How do does radio signal keep on travelling in space? Shouldn’t it just fade away.
In: Engineering
What is there to fade it? On earth the atmosphere interferes, so the waves don’t reach very far, but in space there’s nothing.
That’s not to say there’s no fading. The source can only emit a given amount of radiation. This intensity lowers the farther you go.
For an analogy, imagine a huge [bicycle wheel](https://cdn1.vectorstock.com/i/1000×1000/93/05/bicycle-wheel-vector-4419305.jpg) with spokes. At the centre, the spokes might occupy all the directions, but at a distance, the spokes only occupy certain areas of the edge. That “frequency of spokes per length of edge of wheel” is analogous to “the intensity of waves per unit area”. Nowhere is the middles the spokes change.
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