Many galaxies, as taken by the Hubble Telescope (NASA)
Click to enlarge
Wednesday, March 4, 2015
Monday, March 2, 2015
Universes: Parallel or Unique? (Part 2)
There's
a second way in which the concept of parallel universes comes up in
modern physics: Not so long ago our understanding of the cosmos was
far more limited than today. It was literally a smaller universe. The
more we learn, however, the bigger it all appears to be. In fact,
some scientists pose the possibility that the universe is
unimaginably huge; even infinite. There is currently no known reason
why it couldn't be. If so, it opens up the possibility for something
very weird: If the universe is actually infinite, there may be
an infinite number
universes contained within
it. No limit.
Since
there are only a finite number of elements that make up everything,
an infinite universe offers the chance of an infinite number of ways
that things can arrange themselves. Sooner or later, you and I will
find ourselves being duplicated. It's like giving 100 monkeys 100
typewriters to play with (OK, today, it'd be 100 PCs). Given enough
time (infinite), they would write all of Shakespeare's plays. It's a
crazy thought... but it's theoretically possible.
And
finally, there's a third way that parallel universes come up: via
string theory. There are currently three contrasting ways that
physicists model our universe: (1) classical mechanics (Newton's
baby), (2) relativity (Einstein's baby), and (3) quantum mechanics.
Each one uses a type of mathematics that works quite well within its
domain—either large and slow, very fast, or at atomic scales. But
when two of these domains intersect or overlap, they clash in their
predictions of how things behave. These three approaches disagree
with one another in that overlapping zone—something that causes the
stomachs of physicists to wildly churn, or creates painful scientific
headaches.
A
few decades ago a novel theory came into existence to deal with this
disagreement: string theory. It irons out a lot of overlapping
wrinkles in the old theories—providing a seamless description of
our world; big, small, fast, slow, etc. String theory has introduced
a few wrinkles of its own, however. One is that science may never be
able to come up with experiments to test its validity. That's a
bummer in the eyes of physicists who know they'll eventually have to
have experimental verification of their theories. So string theory,
although attractive, awaits (maybe forever) some kind of proof.
(Interestingly, Einstein's theory of relativity remained an abstract
curiosity for a couple of decades until an experiment in 1919 proved
it true, and Albert became an overnight sensation.)
A
particular aspect of string theory also suggests the possibility of
parallel universes. So science now has at least three ways to suggest
the possibility of parallel universes: quantum mechanics, the
realization that the universe may be infinite, and string theory. As
a result, other universes are coming into vogue and several new terms
have entered the discussion: parallel worlds, the multiverse, the
metaverse, the megaverse, alternative universes, etc. The
imaginations of science fiction writers have been stimulated by all
these developments. The possibilities are endless.
As
yet, however, the evidence for parallel universes is only
conceptually
possible. There is no proof. There may never be. That's disturbing
for some physicists and has others toying with the many potential
implications. Nobody yet knows. So expect ongoing speculation for
some time yet... and maybe the dilemma will foster a bunch more great
science fiction stories and movies.
Tuesday, February 24, 2015
Universes: Parallel or Unique? (Part 1)
People
have enjoyed playing with the notion of parallel universes for many
years. Science fiction stories have featured myriad possibilities
of the existence of them, and often describe a hero accidentally
being dumped into one of them, followed by harrowing and strange
adventures. Our hero will discover the weird characteristics of the
new universe, become trapped within it, finally escape, and return
safely home, back to our unique universe. It's been a rich topic to
explore.
One
of the more modern fictional depictions of parallel universes is the
notion that multiple, split-off copies of each of us exists in
these countless other universes. How does this happen? At each moment, we
are presented with multiple choices; the road branches again and
again. We choose one path, but other copies of us (in other
universes) make other choices, each time creating endless copies of
ourselves that do their own thing in their own universe. These
replicas of us carry on in their lives pretty much as we do, but
pursue an infinite number of alternative possibilities.
After
each moment's decision that we make, we sometimes wonder: What if I were
to have chosen another path? (The fun part of the fiction is that
another “me” did so, in another parallel universe.) What
would my life be like today? If only I could peer into one of those
alternative worlds. These fanciful questions often occur to us, and
we can get into daydreams about another path that we might have
taken. Another playground for science fiction.
Once
the sole realm of science fiction, the possibility of the existence
of parallel universes has entered mainstream science in recent years.
Parallel universes pop up in physics and cosmology in several ways.
One of the ways is via the field of quantum mechanics. Its
predecessor, classical mechanics (the result of Isaac Newton's
insights), described an exact, unique universe—in which the laws of
physics allowed us to make precise predictions of the future behavior
of things such as planets and billiard balls. Given enough
information, one could describe precisely where that planet would be
in a hundred million years, or in which pocket a billiard ball would
eventually drop. Classical mechanics offered a certainty that we humans like to
have.
But
then quantum mechanics entered the picture and introduced the fact
that chance, instead, may rule our beloved universe. Physics was
transformed from an exact science to a probabilistic one. (This irked the hell out of some scientists... Einstein was one of them.) Quantum
mechanics tells us that an event, rather than being unique, may have
any number of outcomes—each with a given probability of happening.
We won't know what outcome actually will occur, until we run the
experiment. Afterwards, we may wonder why that particular result
occurred. Another outcome theoretically could have happened.
This probabilistic nature of the quantum world posits the possibility
of multiply-different outcomes in multiply-different universes—each
outcome equally likely to have occurred in its own universe. Weird!
More
on alternative universes next time...
Saturday, February 21, 2015
Tuesday, February 10, 2015
Scarce as Hen's Teeth
Most
everyone knows that birds come with a hard beak, empty of any teeth.
Thus the old saying I often heard my mom say, when something couldn't
be found: “It's as scarce as hen's teeth.” Little did Mom know
that hens—or, rather their deep ancestral forebears—once did
have teeth. In fact, those toothy critters were birds' very
deep ancestors (actually, dinosaurs), who lived over 100 million
years ago.
In
that ancient time the ancestors of today's birds were small, toothed
dinosaurs that cohabited the planet with the really big toothy
dinosaurs, like the formidable T-Rex. A great many species of
dinosaurs presided over all living creatures on Earth, until that
fateful day when an asteroid crashed down near the Mexican Gulf
coast, 65 million years ago. The resultant disruption to Earth's
climate soon wiped out the great dinos, but the smaller, feathered
ones managed to squeak through.
Well
before that asteroid crash, however, those bird ancestors had already
lost their teeth. How do we know? New genetic analyses show that the
toothed dinos long ago first lost their teeth at the front of their
jaw, and the tooth loss then gradually moved rearward on the jaw. As
this loss progressed, the hard beak slowly developed (I guess to give
them something hard to mash their food with).
Bird
evolution continued to occur, as the proto-birds also evolved flight
feathers and even began to sing. As a fascinating example of how
genes are shared across species (good evidence that we all co-evolved
from even more primitive critters), the 50 or so genes that permitted
birds to begin to sing are shared by us humans. These genes give us
the ability to speak—and yes, sing, but certainly not like a bird.
But
back to hen's teeth: Was a toothless bird more suited for surviving
the asteroid impact than the dentally-equipped large dinosaurs? It
was more likely a case of their larger size and the
over-specialization of the huge dinos that did them in. In any case,
the surviving proto-birds found countless available niches, after
their dino cousins disappeared. When many niches are available, a
species can rapidly multiply into many new species. That's why Earth
currently supports more than 10,000 species of birds.
So,
the proliferation of birds happened because the big dinosaurs, some
65 million years ago, became scarcer than hen's teeth.
Thursday, February 5, 2015
Monday, February 2, 2015
Outwitting Ourselves
There
is a barrage of new findings currently being published by
psychological researchers. It's even sort of a golden age, as
constantly-improving brain-scanning techniques allow neuroscientists
and psychologists to probe deep into the brain and make connections
between our behaviors and our brain states.
One
area that has yielded some fascinating findings is the manner in
which we can be deceitful. We all know that honesty is the best
policy—we've had this message handed to us throughout our lives by
parents, teachers, and religious leaders. Yet every one of us has to
admit to behaving deceptively at times. Why do we do this? Primarily
to fool others, to take advantage of them. We often find ourselves in
competition with other people—for food, sex, winning games, etc.;
and we want to win. If we strut around in a posturing manner,
we may hoodwink our competition into concluding that we're much more
gallant and fierce-some than we really are. We've gotten the upper
hand, before any real competition has begun.
An
interesting twist on this game is that we're really not quite as
dishonest as we appear to be, because we're not always intentionally
deceitful. Sometimes we do it because we've deceived ourselves
first. We tell ourselves lies, in order that our lies to others don't
seem to be quite so unscrupulous. If we ourselves believe this stuff,
others will be more likely to swallow it, and we won't feel all that
guilty.
But
how can we be so disingenuous, and how do we manage to live with
ourselves, when we deceive other people and ourselves as much
as we do? If we know that honesty is the best policy, won't our
conscience tend to bother us? Well, if we've fooled ourselves into
believing our own falsehoods, we don't even realize we're
being dishonest.
What's
the mechanism going on here? How can we not comprehend that we've
duped even ourselves? (Of course, we don't do this all the time, or
our lives would be phony and unreal.)
It
all begins with our senses, which have evolved to give us a very
accurate view of reality. If not, we'd probably not survive, and
evolution would have done away with humans long ago. So our senses
provide us with a good sample of the world. The problem occurs in the
brain. Our ultimate perception of our world is what our brain makes
it out to be—what it decides all those electrical signals delivered
to the brain mean. Accuracy is not maintained if the signals get
degraded or scrambled. And accuracy is lost in the process of making
memories. How?
Much
of our conception of our world is based on memories. Something
happens. We perceive it in some manner, and then stash it in
memory—to later retrieve it when we need it. The experiences we
have range all over the place—from good to bad, painful to
thrilling, sad to joyful, scary to comforting. Our brain will
sometimes distort our memory of these experiences—by making them
more to our liking. We repress painful memories, create false
memories, sugar coat memories, and choose to notice only those things
that feed our biases.
These
distortions of our memories are often unconsciously formed, so that
our conscious mind—unaware of the falsification of a memory—hangs
onto it, as if it were valid. We've outwitted ourselves, and in the
process, we may fool others as well.
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