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Today's Topics:
1. AI could help resolve Hubble tension (Stephen Loosley)
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Message: 1
Date: Sun, 01 Sep 2024 13:50:20 +0930
From: Stephen Loosley <[email protected]>
To: "link" <[email protected]>
Subject: [LINK] AI could help resolve Hubble tension
Message-ID: <[email protected]>
Content-Type: text/plain; charset="UTF-8"
AI uncovers the universe 'settings' with unprecedented precision, and it could
help to resolve the Hubble tension
By Ben Turner published 2 days ago
https://www.livescience.com/space/astronomy/ai-uncovers-the-universes-settings-with-unprecedented-precision-and-it-could-help-to-resolve-the-hubble-tension
The new AI system can estimate cosmological parameters with stunning precision,
and it could help astronomers unpick one of the thorniest problems in the field.
Astrophysicists have used artificial intelligence (AI) to precisely estimate
five of the universe's six "settings" with unprecedented precision.
The system could one day help researchers crack the mystery of the Hubble
tension.
Scientists use six cosmological parameters to describe the large-scale makeup
of our universe. These describe the density of its ordinary matter, or baryons;
the density of dark matter and dark energy; and the conditions immediately
following the Big Bang ? including the universe's opacity and clumpiness.
Getting precise estimates of these numbers is important for understanding how
our universe began and how it will evolve.
But traditional methods typically only estimate these parameters by looking at
the way galaxies are spread out over large scales.
By applying AI to the problem, the researchers were able to extract numbers for
the parameters across smaller scales, yielding a result for our universe's
matter clumping that had less than half the uncertainty of previous results.
The scientists published their findings Aug. 21 in the journal Nature Astronomy.
https://www.nature.com/articles/s41550-024-02344-2.epdf
"Each of these [telescope] surveys costs hundreds of millions to billions of
dollars," study co-author Shirley Ho, a group leader at the Flatiron
Institute's Center for Computational Astrophysics (CCA) in New York City, said
in a statement.
"The main reason these surveys exist is because we want to understand these
cosmological parameters better. So if you think about it in a very practical
sense, these parameters are worth tens of millions of dollars each. You want
the best analysis you can to extract as much knowledge out of these surveys as
possible and push the boundaries of our understanding of the universe."
The researchers trained their AI system on 2,000 models of box-shaped
universes, each with different cosmological settings and muddied data to
reflect the limitations in real-life observations. This enabled their model to
spot patterns in how galaxies looked based upon the alterations made to each
universe setting.
Then, the researchers presented the AI with 109,636 real galaxies measured by
the Baryon Oscillation Spectroscopic Survey.
The system produced estimates for the cosmological parameters that were as
precise as a traditional survey using four times as many galaxies.
Past efforts to estimate the parameters "haven't been able to go down to small
scales," study lead author ChangHoon Hahn, an associate researcher at Princeton
University, said in the statement.
"For a couple of years now, we've known that there's additional information
there; we just didn't have a good way of extracting it."
The researchers have proposed a number of applications for their method,
possibly the most exciting of which will be to study the Hubble tension.
For years, scientists have been locked in a fierce debate over the tension ? a
problem which arises from mismatched estimates showing the universe expanding
at different rates depending on where in space astronomers look.
By feeding data from new cosmic surveys coming online in the next few years
into their model, the researchers hope to arrive at an understanding of whether
the tension can be resolved, or if it demands a completely new model of the
universe.
"If we measure the quantities very precisely, and can firmly say that there is
a tension, that could reveal new physics about dark energy and the expansion of
the universe," Hahn said.
Ben Turner Staff Writer Ben is a U.K. based staff writer at Live Science. He
covers physics and astronomy, among other topics like tech and climate change.
He graduated from University College London with a degree in particle physics
before training as a journalist. When he's not writing, Ben enjoys reading
literature, playing the guitar and embarrassing himself with chess.
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