While studying the remnants of a supernova in the "nearby" Small Magellanic Cloud, a team of scientists at UC Berkeley made an odd discovery: the amount of interstellar dust was only a small fraction of what it should have been.

Supernovae - exploding stars - have long been thought to be the source of most of the interstellar dust in the universe. New observations with the latest equipment is showing this may not necessarily be true. As astrophysicist Snezana Stanimirovic notes, "observations of supernova remnants in the Milky Way show much less dust than expected."

What gives?

According to studies by Ben Sugerman of the Space Telescope Science Institute in Baltimore,  it may be the result of some mistaken assumptions. Earlier scientists had assumed that supernova dust spreads uniformly, "like a big, spherical, hot bubble." The reality is that the dust may actually spread in a fashion that is "very clumpy." Doug Welch of McMaster University also points out that supernova dust quickly cools in outer space - and cold dust is not observable by infrared telescopes. This fact may account for the "apparent dust deficit" in earlier observations.

However, Stanimirovic points out that "a lot of dust grains get destroyed as the blast wave propagates." Dust grains grind against each until they're small to detect.

According to an international study published in Science Express recently, behemoth star supernovae have been major dust factories ever since the earlier generations of stars formed several 100 million years after the Big Bang. The study was co-authored by McMaster University Physics and Astronomy Professor, Doug Welch, and Louisiana State University's Geoff Clayton.

Together with a scientific team, they trained their telescopes on Supernova 2003gd (within the white box), which exploded in the NGC 628 spiral galaxy 30 million light-years from Earth.

The light from the 2003gd first reached Earth on March 17, 2003. While many supernovae are discovered each year, this particular one stood out because it was relatively nearby and could be followed for a longer-than-usual time by the specialized infrared detectors of the Spitzer Space Telescope, and by a spectrograph on the Gemini North telescope.

The study utilized Hubble Space Telescope data as well as new observations from the Spitzer Space Telescope (currently trailing the Earth along its orbit) and the Gemini North telescope of the Gemini Observatory on Mauna Kea, Hawaii. It was funded in part by the Natural Sciences and Engineering Research Council.

According to Professor Welch, "2003gd is, quite literally, the smoking gun...These carbon and silicon dust particles which form from the supernovae blast make possible the many generations of high-mass stars and all the heavy elements they produce. These are elements which make up the bulk of everything around us on Earth, including you and me." In that case, thank you, supernovae blasts!

Supernovae expand and dissipate into space quickly, so scientists require extremely sensitive telescopes to study them even a few months after the initial explosion. Dust does not begin to form until two years after an explosion, so while astronomers have suspected that most supernovae do produce dust, their ability to confirm this stellar dust production in the past was limited by the available technology.