0 Persons are tagged with #darkmatter

#darkmatter

waynerad@diasp.org
Wayne Radinsky

"Dark energy, which most physicists have long held to be unchanging, may in fact be weakening."

"Since 1998, we've known that the expansion of the universe is accelerating. Dark energy is the name given to the accelerant. In the standard theoretical model of the cosmos, dark energy has a simple form: It is spread uniformly in space, maintaining a constant density at all times. Dark energy of this type, known as the cosmological constant, would not get diluted as the universe expands. Rather, as space grows, the amount of dark energy grows with it. And so this accumulating energy expands the universe with ever-increasing gusto."

"But the constancy of dark energy is merely a hypothesis, one that the Dark Energy Spectroscopic Instrument (DESI) experiment set out to check."

Analysis of 6.4 million galaxies "hints" that dark energy decreases with time.

The experiment isn't over and will run for 5 years, and will analyze 40 million galaxies. After that we should have a definitive answer.

Waning dark energy may evade 'swampland' of impossible universes | Quanta Magazine

#astronomy #cosmology #darkmatter

Waning Dark Energy May Evade ‘Swampland’ of Impossible Universes | Quanta Magazine

The largest-ever 3D map of the cosmos hints that the dark energy that’s fueling the universe’s expansion may be weakening. One community of theoretical physicists expected as much.

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waynerad@diasp.org
Wayne Radinsky

"Dark energy, which most physicists have long held to be unchanging, may in fact be weakening."

"Since 1998, we've known that the expansion of the universe is accelerating. Dark energy is the name given to the accelerant. In the standard theoretical model of the cosmos, dark energy has a simple form: It is spread uniformly in space, maintaining a constant density at all times. Dark energy of this type, known as the cosmological constant, would not get diluted as the universe expands. Rather, as space grows, the amount of dark energy grows with it. And so this accumulating energy expands the universe with ever-increasing gusto."

"But the constancy of dark energy is merely a hypothesis, one that the Dark Energy Spectroscopic Instrument (DESI) experiment set out to check."

Analysis of 6.4 million galaxies "hints" that dark energy decreases with time.

The experiment isn't over and will run for 5 years, and will analyze 40 million galaxies. After that we should have a definitive answer.

#astronomy #cosmology #darkmatter

https://www.quantamagazine.org/waning-dark-energy-may-evade-swampland-of-impossible-universes-20240819/

Waning Dark Energy May Evade ‘Swampland’ of Impossible Universes | Quanta Magazine

The largest-ever 3D map of the cosmos hints that the dark energy that’s fueling the universe’s expansion may be weakening. One community of theoretical physicists expected as much.

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rhysy@diaspora.glasswings.com
Rhysy

Excellent summary of the current state of the argument as to whether binary stars observed in Gaia favour dark matter or modified gravity. TLDW : prominent MOND supporter completely changes their mind and finds 16 sigma (!) significance evidence that MOND doesn't work. Previous test using the same data included points with much too large errors and found the opposite result. Doesn't actually validate dark matter, just disproves MOND.

#Science
#Astronomy
#Astrophysics
#DarkMatter

https://youtu.be/HlNSvrYygRc?si=wn9qI852Hd5DV7UQ

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anonymiss@despora.de
anonymiss

#Euclid test images tease of riches to come

source: https://www.esa.int/Science_Exploration/Space_Science/Euclid/Euclid_test_images_tease_of_riches_to_come

Euclid’s VISible instrument (VIS) will take super sharp images of billions of #galaxies to measure their shapes. Looking closely at this first image, we already get a glimpse of the bounty that VIS will bring; whilst a few galaxies are very easy to spot, many more are fuzzy blobs hidden amongst the #stars, waiting to be unveiled by Euclid in the #future.

enter image description here

By combining distance information with that on galaxy shapes measured by VIS, we will be able to map how galaxies are distributed throughout the #Universe, and how this distribution changes over time. Ultimately, this 3D map will teach us about dark matter and dark energy.

#darkMatter #science #space #exploration #news #photo #galaxy #esa

Euclid test images tease of riches to come

Euclid’s two instruments have captured their first test images. The mesmerising results indicate that the space telescope will achieve the scientific goals that it has been designed for – and possibly much more.

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rhysy@diaspora.glasswings.com
Rhysy

Ahh, the latest "there's no dark matter, it's all just MOND" claim. The press release sounds awfully convincing, as usual, but every damn time one digs into MONDian claims, one finds they're at best heavily overstated. I'm doing a lengthy write-up on MOND versus CDM from a philosophy of science perspective, but I'll probably skip this particular claim.

The latest Gaia data indicates that Newtonian-like gravity is completely sufficient, and that the MOND-like behaviour, which should take over in the low acceleration regime if the idea is correct, is absent. It’s absent, in fact, at the ~16-sigma level: a tremendous significance. The paper that’s been getting the recent publicity... draws the opposite conclusion: claiming to see a better agreement with MOND than with Newtonian gravity, and at just over 5-sigma significance.

It’s not that someone is definitively right and someone is definitively wrong; it’s that there are assumptions that go into choosing and analyzing the data, and simply by making different assumptions (and not quantifying the associated errors that come along with making them), you can wind up drawing vastly different conclusions. This problem will always plague an observational science like astronomy, and is almost certainly the culprit behind another wild, dubious assertion that was made in 2023: that black holes are the cause of the dark energy in our Universe.

#Science
#Galaxies
#DarkMatter
#MOND

https://bigthink.com/starts-with-a-bang/binary-stars-prove-modified-gravity/

Ask Ethan: Do binary stars prove modified gravity?

Einstein's laws of gravity have been challenged many times, but have always emerged victorious. Could wide binary stars change all that?

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denissalem@diasp.eu
Denis Salem

Dark Matter Gears

Damn that was hard and long. While the idea of dark matter is hypothetical and speculative I came with the idea of painting it as gears supporting galaxies. The original picture in my head was way much darker. I feel like I mess with the background ...

The gears also refer to the voltaire's idea of an autonomous universe, tuned like a clock and left alone by god.

Please share if your like :3

XCF Source here under #cc-by-sa licence

#cosmos #galaxy #stars #astral #sf #science #science-fiction #sf #illustration #symbol #symbolism #darkmatter #gears #digitalpainting #cg #computergraphic #space #drawing #dessin #thegimp #gimp #artwork #diaspoart #cc-by-sa #creative-commons #art #freeart #artlibre #free #libre #culturelibre #utopia #space-time

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netmassimo@pluspora.com
Massimo Luciani

#astronomy #cosmology #DarkMatter An article published in the journal "Physical Review Letters" reports the results of an analysis of dark matter distribution around 1.5 million primordial galaxies. A team of researchers led by Hironao Miyatake of the Japanese University of Nagoya used observations conducted with the Subaru telescope and analyzed data collected by the Planck Surveyor space probe to detect distortion of the cosmic microwave background (CMB).

https://english.tachyonbeam.com/2022/08/02/a-study-of-the-distribution-of-dark-matter-in-the-early-universe/