Blueshift

A blueshift is any decrease in wavelength, with a corresponding increase in frequency, of an electromagnetic wave; the opposite effect is referred to as redshift. In visible light, this shifts the color from the red end of the spectrum to the blue end.

Doppler blueshift

Doppler blueshift is caused by movement of a source towards the observer. The term applies to any decrease in wavelength and increase in frequency caused by relative motion, even outside the visible spectrum. Only objects moving at near-relativistic speeds toward the observer are noticeably bluer to the naked eye, but the wavelength of any reflected or emitted photon or other particle is shortened in the direction of travel.

Doppler blueshift is used in astronomy to determine relative motion:

Blueshift (disambiguation)

In astronomy, a blueshift is a decrease in electromagnetic wavelength caused by the motion of a celestial object toward an observer.

Blueshift or blue shift may also refer to:

See also

Blue Shift (short story)

"Blue Shift" is the tenth story chronologically to appear in Stephen Baxter's collection of linked stories anthology novel Vacuum Diagrams. "Blue Shift" was originally published in Writers of the Future volume 5 in 1989.

Plot summary

Set in A.D. 5406, the story begins on an Earth that has been occupied by the Qax, an amorphous lifeform that profits from information and technology trade, for four centuries. Jim Bolder, a space pilot on the run from creditors, accepts an assignment from the Qax through a human intermediary to determine just what the Xeelee are constructing at the center of the local supercluster. Bolder is provided with a Xeelee nightfighter that can travel faster than light, and when he uses the drive, the stars around him appear blue—the "blue shift" of the title.

As Bolder in the nightfighter approaches the Great Attractor, he discovers the Xeelee are constructing a massive ring from its matter, which they intend to use to flee the universe itself. But the Qax will not allow this information to be released, intending to keep it—and a possible defense against the Xeelee—for their own profit. Bolder dodges the Qax and launches a "starbreaker" that will gradually cause the Qax homeworld's sun to go nova, requiring them to divert their resources from the occupation of Earth, liberating the planet.