Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Damien Huxley on 21/08/2009 04:52:25

Title: Why do supernovae explode in a ring shape?
Post by: Damien Huxley on 21/08/2009 04:52:25
Why do supernovas explode in a ring?
Why isn't it a ball shape explosion?
Or is it a ball shape and it our perspective?
Is it the same sort of force that keeps the planets in a disc?
Title: Re: Why do supernovae explode in a ring shape?
Post by: Nizzle on 21/08/2009 07:46:51
I may have an analogy for this:

Take a ball (pingpong, soccer, basket; any round ball will do) and make it wet.
Then spin it as fast as possible and look how the drops come off: ring like around the 'equator' or to all directions.

So i would say the ring shaped explosion is due to the rotation of the star.
Title: Re: Why do supernovae explode in a ring shape?
Post by: Soul Surfer on 21/08/2009 08:13:56
Supernovas do not always explode tidily but when they do the explosion expands as a spherical shell when this gets quite big and thin it is visible from the earth.  This spherical shell is glowing with the last remnants of the energy of the explosion this glow is in all directions but the glow is brightest when we look through the thickest amount of this transparent glowing shell.  the brightest bit is therefore in a ring around the shell because you are looking through more of the glowing gas there.
Title: Re: Why do supernovae explode in a ring shape?
Post by: syhprum on 21/08/2009 11:28:38
Although stars that explode as supernova throw off material in an approximately spherical manner before collapsing into Neutron stars or blackholes these are not the stars around which planets form.
Planet formation takes place around stars that form from collapsing gas clouds that may well contain material thrown off by supernova's.
As these clouds originally have some degree of spin the resulting star ends up spinning quite rapidly and tends to be surrounded by a disk of material that coalesces into planets.
Title: Re: Why do supernovae explode in a ring shape?
Post by: LeeE on 21/08/2009 16:07:20
As Soul Surfer says, the ring effect is due to the supernova throwing off material in roughly spherical 'shells' so that when you look at it from a distance you are looking through more of the gas at the edges than at the center.  You get the same effect when you look at the Earth's atmosphere from high orbit, where it shows up as the hazy blue outline.  When you look straight down though, it looks clear.

All of the elements, apart from hydrogen, that make up the material in solar systems and planets were created in supernovae.  The clouds of gases that eventually collapse and coalesce into solar systems don't just contain material thrown off by supernovae; apart from the hydrogen, it's all supernovae debris.
Title: Re: Why do supernovae explode in a ring shape?
Post by: syhprum on 21/08/2009 20:24:50
Not quite all the elements there would be some primordial Helium,Deuterium and lithium in the gas cloud.