The crisis in Cosmology--Solved?

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andmar74
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The crisis in Cosmology--Solved?

Post by andmar74 »

What is the crisis?

"Two divergent measurements of how fast the universe is expanding cannot both be right. Something must give—but what?"
https://www.scientificamerican.com/arti ... al-crisis/

Solution? Better distance measurements (maybe): At 25:20.
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caltrek
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Re: The crisis in Cosmology--Solved?

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The following article is not really about the "crisis" but as it is about cosmology. It would seem to be a good fit for this thread.

Do ‘Bouncing Universes’ Have a Beginning?
August 9, 2022

Introduction:
(EurekAlert) BUFFALO, N.Y. — In trying to understand the nature of the cosmos, some theorists propose that the universe expands and contracts in endless cycles.

Because this behavior is hypothesized to be perpetual, the universe should have no beginning and no end — only eternal cycles of growing and shrinking that extend forever into the future, and forever into the past.

It’s an appealing concept in part because it removes the need for a state called a singularity that corresponds to the “beginning of time” in other models.

But a new study by University at Buffalo physicists Will Kinney and Nina Stein highlights one way that cyclic or “bouncing” cosmologies fall flat.

The research shows that the latest version of this theory — a cyclic model that resolves long-standing concerns about entropy — introduces a new problem (or rather, returns to an old one). Cyclic universes described under this model must have a beginning, Kinney and Stein conclude.
Read more here: https://www.eurekalert.org/news-releases/961350

Edit: Also, Science Alert has an article that discusses this same study and includes a little more context: https://www.sciencealert.com/eternal-bo ... somewhere
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caltrek
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Re: The crisis in Cosmology--Solved?

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Long term, maybe the James Webb telescope will help us resolve questions related to the crisis in cosmology. For now, the immediate result of new data pouring in is that it seems to have left scientists even more confused about their conclusions regarding cosmology.

Distant Galaxies in Webb Images Suggest We Need to Rethink Star and Galaxy Evolution in the Early Universe.
by Govert Schilling
August 10, 2022

Introduction:
(Sky & Telescope) The very first results from the James Webb Space Telescope seem to indicate that massive, luminous galaxies had already formed within the first 250 million years after the Big Bang. If confirmed, this would seriously challenge current cosmological thinking. For now, however, that’s still a big “if.”

Shortly after NASA published Webb’s first batch of scientific data, the astronomical preprint server arXiv was flooded with papers claiming the detection of galaxies that are so remote that their light took some 13.5 billion years to reach us. Many of these appear to be more massive than the standard cosmological model that describes the universe’s composition and evolution.

“It worries me slightly that we find these monsters in the first few images,” says cosmologist Richard Ellis (University College London).
Read more here: https://skyandtelescope.org/astronomy- ... ronomers/
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Re: The crisis in Cosmology--Solved?

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Black Hole Collisions May Clarify How Fast the Universe is Expanding
by Louise Lerner
August 27, 2022

Introduction:
(Futurity) In a new study, two astrophysicists lay out a method for how to use pairs of colliding black holes to measure how fast our universe is expanding—and thus understand how the universe evolved, what it is made out of, and where it’s going.

In particular, the scientists think the new technique, which they call a “spectral siren,” may be able to tell us about the otherwise elusive “teenage” years of the universe.

There’s a major ongoing scientific debate over exactly how fast the universe is expanding—a number called the Hubble constant. The different methods available so far yield slightly different answers, and scientists are eager to find alternate ways to measure this rate. Checking the accuracy of this number is especially important because it affects our understanding of fundamental questions like the age, history, and makeup of the universe.

The new study offers a way to make this calculation using special detectors that pick up the cosmic echoes of black hole collisions.
Read more here: https://www.futurity.org/black-holes-u ... 87072-2/

Here is a somewhat technical abstract of the study: https://journals.aps.org/prl/abstract/ ... 129.061102
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Re: The crisis in Cosmology--Solved?

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University of Hawaii Astronomers Map Distances to 56,000 Galaxies to Help Answer Basic Questions About Our Universe
September 26, 2022

Introduction:
(EurekAlert) How old is our universe, and what is its size? A team of researchers led by University of Hawaiʻi at Mānoa astronomers Brent Tully and Ehsan Kourkchi from the Institute for Astronomy have assembled the largest-ever compilation of high-precision galaxy distances, called Cosmicflows-4. Using eight different methods, they measured the distances to a whopping 56,000 galaxies. The study has been published in the Astrophysical Journal.

Galaxies, such as the Milky Way, are the building blocks of the universe, each comprised of up to several hundred billion stars. Galaxies beyond our immediate neighborhood are rushing away, faster if they are more distant, which is a consequence of the expansion of the universe that began at the moment of the Big Bang. Measurements of the distances of galaxies, coupled with information about their velocities away from us, determine the scale of the universe and the time that has elapsed since its birth.

“Since galaxies were identified as separate from the Milky Way a hundred years ago, astronomers have been trying to measure their distances,” said Tully. “Now by combining our more accurate and abundant tools, we are able to measure distances of galaxies, and the related expansion rate of the universe and the time since the universe was born with a precision of a few percent.”

From the newly published measurements, the researchers derived the expansion rate of the universe, called the Hubble Constant, or H0. The team’s study gives a value of H0=75 kilometers per second per megaparsec or Mpc (1 megaparsec = 3.26 million light years), with very small statistical uncertainty of about 1.5%.

There are a number of ways to measure galaxy distances. Generally, individual researchers focus on an individual method. The Cosmicflows program spearheaded by Tully and Kourkchi includes their own original material from two methods, and additionally incorporates information from many previous studies. Because Cosmicflows-4 includes distances derived from a variety of independent, distinct distance estimators, intercomparisons should mitigate against a large systematic error.
Read more here: https://www.eurekalert.org/news-releases/965897
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Re: The crisis in Cosmology--Solved?

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New Study Finds That Universe Has Less Dark Energy Than Previously Theorized
by Jeff nagle
October 27, 2022

Introduction:
(Inverse) THE MAKEUP and the growth of the Universe have never been clearer — or as confusing — as they’ve been revealed to be in a massive new survey of the markers astronomers use to measure the cosmos.

A new analysis called Pantheon+ has narrowed down the uncertainty in the expansion and makeup of the Universe. To do this, Pantheon+ builds on two long-standing astronomical projects — one called Pantheon, combining observations of 1,550 supernovae reaching back 10 billion years; and another called SH0ES, which measures relatively close pulsing stars known as Cepheids within 10 million light years.

The Pantheon+ analysis of the makeup and expansion of the Universe published recently in The Astrophysical Journal finds that 66.2 percent of the Universe is made up of dark energy, the mysterious accelerator driving the Universe’s speeding expansion, slightly less than past estimates of about 68 percent.

Only 33.8 percent of the Universe is matter — and the vast majority of that is impossible-to-observe dark matter, whose existence astronomers can only infer from galactic-scale gravitational effects. At the accepted rate of 85 percent dark matter to 15 percent normal (baryonic) matter, that means just slightly less than 5 percent of the mass of the Universe is the stuff we can see around us.

Pantheon+ was also able to measure the Universe’s expansion to within 1.3 percent uncertainty, close enough that it is now undeniable that the early Universe and the current Universe don’t expand at the same pace.
Read more of the Inverse article here: https://www.inverse.com/science/dark-energy-ratio

For a technical presentation of the results of the study as presented in The Astrophysical Journal: https://iopscience.iop.org/article/10.3 ... 57/ac8e04
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Re: The crisis in Cosmology--Solved?

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First Glimpse of What Gravity Looks Like on Cosmological Scales
November 4, 2022

Introduction:
(EurekAlert) Scientists from around the world have reconstructed the laws of gravity, to help get a more precise picture of the Universe and its constitution.

The standard model of cosmology is based on General Relativity, which describes gravity as the curving or warping of space and time. While the Einstein equations have been proven to work very well in our solar system, they had not been observationally confirmed to work over the entire Universe.

An international team of cosmologists, including scientists from the University of Portsmouth in England, has now been able to test Einstein's theory of gravity in the outer-reaches of space.

They did this by examining new observational data from space and ground-based telescopes that measure the expansion of the Universe, as well as the shapes and the distribution of distant galaxies.

The study, published in Nature Astronomy, explored whether modifying General Relativity could help resolve some of the open problems faced by the standard model of cosmology.
Read more here: https://www.eurekalert.org/news-releases/970268
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Re: The crisis in Cosmology--Solved?

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We're on the Brink of Hearing the Universe's Background Hum. Here's Why We're Listening
by Michele Starr
January 3, 2023

Extract::
(Science Alert) Every supernova, every merger between neutron stars or black holes, even rapidly spinning lone neutron stars, could or should be a source of gravitational waves.

Event the rapid inflation of space following the Big Bang 13.8 billion years ago should have produced its own cascade of gravitational waves…

The new frontier in space exploration

It's thought – just as the discovery of the cosmic microwave background did before it (and continues to do) – that finding the gravitational wave background will blow our understanding of the Universe and its evolution wide open.

"Detecting a stochastic background of gravitational radiation can provide a wealth of information about astrophysical source populations and processes in the very early Universe, which are not accessible by any other means," explains theoretical physicist Susan Scott of the Australian National University and the ARC Centre of Excellence for Gravitational Wave Discovery.

"For example, electromagnetic radiation does not provide a picture of the Universe any earlier than the time of last scattering (about 400,000 years after the Big Bang). Gravitational waves, however, can give us information all the way back to the onset of inflation, just ∼10-32 seconds after the Big Bang."
Read more here: https://www.sciencealert.com/were-on-t ... listening
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Re: The crisis in Cosmology--Solved?

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caltrek wrote: Mon Aug 15, 2022 8:51 pm Long term, maybe the James Webb telescope will help us resolve questions related to the crisis in cosmology. For now, the immediate result of new data pouring in is that it seems to have left scientists even more confused about their conclusions regarding cosmology.

Distant Galaxies in Webb Images Suggest We Need to Rethink Star and Galaxy Evolution in the Early Universe.
by Govert Schilling
August 10, 2022

...
Read more here: https://skyandtelescope.org/astronomy- ... ronomers/
Looks like further study is confirming early galaxy formation:
(Futurity) In their new study, the researchers discovered 87 galaxies that could be the earliest known galaxies in the universe.

“…WE MIGHT NEED TO REVISE OUR PREVIOUS UNDERSTANDING OF GALAXY FORMATION.”

The finding gets the astronomers one step closer to finding out when galaxies first appeared in the universe—about 200-400 million years after the Big Bang, says Haojing Yan, associate professor of physics and astronomy at the University of Missouri and lead author of the study.

The researchers used data from NASA’s James Webb Space Telescope (JWST) Early Release Observations.

“Finding such a large number of galaxies in the early parts of the universe suggests that we might need to revise our previous understanding of galaxy formation,” Yan says. “Our finding gives us the first indication that a lot of galaxies could have been formed in the universe much earlier than previously thought.”
Source: https://www.futurity.org/galaxies-forme ... e-2860022/

For a technical discussion as presented in The Astrophysical Journal Letters: https://iopscience.iop.org/article/10.3 ... 13/aca80c
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Re: The crisis in Cosmology--Solved?

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Scientists Reveal the Most Precise Map of All The Matter in The Universe
by Michele Starr
February 1, 2023

Introduction:
(Science Alert) A gargantuan effort by a huge international team of scientists has just given us the most precise map of the all matter in the Universe obtained to date.

By combining data from two major surveys, the international collaboration has revealed where the Universe does and doesn't keep all its junk – not just the normal matter that makes up the planets, stars, dust, black holes, galaxies, but the dark matter, too: the mysterious invisible mass generating more gravity than the normal matter can account for.

The resulting map, showing where the matter has congregated over the 13.8-billion-year lifespan of the Universe, will be a valuable reference for scientists looking to understand how the Universe evolved.

Indeed, the results already show that the matter isn't distributed quite how we thought it was, suggesting there could be something missing from the current standard model of cosmology.

According to the current models, at the point of the Big Bang, all the matter in the Universe was condensed into a singularity: a single point of infinite density and extreme heat that suddenly burst and spewed forth quarks that rapidly combined to form a soup of protons, neutrons and nuclei. Hydrogen and helium atoms came a few hundred thousand years later; from these, the entire Universe was made.
Read more here: https://www.sciencealert.com/scientist ... -universe
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