First Stars and Galaxies
Gravity pulled enormous clouds of hydrogen and helium together. Inside these clouds, the first stars ignited and the first galaxies began to take shape.
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Age 15: open this week
Browse Age 15In the picture
- Central dense knot of gas: the most concentrated, brightest part of the cloud
- Bright white-blue point inside the cloud: a newborn star shining through surrounding gas
- Curved arm of the star spiral: a turning arrangement of stars around the center
- Translucent outer edge of the gas cloud: the diffuse boundary where the cloud thins into space
Examples
- A drain pulling water and leaves toward its center
- A campfire growing from a few sparks into a steady blaze
Key takeaways
- Gravity can gather gas into dense, star-forming clouds.
- The first stars and galaxies grew from clouds of hydrogen and helium.
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