Found this recently, although I can’t remember where. Perhaps one of the people I’m following on tumblr..? (feel free to drop your name in the comments if you think it was you, I’ll credit accordingly!)
Anyway, it’s “A comparison between a flame on Earth and a flame in a microgravity environment.”:

Yeah, cool picture. So what’s ‘the point’?
Well, flame has long been consider an symbol of creativity, assertiveness, and will power. It’s associated with the wands suite in tarot, and it might also be seen as the original spark of mankind’s dominance over nature. After all, it was fire that gave us the ability to cook food, keep away predators, and burn up underbrush (making travel, and therefore communication, much easier).
But it can be dangerous too. It’s what Prometheus brought us from the gods, and look what happened to him:

And it was tongues of flame that descended on the disciples at Pentecost after Christ was crucified.

Whether it’s a Titan or a Son of God, it seems someone’s always had to suffer in order to bring down the holy fires…
So then, what conclusions can be drawn from the effect of weightlessness on that candle flame?
Well, the difference between the two flames is that the yellow flame on the left is subject to gravity’s influence, while the blue flame on the right is not. And we first have to ask: To what can we liken gravity?
Wikipedia describes gravity as: “a natural phenomenon by which objects with mass attract one another”. And yet, in the very next sentence, it is described as “the agency which lends weight to objects with mass.” So mass, by itself, is kind of useless, unless there’s some other mass upon which it can act.
But if there is another mass, both of the masses act upon each other, and this gives them both “weight”. And weight is a measurement of the speed at which each is attracted to the other.
So what causes that attraction?

Here’s how Sir Issac Newton felt about it:
“That one body may act upon another at a distance through a vacuum without the mediation of anything else, by and through which their action and force may be conveyed from one another, is to me so great an absurdity that, I believe, no man who has in philosophic matters a competent faculty of thinking could ever fall into it.”
And it turns out that we still don’t really know how it works:
Today scientists describe the universe in terms of two basic partial theories – the general theory of relativity and quantum mechanics… The general theory of relativity describes the force of gravity and the large-scale structure of the universe, that is, the structure on scales from only a few miles to as large as a million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe. Quantum mechanics, on the other hands, deals with phenomena on extremely small scales, such as a millionth of a millionth of an inch. Unfortunately, however, these two theories are known to be inconsistent with each other – they cannot both be correct.

Well, since science is not too helpful, lets look at this a little more poetically. What seems to be the symbolic difference to be between the two flames?
To me, the one under the sway of gravity is standing upright, burning brightly, and so suggests a certain healthiness. It seems livelier.
The flame in the ‘microgravity environment’ is spherical, suggesting a kind of perfection. Yet, it doesn’t have the same range of color and, seemingly, would not have the same range of movement as the flickering, gravity-bound flame on the left. The purely blue flame is still, lacking movement.
Wikipedia tells us that this is because: “In microgravity or zero gravity environment, such as on a circular orbit , convection no longer occurs and the flame becomes spherical, with a tendency to become bluer and more efficient.”
More efficient… Because there’s no longer any convection causing the soot to rise to the top of a flame, turning the flame from blue to yellow as the soot trails away. In zero gravity, any soot is burned off equally in all directions, and therefore, it cannot be seen and has no effect on the flame.
But when a flame burns within gravity, the soot is moved away from the source of the heat in a singular direction, making it much more observable. This is caused by the attractive force between the flame and the earth, as it pulls the source of flame down towards a union with the earth.

Gravity is something we struggle against. It’s the thing that forces us to keep our feet on the ground, the thing that makes us trip when we’re not paying attention. Without gravity, we’d be able to fly.
But without gravity, we’d never be able to stop floating away either. In the perfect sphere of flame, in the heaven of zero gravity, there’s no involuntary attraction or movement. No connection, no convection.
And with no convection, how would we know where the soot was?
