Astonomers study stars and galaxies at crucial times in their cosmic lifespan - while they're forming in clouds of gas and dust, when they're born and are growing up and, finally, when they die. These snapshots help scientists understand life and death in the universe.
This image from NASA's Spitzer Space Telescope shows the death of a star about the size of our sun. The Helix nebula, made of gaseous shells and disks from the dying star, will eventually expand and fade away.
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