The Giant Arc is a large-scale structure discovered in June 2021 that spans 3.3 billion

light years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

. The structure of

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

exceeds the 1.2 billion light year threshold, challenging the

cosmological principle In modern physical cosmology, the cosmological principle is the notion that the spatial distribution of matter in the universe is homogeneous and isotropic when viewed on a large enough scale, since the forces are expected to act uniformly throu ...

that at large enough scales the universe is considered to be the same in every place (

homogeneous Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, siz ...

) and in every direction (

isotropic Isotropy is uniformity in all orientations; it is derived . Precise definitions depend on the subject area. Exceptions, or inequalities, are frequently indicated by the prefix ' or ', hence ''anisotropy''. ''Anisotropy'' is also used to describe ...

). The Giant Arc consists of galaxies, galactic clusters, as well as gas and

dust Dust is made of fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian process), volcanic eruptions, and pollution. Dust in homes ...

. It is located 9.2 billion light-years away and stretches across roughly a 15th of the radius of the observable universe. It was discovered using data from the

Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...

by the team of Alexia M. Lopez, a doctoral candidate in cosmology at the

University of Central Lancashire , mottoeng = "From the Earth to the Sun" , established = as Institution for the Diffusion of Useful Knowledgere-established 1992 (University status granted) , type = Public , chancellor ...

. If the Giant Arc were visible in the night sky it would form an arc occupying as much space as 20 full moons, or 10 degrees on the sky.

References

Galaxy filaments Physical cosmology Large-scale structure of the cosmos {{physical-cosmology-stub

See also

References