When you start reading this article, keep in mind the numerous discussions put forward on this blog about agreement reality. It is where we exist (in agreement) and the only place we can truly exist in any sense of being 'real'. Regardless, of what we think is happening as the process of reality that seem to define what is real whether using tools, telescopes, computers and whatever else... its only what we agree on that really counts and provides us with some kind of 'reality'... the social reality that is only located in the social imagination. And, understand the intention is not to mock or defame but to show the truth as it really is... in agreement reality ~ efg.
Since Edwin Hubble first discovered in 1929 that
galaxies are getting farther apart over time, allowing scientists to trace the
evolution of the universe back to an initial Big Bang, astronomers have
struggled to measure the exact rate of this expansion. In particular,
astronomers want to determine a number called the Hubble parameter, a
measurement of how fast the cosmos is expanding as we speak. The Hubble
parameter tells us the age of the universe, so measuring it was a major goal
for many astronomers in the latter half of the 20th century.
The problem,
however, is that measuring the Hubble parameter is, perhaps
unsurprisingly, quite difficult. There are multiple methods for
doing so, and modern observatories are coming up with different numbers
depending on which method they use. It seems the number obtained based on the
appearance of the universe shortly after the Big Bang is significantly smaller
than the number obtained when looking at measurements involving objects closer
by.
The early universe Hubble parameter, derived from observations by the European Space Agency's Planck satellite,
tells us the universe is about 13.8 billion years old. Meanwhile, the local
cosmos measurements might yield an age nearly a billion years younger. If that
smaller age is correct, it throws off the entire timeline of cosmic history,
and could mess up our understanding of when and how various major events
happened in the evolution of the universe.
To be clear: This discrepancy isn't so huge that the
Big Bang theory is in trouble, or that we have to rethink everything we know
about the cosmos. But the discrepancy is large enough that some
cosmologists — scientists studying the history and makeup of the universe as a
whole — are suggesting the field is in crisis.
Adam Riess, the Johns Hopkins cosmologist who shared
the 2011 Nobel Prize in physics, has argued strongly that we can't ignore the discrepancy,
because it keeps appearing, over and over again, in
too many independent local cosmos observations to be a fluke. "If
the universe fails this crucial end-to-end test (it surely hasn't yet passed),
what might this tell us?" Riess wrote in Nature. "It is tempting to think
we may be seeing evidence of some 'new physics' in the cosmos."
That could be the case, but "I would say it's at
least as likely that we still don't understand what all the subtleties
in these measurements are," says cosmologist Arthur Kosowsky of the
University of Pittsburgh (who was the author's Ph.D. advisor), "and eventually
they'll converge to a single value [for the Hubble parameter]." (of course they will eventually converge because eventually we have to have agreement)
Indeed, the discrepancy could come down to little
more than hidden biases in the measurements. To use an analogy, if you have
an air rifle that pulls very slightly to the right as you shoot at a target,
all your shots may be clustered around a single point, but that point will be
to the right of the actual bullseye. The rifle introduces a systematic error to
your normally good aim, right?
But the analogy is imperfect because in cosmology, we
don't know where the "bullseye" (agreement) is: The precise value of the Hubble
parameter can't be calculated independently of measurements.
Complicating matters further, none of the observations measure the Hubble
parameter directly.
Instead, they link different observable phenomena to the
rate of cosmic expansion. The trick is to use multiple independent
measurements as a check on one another, hoping that any systematic
effects can be spotted in the process. (hoping for agreement)
For example, the Planck satellite's early-universe
observations — those that tell us the universe is expanding more slowly — are
based on something called the cosmic microwave background (CMB), which is light
left over from about 400,000 years after the Big Bang. However, we aren't
seeing this light as it was way back then; we're seeing it after it's passed
through clusters of galaxies and entered the Milky Way, with extra light from
other sources added in. To get anything useful out of CMB data, astronomers
have to subtract everything that isn't primordial; while they're very good at that,
there might still be room for systematic bias in the way the subtraction is
done.
Measurements based on closer objects — which yield a
slightly younger age — are based on type Ia supernovas, which are the
explosions of super-dense objects called white dwarfs; the pulsations of very
large stars; and the gravitational distortion of light as it passes by galaxies.
Each type of measurement has its own set of systematic biases that must
be corrected (be made subject to agreement). It's also worth noting that while their Hubble parameter values
are close to each other, they aren't in precise agreement either. In
other words, all of these observations are complex enough that their results
aren't completely settled.
New types of observation are underway, which might
help identify where bias exists in Hubble parameter measurements. Removing
those biases would bring the Hubble numbers into agreement.
But what if the numbers are right? That could be
indicative of some previously unknown phenomenon in the very early universe,
from the epoch before the first atoms formed. Perhaps dark energy, which we
know is driving cosmic expansion to accelerate in the modern era, played a role
far earlier than most cosmologists think. Maybe there are extra particles that
were important when the universe was smaller and denser, but whose influence
was diluted over billions
of years. None of these possibilities are perfect, but whatever
the right answer, it's a big deal.
"I don't have a crystal ball better than anyone
else, but I think that these measurements are just really hard,"
'cosmologist' Kosowsky says. However, his caution doesn't mean he wouldn't be happy to be
wrong. "I'm rooting for it to come out the other way, that this is
actually showing us something exciting about cosmology." (rooting for an agreement)
Online Source ~ https://www.yahoo.com/news/growing-crisis-cosmology-105501754.html
Full Title - The Growing Crisis in Cosmology found in 'The Week', Author: Matthew Francis, dated Feb. 20, 2020.