Asteroids or planets might trigger a supernova
Type 1a explosions may result when rocky debris falls onto white dwarf
![Expanding gas cloud](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/02/cc_65906main_image_feature_219_jwfull.jpg?fit=860%2C460&ssl=1)
EXPLODING STAR An expanding cloud of gas, 14 light-years across, is all that remains of a type 1a supernova that exploded in 1604. This composite image combines visible, infrared and X-ray light.
NASA