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Veritasium
What Actually Expands In An Expanding Universe?
This video discusses the concept of redshift and the expansion of the universe, starting with the discovery of the universe's expansion through the redshift of light from distant galaxies. It explains the three types of redshift: Doppler...
Physics Girl
Is energy always conserved?
When light passes through the universe and is redshifted by the expansion of space itself, how is energy conserved? The stretched light has a longer wavelength and therefore a lower energy. Is energy conserved? If so, where does it go?
Other
Physics Girl: Is Energy Always Conserved?
When light passes through the universe and is redshifted by the expansion of space itself, how is energy conserved? The stretched light has a longer wavelength and therefore a lower energy. Is energy conserved? If so, where does it go?...
Crash Course
Crash Course Physics #46: Astrophysics and Cosmology
It's time for the end. At least the end of our first series on Physics here at Crash Course. In this video episode of Crash Course Physics, Shini sits down to talk about Astrophysics and Cosmology. By using what we've learned this year,...