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List of the most distant astronomical objects
This article documents the farthest known astronomical objects, and the time periods in which they were so classified.
Apart from relatively nearby galaxies, beyond the Milky Way distances to remote objects are nearly always inferred by measuring the cosmological redshift of their light. By their nature, very distant objects tend to be very faint, and these distance determinations are difficult and subject to errors. An important distinction is whether the distance is determined via spectroscopy or using a photometric redshift technique. The former is generally both more precise and also more reliable, in the sense that photometric redshifts are more prone to being wrong due to confusion with lower redshift sources that have unusual spectra. For that reason, a spectroscopic redshift is conventionally regarded as being necessary for an object's distance to be considered definitely known, whereas photometrically determined redshifts identify "candidate" very distant sources. Here, this distinction is indicated by a "p" subscript for photometric redshifts.
==Notably distant objects==
1 Gly = 1 billion light-years.
, there were about 50 possible objects z=8 or farther, and another 100 z=7 candidates, based on photometric redshift estimates.〔FirstGalaxies, (Our Latest Results ) 〕 Not everything is included here.〔
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