This article lists the most distant astronomical objects discovered and verified so far, and the time periods in which they were so classified. An alternative to the most commonly used distance measurements for high redshift objects is to calculate their ages in relation to the Big Bang. For comparisons with the years after the Big Bang of the astronomical objects listed below, the age of the universe is currently estimated as 13.787 ± 0.020 billion years. However, the estimated age of the universe has increased over the years as the observational techniques have been refined. At the time of the discovery of IOK-1 in 2006, the estimated age was just 13.66 billion years. 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, so these distance determinations are difficult and subject to errors. An important distinction is whether the distance is determined via spectroscopic or photometric redshift techniques. The former is generally both more precise and also more reliable, as photometric redshifts can be more prone to confusion with lower redshift sources that may 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.
Most distant spectroscopically-confirmed objects
Candidate most distant objects Since the beginning of the James Webb Space Telescope's (JWST) science operations in June 2022, numerous distant galaxies far beyond what could be seen by the Hubble Space Telescope (z = 11) have been discovered thanks to the JWST's capability of seeing far into the infrared. Previously in 2012, there were about 50 possible objects z = 8 or farther, and another 100 candidates at z = 7, based on photometric redshift estimates released by the Hubble eXtreme Deep Field (XDF) project from observations made between mid-2002 and December 2012. Some objects included here have been observed spectroscopically, but had only one emission line tentatively detected, and are therefore still considered candidates by researchers.
List of most distant objects by type
Timeline of most distant astronomical object recordholders 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. Distances to astronomical objects may be determined through parallax measurements, use of standard references such as cepheid variables or Type Ia supernovas, or redshift measurement. Spectroscopic redshift measurement is preferred, while photometric redshift measurement is also used to identify candidate high redshift sources. The symbol z represents redshift.
See also Age of the universe List of largest cosmic structures List of exoplanet extremes Lists of astronomical objects List of most distant stars Timeline of knowledge about galaxies, clusters of galaxies, and large-scale structure
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