planetary stuff‘round a dying
sun-like star –unending cycle
Photo: The Helix Nebula (NASA photo)
From How It Works Daily:
The nearest planetary nebula to Earth is the Helix Nebula,
which began expanding around 12,000 years ago. It’s roughly 700 light years
from our world…When a Sun-like star is dying, it doesn’t have the mass to go
supernova and so it throws off layers in huge coronal mass ejections (CMEs)
until it becomes a bright shell of expanding gas known as a white dwarf. The
shapes that the 1,000 or so cataloged nebulas form as the star ejects its
outer shell are as varied as snowflakes – a fact that NASA is struggling to
explain.
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