In this Grade 6 Earth Science lesson from Chapter 22, students learn how the Doppler effect provides evidence that galaxies are moving farther apart and that the universe is expanding. Students explore key vocabulary including the Doppler effect and the big bang, and examine how astronomers use the stretching of light wavelengths from distant galaxies to draw conclusions about the universe's development. The lesson also introduces concepts such as superclusters and the vast scale of the universe, which contains roughly 100 billion galaxies.
Section 1
Galaxies Move Apart as Universe Expands
Scientists observe galaxies moving away from each other, with distant ones moving faster than nearby ones. This expansion, like raisins in rising bread dough, indicates our universe is getting bigger.
Section 2
Doppler Effect Reveals Galaxy Movement
When galaxies move away from Earth, their light stretches to longer wavelengths, creating a red shift. This effect helps astronomers determine that galaxies are moving apart throughout the universe.
Section 3
Big Bang Initiates Universe's Expansion
About 14 billion years ago, the universe rapidly expanded from an extremely hot, dense state. Evidence includes microwave radiation, galaxy motion patterns, and deep-space observations of ancient galaxies.
Section 4
Scientists Reconstruct Universe's Early Development
Researchers use particle accelerators, telescope observations, and computer models to understand how the universe changed after the Big Bang, from extreme heat to forming elements, stars and galaxies.
Section 5
Light Travels Time Reveals Cosmic History
When astronomers observe distant galaxies, they see light emitted millions or billions of years ago. This allows scientists to view the universe at different stages of development, like a cosmic photo album.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter
Expand to review the lesson summary and core properties.
Section 1
Galaxies Move Apart as Universe Expands
Scientists observe galaxies moving away from each other, with distant ones moving faster than nearby ones. This expansion, like raisins in rising bread dough, indicates our universe is getting bigger.
Section 2
Doppler Effect Reveals Galaxy Movement
When galaxies move away from Earth, their light stretches to longer wavelengths, creating a red shift. This effect helps astronomers determine that galaxies are moving apart throughout the universe.
Section 3
Big Bang Initiates Universe's Expansion
About 14 billion years ago, the universe rapidly expanded from an extremely hot, dense state. Evidence includes microwave radiation, galaxy motion patterns, and deep-space observations of ancient galaxies.
Section 4
Scientists Reconstruct Universe's Early Development
Researchers use particle accelerators, telescope observations, and computer models to understand how the universe changed after the Big Bang, from extreme heat to forming elements, stars and galaxies.
Section 5
Light Travels Time Reveals Cosmic History
When astronomers observe distant galaxies, they see light emitted millions or billions of years ago. This allows scientists to view the universe at different stages of development, like a cosmic photo album.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter