The debate
over whether the universe is expanding at an accelerating rate appeared to be
settled. Because several Nobel laureates in Physics agreed over the years,
accelerated expansion became the standard model of universal Physics. A new
study, however, casts doubt on this long-held belief. But it’s also much promising
as the theory of Big Bang.
Since the
Big Bang created our universe, astronomers have scoured the radiographic
wreckage of that immense event for clues on where we came from and where we’re
headed. Among the debris that cooled and condensed to form our universe (like
nebulas, galaxies, and planets), astronomers find startling mysteries like dark
energy and try to unravel them.
Edwin
Hubble, Dark Energy, and the Expanding Universe
Edwin Hubble
was arguably the first to witness distant galaxies that seemed to pull away
from us. In his velocity-distance relationship published in 1929, he argued
that once the gravitational effects of nearby galaxies are controlled, galaxies
move away from one another. Astronomers interpreted the discovery to mean that
the universe is expanding. The finding was also in agreement with Einstein’s
equations that theoretically predicted an expanding universe.
In the
1990s, three astronomers were awarded the Nobel Prize, the Gruber Cosmology
Prize, and the Breakthrough Prize in Fundamental Physics for their discovery
that the universe expands at an accelerating pace. This led to the widespread
acceptance that a force called “dark energy” was abundant in the universe and
behaved as a universal constant. This became the standard model of cosmology. Earlier
this year, another team of astronomers using the Hubble Telescope discovered that
the universe is expanding at a faster rate than expected.
Nobel
Laureate Adam Riess led the team that made the discovery. The team affirmed the
widely held view that dark matter is the reason for accelerating expansion.
“All of these tests are indirect and carried out in the framework of an assumed model.”
Reasons for
Doubt
According to
Professor Subir Sarkar of Oxford University‘s Department of Physics, the
evidence of accelerating expansion falls short of a “5 sigma” standard required
for a discovery of fundamental significance. Five Sigma measures the p-value or
probability of 3×10^-7. At less than five sigma, it is possible that the
finding of an accelerating expansion was due to a statistical anomaly.
Five Sigma
measures the p-value, or probability, of 3×10^-7. At less than five sigma, it
is possible that the findings indicating an accelerating expansion were due to
a statistical anomaly.
The team
used a dataset from analysis of Type IA supernovae, which is the same body of
evidence used to affirm the theory of accelerated expansion. The difference was
Sarkar’s team had more data to pull from than was previously available.
Of the previous Nobel Prize-winning research which he refutes, Sarkar says, “all of these tests are indirect, carried out in the framework of an assumed model, and the cosmic microwave background is not directly affected by dark energy.”
Source:
University Of Oxford