Is the total weight of the Earth with everything on it evolving? I mean if we build a skyscraper, then all matter is already there on earth, just in a different form (sand, water, iron ore,..) and it is only processed and moved.
When animals or people are born, you would think that the weight of the earth is increasing. Yet they also eat and drink what was already present and nothing is actually added from the outside
Answer
You actually already answered your question yourself.
The Earth can be seen as a closed system. We call it “System Earth”. In a closed system there is no exchange of matter with the environment, only exchange of energy. This is how we receive solar energy on Earth. The Earth then loses part of its internal heat to space.
There is very little exchange of matter with the environment. In the highest parts of the atmosphere, System Earth does lose some hydrogen molecules to space; and every now and then a space fragment falls to Earth.
So everything that happens on Earth is actually a transformation of matter from one form (eg the apple that a mother-to-be eats) into another form (eg a new human). And for these transformations you need energy.
Answered by
Prof. Manuel Sintubin
Tectonics Geodynamics Earthquake Geology Earthquake Archaeology
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