Redshift | Wikipedia audio article
Channel: wikipedia tts
Date: 24/12/2018

This is an audio version of the Wikipedia Article:
https://en.wikipedia.org/wiki/Redshift


00:02:30 1 History
00:05:54 2 Measurement, characterization, and interpretation
00:08:35 3 Redshift formulae
00:09:01 3.1 Doppler effect
00:12:51 3.2 Expansion of space
00:14:40 3.2.1 Mathematical derivation
00:15:08 3.2.2 Distinguishing between cosmological and local effects
00:16:09 3.3 Gravitational redshift
00:16:23 4 Observations in astronomy
00:18:42 4.1 Local observations
00:29:02 4.2 Extragalactic observations
00:33:30 4.3 Highest redshifts
00:35:09 4.4 Redshift surveys
00:37:02 5 Effects from physical optics or radiative transfer
00:38:26 6 References
00:39:12 7 Sources
00:41:06 7.1 Articles
00:41:33 7.2 Books
00:44:54 8 External links
00:45:32 8.6, corresponding to 600 million years after the Big Bang. Slightly less reliable are Lyman-break redshifts, the highest of which is the lensed galaxy A1689-zD1 at a redshift z
00:45:59 7.0. The most distant observed gamma-ray burst with a spectroscopic redshift measurement was GRB 090423, which had a redshift of z
00:46:27 7.54. The highest known redshift radio galaxy (TN J0924-2201) is at a redshift z
00:46:58 6.42Extremely red objects (EROs) are astronomical sources of radiation that radiate energy in the red and near infrared part of the electromagnetic spectrum. These may be starburst galaxies that have a high redshift accompanied by reddening from intervening dust, or they could be highly redshifted elliptical galaxies with an older (and therefore redder) stellar population. Objects that are even redder than EROs are termed hyper extremely red objects (HEROs).The cosmic microwave background has a redshift of z
00:48:06 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.
00:48:22 Redshift surveys
00:48:32 With advent of automated telescopes and improvements in spectroscopes, a number of collaborations have been made to map the Universe in redshift space. By combining redshift with angular position data, a redshift survey maps the 3D distribution of matter within a field of the sky. These observations are used to measure properties of the large-scale structure of the Universe. The Great Wall, a vast supercluster of galaxies over 500 million light-years wide, provides a dramatic example of a large-scale structure that redshift surveys can detect.The first redshift survey was the CfA Redshift Survey, started in 1977 with the initial data collection completed in 1982. More recently, the 2dF Galaxy Redshift Survey determined the large-scale structure of one section of the Universe, measuring redshifts for over 220,000 galaxies; data collection was completed in 2002, and the final data set was released 30 June 2003. The Sloan Digital Sky Survey (SDSS), is ongoing as of 2013 and aims to measure the redshifts of around 3 million objects. SDSS has recorded redshifts for galaxies as high as 0.8, and has been involved in the detection of quasars beyond z
00:50:12 Effects from physical optics or radiative transfer



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SUMMARY
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In physics, redshift is a phenomenon where electromagnetic radiation (such as light) from an object undergoes an increase in wavelength. Whether or not the radiation is visible, "redshift" means an increase in wavelength, equivalent to a decrease in wave frequency and photon energy, in accordance with, respectively, the wave and quantum theories of light.
The emitted light is not actually red; instead, the term refers to the human perception of longer wavelengths at the red end of the visible spectrum. Examples of redshifting are a gamma ray perceived as an X-ray, or initially visible light perceived as radio waves. The opposite of a redshift is a blueshift, where wavelengths shorten and en ...