Redshift — Science definition
Defined in 2 courses:
- A shift of identified spectral features toward longer wavelengths. (Earth & Space Science)
- An increase in observed wavelength relative to a reference. (Physics & Environmental Science)
Where it is taught
- Spectra & Evidence for an Expanding Universe — Stars & the Universe, Earth & Space Science, Grade 9
- Doppler Effect & Relative Motion — Waves, Sound & Optics, Physics & Environmental Science, Grade 12
In use
For distant galaxies, a broad relationship between distance and cosmological redshift supports expansion of space.
Spectra & Evidence for an Expanding Universe
A longer observed wavelength is redshift under this convention; the interpretation needs source and observer context.
Doppler Effect & Relative Motion
Questions using redshift
Problem 1
Why does a galaxy redshift–distance pattern support expansion more strongly than one spectrum?
Hints
State what the supplied observations or conditions establish, and separate that from any assumption.
Answer and explanation
A systematic relationship across many galaxies tests a global model rather than one object's local motion.