Is nuclear fusion the future? The race is heating up to bring star power down to Earth. But some scientists are sceptical this technology will ever be more than science fiction.
China's artificial sun sets new world record
Is nuclear fusion the future? The race is heating up to bring star power down to Earth. But some scientists are sceptical this technology will ever be more than science fiction.
<h2 class="wp-block-heading eplus-wrapper" id="crosshead">Star power</h2>
A gigantic nuclear reactor burns at the centre of our solar system. Its core is a ferocious 15 million degrees Celsius. Every second, 500 million tonnes of hydrogen fuse under extreme pressure. The energy released makes life on Earth possible.
Scientists have spent over 70 years trying to mimic the fusion reactions in the Sun. Many think a "star in a jar" can solve humanity's energy problems, provide limitless clean power and end our need for fossil fuelsFuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming..
Last week, one of these "artificial suns" ran for a record-breaking 403 seconds. China's Experimental Advanced Superconducting Tokamak (EAST) is a doughnut-shaped machine that uses powerful magnets to hold together superheated plasma. Inside, hydrogen atoms fuse to form helium and energy to generate electricity.
Physicists are celebrating several breakthroughs in fusion technology. Last December, an experiment in the US was the first to achieve "ignition" - producing more energy than it consumed.1 Meanwhile, German researchers have found a way to create smaller, cheaper devices.2
The goal is the modern version of alchemy: the quest to turn base metals into gold. A litre of seawater contains enough fusion material to produce energy equivalent to 300 litres of petrol. But alchemy was a medieval pipe dreamSomething that will never happen - that a smoker might dream about while puffing on a pipe.. Will the race to bottle the Sun also fail?
"Fusion power is 50 years away - and probably always will be." Academic Ian Lowe says this is the standard joke about fusion. Getting reactions going is immensely difficult. It requires temperatures ten times hotter than the Sun and powerful lasers and magnets to contain it. All of this is very expensive.3
Lowe says fusion will arrive "too late" to stop climate change. Physicist Daniel Jassby says it is not the "perfect" energy source, has many drawbacks and is an enormous black hole for money and resources.4 The only solution is to switch to renewables.
Physicist Arthur Turrell disagrees. Building these "star machines" is humanity's greatest challenge. A global effort now "could provide millions, perhaps billions, of years of clean energy". Limitless power everywhere would radically change the world, ending energy poverty and wars over fuel.
Many scientists are betting big on a fusion future. In 2025, the world's largest fusion experiment will go online in southern France. The International Thermonuclear Experimental Reactor (ITER) is a joint project of 35 nations. It will use the most powerful magnet ever built, strong enough to lift an aircraft carrier off the ground.
The word nuclear conjures up images of ChernobylThe disaster, in 1986, involved a meltdown at a nuclear plant in Ukraine., nukes and radioactive waste. But fusion is not fission. Splitting atoms in fission sets off dangerous chain reactions. "In fusion," says expert Chris Warrick, "we have the opposite problem". Keeping it going is very difficult, so it is "inherently safe".
And if we can keep them running, Turrell says fusion rockets will be our "best hope" for interstellar travel. Humanity's future in space may depend on building stars on Earth.
Yes: Fusion is the longest of long shots - the hardest thing we have ever done. It may take decades to perfect, but this ambition and foresight will give future generations the gift of limitless energy.
No: Fusion is science fantasy. Physicists and governments are wasting time and money on a pet project while the world burns. We already have the technology of the future in wind and solar power.
Or... No single technology will decide our future. Optimists always believe new technology will change everything and fix all our problems. In reality, we will need a variety of inventions working together.
Fossil fuels - Fuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming.
Pipe dream - Something that will never happen - that a smoker might dream about while puffing on a pipe.
Chernobyl - The disaster, in 1986, involved a meltdown at a nuclear plant in Ukraine.
<h5 class="wp-block-heading eplus-wrapper" id="question"><strong>Is nuclear fusion the future? </strong></h5>
China’s artificial sun sets new world record

Glossary
Fossil fuels - Fuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming.
Pipe dream - Something that will never happen - that a smoker might dream about while puffing on a pipe.
Chernobyl - The disaster, in 1986, involved a meltdown at a nuclear plant in Ukraine.