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Author Topic:   Cosmological Constant and Dark Energy has been in the news for months.
Posts: 2496
Joined: 12-22-2015

Message 1 of 2 (917475)
04-09-2024 12:52 AM

But the last week, it has been reported widely.
The largest survey of the sky, reported back in January, showed that there was probably only a 5% chance Dark Energy had the numbers that matched up with a supposed value of the "Cosmological Constant".
I always preferred a 100% flat universe, as it was seen as the most consistent cosmological topography which was consistent with the Many Worlds Theory.
But I doubted the Dark Energy was very good proof of the perfect "cosmological constant".
I dont feel a 100% flat universe is needed for the Many Worlds Theory to be possible.
(Copenhagen is still about to get buried overnight, when psychic studies are finally released
The relevant study, released in January (But the developing results have been leaked for years).
Will We Ever Know the True Nature of Dark Energy? | NOVA | PBS
Astronomers discovered dark energy in 1998, but are we any closer to understanding what it really is?
Future observations should help narrow down the possibilities. Dark energy’s behavior over time, which is measured by the ratio of its pressure and energy density (called its equation of state, or w) is measured to a precision of about 5% today. But in the next five years, new observations, including those with a special camera fitted onto a telescope in Chile called the Dark Energy Survey , will increase the precision to 2% or 3%, says Mortonson. Future ground- and space-based missions, including a planned European space mission called Euclid and a possible US probe called WFIRST , could make even finer measurements.
These missions will not only probe the expansion history of the universe but also chronicle how the distribution of matter has changed over time. One way to do this is with a method called weak gravitational lensing, which looks for distortions in the light from distant galaxies due to any mass that the light passes on its way to a telescope. If dark energy changes over time or if gravity behaves unexpectedly at large scales, we might see evidence of it in the changing “clumpiness” of matter over space and time.
But Eisenstein points out that there are always going to be exotic dark energy models that behave just like the cosmological constant. “The worry is that if we do all these very accurate measurements, and it still looks like a cosmological constant, then we haven’t actually ruled out a lot of the models,” he says. “I think we have a major challenge on the theory side to try to understand what else we can look for.”
“[To understand] dark energy, we will probably require more time, and I would say not less than 10 years,” says Pettorino.
But it’s worth trying to get to the bottom of the mystery, say the researchers. “We thought we had four forces of nature: gravity, electromagnetism, and the weak and strong nuclear forces. Dark energy is either some new force, or some substantial modification to gravity,” says Eisenstein. “It’s a major actor in cosmology and in the history of the universe.”
Dark energy survey result dims hope for cosmological constant
January 10,2024
A dark energy survey 10 years in the making has made a surprise finding, suggesting that the theory of the expansion of the universe might not be correct.
The final Dark Energy Survey (DES) measurement was released at the 243rd American Astronomical Society meeting in New Orleans and published on pre-print server arXiv.
Dark energy is dark matter’s even more elusive cousin. Studies have suggested that dark energy is estimated to make up almost 70% of the observable Universe and is immensely important for measurements of the acceleration of the Universe’s expansion. But, scientists also have no idea what it is.
One theory is that this dark energy should fit nicely into something called the ‘cosmological constant’ which Einstein added, and then removed, from his calculations into general relativity.
Although Einstein tossed it, it was later revived when it was realised that the universe was expanding at an accelerating rate.
Supernova ‘standard candles’ not so standard after all
“Einstein’s concept of the cosmological constant could actually explain dark energy if it had a positive value (allowing it to conform to the accelerating expansion of the cosmos),” said Professor Robert Nichol, a member of the DES collaboration in a piece for The Conversation. Nichol is also a Pro Vice Chancellor at the University of Surrey.
If dark energy is the cosmological constant, the “equation of state” of dark energy would equal -1. The DES used the best space object we have to try and measure this equation of state – Type Ia supernovae or ‘standard candles’. These are stellar explosions which release consistently bright flashes, allowing researchers to measure how far away they are in the Universe.
“It is very exciting times to see this innovative technology to harness the power of large astronomical surveys”, says one of the researchers, Dr Anais Möller from Swinburne University of Technology.
“Not only we are able to obtain more type Ia supernovae than before, but we tested these methods thoroughly as we want to do more precision measurements on the fundamental physics of our universe.”
An international team of more than 100 scientists mapped an area almost one-eighth of the sky using the 570-megapixel Dark Energy Camera. They took data for 758 nights across six years.
But the results, weren’t what they were expecting. Instead of an equation of state of -1, the end result from the DES was -0.8.
That’s a pretty large difference in astronomy terms, and would suggest that the cosmology constant is wrong. But scientists aren’t so sure yet.
First there’s the error bars – about plus or minus 0.18. Combined with data from the ESA’s Plank telescope the uncertainty is large enough that there’s still a 5% chance of -1.
That’s only a 1 in 20 odds, not ideal, but the results aren’t sure enough for researchers to confirm either way.
“As usual, scientists want more data,” said Nichol.
“The DES results suggest that our new techniques will work for future supernova experiments with ESA’s Euclid mission (launched July 2023) and the new Vera Rubin Observatory in Chile.”
[ Originally published by Cosmos as Dark energy survey result dims hope for cosmological constant ]

It was only a matter of time until the numbers did not match up.
I have mixed feelings :
I feel it is a blow to see the absolutely perfect critical density Dark Energy number miracle fall apart.
But, the (um)clue is a fortunate one, if one values science. It is actually scary to think that a pure coincidence could have caused us to assume all of the expansion of space was due to a "cosmological constant" when our perfect number inflation observation was more of an artifact fluke.
(The more logical heads always knew that the number match value, per the Ia supernova observations, could be just a coincidence, as coincidences can and do happen all the time. Not all observations carry the same weight. This 25 year old - now obsolete - "cosmological constant" is an example of an observation that always could have been interpreted differently)
(A good example of a non-coincidence example would be the hypothetical VHS tape of an alternate universe 1983 AFC Championship game featuring John Elway & the L.A. Raiders defeating Dan Marino's Baltimore Colts at Memorial Stadium in early 1984, then a tape of the Raiders beating the Redskins in the Superbowl with Van McCelroy winning the MVP after intercepting a pass and making 6 tackles. A piece of evidence for a Quantum Tuner, it would be! If only...)

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