Though this remnant is not from the early universe, its proximity to us makes it easier to address the question of whether supernovae have the ability to synthesize significant amounts of dust. Rho and her colleagues analyzed the Cassopeia A supernova remnant, located about 11,000 light-years away. Spitzer recently found evidence that highly energetic black holes, called quasars, could, together with supernovae, manufacture some dust in their winds ( ). Other objects in addition to supernovae might also contribute to the universe's first dust. These first stars, called Population III, are the only stars that formed without any dust.

Because massive stars don't live very long, theorists reasoned that the very first exploding massive stars could be the suppliers of the unaccounted-for dust. These violent explosions occur when the most massive stars in the universe die. But back when the universe was young, sun-like stars hadn't been around long enough to die and leave dust. In our nearby universe, dust is pumped out by dying stars like our sun. Developing stars need dust to cool down enough to collapse and ignite, while planets and living creatures consist of the powdery substance. Space dust is everywhere in the cosmos, in our own neck of the universe and all the way back billions of light-years away in our infant universe. Rho is the lead author of a new report about the discovery appearing in the Jan. This finding was possible because Cassiopeia A is in our own galaxy, where it is close enough to study in detail,' said Jeonghee Rho of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. 'Now we can say unambiguously that dust – and lots of it – was formed in the ejecta of the Cassiopeia A explosion. Spitzer's sensitive infrared detectors have found 10,000 Earth masses worth of dust in the blown-out remains of the well-known supernova remnant Cassiopeia A. Scientists had suspected that exploding stars, or supernovae, were the primary source, but nobody had been able to demonstrate that they can create copious amounts of dust – until now. The findings, made with NASA's Spitzer Space Telescope, are the most significant clue yet in the longstanding mystery of where the dust in our very young universe came from.

Astronomers have at last found definitive evidence that the universe's first dust – the celestial stuff that seeded future generations of stars and planets – was forged in the explosions of massive stars.

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