Elon Musk Says the Sun Can Power All of Civilization. Of Course He's Right.

In a tweet yesterday, Elon Musk suggested we could all pay a little more tribute to the powerful orb that keeps our planet alive. Musk said the sun—that “free fusion reactor in the sky”—can power all of civilization.

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Solar energy runs through many of Musk’s long-term plans, and as the cost of solar technology falls, the SpaceX/Tesla/Boring Company head honcho will likely invest even more—sending a powerful message to other business and community leaders around the world. Musk’s comments also draw attention to some interesting facts about solar energy, as well as nuclear fusion experiments.

In the technical sense, Musk’s tweet is of course correct: The sun is a naturally occurring fusion reactor that cranks out an unfathomable amount of energy. Earth, which is protected by a thick, but livable atmosphere enabled by our own internal energy source—the spinning dynamo of our molten iron core—is the only inner planet with adequate protection from the sun.Mercury and Mars have both been totally blasted by cosmic radiation, even though Mars is much farther than Earth. Venus, wrapped in the atmospheric equivalent of a fiberglass insulation roll, is like a parked black car on a hot, sunny day.

How much energy really comes out of the solar system’s life-giving nuclear fusion reactor? The answer involves a metric prefix you’ve likely never heard of: 385 yotta watts—or about 3.85 times 10 to the 26th power. Of that, about two-thirds strikes the Earth after a 92-million-mile journey. This means any discussion of the sun’s power must also include a reverent moment for our atmosphere, because we don’t all cook where we stand every second of every day.

Even so, the amount that makes it through is still wildly powerful. As the University of Tennessee agriculture school confirms:

“If all the sunlight energy striking the Earth's surface in Texas alone could be converted to electricity, it would be up to 300 times the total power output of all the power plants in the world!”

If the largest human-planned nuclear fusion reactor to date—ITER, at 500 gross megawatts in theory—were itself the center of a solar system, its Earth would be an immeasurably minuscule distance away.

As with Musk’s early investment in mainstream electric cars, he’s now made some pivotal, large investments in solar energy to pair with his Tesla battery storage. Musk may make waves with his hot takes on Twitter, but the way he studies and invests in technology is pretty straightforward.Musk identified batteries as the pain point in electric cars and decided to make better batteries. He identified storage as a pain point in the burgeoning renewables industry around the world, and began fitting battery solutions that can work for these grids.

In this case, Musk’s comment about the sun was prompted by a fan who shared the recent news that project cost of solar energy is now the cheapest energy source in history. Imagine a near future where Musk’s love of space and solar combines into a solar array in low-Earth orbit, for example, the way many satellites are already powered by solar panels.

Especially with leaps forward in wireless energy transmission, the future certainly includes a lot of sunny days.