WWW.ASTRONOMY.COM 33“Science is useful insofar as it explains and predicts
why things are the way they are and not some other way,”
he wrote. “... A Theory of Anything is useless because it
does not rule out any possibility and worthless because it
submits to no do-or-die tests.”
Still, “parallel universes” are such a sci-fi staple, they’re
more familiar to the public than most other aspects of
theoretical physics and astronomy. TV science specials
remain in love with the multiverse idea and usually let its
champions make on-screen claims of putative evidence.
In 2014, the most convincing ever astrophysical sup-
port emerged for the multiverse and made front pages
around the world.
Evidence clouded
It was a South Pole experiment called BICEP2. Yet dra-
matically and amazingly, within a few short months, the
find was discredited. Turned out, it wasn’t the experiment
but the interpretation that proved faulty. Globally head-
lined as the first-ever verification of gravity waves that are
the supposed signature of inf lation — the wild expansion
of the newborn universe — the observations
are now thought to be at least most-
ly, if not completely, due to the
existence of cosmic dust
particles in our Milky
Way G a la x y.
Before the BICEP2
results were discred-
ited, they were cited by
some multiverse cheer-
leaders as support for the
chaotic inf lation model,
which was in turn offered as evi-
dence for parallel universes. Critics howled
at what they characterized as chains of unwarranted
assumptions. Some continue to ask why the multiverse
idea always seems exempt from science’s normally strict
standards and is allowed to tiptoe along the shorelines of
mere conjecture.
Actually, as long as speculative cosmological models
are allowed into the party, it’s also possible that reality lies
in the opposite direction from the multiverse. We’re talk-
ing about the notion that even our own cosmos is simple
rather than multifarious.
Ancient Greek thinkers like Parmenides and Zeno
were among the first to argue that the cosmos (or “Being”)
is a single undifferentiated entity. By this account, there
are no separate events happening around us. Rather, the
cosmos is a single event. This view of fundamental one-
ness, which has some modern quantum support, has
appeared in nearly all cultures through the centuries and
is antithetical to multiverses.
The bottom line seems to be that while “multiverse” is
mind-stretching and certainly possible, it may be pointless
and even counterproductive as an explanation for our vis-
ible universe’s properties. Meanwhile, debate rages over
whether any observation could ever disprove multiverse
models — which pushes them outside the realm of science.
In a Newsweek cover story in 2012, Columbia
University cosmologist Brian Greene wrote: “Evidence for
the multiverse might come from potential collisions
between our expanding universe and its neighbors. Such a
cosmic fender bender would generate an additional pat-
tern of temperature variations in the microwave back-
ground radiation [the remnant radiation of the Big Bang]
that sophisticated telescopes might one day detect. Many
consider this the most promising possibility for finding
evidence in support of the multiverse. That there are ways,
long shots to be sure, to test the multiverse proposal
ref lects its origin in careful mathematical analysis.
Nevertheless, because the proposal is unquestionably ten-
tative, we must approach it with healthy skepticism and
invoke its explanatory framework judiciously.”
Tegmark agrees: “Parallel universes are not a theory,
but [they’re] predictions of certain theories which are
arguably testable, for example cosmological inf lation. This
is why they’re discussed not only in science fiction, but
increasingly also at science conferences.”Not even wrong?
It’s noteworthy that highly cre-
dentialed individuals still
use equivocal language
as they describe even
the most plausible
multiverse models
out there. Evidence
might one day be
detected for certain
theories which are “argu-
ably testable?”
Is such fuzziness good enough to
qualify as science?
Given the current multiverse infatuation, it may be
fairest to give the last word to a prominent skeptic.
Columbia University mathematical physicist Peter Woit,
who maintains the popular multiverse-critical blog Not
Even Wrong, pulls no punches.
“Physicists had huge success in coming up with power-
ful compelling fundamental theories during the 20th cen-
tury,” he explains, “but the last 40 years or so have been
difficult, with little progress. Unfortunately, some promi-
nent theorists have now basically given up and decided to
take an easy way out. The multiverse is invoked as an all-
purpose, untestable excuse. They allow theoretical ideas
like string theory that have turned out to be empty and
consistent with anything to be kept alive instead of aban-
doned. It’s a depressing possibility that this is where phys-
ics ends up. But I still hope this is a fad that will soon die
out. Finding a better, deeper understanding of the laws of
physics is incredibly challenging, but it’s within our capa-
bility as humans, as long as the effort is not overwhelmed
by those selling a non-answer to the problem.”
Whoa, intense. We’ve got to toss the multiverse if we
care about physics!
Of course, if an infinite multiverse does exist, some
other Woit is out there saying the exact opposite.WHAT HAPPENS IF STRING THEORY IS WRONG? FIND OUT AT http://www.Astronomy.com/toc.ESA
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