But interstellar gas and dust is important in the BIRTH of stars, too. Stars form out of huge clouds of gas and dust, and when they die, they RETURN part of themselves back to the interstellar medium. Everything on earth, and all the planets and stars
in the Universe; they all formed out of interstellar gas and dust. We, and all the animals and all the plants and all the rocks on earth, were all formed out of matter that was originally spread out between the stars, in interstellar space.

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