Is there a new anomaly affecting the entire universe?

Sorry, astronomers: an expanding universe doesn’t add up.


The galaxies shown in this image are all outside the Local Group, and as such, they are all gravitationally unbound from us. As a result, as the universe expands, the light emitted by them turns into longer and redder wavelengths, and these objects end up farther, in light years, than the number of years it actually takes for the light to travel from them to our own. eyes. As the expansion continues unabated, they will gradually wind up farther and farther away.

(Credit: ESO/INAF-VST/OmegaCAM. Acknowledgments: OmegaCen/Astro-WISE/Kapteyn Institute)

The biggest anomaly is the Hubble tension.

universe expansion

Two of the most successful methods for measuring large cosmic distances are based on either their apparent brightness (left) or their apparent angular size (right), both of which are directly observable. If we can understand the intrinsic physical properties of these beings, we can use them either as standard candles (left) or standard rulers (right) to determine how the universe has expanded, and thus what it is made of, over its cosmic history. Geometry how bright or large an object is in an expanding universe is not trivial.

(Credit: NASA/JPL-Caltech)

Two methods of measuring the rate of expansion give incompatible values.

Cold spots (shown in blue) in the cosmic background radiation are not inherently cooler, but represent regions where there is greater gravitational force due to greater density of matter, while hot spots (in red) are only hotter because the radiation in that region lives in Shallow gravity well. Over time, regions of increased density are more likely to grow into stars, galaxies, and clusters, while less dense regions are less likely to do so. Evidence for defects in the CMB and in the large-scale structure of the universe provides a way to reconstruct the rate of expansion.

(Credit: EM Huff, SDSS-III/South Pole Telescope, Zosia Rostomian)

The early remnant method produces, via cosmic defects, 67 km/s/million segments.

Pantheon +

Although there are many aspects of our universe that all data sets agree on, the rate of expansion of the universe is not one of them. Based on supernova data alone, we can infer an expansion rate of 73 km/s/million segments, but supernovae do not explore the first 3 billion years of our cosmic history. If we include data from the cosmic microwave background, which is itself emitted near the Big Bang, then there are irreconcilable differences at this moment in time, but only at a level of <10%!

(Credit: D. Brout et al./Pantheon+, ApJ Submitted, 2022)

The distance ladder method, from individually measured objects, yields 73 km/s/million segments.

Measurement in time and distance (to the left of “day”) can show how the universe will evolve and accelerate/decelerate far into the future. By relating the expansion rate to the matter and energy contents of the universe and measuring the expansion rate, we can arrive at a value for the Hubble time in the universe, but this value is not a constant; It evolves as the universe expands and time flows into it.

(Credit: Saul Perlmutter/UC Berkeley)

But another cosmic anomaly is similarly puzzling.

universe expansion

Using the cosmic distance ladder means grouping different cosmic scales together, as one always worries about the uncertainty where the different “rungs” of the ladder relate. As shown here, we’ve now come to no less than three “runs” on this ladder, and the entire set of measurements agree with each other amazingly.

(Credit: AG Riess et al., ApJ, 2022)

Consider the cosmic microwave background (CMB): residual radiation from the Big Bang.

According to the original observations of Penzias and Wilson, the galactic plane released some astrophysical sources of radiation (center), but above and below, all that remained was a near-perfect and uniform background of radiation. The temperature and spectrum of this radiation have now been measured, and agreement with the Big Bang predictions is staggering. If we could see microwave light with our own eyes, the entire night sky would look like the green oval on display.

(Credit: NASA/WMAP Science Team)

Although the direction is mostly uniform, one direction is 3.3 mK hotter while the opposite is similarly cooler.

Although the cosmic microwave background is the same coarse temperature in all directions, there is an aberration of 1 in 800 parts in one specific direction: consistent with this is our motion across the universe. At 1-part-in-800 the total size of the same CMB, this corresponds to a motion of about 1 part at 800 the speed of light, or ~368 km/sec from the Sun’s perspective.

(Source: J. Delabrouille et al., A&A, 2013)

The CMB dipole reflects the relative motion of our Sun to the CMB: about 370 km/s.

An accurate model of how the planets revolve around the sun, which then move through the galaxy in a different direction of motion. The distance between each planet and the sun determines how much total radiation and energy it receives, but that’s not the only factor that plays a role in determining a planet’s temperature. In addition, the Sun moves through the Milky Way, which moves through the Local Group, which moves through the larger universe.

(credit: Rhys Taylor)

Our domestic group moves much faster: about 620 km / s.

This illustrative map of the local supercluster, the Virgo Supercluster, spans more than 100 million light-years and contains our Local Group, which includes the Milky Way, Andromeda, a Triangle, and about 60 smaller galaxies. Regions of dense gravity attract us, while regions of lower-than-average densities effectively repel us relative to the cosmic average attraction.

(Credit: Andrew Z. Colvin / Wikimedia Commons)

This must be due to the imperfections of cosmic gravity that attract us.

Since matter is distributed almost uniformly throughout the universe, it is not only dense regions that gravitationally influence our motions, but also less dense regions. A feature known as a dipolar repeller, shown here, was discovered only recently and may explain the strange motion of our local group relative to other organisms in the universe.

(Credit: Y. Hoffman et al., Nature Astronomy, 2017)

The motions of nearby galaxies constantly support this picture.

The motions of neighboring galaxies and galaxy clusters (shown by the “lines” along which their velocities flow) are plotted with the nearby mass field. The largest excess densities (in red/yellow) and densities (in black/blue) arose from very small gravitational differences in the early universe. In the vicinity of denser regions, individual galaxies can move at strange speeds of up to several thousand kilometers per second, but what is seen is generally consistent with our observed local motion across the universe.

(Source: HM Courtois et al., Astronomical Journal, 2013)

However, remote motion tracking tools conflict with it.

On scales larger than our local supercluster, or more than a few hundred million light years, we no longer see differences in different directions that correspond to the predicted and measured motion across the universe. Instead, the observed effects are inconsistent, both with measurements of the local universe and with each other in many cases.

(Credit: Andrew Z. Colvin and Zeryphex/ Astronom5109; Wikimedia Commons)

Plasma within the clusters indicates smaller total motions: less than ~260 km/s.

The Planck satellite measurements of the cosmic background radiation temperature on small angular scales can reveal temperature improvements or decreases of tens of microkelvins caused by the motions of objects: the kinetic Sunyaev-Zel’dovich effect. From clusters of galaxies, they see an effect corresponding to 0, which is much weaker than one would expect from our inferred motion through the universe.

(credit: Websky simulation)

However, the brightest clusters of galaxies reveal even greater motions: ~689 km/s.

biggest galaxy

The giant group of galaxies, Abell 2029, has galaxy IC 1101 at its core. At 5.5 to 6.0 million light-years across over 100 trillion stars and a mass of roughly a quadrillion suns, it’s the largest galaxy ever known by many measures. A scan of the brightest galaxy within each Abell cluster reveals a cosmic motion that is incompatible with the CMB dipole.

(Credit: Digitized Sky Survey 2; NASA)

X-ray emissions reveal giant emissions (in the wrong direction!) of about 900 km/s.

The discrepancy in the number of X-ray galaxies is much greater in size and also in the wrong direction than would be expected from our motion through the universe: another example of a sudden but significant cosmic tension.

(Source: K.Migkas et al., A&A, 2021)

The anisotropy in the numbers of galaxies reveals more than twice the expected effect.

Maps of galaxies covering the entire sky reveal that there are more galaxies located at the same brightness/distance thresholds in one direction over another. This so-called rocket effect has a predicted amplitude of the dipole seen in the CMB, but what is observed is more than twice the expected effect.

(Credit: T. Jarrett (IPAC/Caltech))

The numbers of radio galaxies are even worse: four times the expected amplitude.

When the entire sky is viewed at various wavelengths, some corresponding sources of distant objects outside our galaxy are revealed. At radio wavelengths, galaxies can be seen in all directions, but the slight difference in one set of directions over the other appears to be much greater than the difference expected from our observed motion through the universe.

(Credit: ESA, HFI, and LFI consortia; CO map from T. Dame et al., 2001)

Quasar enumeration from WISE have the same problem.

Surveying infrared radiation across the entire sky, NASA’s Wide Field Infrared Explorer, or WISE, has identified millions of candidate quasars, outlined throughout the sky (and shown in a small area here) with yellow circles. The clustering of quasars shows an abnormally large signal in that one direction has a higher number of quasars (and vice versa) than would be expected by a much larger amount than our observed motions lead us to expect.

(Credit: NASA/JPL-Caltech/UCLA)

Coming surveys on a larger scale could strongly confirm the second “Hubble tension”.

The European Space Agency’s EUCLID mission, scheduled for launch in 2023, will be one of three major endeavors this decade, along with the NSF Observatory’s NSF Observatory and NASA’s Nancy Roman mission, to map the universe at large scale and extraordinary resolution.

(credit: ESA)

Mostly Mute Monday tells an astronomical story with pictures, visuals, and no more than 200 words. taciturn; smile more.

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