I have bumped into some interesting questions while I was looking for some information on one space forum. The question is: What is the biggest object ever been discovered in space? Please share your ideas. It would be great to have a look at them.
Light forms the largest structures. Starlight/galaxy light is just a very small piece of a sphere of expanding light. A 3D expansion at c. And if you are of a mind that light travels forever, then the largest structures are being constantly replaced. We have detected 13.5 billion light year spheres so far. That's a small chunk of forever.
If we should talk about the existence of objects we already know ( I mean those we have in the Solar system) so I can assume that it`s Sun. But on other space forums, I`ve read that a lot of people consider the biggest object ever been discovered in space is our universe.
It may seem that answer is evident, and the biggest object in space is the Sun. However, we shouldn't forget about the a multitude of black holes, galaxies, stars, planets and galaxies. Not so long ago I faced an article about Hercules-Corona Borealis Great Wall. Just imagine - its size is 10 billion light years. Perhaps, there are even bigger objects in space, but we can’t observe them now.
While the LQG may not be the largest structure in the universe, in absolute terms, but it is remarkably large.
An international team of astronomers, led by academics from the University of Central Lancashire (UCLan), found one of the largest known structures in the universe in January, 2013. The large quasar group (LQG) is so large that it would take a vehicle travelling at the speed of light some 4 billion years to cross it.
Quasars are the nuclei of galaxies from the early days of the universe that undergo brief periods of extremely high brightness that make them visible across huge distances. These periods are 'brief' in astrophysics terms but actually last 10-100 million years.
Since 1982 it has been known that quasars tend to group together in clumps or 'structures' of surprisingly large sizes, forming large quasar groups or LQGs.
The team, led by Dr Roger Clowes from UCLan's Jeremiah Horrocks Institute, has identified the LQG which is so significant in size it also challenges the Cosmological Principle: the assumption that the universe, when viewed at a sufficiently large scale, looks the same no matter where you are observing it from.
The modern theory of cosmology is based on the work of Albert Einstein, and depends on the assumption of the Cosmological Principle. The Principle is assumed but has never been demonstrated observationally 'beyond reasonable doubt'.
To give some sense of scale, our galaxy, the Milky Way, is separated from its nearest neighbour, the Andromeda Galaxy, by about 0.75 Megaparsecs (Mpc) or 2.5 million light-years.
Whole clusters of galaxies can be 2-3 Mpc across but LQGs can be 200 Mpc or more across. Based on the Cosmological Principle and the modern theory of cosmology, calculations suggest that astrophysicists should not be able to find a structure larger than 370 Mpc.
The coloured background indicates the peaks and troughs in the occurrence of quasars at the distance of the LQG. Darker colours indicate more quasars, lighter colours indicate fewer quasars. The LQG is clearly seen as a long chain of peaks indicated by black circles. (The red crosses mark the positions of quasars in a different and smaller LQG). The horizontal and vertical axes represent right ascension and declination, the celestial equivalent of longitude and latitude. The map covers around 29.4 by 24 degrees on the sky, indicating the huge scale of the newly discovered structure. Credit: R. G. Clowes / UCLan
Dr Clowes' newly discovered LQG however has a typical dimension of 500 Mpc. But because it is elongated, its longest dimension is 1200 Mpc (or 4 billion light years) -- some 1600 times longer than the distance from the Milky Way to Andromeda.
Dr Clowes said: "While it is difficult to fathom the scale of this LQG, we can say quite definitely it is the largest structure ever seen in the entire universe. This is hugely exciting -- not least because it runs counter to our current understanding of the scale of the universe.
'Even travelling at the speed of light, it would take 4 billion ... years to cross. This is significant not just because of its size but also because it challenges the Cosmological Principle, which has been widely accepted since Einstein. Our team has been looking at similar cases which add further weight to this challenge and we will be continuing to investigate these fascinating phenomena."
Additionally, Roger G. Clowes, Luis E. Campusano, Matthew J. Graham, Ilona K. Söchting published in the Monthly Notices of the Royal Astronomical Society, Volume 419, Issue 1, January 2012, Pages 556–565, https://doi.org/10.1111/j.1365-2966.2011.19719.x :
This paper has re-examined the Clowes & Campusano (1991) LQG, originally known with 18 members, using data from the SDSS DR7QSO catalogue. It is found as the unit U1.28 of 34 100-Mpc-linked quasars, with mean redshift
. While the western, northern and southern boundaries remain essentially unchanged, apart from two compact clumps to the north and south-west, there is an extension eastwards, beyond the original survey, of ∼2°.
A new LQG, U1.11, was discovered in the same direction – 1°.97 from U1.28. It has 38 members and mean redshift
. A third candidate, U1.54, in the same direction at 1°.62 from U1.28, appeared statistically insignificant, although it is a re-discovery of a known (marginal) LQG (Newman et al. 1998; Newman 1999).
We have also presented the ‘CHMS method’ for assessing the statistical significance and overdensity of groups such as LQGs that have been found by linkage of points.
Attention was first drawn to peculiarities in this area of sky by Cannon & Oke (private communication) who, in the early days of quasar surveys, noted the unusual ease with which they could find the then hard-to-find quasars with z ∼ 1.0–1.6. It may be that, now we know there are not one but two LQGs of unusually high membership in this direction, we finally have the complete explanation of their result.
While some astronomers claim that the Huge-LQG is real, others posit that the quasars are randomly placed and not part of any large structure. Another researcher took a look at the Huge-LQG and found it to be nothing more than randomly spaced objects. Whether it exists or not is still up for debate, although evidence is leaning toward the Huge-LQG being a legitimate discovery. I believe that the universe holds many similarly huge structures which stretch the limits of our observational and computational abilities and will always do so.