Add thelocalreport.in As A Trusted Source
size of the universe It’s not something we think about often. But my colleagues and I have published a new study that suggests it may be asymmetric or one-sided, meaning not the same in every direction.
Should we care about this? Well, today’s “standard cosmological model” – which describes the dynamics and structure of the universe as a whole – is based entirely on the assumption that it is isotropic (looks the same in all directions), and homogeneous when averaged over large scales.
But several so-called “tensions” – or disagreements in the data – pose challenges to this idea of a uniform universe.
we have just published a paper Let’s look at one of the most important of these tensions, called the cosmic dipole anomaly. We conclude that the cosmic dipole anomaly poses a serious challenge to the most widely accepted description of the universe, the Standard Cosmological Model (also known as the Lambda-CDM model).
So what is the cosmic dipole anomaly and why is it such a problem in efforts to provide a detailed description of the universe?
Let’s start with the cosmic microwave background (CMB), which is the leftover radiation big bangThe CMB is uniform across the sky to within one part in a million,
Cosmologists therefore feel confident in modeling the universe using a “maximum symmetric” description of space-time. Einstein’s theory of general relativityThis symmetric view of the universe, where it looks the same everywhere and in all directions, is known as the “FLRW description”,
This greatly simplifies the solution of Einstein’s equations and is the basis of the Lambda-CDM model.
But there are several important anomalies, including the widely discussed Hubble tension. It is named after Edwin Hubble, who is credited with discovering it in 1929 the universe is expanding,
Tensions began to emerge from various datasets in the 2000s, primarily from Hubble Space TelescopeAnd also recent data from the Gaia satellite. This tension is a cosmological disagreement, where measurements of the universe’s expansion rate from the early days do not match measurements of the nearby (more recent) universe.
The cosmic dipole anomaly has received much less attention than the Hubble stress, but it is even more fundamental to our understanding of the universe. then what is it?
Having established that the cosmic microwave background is symmetric on large scales, variations in this relic radiation from the big bang have been found. One of the most important is called the CMB dipole anisotropy. This is the largest temperature difference in the CMB, where one side of the sky is hot and the opposite side is cold – about one part in a thousand.
This variation in the CMB does not challenge the Lambda-CDM model of the universe. But we should find similar variations in other astronomical data also.
In 1984, George Ellis and John Baldwin asked whether a similar variation, or “dipole anisotropy”, existed in the sky distribution of distant astronomical sources such as radio galaxies and quasars. The sources must be very far away because nearby sources can create a spurious “clustering dipole”.
If the “symmetric universe” FLRW assumption is correct, then this variation in distant astronomical sources should be directly determined by the observed variation in the CMB. This is known as the Ellis–Baldwin test, named after astronomers.
Consistency between variations in the CMB and in case Will support the standard Lambda-CDM model. Discord would directly challenge this, and indeed the FLRW description. Because this is a very precise test, the data catalog needed to perform it has only recently become available.
The result was that the universe failed the Ellis-Baldwin test. The variation in matter does not match the CMB. Since the potential sources of error are quite different for telescopes and satellites and for different wavelengths in the spectrum, it is reassuring that the same results are obtained with terrestrial radio telescopes and satellites observing at mid-infrared wavelengths.
About the author
Subir Sarkar is Emeritus Professor at the University of Oxford. This article is republished from Conversation Under Creative Commons license. read the original article,
The cosmic dipole anomaly has thus established itself as a major challenge to the standard cosmological model, even if the astronomical community has largely chosen to ignore it.
This may be because there is no easy way to fix this problem. This requires abandoning not only the lambda-CDM model but also the FLRW description and going back to square one.
Yet a huge surge of data is expected from new satellites like Euclid and SPHEREX and telescopes like the Vera Rubin Observatory and the Square Kilometer Array. It is conceivable that we may soon gain bold new insights about how to build a new cosmological model using recent advances in the subset of artificial intelligence (AI) called machine learning.
Its impact on fundamental physics and our understanding of the universe will be truly enormous.