Dust is all the rage at the moment, thanks to Phillip Pullman’s widely popular His Dark Materials trilogy. But what of the dust that formed what we know and love today; the dust that, for all intents and purposes, we are all made from.
Humans have for a long time been writing about how we all came from the same stuff that made the stars. It makes for nice poetry and music, and to help matters out, it is effectively true. But where did all that dust come from?
Astronomers, theorists and physicists often have the chicken and the egg problem; puzzling out which came first, and at what point it all just started.
Well, thanks to recent discoveries thanks to NASA's Spitzer Space Telescope, astronomers have been able to determine where at least our dust – the dust that has formed everything we are aware of – came from.
They have found that in the remnants of the well-known supernova remnant Cassiopeia A there is a massive amount of space dust; a total equaling 10,000 Earth’s worth of the stuff. This is the first time that scientists have been able to prove their theories, which have for a long time speculated that dust was formed from the massive star explosions we know as supernova.
"Now we can say unambiguously that dust - and lots of it - was formed in the ejecta of the Cassiopeia A explosion. 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. Rho is the lead author of a new report about the discovery appearing in the Jan. 20 issue of the Astrophysical Journal.
Due to the fact that space dust is everywhere, it has naturally been a focus for astronomers the world over. In fact, NASA’s Spitzer Space Telescope was designed with a sensitivity to dust, so that further discoveries could be made. So when it was focused on the remnants of the Cassiopeia A explosion, the discovery was made.
Prior to this discovery, space dust had been traced back all the way to the early part of our universes existence. Thanks to the way light works, we are able to peer back in to time simply by looking to the left or right, witnessing the events of many millennia past.
Thus, scientists believe that the dust that formed the early universe – the suns, the planets, etc – was as a result of explosions of multiple large stars. Known as Population III, these stars are the only ones known to form without dust – a catalyst needed to cool the stars so that they will collapse and ignite.
Rho and her colleagues were able to focus their attention on Cassopeia A supernova remnant due to its relative closeness to us. At just a mere 11,000 light-years away scientists were able to witness whether a supernova had the ability to create the dust previously theorized. "Because Spitzer is extremely sensitive to dust, we were able to make high-resolution maps of dust in the entire structure," said Rho.
The smoking gun to their discoveries was that the dust in the vicinity of the explosion matches up perfectly with the gas, also known as ejecta, known to have been expelled from the supernova. "Dust forms a few to several hundred days after these energetic explosions, when the temperature of gas in the ejecta cools down," said Takashi Kozasa, a co-author at the Hokkaido University in Japan.
Joshua Hill, a Geek’s-Geek from Melbourne, Australia, Josh is an aspiring author with dreams of publishing his epic fantasy, currently in the works, sometime in the next 5 years. A techie, nerd, sci-fi nut and bookworm.
