As early as 700 million years after the Big Bang, galaxies were already filled with cosmic dust. But where did it come from? There are two known sources of dust: old stars and supernovae. Astronomers studied nearby supernovae SN 2003gd using the Spitzer space telescope, and found that it had produced tremendous amounts of dust. Since there were many supernovae in the early Universe, they could be the source of all this dust.

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