redshift

American  

[red-shift] / ˈrɛdˌʃɪft /

Or red shift

noun

Astronomy.

1. a shift toward longer wavelengths of the spectral lines emitted by a celestial object that is caused by the object moving away from the earth.

---

redshift British  

/ ˈredˌʃɪft /

noun

1. Compare: blueshift.  a shift in the lines of the spectrum of an astronomical object towards a longer wavelength (the red end of an optical spectrum), relative to the wavelength of these lines in the terrestrial spectrum, usually as a result of the Doppler effect caused by the recession of the object

---

Etymology

Origin of redshift

First recorded in 1920–25; red ¹ + shift

Compare meaning

How does redshift compare to similar and commonly confused words? Explore the most common comparisons:

• redshift vs. blueshift

Example Sentences

Astronomers call a shift to longer wavelengths a redshift.

From Salon • Feb. 14, 2025

Keck Observatory on Hawaii's Mauna Kea, they could detect slight variations in stellar motion via the redshift and blueshift of the Doppler effect -- which helped them determine planetary mass readings of unprecedented precision.

From Science Daily • Jan. 26, 2024

"The main result of the study is to confirm the σ8 tension between CMB measurements and weak lensing exists out to redshift 2, ten billion years ago."

From Science Daily • Dec. 21, 2023

These objects were high in redshift, meaning they emitted light skewed toward the red side of the electromagnetic spectrum, which is a sign of old and distant objects.

From Scientific American • Jul. 20, 2023

When used in conjunction with ground-based instruments, they’ll be able to convert redshift into length to infer the distances to each galaxy.

From New York Times • Jul. 1, 2023