Answer:
According to Einstein's theory of relativity, mass causes the curvature of space-time and this curvature is what we call gravity.
This means, fluctuations or disturbances of space-time produced by a massive accelerated body, are able to modify the distances and the dimensions of objects in an imperceptible way
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If we see the space-time as a huge fabric, and place two objects (one more massive than the other), both objects will bend this "fabric" and will be "attracted" to each other. Nevertheless, this "attraction" is due to the bending of the space around each object.
