Interstellar dust may come from supernovae after all
NASA, ESA, J. Hester and A. Loll (Arizona State University)

Interstellar dust may come from supernovae after all

New observations confirm that interstellar dust can come from explosions known as supernovae, an idea that has been controversial. The big bang gave us a universe filled with pristine gases—mostly hydrogen—from which the first stars and galaxies formed. But astronomers looking back at those early galaxies see signs of lots of dust, and they don't know what produced it. Within stars, hydrogen nuclei fuse into heavier elements, just what you need to create dust. Models suggest that supernovae—massive explosions that occur when stars run out of fuel and collapse—generate dust, ejecting it out into space in an expanding sphere of material called a supernova remnant. But there’s a catch: When an expanding supernova remnant hits the cooler gas between stars, known as the interstellar medium, it creates a shock wave that propagates inward through the remnant and could potentially break up the dust particles. Observations of recent supernovae suggest they may be destroying more dust than they create. Now, a team of astronomers using the Stratospheric Observatory for Infrared Astronomy, or SOFIA, a telescope mounted in a Boeing 747, has studied a 10,000-year-old supernova remnant near the center of the Milky Way called Sagittarius A East and concluded that between 7% and 20% of the dust it originally created has survived the shock wave, they report online today in Science. If that’s the case, untidiness in the early universe can be blamed on supernovae after all.