Question

in zero gravity environment , such as in the orbit of earth the shape of the flame is spherical in nature . why is it so???

Answer 1

Candle flames behave differently in outer space (microgravity) than they do on earth, primarily because microgravity provides an environment that lacks buoyant convection, which normally plays an important role in maintaining and shaping a flame on earth.

Answer 2

Here on Earth, when a flame burns, it heats the surrounding atmosphere, causing the air to expand and become less dense. The pull of gravity draws colder, denser air down to the base of the flame, displacing the hot air, which rises. This convection process feeds fresh oxygen to the fire, which burns until it runs out of fuel. The upward flow of air is what gives a flame its teardrop shape and causes it to flicker.

But odd things happen in space, where gravity loses its grip on solids, liquids and gases. Without gravity, hot air expands but doesn’t move upward. The flame persists because of the diffusion of oxygen, with random oxygen molecules drifting into the fire. Absent the upward flow of hot air, fires in microgravity are dome-shaped or spherical.