Le 11 juillet 2014, 06:38 dans Humeurs • 0
There are billions of stars and planets in the universe. A star is glowing sphere of gas, while planets like Earth are made up of solids. The planets are formed in dust clouds that swirled around a newly formed star. Dust grains are composed of elements like carbon, silicon, oxygen, iron, and magnesium. But where does the cosmic dust come from? New research from the Niels Bohr Institute at the University of Copenhagen and Aarhus University shows that not only can grains of dust form in gigantic supernova explosions, they can also survive the subsequent shockwaves they are exposed to.
The results are published in the scientific journal, Nature.
How the cosmic dust is formed has long been a mystery to astronomers.
The elements themselves are formed out of the glowing hydrogen gas in stars. The hydrogen atoms fuse together into heavier and heavier elements and in the fusion process the star emits radiation in the form of light, that is, energy. When all the hydrogen is exhausted and no more energy can be extracted, the star dies and giant clouds of gas are slung out into space, where they are recycled into new stars in a vast cosmic cycle.
The heavy elements are primarily formed in supernovae, which are massive stars that die in a gigantic explosion. But how do the elements grow into 'larger clumps' like cosmic dust grains?