List of most distant astronomical object record holders

This article documents the most distant astronomical objects so far discovered, and the time periods in which they were so classified.

Distances to remote objects, other than those in nearby galaxies, 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.

1 Gly = 1 billion light-years.

§ The tabulated distance is the light travel distance, which has no direct physical significance. See discussion at distance measures and Observable Universe

As of 2012^[update], there were about 50 possible objects z = 8 or farther, and another 100 z = 7 candidates, based on photometric redshift estimates released by the Hubble eXtreme Deep Field (XDF) project from observations made between mid-2002 and December 2012. Not everything is included here.

§ The tabulated distance is the light travel distance, which has no direct physical significance. See discussion at distance measures and Observable Universe

Objects in this list were found to be the most distant object at the time of determination of their distance. This is frequently not the same as the date of their discovery.

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