[metric10]

Yes. Back of envelope, took physics in college many years ago[1] analysis:

E=mc^2, or energy = mass * (speed of light)^2. According to Wikipedia a candle can produce 77 watts of energy "combined." I guess that means 77 joules (1 watt = 1 J/s). So we have:

77 = m * (299792458)^2

Solving for m via Wolfram Alpha:

m = 11 / 12839369696240252

Which is in grams. That's a _very_ small amount, but it's not zero.

edit:

[1] If I'm being honest, I got E=mc^2 from watching the Twilight Zone as a kid, not college physics.

[MauranKilom]

> According to Wikipedia a candle can produce 77 watts of energy "combined." I guess that means 77 joules (1 watt = 1 J/s).

Watts is energy/time. 77 watts for a candle sounds about right. That means it is producing 77 joules per second. The amount of energy released by burning such a candle is therefore proportional to how long it burns, which is proportional to its mass. The thing you are looking for is the specific energy, listed as 45 MJ/kg upthread. See https://news.ycombinator.com/item?id=26973765 for the rest of the calculation.

[Ovah]

Kind of pedantic but I've never understood why it's E=mc^2 and not E=Δmc^2. In Einsteins original paper he derives the equation with a delta m: a change of mass corresponds to some amount of energy. To me that is different than to say that a whole mass corresponds to a some amount of energy. I've never seen a justification why the delta can be omitted and why the equation still would hold true.

[benchaney]

There isn't a delta because E=mc^2 isn't just describing a reaction, or a conversion. It is describing the fundamental equivalence between mass and energy. It is true even in situations where ΔE and Δm aren't defined.

[mannerheim]

I would assume it has to do with relativistic mass, which used to be somewhat commonly used (m used for relativistic mass, m_0 for rest or invariant mass), but which is now disfavoured. For m as relativistic mass, E = mc^2 holds.

[snissn]

usually the momentum is really low so it's fine, you could read this wikipedia article about it, share questions if that doesn't clear things up

https://en.wikipedia.org/wiki/Energy%E2%80%93momentum_relati...

[colinmhayes]

The delta is implied. If you're being rigorous yea you'd include it. But you never see it used rigorously.