Supernovas destroy worlds as stars blast apart planetary systems. Using the Nuclear Spectroscopic Telescope Array, or NuSTAR observatory in space, astronomers may now know what causes these tremendous explosions.
NuSTAR is a X-ray telescope with the ability to record maps showing radioactive gases that remain after a supernova explosion. It is the first instrument able to look into the core of a supernova remnant. The craft was launched in 2012, orbiting 300 miles above the Earth.
Like living beings, stars are born, live out their lives, and perish as they run out of gas. Which process the star follows while meeting its fate depends entirely on the object's mass. Massive stars explode in a massive supernova. Exactly how these are triggered, however, remained unanswered since the early 20th century.
"This has been a mystery for many decades. When physicists try to run computer codes to see how stars explode, they can't make it happen but we know it's something that happens robustly," Fiona Harrison, NuSTAR principal investigator, told the Daily News.
Researchers looking for the causes of these events began studying Cassiopeia A. They compared images of the supernova remains to computer simulations. The presence and movement of several materials was measured, including titanium, iron, magnesium and silicon. Harrison and her team looked at how materials are dispersed throughout space during these events. While titanium behaved much as predicted in computer models, real-world actions of nickel and iron were far different than suggested.
"Stars are spherical balls of gas, and so you might think that when they end their lives and explode, that explosion would look like a uniform ball expanding out with great power. Our new results show how the explosion's heart, or engine, is distorted, possibly because the inner regions literally slosh around before detonating," Harrison said.
In computer models, shock waves stalled, halting the process. During the real-life event, bubbles formed as the core sloshed around. These ruptured, adding energy to this pressure wave, shattering the star in a cataclysmic event.
The explosion of the star, which created the supernova, took place 600 years ago. It lies 300 light years from Earth, so the light from that event reached our world 300 years ago, possibly in 1680. It was not seen by most people, due to gas and dust surrounding the explosion.
Supernovas are the ultimate source of every element in the Universe, except for hydrogen, helium and lithium. The oxygen, calcium, and carbon in our bodies were all created in these massive explosions.
Underlying mechanisms of supernovas were profiled in the journal Nature on 20 February.