Can we harness solar energy from other stars?

Jul 4, 2025

A listener wonders if we can capture energy from stars beyond our sun. Each star emits a staggering amount of energy, leading to fascinating possibilities. Experts discuss measuring star brightness and showcase a unique telescope experience. The idea of a Dyson Sphere emerges—an ambitious concept of harvesting energy by placing panels in orbit around distant stars. Advanced solar technologies may one day enable us to harness this cosmic power, pushing the boundaries of renewable energy. The future of starlight as a resource sparks creative innovation.

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INSIGHT

Starlight Is Extremely Dim

Light from stars other than the sun is about 10 billion times weaker than sunlight on Earth.
Energy from starlight is extremely faint, limiting practical energy capture on Earth.

ADVICE

Place Solar Panels in Space

To harness stellar energy effectively, use photovoltaic technology in space, not on Earth.
Develop lightweight, high-efficiency multi-junction solar cells and build arrays in orbit.

INSIGHT

Concept of Dyson Sphere Explored

A Dyson Sphere is a swarm of solar panels orbiting a star to capture all its energy.
Building one requires enormous surface area and advanced technology, likely thousands of years away.

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Listener Dickson Mukisa from Uganda has been gazing up at the stars. But he’s not making wishes. He wants to know whether we can harness their energy, in the same way we do with our OWN star – the sun. After all, they may seem small and twinkly to us, but each one is a gigantic flaming ball of energy, with a power outputs averaging around 40 quadrillion kilowatt-hours per year – EACH! With somewhere between 100 and 400 BILLION stars in our own galaxy alone, that’s a lot of power! Can we get ‘solar power’ from stars that are such a long way away from earth? And what might we use it for?

Alex Lathbridge heads to the University College London Observatory, to peer through the eyepiece of an enormous telescope and see some stars for himself. Professor Steve Fossey explains just how much of the light energy of the stars reaches us on earth. In other words, how BRIGHT they are.

Once the starlight reaches earth of course, we have to capture it. Could traditional solar panels do the job? Alex meets Professor Henry Snaith from the University of Oxford, to find out about the future of photovoltaic technology, and why it could all be heading out to space.

Once in space, things start getting weird! What if we made an enormous fleet of solar panels, and put them all into orbit around a star, soaking up every last drop of that precious energy? That might sound like science fiction, but the idea has been around for decades. It’s called a Dyson Sphere, or Dyson Swarm. Swedish researcher at the Insitute for Future Studies, Anders Sandberg explains how we might be able to build one around a neighbouring star... in around 10,000 years or so.

But maybe it’s not all about light. Finally, Alex explores the mysterious, invisible energy of the ‘solar wind’, with Pekka Janhunen, Finnish physicist and inventor of the “E-Sail”, which might be able to harness the power of the stellar wind, too.

Presenter: Alex Lathbridge Producer: Emily Knight Series Producer: Ben Motley

(Image: Astronomer looking at the starry skies with a telescope. Credit: m-gucci via Getty Images)