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Title: 'Hubble Tension' and the Nobel Prize Winner Who Wants to Replace
Cosmology's Standard Model

Link: https://science.slashdot.org/story/25/06/02/0...

Adam Riess won a Nobel Prize in Physics for helping discover that the
universe's acceleration is expanding, remembers The Atlantic. But then
theorists "proposed the existence of dark energy: a faint, repulsive force
that pervades all of empty space... the final piece to what has since come to
be called the 'standard model of cosmology.'" Riess thinks instead we should
just replace the standard model: When I visited Riess, back in January, he
mentioned he was looking forward to a data release from the Dark Energy
Spectroscopic Instrument, a new observatory on Kitt Peak, in Arizona's
portion of the Sonoran Desert. DESI has 5,000 robotically controlled optic
fibers. Every 20 minutes, each of them locks onto a different galaxy in the
deep sky. This process is scheduled to continue for a total of five years,
until millions of galaxies have been observed, enough to map cosmic expansion
across time... DESI's first release, last year, gave some preliminary hints
that dark energy was stronger in the early universe, and that its power then
began to fade ever so slightly. On March 19, the team followed up with the
larger set of data that Riess was awaiting. It was based on three years of
observations, and the signal that it gave was stronger: Dark energy appeared
to lose its kick several billion years ago. This finding is not settled
science, not even close. But if it holds up, a "wholesale revision" of the
standard model would be required [says Colin Hill, a cosmologist at Columbia
University. "The textbooks that I use in my class would need to be
rewritten." And not only the textbooks - the idea that our universe will end
in heat death has escaped the dull, technical world of academic textbooks. It
has become one of our dominant secular eschatologies, and perhaps the best-
known end-times story for the cosmos. And yet it could be badly wrong. If
dark energy weakens all the way to zero, the universe may, at some point,
stop expanding. It could come to rest in some static configuration of
galaxies. Life, especially intelligent life, could go on for a much longer
time than previously expected. If dark energy continues to fade, as the DESI
results suggest is happening, it may indeed go all the way to zero, and then
turn negative. Instead of repelling galaxies, a negative dark energy would
bring them together into a hot, dense singularity, much like the one that
existed during the Big Bang. This could perhaps be part of some larger
eternal cycle of creation and re-creation. Or maybe not. The point is that
the deep future of the universe is wide open... "Many new observations will
come, not just from DESI, but also from the new Vera Rubin Observatory in the
Atacama Desert, and other new telescopes in space. On data-release days for
years to come, the standard model's champions and detractors will be
feverishly refreshing their inboxes..." And Riess tells The Atlantic he's
disappointed when complacent theorists just tell him "Yeah, that's a really
hard problem." He adds, "Sometimes, I feel like I am providing clues and
killing time while we wait for the next Einstein to come along."

Read more of this story at Slashdot.

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