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Why We Will Never Make A Nuclear Fusion Reactor As Good As The Sun

Fusion fightMike Garrett and NASANuclear fusion containment vessel on the left vs. the sun on the right. Fight!

Atoms, the tiny structures that make up you, me, and everything we see on Earth, are mesmerising in their ability to both create and destroy.


ElugelabFastfissionThe ill-fated island of Elugelab did not survive the power of nuclear fusion.



We’ve been searching for ways to make cleaner power — using the sun’s energy, or the wind’s, but the cost, infrastructure, and technology have not come close to powering the world. Clean, limitless energy is the real holy grail. Combine that desire with the awesome power we first saw with the< H-bomb, and we’ve been dreaming of a way to harness nuclear fusion of the sun as a source of clean, endless energy.

But so far, only Hollywood has managed.

Spider man nuclear fusionJoaquin Sharpe Jr.Scene from the 2004 film Spiderman 2.



Fusion generates tremendous amounts of energy, but you have to give a lot to get a lot. If any of that energy leaks out without being captured as electricity, it’s unlikely that you will get any kind of surplus from your fusion system.

Right now, that’s the problem with nuclear reactors on Earth: The amount of energy we need to produce the conditions for nuclear fusion is more than the energy we get out. And we’ve been coming up short for decades with little signs of improvement, according to Charles Seife, author of the book “Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking who has written about the turtle-paced race for nuclear fusion for Slate.

So, what does the sun have that we don’t?

Rotating sunNASA Goddard Spaceflight CenterThe sun is the best nuclear fusion reactor around.

Quite simply: Gravity.

Fusion in the sun’s center works by pressing four hydrogen atoms together to form one helium atom and energy. The extreme weight of the sun provides the pressure needed, without extra energy needing to be put into the equation to start it, like here on Earth.

When this fusion of hydrogen into helium happens, a little bit of the atoms’ mass is lost in the form of energy. A LOT of energy.

The sun fuses 620 million metric tons of hydrogen in its core each second. If you do the maths, that means that in a single second, the sun produces enough energy to power New York City for about 100 years.

Unfortunately for us, it is incredibly difficult to fuse hydrogen atoms together. It takes extreme pressure and heat, something that the sun’s strong gravitational force does naturally in its core. But we don’t have access to this kind of gravity here on our comparatively tiny Earth, and the only way to manufacture it is to expend a ton of energy to create it.

Planets and sun size comparisonLsmpascalTo scale comparison of the sun and the planets in our solar system.



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