A new X-ray look at the mesmerizing Helix Nebula reveals an alleged planet killer: a white dwarf that might be the source of ...

When low-mass stars die, they collapse under their own weight until their centers act in some ways like a solid. A star like the Sun will collapse at the end to be about twice the size of Earth ...

But Earth has faced at least five mass extinctions ... ago and another 445 million years ago—may have started with dying stars light-years away. Supernovas and Ice Ages A new study suggests ...