.Danielle Fong 🔆 is building a light-powered engine. It converts fuel → heat → light → electricity, giving it the energy density of a hydrocarbon-powered engine and the mobility of a battery. Basically, its a portable Dyson Sphere. Here's how it works:

All of our @1stPrinciplesFM guests are equally amazing, but some are more equal than others... This was one of my favorite episodes EVER. Danielle is just so great at explaining why things work the way they do, which is of course the entire point of this show.

I got to GAZE INTO THE FLAME in person, and it's a wild experience. It's hard to express how bright it is — and this is just the precursor to the version that will be the brightness of 3000 suns.

Many folks are asking about efficiency, Danielle has a very helpful chart here: The important context is that the fuel entering the top of the funnel is at least 10x more energy-dense than a normal battery. (And gasoline would be like 40x or something)

helpful energy flow diagram!

i’m not even officially YC (tho @sama said i was honorary YC) and @garrytan retweets this *first*, on demo day! class act!

@sama @garrytan It's thematically YC Demo Day, shares the same color palette 🧡

is that... efficient?? the power of a dyson sphere is you're capturing energy that's being produced anyway. captured in the form the energy is produced (heat and light) and taking the minimal number of conversions to a form we use (electricity). this sounds like a lot of conversions to lose efficiency through.

@DanielleFong Short answer: batteries are *so* much less dense than hydrocarbons that you can lose a lot of efficiency and still get more power per kg/volume.

@DanielleFong FATHER, MOTHER I CRAVE LIGHT ENGINES

@DanielleFong Yesssssssss