Oct 2, 2025 02:39 AM
Dark matter and dark energy may only be a cosmic illusion
https://www.uottawa.ca/about-us/news-all...c-illusion
EXCERPT: “The universe’s forces actually get weaker on the average as it expands,” Professor Gupta explains. “This weakening makes it look like there’s a mysterious push making the universe expand faster (which is identified as dark energy). However, at galactic and galaxy-cluster scale, the variation of these forces over their gravitationally bound space results in extra gravity (which is considered due to dark matter). But those things might just be illusions, emergent from the evolving constants defining the strength of the forces.”
He adds, “There are two very different phenomena needed to be explained by dark matter and dark energy: The first is at cosmological scale, that is, at a scale larger than 600 million light years assuming the universe is homogeneous and the same in all directions. The second is at astrophysical scale, that is, at smaller scale the universe is very lumpy and direction dependent. In the standard model, the two scenarios require different equations to explain observations using dark matter and dark energy. Ours is the only one that explains them with the same equation, and without needing dark matter or dark energy.”
He adds, “What’s really exciting is that this new approach lets us explain what we see in the sky: galaxy rotation, galaxy clustering, and even the way light bends around massive objects, without having to imagine there’s something hiding out there. It’s all just the result of the constants of nature varying as the universe ages and becomes lumpy.” (MORE - missing details, no ads)
PAPER: https://www.mdpi.com/2075-4434/13/5/108
Cassini proves complex chemistry in Enceladus ocean
https://www.eurekalert.org/news-releases/1099915
INTRO: Scientists digging through data collected by the Cassini spacecraft have found new complex organic molecules spewing from Saturn’s moon Enceladus. This is a clear sign that complex chemical reactions are taking place within its underground ocean. Some of these reactions could be part of chains that lead to even more complex, potentially biologically relevant molecules.
Published today in Nature Astronomy, this discovery further strengthens the case for a dedicated European Space Agency (ESA) mission to orbit and land on Enceladus.
In 2005, Cassini found the first evidence that Enceladus has a hidden ocean beneath its icy surface. Jets of water burst from cracks close to the moon’s south pole, shooting ice grains into space. Smaller than grains of sand, some of the tiny pieces of ice fall back onto the moon’s surface, whilst others escape and form a ring around Saturn that traces Enceladus’s orbit.
Lead author Nozair Khawaja explains what we already knew: “Cassini was detecting samples from Enceladus all the time as it flew through Saturn’s E ring. We had already found many organic molecules in these ice grains, including precursors for amino acids.
The ice grains in the ring can be hundreds of years old. As they have aged, they may have been ‘weathered’ and therefore altered by intense space radiation. Scientists wanted to investigate fresh grains ejected much more recently to get a better idea of what exactly is going on in Enceladus’s ocean.
Fortunately, we already had the data. Back in 2008, Cassini flew straight through the icy spray. Pristine grains ejected only minutes before hit the spacecraft’s Cosmic Dust Analyzer (CDA) instrument at about 18 km/s. These were not only the freshest ice grains Cassini had ever detected, but also the fastest.
The speed mattered. Nozair explains why:
“The ice grains contain not just frozen water, but also other molecules, including organics. At lower impact speeds, the ice shatters, and the signal from clusters of water molecules can hide the signal from certain organic molecules. But when the ice grains hit CDA fast, water molecules don’t cluster, and we have a chance to see these previously hidden signals.”
It took years to build up knowledge from previous flybys and then apply it to decipher this data. But now, Nozair’s team has revealed what kind of molecules were present inside the fresh ice grains.
They saw that certain organic molecules that had already been found distributed in the E ring were also present in the fresh ice grains. This confirms that they are created within Enceladus’s ocean.
They also found totally new molecules that had never been seen before in ice grains from Enceladus. For the chemists reading, the newly detected molecular fragments included aliphatic, (hetero)cyclic ester/alkenes, ethers/ethyl and, tentatively, nitrogen- and oxygen-bearing compounds.
On Earth, these same molecules are involved in the chains of chemical reactions that ultimately lead to the more complex molecules that are essential for life... (MORE - details, no ads)
https://www.uottawa.ca/about-us/news-all...c-illusion
EXCERPT: “The universe’s forces actually get weaker on the average as it expands,” Professor Gupta explains. “This weakening makes it look like there’s a mysterious push making the universe expand faster (which is identified as dark energy). However, at galactic and galaxy-cluster scale, the variation of these forces over their gravitationally bound space results in extra gravity (which is considered due to dark matter). But those things might just be illusions, emergent from the evolving constants defining the strength of the forces.”
He adds, “There are two very different phenomena needed to be explained by dark matter and dark energy: The first is at cosmological scale, that is, at a scale larger than 600 million light years assuming the universe is homogeneous and the same in all directions. The second is at astrophysical scale, that is, at smaller scale the universe is very lumpy and direction dependent. In the standard model, the two scenarios require different equations to explain observations using dark matter and dark energy. Ours is the only one that explains them with the same equation, and without needing dark matter or dark energy.”
He adds, “What’s really exciting is that this new approach lets us explain what we see in the sky: galaxy rotation, galaxy clustering, and even the way light bends around massive objects, without having to imagine there’s something hiding out there. It’s all just the result of the constants of nature varying as the universe ages and becomes lumpy.” (MORE - missing details, no ads)
PAPER: https://www.mdpi.com/2075-4434/13/5/108
Cassini proves complex chemistry in Enceladus ocean
https://www.eurekalert.org/news-releases/1099915
INTRO: Scientists digging through data collected by the Cassini spacecraft have found new complex organic molecules spewing from Saturn’s moon Enceladus. This is a clear sign that complex chemical reactions are taking place within its underground ocean. Some of these reactions could be part of chains that lead to even more complex, potentially biologically relevant molecules.
Published today in Nature Astronomy, this discovery further strengthens the case for a dedicated European Space Agency (ESA) mission to orbit and land on Enceladus.
In 2005, Cassini found the first evidence that Enceladus has a hidden ocean beneath its icy surface. Jets of water burst from cracks close to the moon’s south pole, shooting ice grains into space. Smaller than grains of sand, some of the tiny pieces of ice fall back onto the moon’s surface, whilst others escape and form a ring around Saturn that traces Enceladus’s orbit.
Lead author Nozair Khawaja explains what we already knew: “Cassini was detecting samples from Enceladus all the time as it flew through Saturn’s E ring. We had already found many organic molecules in these ice grains, including precursors for amino acids.
The ice grains in the ring can be hundreds of years old. As they have aged, they may have been ‘weathered’ and therefore altered by intense space radiation. Scientists wanted to investigate fresh grains ejected much more recently to get a better idea of what exactly is going on in Enceladus’s ocean.
Fortunately, we already had the data. Back in 2008, Cassini flew straight through the icy spray. Pristine grains ejected only minutes before hit the spacecraft’s Cosmic Dust Analyzer (CDA) instrument at about 18 km/s. These were not only the freshest ice grains Cassini had ever detected, but also the fastest.
The speed mattered. Nozair explains why:
“The ice grains contain not just frozen water, but also other molecules, including organics. At lower impact speeds, the ice shatters, and the signal from clusters of water molecules can hide the signal from certain organic molecules. But when the ice grains hit CDA fast, water molecules don’t cluster, and we have a chance to see these previously hidden signals.”
It took years to build up knowledge from previous flybys and then apply it to decipher this data. But now, Nozair’s team has revealed what kind of molecules were present inside the fresh ice grains.
They saw that certain organic molecules that had already been found distributed in the E ring were also present in the fresh ice grains. This confirms that they are created within Enceladus’s ocean.
They also found totally new molecules that had never been seen before in ice grains from Enceladus. For the chemists reading, the newly detected molecular fragments included aliphatic, (hetero)cyclic ester/alkenes, ethers/ethyl and, tentatively, nitrogen- and oxygen-bearing compounds.
On Earth, these same molecules are involved in the chains of chemical reactions that ultimately lead to the more complex molecules that are essential for life... (MORE - details, no ads)