To say whether an object is alive depends on your perspective. Our everyday perspective is full of things that are easy to label as living, but a new perspective offered by steady extension of the range of our senses present far more challenging scenarios where we must discriminate between what is animate and what is merely mechanical.
One of the greatest challenges to our perspective comes from simply adjusting the scale with which we observe the world. Close examination of the human body indicates that we are teeming with life at the micro-scale. An individual is a colony of macrophages, lipocytes, neurons and others. Each cell seems more alive than purely mechanical. After all, a cell swimming around in a lake is enough to be called an organism. Why not the same title for those swimming around your body? Or have they lost part of what makes them alive for the sake of cooperation with other cells?
As the range of our senses steadily expands we may meet new challenges to our definition of life. My piece Surface Images of Satellite #3 intends to raise such questions.