The structure resulting from the explosion of a star in a supernova. It consists of ejected material expanding from the explosion and the shocked interstellar medium it sweeps up.
Source: apod.nasa.gov

04/01/2018

28/12/2017

10/11/2017

29/09/2017

19/09/2017

18/05/2017

11/05/2017

01/05/2017

07/01/2017

18/10/2016

18/09/2016

29/08/2016

15/07/2016

01/06/2016

25/04/2016

17/09/2015

28/08/2015

06/03/2015

01/01/2015

03/12/2014

21/11/2014

30/10/2014

12/09/2014

25/07/2014

12/07/2014

04/04/2014

21/02/2014

13/02/2014

01/11/2013

30/10/2013