Let's see whether such claims can hold up to scrutiny.
Laura
Mersini-Houghton lists nine pieces of evidence that she calls “Secret
Codes of the Multiverse.” She says these are
“nine observable signatures of the entanglement of our universe
with other universes.” You can click on the link above to see the
entire list.
Secret Codes of the Multiverse?
Those who examine
the list looking for sensational cosmic weirdness will be very
disappointed. There is nothing in her list of observations that
cries out as being evidence of a multiverse or entanglement of our
universe with other universes. None of her nine items is anything
particularly weird or inexplicable. The items on the list are all
pretty much yawners, items not a hundredth as weird and
hard-to-explain as, say, dark energy or the Big Bang.
Let us look
carefully at the last two items on this list of supposed “Secret
Codes of the Multiverse,” two items which have a particularly high
bunk content.
Item 8 on this list
is listed by Mersini-Houghton like this:
The
“tilting” of the gravitational potential of the universe, giving
rise to a uniform flow of structure in a particular direction, called
the “Dark Flow.”
The hypothesis of
“Dark Flow” is the idea that some part of the universe is moving
in a strange way. Mersini-Houghton seems to think that this is
evidence of some other universe exerting a gravitational pull on part
of our universe.
In short, item 8 on
Mersini-Houghton's “Secret Codes of the Multiverse” is bunk
because the “Dark Flow” phenomenon she cites is not actually
occurring.
Now let's look at
item 9 on Mersini-Houghton's “Secret Codes of the Multiverse”
list. She states it as follows:
The
failure of the Large Hadron Collider to detect the breaking of an
underlying symmetry of nature known as Supersymmetry (SUSY) at TeV
energies.
This piece of
supposed “evidence for the multiverse” is actually a
non-observation, a null, a piece of non-evidence. It is actually a
negative result that is quite contrary to the theoretical
underpinnings of Mersini-Houghton's
cosmology. She is a proponent of a string theory conception of the
multiverse. String theory is built upon the theory of supersymmetry
(SUSY). When the Large Hadron Collider failed to find any of the
particles predicted by supersymmetry, this was a serious blow to that
theory and the string theory on which it is based. The string theory
advocates were hoping very much that the Large Hadron Collider would
find some of the particles predicted by supersymmetry, so that we
might start to get a little evidence for something along the lines of
string theory.
So it is quite
ridiculous for Mersini-Houghton to be quoting this particular
non-observation (the failure to discover particles predicted by
supersymmetry) as “a secret code of the multiverse.” It is
absurd to cite any non-observation as support for a theory of
a multiverse. Consider how laughable is the conversation below.
Student: We
tried to get those observations, Professor. But we came up
empty-handed, and found nothing.
Professor Jones:
That's it! You've found evidence of a multiverse!
Mersini-Houghton's
approach seems to be to mainly look for cosmological observational
riddles she doesn't understand, and trumpet those as signs of a
multiverse, perhaps using some “how else can we explain this
mystery” insinuations. I find that approach to be very flawed.
There are always dozens of ways to explain any current observational
anomaly without resorting to a multiverse.
We don't actually
have any evidence for a multiverse, but it might be interesting to
consider the question: what type of observations could one make that
might be evidence of a multiverse? It would be evidence dramatically
different from anything in Mersini-Houghton's list.
Real evidence of a
multiverse would not be merely something like an observation of part
of our universe flowing in an unexpected way. Such an observation
would at best be evidence of one “sister universe” exerting a
gravitational effect on our universe. It would not be evidence for an
ensemble of universes, each with varying physics and fundamental
constants.
Here are two
hypothetical ways in which one could actually get evidence of a
multiverse:
Method 1: We
look up in our telescopes and see radically different physics going
on in different parts of the sky. Perhaps in one part of the sky we
see light traveling at, say, 50 times the speed of light on our
planet; then in some other part of the sky, we see light traveling at
one tenth the speed of light on our planet. This might be evidence
that we are somehow peering into other universes with different
physics from the physics of our universe. But no such observations
have ever been reported. We have peered deep into the universe, to the observational
limits of our telescopes, and found no such thing. Instead we have
found great uniformity of the fundamental physical constants and laws
wherever we look.
Method 2: We
invent a machine capable of teleporting itself to some other
universe. The machine could then make some observations to verify
that the other universe had physics radically different from ours.
For example, the machine might release a gram of matter on a flat
windless plain. If the matter floated up rather than falling down, it
might be evidence that the machine was in some weird other universe
where gravity acted differently. The machine could then be
teleported back to our universe to give us proof of its observations.
There are numerous
reasons why it is extremely improbable that Method 2 will ever be
applied successfully. The first is that no one has the slightest
idea how to teleport a machine to a different universe (black holes
won't do the job, since everything tells us that they will completely
destroy any machine trying to pass through them). The second is that
no one has the slightest idea how to teleport a machine back from another
universe to our universe. The third is that if we assume that
alternate universes would have a random collection of physics and
fundamental constants, it would be more than 99.99999999% likely that
a machine teleported to some other universe would be instantly
destroyed as soon as it got there, because that universe would be
very unlikely to have physics allowing for stable atoms and
molecules. It requires a great deal of fine-tuning of various items
of physics (such as the charge of the proton and the electron, and
the strong nuclear force) for you to even have a universe in which
objects as large as a small machine can exist without flying apart.
In short, the
prospects of getting any real evidence for a multiverse are very,
very slim.
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