Hello, SFIA audio listeners.

In this month's Nebula exclusive, big alien theory, we're asked at the reason alien civilizations might be rare is because most aliens are huge.

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There's an old joke that Fusion is the energy technology of 20 years from now, and always

will be, and yet that technology may finally be on the horizon.

Welcome to Science and Futurism with Isaac Arthur, and I am your aforementioned host,

Isaac Arthur, bringing you hopefully accurate glimpses into the future for the last decade,

and now with 90% more that are ours, though there are subtitles available on all our episodes.

Besides having a stubbornly lingering speech impediment and a science show,

I am also a physicist, and one of the things that attracted me to the field was energy production.

I grew up in the 1980s when fear of nuclear war was probably at its peak. Fossil fuel concerns

were beginning to arise, and solar was a distant dream.

Global population growth was very fast, and there was always a concern bordering on dread

that we were going to have a Malthusian catastrophe, and all ended up living in the burnt-out

ruins of a deforested, toxic, and irradiated planet.

This was all about the time that nuclear

fusion was getting its first developmental disappointment phase with the public, as it had

started getting talked about as an option that we might have in a couple decades in the 1950s and

60s, and seems still almost entirely theoretical. Add to it, we would soon get inundated

with a lot of cold fusion designs, and with some were at least reasonably sincere and sane,

many more were utter scams and hoaxes. At the same time, even nowadays where we've got

...