Does the Sun contain fire? Or some pure form of energy?
If space has no air how can fire exist there? It may exist cause a burning piece of magnesium keeps on burning in vacuum but, to start fire, oxygen is required.
It depends on what you call a medium; I assume you refer to matter as a medium.
Then, roughly speaking: yes, there is radiation, like light, or heat radiation, that can exist without matter as medium. I think you could call this "energy" in this sense.
You can transfer light through a vacuum, of course.
The sun, fire or burning magnesium are about matter that is hot - which is very different.
Like a rocket provides oxygen to burn fuel in space, so the sun provides its own energy. Like you, I'm not necessarily convinced the space in an of itself it not a medium since light travels at a constant speed within it and matter is capable of traveling within it. Planets bleed their own atmospheres into space as well.
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