pons made the most famous claims. Fleischmann was a leading scientist at the University of Southampton. Pons worked at the University of Utah. They announced their findings at a press conference in March 1989. This announcement caused a massive sensation in the news.

Many details from these experiments are still studied today. The researchers used heavy water, which contains deuterium, to run their tests. They found small amounts of neutrons and tritium during their work. These tiny amounts are usually only found from cosmic rays or natural decay. In 1989, the United States Department of Energy reviewed the results. They decided the evidence was not convincing enough to provide funding. A second review in 2004 reached the same conclusion.

Many scientists eventually labeled the field as pathological science.

Even though most scientists moved on, some interest remains. A small community of 100 to 200 researchers still investigates these effects. They often use different names like low-energy nuclear reactions or CMNS. In 2019, a failed replication attempt was even published in the journal Nature. This shows that people are still curious about these unusual heat changes. It is a bit like a mystery that people cannot stop trying to solve. They hope to find a way to make the science work correctly.

Cold fusion is a hypothesized type of nuclear reaction. It is theorized to occur at or near room temperature. This concept differs greatly from thermonuclear fusion. Thermonuclear fusion is the process that powers stars and occurs in hydrogen bombs. That process requires temperatures of millions of degrees. Cold fusion would be a much calmer version of this energy release. Currently, there is no accepted theoretical model to explain how it could happen. If it were possible, it could provide a cheap and abundant source of energy.

The mechanism involves a process called electrolysis. In these experiments, researchers use a palladium (Pd) electrode. They place this electrode into a container of heavy water. This container is a calorimeter, which is an insulated vessel used to measure heat. Heavy water contains deuterium, an isotope of hydrogen. The researchers apply a continuous electric current to the liquid for many weeks. They hypothesized that the high compression and mobility of deuterium within the palladium metal might trigger fusion. During the process, the temperature of the cell might stay stable at 30 °C. However, the temperature could suddenly rise to about 50 °C. This sudden rise creates what researchers call "excess heat." This heat is significantly higher than the electrical power put into the system.

There are different ways to think about these nuclear reactions. One known method is muon-catalyzed fusion. This is a way to induce fusion without high temperatures using muons. Another concept is geo-fusion, which involves fusion in a planetary core. Some researchers now use different names for these phenomena. They call them low-energy nuclear reactions (LENR). Others call them condensed matter nuclear science (CMNS). These terms help distinguish the work from traditional thermonuclear fusion.

The history of these ideas dates back much further than 1989. In the 19th century, Thomas Graham recognized that palladium could absorb hydrogen. In the late 1920s, Friedrich Paneth and Kurt Peters reported hydrogen transforming into helium. They claimed this happened through nuclear catalysis in palladium at room temperature. However, they later retracted their report. They found the helium came from the air instead. In 1927, John Tandberg also reported fusing hydrogen into helium using an electrolytic cell. He even applied for a Swedish patent to produce helium and reaction energy. His patent was denied because he could not explain the physical process.

The most famous event occurred in March 1989. Electrochemists Martin Fleischmann and Stanley Pons announced their findings. They claimed their apparatus produced excess heat through nuclear processes. They also reported measuring neutrons and tritium. Tritium is a form of hydrogen produced by the fusion of deuterium. These findings caused a massive media sensation. People hoped for a limitless source of clean energy using only seawater. This hope was high because of the 1973 oil crisis and concerns about global warming.

However, the scientific response was largely negative. Many physicists tried to replicate the results but failed. They identified methodological flaws and experimental errors in the original study. By late 1989, most scientists considered the claims dead. The field gained a reputation as pathological science. In 1989, the United States Department of Energy (DOE) reviewed the evidence. They concluded it was not convincing and decided against funding. A second DOE review in 2004 reached the same conclusion. Most research on this topic is no longer published in mainstream peer-reviewed journals.

Despite this, a small community of interest remains. There are between 100 and 200 researchers still investigating these effects. They continue to present work at meetings like the American Chemical Society. Even in 2019, a failed replication attempt was published in the journal Nature. These researchers believe there is too much evidence of unusual effects to ignore. They continue to search for a way to prove these reactions can truly occur.