In the year 2040 when our
little nation was attacked by the mighty superpower, the superpower
wrapped itself in a cloak of good intentions. The superpower told the
world that it had invaded our small country to bring greater
prosperity to our citizens. But we knew the real truth. We had been
invaded so that the superpower could grab our resources, resources
that were all the more important in a world troubled by energy and
mineral shortages.
I was the leader of the
nation, so I met with the Defense Secretary to discuss how we would
try to defend ourselves against the attack.
“Their divisions have
stormed the border, and are heading towards this city,” I said.
“Have we been able to maintain a decent defense line?”
“No,” said the Defense
Secretary with an odd smile. “Not at all.”
“You don't seem too
concerned about the situation,” I said, “but I am. What is the
ratio of our forces and theirs?”
“The superpower has invaded
us with twice as many soldiers as we have in our army,” said the
Defense Secretary. “But don't worry, everything will be fine.”
Near our border the enemy
divisions routed our small defense forces. Soon the enemy's divisions
approached the nation's capital. I called an urgent meaning with the
Defense Secretary.
“We're on track to lose
this war, and lose this country to the enemy,” I said. “Isn't
there something we can do, some last gamble?”
“There is,” said the
Defense Secretary, smiling. “Come with me, and I'll show it you.”
The Defense Secretary
arranged for us to travel to a huge factory ten miles away. When we
got out of our vehicle, the Defense Secretary pointed to the
building.
“There it is,” said the
Defense Secretary. “This is going to win us this war.”
“A factory?” I said
skeptically. “Our troops have been devastated. It's too late to get
them some new weapon.”
“It's almost time for the
moment of release,” said the Defense Secretary. “This is going to
be a moment you'll never forget.”
And so it was. A short time
later, I saw a stream of flying objects coming out of the factory.
The objects formed into what looked like a dark cloud. The cloud kept
getting bigger and bigger and bigger. Before long the cloud seemed to
fill the whole sky, making it look like a summer sky that was about
to erupt in a downpour.
“There it is,” said the
Defense Secretary. “The Cloud of Victory. The cloud that
will save us from the invaders.”
The giant dark cloud broke up
into four smaller clouds, and each flew away into different
directions, one to the east, one to the west, one to the north, and
one to the south.
Later I learned the technical
details. Each object in the cloud was a small flying drone, only
about as long as a man's foot – a device called a mini-drone. Each
mini-drone contained a power source, a metal detector, a motion
detector, and an explosive. The original "Cloud of Victory" contained
30,000 small drones.
Each mini-drone had some
simple programming. Each mini-drone was programmed to look for moving
metal. When it detected a large piece of moving metal, the mini-drone
would descend from the sky, crashing into the moving metal.
Almost all of the tanks of
the invaders were destroyed from the sky by the mini-drones. The
small mini-drones made little noise, and were hardly even visible in
the sky, so it was all but impossible for a tank driver to know if a
mini-drone was in the sky above him. One minute a tank driver might
be driving along, thinking that there was no trouble anywhere near.
The next minute a small mini-drone would descend from the sky,
crashing into the tank and blowing it up.
Something similar happened to
most of the enemy's soldiers. The soldiers were wearing armor, and
carrying metal guns. When a small mini-drone in the sky detected the
moving metal, the mini-drone would descend from the sky, crashing
into the soldier, blowing him to bits.
The day before the Cloud of
Victory appeared, the enemy was winning the war. But a few days
later, the enemy's invading force was in shattered shambles.
Humiliated, the defeated invaders withdrew.
I congratulated the Defense
Secretary on his brilliant tactic.
“But what if the enemy
comes back in a few years, armed with some defense against the Cloud
of Victory?” I asked.
“Don't worry,” the
Defense Secretary said. “By then we will have perfected the
Annihilation Spray.”
Sunday, March 30, 2014
Friday, March 28, 2014
A Precognitive Dream of Flight 370?
I
often wake up remembering extremely detailed stories and images from
my dreams. Last night, for example, I woke up remembering a very
vivid and elaborate dream: a story of a rich man with a huge mansion
who had some woman redecorate his mansion in some
astonishingly colorful way.
But
on about 9:00 AM EST on March 7, 2014 I awoke from a dream with the
following strange thought in my mind: 6 Indian women murdered.
I didn't remember any story associated with this dream, and couldn't
recall any images associated with it. All I remembered was a phrase:
6 Indian women murdered.
After
I ate breakfast and turned on my computer, I recorded my dream in a
text file in which I occasionally record dreams I have had. I did a
Google search to see whether there was any news report of six Indian
women having been murdered. I found nothing, so I forgot about the
matter for several days.
A
few months ago I had started recording my dreams because a certain
number of months before the attack on the World Trade Center on
September 11, 2001, I had a dream that the World Trade Center
collapsed. In the dream I was an observer in the World Trade Center,
and the floor gave way. I and everyone else plunged downward as the
whole building collapsed. I then woke up, as I always do whenever I
reach a terrifying or horrifying point in any dream I am having.
I
mentioned to my wife that I had a dream that the World Trade Center
collapsed, but then gave the matter no further thought until the
events of September 11, 2001.
When
I later realized this coincidence, I did a web search to find out how
many Indian people on the jet died. According to this link there
were 6 Indian people who died on the plane – 5 Indian nationals,
and one Indian person from Canada.
If
we assume that Flight 370 was lost because of a deliberate act of
terrorism or because of a suicidal pilot, then there would be a fairly close
match between my dream and the reality. I had dreamed that 6 Indian
people were murdered on the same day that 6 Indian people may well
have been murdered.
But
I didn't quite get things exactly right – because only three of the
Indian people who died were women. But presumably if precognition
occurs, it is a rather hazy thing; so we wouldn't necessarily expect
it to be 100% accurate.
There
has been controversial research suggesting that precognition
(knowledge of the future) actually occurs, most notably the “Feeling the Future” experiment done at Cornell University by Daryl Bem.
Studies have been done on what is called presentiment, which is the
alleged tendency of the human mind and body to start reacting to
phenomena an instant before they occur. A recent meta-analysis
examined 26 studies of presentiment, and concluded that there was a
statistically significant effect that is unexplained (see here for a similar scientific paper).
Some
people think that precognition can occur in dreams. A writer named J.
W. Dunne wrote a book called An Experiment With Time, in which
he claimed that after he started recording his dreams after waking
up, he found that many of them came true.
One
fascinating theory is that when events occur, they create ripples in
some cosmic field, rather like the ripples caused when stones are
dropped in a pond. Such ripples may travel forward in time or
backward in time; and the more significant the event, the larger the
ripple. Somehow
the human mind might be able to pick up some of these ripples coming
from the future. Such a theory could make sense only in a larger
philosophical framework with an enlarged concept of the relation
between the human mind and nature, one that transcended the
reductionist dogmas of naturalistic materialism.
Was
my dream an example of precognition, or was it merely a coincidence?
I have no idea. I
have no proof for the tale I have told here, so you can believe it
occurred as I have described it, or you can believe I am just making
it up.
I
offer my heartfelt condolences to the families of all the people who
lost their lives in Flight 370.
Wednesday, March 26, 2014
Humbling Discoveries in Our Cosmic Backyard Suggest Our Astronomical Ignorance
Today
scientists announced two surprising discoveries relating to the
solar system. The first discovery was the discovery of a 250-mile-wide
planetoid some 7.7 billion miles from the sun. The New York Times
described the discovery as follows: “Astronomers have discovered a
second icy world orbiting in a slice of the solar system where,
according to their best understanding, there should have been none.”
The
area mentioned is an area between the orbit of Pluto and the Oort
Cloud, a gigantic cloud- like region of comets believed to surround
our solar system. Scientists originally thought this area was empty,
but then they discovered within it Sedna, a 600-mile wide planetoid three
times farther from the sun than Neptune.
Some
are speculating that the planetoid discovery announced today may hint
at the existence of a super-Earth planet ten times bigger than the
sun, existing too far away from the sun to have been previously
discovered. But if such a planet existed, it would almost certainly
be too cold for life to exist on it, unless the planet had some type
of geological activity that produced heat.
The
second discovery announced today was the discovery of the first ring
ever detected around an asteroid. These observations come as a
surprise as big as the discovery a few weeks ago that a particular
asteroid is disintegrating, for unknown reasons.
Humbling
discoveries such as these make me wonder: why does any scientist
claim to understand exactly what happened during the first second of
the universe's history? Evidently we don't even yet fully understand
our own solar system, our own tiny little cosmic backyard. So give out a hardy
chuckle the next time a scientist speaks as if he has a detailed knowledge of exactly what happened at the dawn of time 13 billion years
ago.
Monday, March 24, 2014
The Impossibility of Verifying a Varying-Constants Multiverse
For
several decades scientists have discovered more and more examples
suggesting our universe is seemingly tailor-made for life. A list of
many examples is discussed here. One dramatic example is the fact
that even though each proton in our universe has a mass 1836 times
greater than the mass of each electron, the electric charge of each
proton matches the electric charge of each electron exactly, to 18 decimal places, as discussed here (the only difference being that one is
positive, the other negative). Were it not for this amazing
coincidence, our very planet would not hold together. But scientists
have no explanation for this coincidence, which seems to require luck
with a probability of less than 1 in 1.000,000,000,000,000,000. As wikipedia
states, “The
fact that the electric
charges of electrons
and protons seem to
cancel each other exactly to extreme precision is essential for the
existence of the macroscopic world as we know it, but this important
property of elementary particles is not explained in the Standard
Model of particle physics.”
Wishing
to cleanse their minds of any suspicions that our universe may not be
the purely accidental thing they imagine it to be, quite a few
materialists have adopted the theory of a multiverse. This is the
idea that there is a vast collection of universes, each very
different from the other. The reasoning is that if there were to be,
say, an infinite number of universes, then we would expect that at
least one of them would have the properties necessary for intelligent
life, no matter how improbable it may be that such properties would
exist.
I will refer to such a collection of
universes as a varying-constants multiverse, since the concept is
that the fundamental constants of different universes in this
collection would vary. The fundamental constants are items such as Planck's constant, the gravitational constant, the speed of light, the proton charge, the electron charge, and the mass ratio of the proton and the electron.
The
question I will consider in this post is: is there any possible way
that such an idea of a varying-constants multiverse could be verified?
Why a Varying-Constants Multiverse Could Not be Verified Through Telescopic Observations
You
might think that we could verify the idea of a varying-constants
multiverse by long-range telescopic observations. You can imagine
scientists building some giant telescopes a thousand times more
powerful than any ever built. If such telescopes were to allow
scientists to look a thousand times farther than they ever looked
before, then you might guess that one day scientists might be able to
see other regions of space where the constants of nature differ. You
might, for example, imagine that scientists looking as far as
possible in one direction might see some distant area where the speed
of light was much higher, and scientists looking as far as possible
in some other direction might see some distant area where the
gravitational constant was much different than it is on Earth.
But
nothing of the sort has happened, and there is a reason why it cannot
ever happen. The reason is that because of the limit set by the speed
of light, whenever we look very far away in space, we are looking
back in time. So when we look 10 billion light-years away (near the
current observational limits of our telescopes), we are looking 10
billion years back in time. Scientists say that our universe began in
the Big Bang about 13 billion years ago. So we have a built-in limit
as to how far our telescopes will ever be able to look. We can never
hope to observe anything, say, 16 billion light years away, simply by
building more and more powerful telescopes.
Our
most powerful telescopes (such as the Hubble Space Telescope) can
look almost as far as humans will ever be able to see with
telescopes, which is about 13 billion light years. There is no chance
at all that by looking a little farther we will be able to see some
sign of another universe. As we approach the observational limit of
about 13 billion years, we are looking back a little more to the
beginning of our own universe. Scientists say that various aspects
of the very early universe and the Big Bang (such as what is called
the recombination era) act as a barrier that will forever block us
from observing all the way back to the time of the universe's birth
in the Big Bang.
So
there is no hope at all of being able to verify any theory of a
varying-constants universe just by looking farther and farther out in
space. But some have suggested two other ways in which we might be
able to lend credence to a multiverse theory by telescopic
observations: (1) by observing strange, unexplained motions of parts
of our universe; (2) by finding evidence of previous cycles of our
universe.
The
first of these involves the idea that we might be able to see that
some fraction of our universe is moving around in an unexplained way,
possibly because of gravitational influences by some nearby universe.
Such an observation is theoretically possible, but would not actually
be any observational support for the idea of a multiverse with
varying constants. If we observed such an unexplained motion, it
would best be explained by postulating new factors and physics within
our observed universe. Even if we were to be forced to conclude that
our universe is being gravitationally tugged by some other universe,
that would at best be support for the idea that our universe has a
“sister universe,” rather than the almost infinitely more
complicated idea that there are a vast collection of universes.
Moreover, such an observation would provide no support for any idea
that other universes have a variety of different physical constants.
The
same thing can be said about the idea of finding evidence that our
universe had previous cycles. If such evidence were found, it might
lead us to think that the universe existed before the Big Bang, and
that the universe is older than 13 billion years. But such evidence
would not give any basis for believing in anything like a
varying-constants multiverse. If our universe had previous cycles,
there is no reason to think that its fundamental constants such as the proton charge would change from one
cycle to the next. Science knows of no mechanism by which the
fundamental constants of the universe could change (here I exclude
the Hubble constant, a measure of the universe's expansion rate,
which is not really a fundamental constant).
Could
we ever verify the theory of a varying-constants multiverse by
verifying the theory of cosmic inflation, the idea that the universe
underwent an exponential expansion during part of its first instant?
No. I may first note that the prospect of being able to verify any
theory of cosmic inflation is far dimmer than many now think. It
is very doubtful that the current technique being pursued (based on
looking for b-mode polarization) will ever provide any real verification.
There are many sources of b-mode polarization that are not caused by
inflation (gravitational lensing, dust, synchrotron radiation, and
others), so trying to find a fingerprint of inflation is like trying
to extract a DNA sample from a bandage that was passed around and shared by ten different people with bleeding wounds.
But
even if scientists were to confirm a theory of cosmic inflation, that
would not verify any theory of a varying-constants multiverse. For
one thing, while some versions of the inflation theory imagine inflation
producing multiple bubbles of space that might be called other
universes, we would have no way of knowing whether such other bubbles
of space had ever formed, as they would be forever unobservable. More
importantly, we would have no license for assuming that such bubbles
of space would be universes with fundamental constants that differed
from our own. If one universe produced bubbles of space that branched
off to become spatially separated from that universe, the
most natural assumption is that such “universes” (or, more
properly, other regions of the same universe) would have the same
fundamental constants as their parent universe, particularly since science knows of no mechanism by which one universe could somehow produce a different universe with different fundamental constants.
There
is still one other technique that might be proposed for verifying the
idea of a varying-constants multiverse: the technique of actually
launching a mission into another universe. One
can imagine some amazing machine that might allow us to travel from
our universe to a different universe. In theory, if mankind or its
successors were to launch several trips to other universes, and
verify that they had different fundamental constants, that might
verify the idea of a varying-constants universe.
But
there are huge problems with such an idea. The first is that science
offers no clue as to how we ever could travel to another universe.
The idea seems like pure fantasy, a thousand times more fanciful and
extravagant than the farfetched idea of instantly traveling to
another star through a space-time wormhole.
The
second reason is that if we were somehow to create some machine
capable of traveling to another universe, there is no reason to think
that it would be capable of traveling back to our universe or sending
signals back to our universe (either of which would be necessary for
any real verification to occur).
The
third reason is that if we were somehow able to create a machine that
traveled to another universe, it would still be all but impossible
for such a device (or people or robots traveling in it) to verify
that the other universe had a set of fundamental constants different
from ours. The measurement of our universe's fundamental constants
has taken decades of work by scientists around the world. There's no
reason to think that a machine transported to another universe would
be able to verify that the fundamental constants of that universe
were different.
The
fourth reason is that if one imagines the scenario of a varying
constants universe (many universes, each with random fundamental
constants), there would be an overwhelmingly high likelihood
(such as 99.999999999%) that any machine transported to such a universe would
be instantly destroyed, along with any robots of humans that came
along for the ride.
To
understand this point, you have to consider the astonishingly high
degree of fine-tuning that allows stable matter to exist in our
universe. In his book The Symbiotic Universe, astronomer George
Greenstein says this
about the equality of the proton and electron charges: "Relatively
small things like stones, people, and the like would fly apart if the
two charges differed by as little as one part in 100 billion.”
There are quite a few other cases of fine-tuning required for the existence
of stable matter, including fine-tuning of the strong nuclear force.
So
if we then imagine a machine being transported to another universe
with random physical constants, we have to imagine the machine (and
any one inside it) being instantly destroyed as soon as it was
transported to another universe. With a 99.9999999% likelihood the
coincidences which allow for stable atoms and molecules in our
universe would not exist in such a universe. As soon as the machine
got over to the other universe, its atoms and molecules would split
apart, as the machine would (with overwhelming likelihood) no longer
be in a universe which favored the existence of atoms and molecules.
A recruiting poster from 4000 AD ?
Because of these various reasons, we can conclude that there is no substantial possibility that any machine could ever be transported to another universe to help verify the concept of a multiverse consisting of many universes, each with a different set of fundamental constants.
It seems that it is quite impossible to ever verify the theory that there are multiple universes with varying fundamental constants. The theory is neither falsifiable nor verifiable. Consequently, the theory is more of a metaphysical theory than a scientific theory, as all truly scientific theories can be either verified or falsified under some reasonable scenario.
Saturday, March 22, 2014
A Scientific Theory is Not Confirmed Merely Because It Seems to Make a Few Correct Predictions
In discussions of scientific theories, it is often argued that
this or that result will confirm some scientific theory because such
a result was predicted by that theory. But such reasoning is often
mistaken. The fact that a theory may seem to make some correct
predictions does not necessarily show that the theory is likely to be
true.
Below are some of the reasons why this is true.
A theory can be a mixture of true and false assumptions, and correct predictions can be made by the true assumptions.
Theories are often a mixture of correct assumptions and mistaken assumptions. Correct assumptions in a theory may imply certain predictions, which may prove successful. But the theory may still contain incorrect assumptions, which did not imply the predictions that turned out true. The correct predictions only tend to confirm (perhaps to at least some degree) those parts of a theory that implied those correct predictions, not other assumptions that did not imply those predictions.
For example, some people advanced the theory in 2002 that the Bush administration had secretly orchestrated the September 11 attacks, to create a pretext for war because it wanted to invade Iraq. Perhaps some of those people then said in 2003 that their theory was confirmed, because the Bush administration really did invade Iraq in that year. But in this case we have a theory making two assumptions: (1) the assumption that the Bush administration orchestrated the September 11 attacks; (2) the assumption that the Bush administration wanted to attack Iraq. The invasion of Iraq in 2003 may tend to confirm the second of these assumptions, but not the first.
So when a particular scientific theory seems to be confirmed by some prediction that eventually matches observations, we need to ask: which parts of the theory tend to predict the prediction that matched observations? Only such parts – if any-- should be considered as having been put (possibly) in a favorable light by the observations.
Multiple theories may make a particular prediction, so a confirmation of the prediction may not really support a particular theory that makes that prediction.
It is too easy to selectively present data in a way that makes
a theory's predictions look true, either by massaging the “observed
data,” by massaging the “predicted data,” or by massaging both,
either deliberately or through unrecognized bias.
Even if a theory is the only theory that predicts an observed
phenomenon, that does not mean the theory is true, because there may
be many possible theories not yet imagined that can explain the
phenomenon.
With sufficient ingenuity, unbelievable theories can be contrived to make predictions that match observations.
Below are some of the reasons why this is true.
A theory can be a mixture of true and false assumptions, and correct predictions can be made by the true assumptions.
Theories are often a mixture of correct assumptions and mistaken assumptions. Correct assumptions in a theory may imply certain predictions, which may prove successful. But the theory may still contain incorrect assumptions, which did not imply the predictions that turned out true. The correct predictions only tend to confirm (perhaps to at least some degree) those parts of a theory that implied those correct predictions, not other assumptions that did not imply those predictions.
For example, some people advanced the theory in 2002 that the Bush administration had secretly orchestrated the September 11 attacks, to create a pretext for war because it wanted to invade Iraq. Perhaps some of those people then said in 2003 that their theory was confirmed, because the Bush administration really did invade Iraq in that year. But in this case we have a theory making two assumptions: (1) the assumption that the Bush administration orchestrated the September 11 attacks; (2) the assumption that the Bush administration wanted to attack Iraq. The invasion of Iraq in 2003 may tend to confirm the second of these assumptions, but not the first.
So when a particular scientific theory seems to be confirmed by some prediction that eventually matches observations, we need to ask: which parts of the theory tend to predict the prediction that matched observations? Only such parts – if any-- should be considered as having been put (possibly) in a favorable light by the observations.
Multiple theories may make a particular prediction, so a confirmation of the prediction may not really support a particular theory that makes that prediction.
It is not necessarily true that a
confirmed prediction tends to show that the theory that predicted it
is true, because there may be many other reasonable theories that
make the same prediction. For example, let's imagine a person in 2007
arguing that sinister forces on Wall Street were trying to
orchestrate a sharp economic downturn, so that they could make lots
of money on certain types of stock market bets called puts (which
increase in value when a stock goes down). In 2008 (when such an
economic downturn occurred) such a person would no doubt say, “Look,
we did have a sharp economic downturn; my theory is
confirmed.” But such reasoning would be invalid, because the same
sharp economic downturn was predicted by various other theories, such
as the theory that a housing bubble would produce such an economic
downturn, and the theory that too much consumer credit would produce
an economic downturn.
The favorite device of a theory
advocate is a “predicted versus actual” line graph. Here is a
very simple example of this type of graph, with the blue line showing
predicted results and the red line showing observed results:
This type of graph can be used to
try to show that a particular theory is matching observations. But be
distrustful when you see such a graph. Why? Because it is easy to
cherry-pick either the data used as the “observed data” or the
data used as the “predicted data,” or both.
This is particularly true in any case
where the data points are not some simple thing (depending on one
observation, as in the case above), but instead require some
complicated summary of multiple observations. In such cases it is all
too easy for a presenter to massage the data in a way that shows a
theory in a favorable light. Given a choice of five different ways of
showing the “observed results” (each using a different source of
data, or a different way of summarizing the data), someone can choose
whichever set of “observed results” is most in agreement with his
theory.
Another way in which bias can be
displayed is by massaging and cherry-picking the “predicted results”
shown in a graph such as the one below. Theories often have multiple
flavors, which vary because of a choice of parameters that can be
used within the theory. In other words, the “predicted results”
from a particular theory are often very fuzzy, rather like an
electron probability cloud. A presenter can pick particular values
within that fuzzy cloud that most closely match the “observed
results,” and plot such values as the “predicted values” on a
line graph. The result will show the theory in the most favorable
light, but may be misleading. For a recent specific example of this type of
cherry-picking, see this blog post.
Another way in which bias can be shown
in matching observed results with predicted results is simply by
choosing the start point and the end point of the data being graphed.
For example, if I have a theory that bonds tend to out-perform
stocks, I may use a start point of January 1, 2000 and an end point
of Dec 1, 2008. That will show a huge advantage for investing in
bonds as compared to investing in stocks. But a different start point
and end point would tell a very different story. A similar technique
can be used to try to show the likelihood of a particular scientific
theory. A supporter can choose to graph whatever start point and end
point shows the closest match between the theory and observations,
even though different start points and end points on the line graph
would show a much smaller degree of agreement.
One type of reasoning sometimes made
is: x is the only theory that predicts the observed phenomenon
y, so x must be true. But that does not follow. The
human imagination is weak, and our ignorance is enormous. Almost any
observed phenomenon can be explained in many different ways, but the
puny human imagination may be able to think of only one or two of
those ways. Back during the days of the Black Plague, the theory of
“God's wrath” may have been the only theory that explained why so
many people were dying, but it would have been wrong at that time to
assume such a theory was correct on that basis.
With sufficient ingenuity, unbelievable theories can be contrived to make predictions that match observations.
Sometimes it is possible for a theory
to make some correct predictions, even though the theory isn't
plausible. One of the most famous examples is the Ptolemaic theory, a
theory of the solar system. The theory held that the Earth was at the
center of the solar system. To make such a theory match observations,
the theory included a complex model of planetary motions, in which
planets orbited in small orbits called epicycles that were part of
much larger orbits. The predictions of the Ptolemaic theory seemed
accurate for centuries, but the theory was quite false.
There are modern-day equivalents of the Ptolemaic theory -- theories that are very suspect because of their excessive complexity and contrivance.
There are modern-day equivalents of the Ptolemaic theory -- theories that are very suspect because of their excessive complexity and contrivance.
Implausible, contrived scientific theories are like this
Scientific theories are only well-confirmed by predictions when
the theories make very many predictions that have been confirmed by
observations.
Thinking that a scientific theory has
been confirmed because it makes a few correct predictions is like
thinking that you've proven you're a great baseball player because
you've pounded out a few base hits. You've only proven yourself a
great baseball player if you've made hundreds or thousands of hits.
Similarly, the only scientific theories that are well-confirmed by
predictions are those that have made hundreds, thousands or millions of
predictions that have been confirmed.
We have a great example of such a
theory: the theory of gravitation. The theory is based on a simple
exact formula that you can use to compute the degree to which massive
bodies attract each other. Scientists and engineers (and the
computers on spacecraft) have used this theory thousands or millions
of times, and the predictions made by the theory have always proven
true. A robot spacecraft could never reach Mars and land on Mars
unless the predictions of the theory of gravitation proved true
thousands of times, nor could the Apollo astronauts have landed on
the moon and returned.
Another such theory is the theory of
electromagnetism. The theory is based on a simple exact formula you
can use to compute the attraction between two electrical charges.
Scientists and engineers have used the formula thousands or millions
of times, and it always gives the right answer.
Compared to these theories, any theory
that claims scientific validation because it seems to make a few
correct predictions is like some kid who claims to be a professional
actor because he acted in a few high-school plays.
According to the standard I mention
here, we might have a reason for regarding many well-known scientific
theories as being on rather shaky ground, as they do not make a huge
number of predictions that have been confirmed. For example, we
might regard as a very shaky theory the theory that life first arose
on planet Earth merely because of a lucky chance combination of chemicals. Such a
theory does not make a huge number of predictions that have been
confirmed, and in fact, does not seem to make any prediction that has
been confirmed.
Thursday, March 20, 2014
More Doubts About BICEP2: The Dubious Part of Their Main Graph
At
a time when many cosmic inflation theory fans are jumping the gun and
popping champagne corks over Monday's BICEP2 study results, calling
it an epic breakthrough, I hate to be a killjoy. I like to join a
party as much as the next man. The problem is that I keep finding
reasons for doubting the claims made about the study, that it
provides evidence for the theory of cosmic inflation. My main reasons
were given in this blog post, and some lesser software-related
reasons were given in yesterday's blog post. Now I will discuss a
very big additional reason for doubting the claims being made about
BICEP2, a reason I haven't previously discussed: their main graph
has a very dubious feature, a curve that is quite
misleading.
The
BICEP2 paper has two versions of the graph, one that is logarithmic
and another that is not. Below is the non-logarithmic version, which
makes it easier to see how the discovered data does not match what is
predicted from the theory of cosmic inflation:
In
this graph the black dots represent the new BICEP2 observations of
b-mode polarization. The vertical lines are error bars representing
uncertainty in the data. The bottom dashed line is a prediction of
b-mode polarization made by one version of the theory of cosmic
inflation (a “wishful thinking” version chosen by the BICEP2
team, as I will explain in a minute). The solid line represents
contributions to b-mode polarization projected to occur from
gravitational lensing. The upper dashed curved line represents the b-mode
polarization that could occur from a combination of gravitational lensing and the version of the inflation theory
that was chosen by the BICEP2 team to make their data match inflation
theory.
Now
the untrained eye can spot a big problem with this graph: the
observations do not match what is expected. While the first two black
dots match the top dashed line (as does the last black dot), several
of the other black dots are way above the top dashed line, in
particular and seventh and eighth dots. On this basis, we are
entitled to say: inflation theory falls way short.
But
here is a very important fact about this graph: the bottom curved
hill-shaped dashed line (the supposed contributions from cosmic
inflation) is not “the” prediction from the theory of cosmic
inflation. It is instead the prediction from a particular version of
the inflation theory carefully chosen by the BICEP2 team so that their
observational results can be matched to inflation theory. The
version in question is one that drastically contradicts conclusions made with a
95% confidence level last year by a much larger team of scientists, using the
Planck space observatory.
The
“prediction from inflation” that appears as the hill-shaped red
dashed line on the above graph all depends on a particular data item
called the tensor-to-scalar ratio, which cosmologists represent with
the letter r. In a scientific paper co-authored last year by more than
200 scientists, the Planck team concluded with a 95% confidence level
that this tensor-scalar ratio is less than .11. But in the graph
above the BICEP2 team chose to disregard these findings, and use on
their graph an extreme version of the inflation theory in which the
tensor-scalar ratio is .2 (200% higher than the maximum value set by
the larger group of scientists).
Why
would the BICEP2 team have done that? Because it allowed them to produce a
graph showing a partial match between their observations and the
predictions of a cosmic inflation theory. A triumph of wishful
thinking. It's rather like a husband reassuring his wife by showing
her a graph in which his projected income rises by 50% for each of
the next five years.
But
what would the key BICEP2 graph have looked like if they had accepted
the limit set by the much larger Planck team? The graph would have looked rather
like the graph below, except that the left half of the top red dashed line would have
to be dropped way down, and none of the observations would be
anywhere near close to matching the predictions from inflation
(except for the last one, at a point in the graph where inflation is
irrelevant, and all contribution is from gravitational lensing).
The BICEP2 team could have produced a graph like the one above (but with the left half of the top dashed line dropped way down, to equal the green line plus the solid red line). That is exactly what they should have done. They might then have made an announcement like this:
We
have some interesting new observations. But we're sorry to report
that, respecting the limits set last year by a much larger team of
scientists, our observations provide no evidence to back up the
theory of cosmic inflation.
Instead,
the BICEP2 team chose to put in a bogus red dashed line in their key
graph, representing a farfetched, extreme wishful-thinking version of
the cosmic inflation theory, one that relies on a version of
inflation with a tensor-scalar ratio (r) about twice as high as the
maximum allowed value according to the larger Planck team. Rather
than candidly showing such a red-dashed line as just one possible
version of inflation, they put it on the graph as if it was the only
version of inflation.
It
was a great way to grab press headlines, but not very honest or
candid.
When
we use the predictions of inflation using the Planck team's
estimate of the upper limit of the tensor-scalar ratio (with a 95%
confidence level), corresponding roughly to the green line in the graph
above, we are led to think that the BICEP2 team's observations
provide no support to a theory of cosmic inflation.
Postscript: This post uses the assumption that smaller values for the tensor-to-scalar ratio (r) cause the "hill" of the inflation prediction to drop much smaller, a point that is clear from looking at this site.
Wednesday, March 19, 2014
Best Practices Software and Cowboy Coding
Let's look at the difference between two very different types of programming: best practices software and cowboy coding.
Best-practices Software
Best-practices
software is software developed according to software industry
guidelines for quality. Examples of these best-practices include the
items below. There is not always time to follow all of these
practices, but the overall quality and maintainability of the code
depends on how many of these standards are followed:
- Each source file contains a comment specifying the type of code in that file.
- Each method, subroutine or function contains a comment explaining what is done by that method or subroutine. The only exception to this rule is when the name of the method, subroutine, or function leaves no doubt as to exactly what is being done.
- There is a short description of each argument to any method that takes arguments, except in the case when the name of an argument leaves no doubt as to what that argument is.
- There are comments explaining the logic in any particularly complicated or hard-to-understand parts of the code.
- Variables are given names that help to document what they stand for.
- Good coding practices are followed by each developer.
- Once the code is finished, it is placed in a version control system. Whenever a source code file is changed, the new version is checked into the version control system, with a comment discussing what changes were made.
- The code is developed by a team of developers, who can cross-check each others' work.
- Once the code is written, documentation is written explaining how the code works and how it can be modified.
- A team of quality assurance experts (known as the QA staff) are finally brought in to rigorously test the code to find any bugs in it.
- Once the code has been released, a meticulous record is kept of all changes in the code and all reported bugs, along with which of the bugs were fixed.
- Any known defects or limitations of the code are clearly documented.
- Each subsequent release of the code is given a new version number, with a description of exactly how the code changed during the latest release.
Practices
such as these are followed by mission-critical software, or software
on which great amounts of money are riding, or software on which
lives depend. For example, if a company were writing software for a
nuclear reactor, or software for an expensive space mission, or
software for guiding a jetliner, it would tend to follow most or all
of these best practices.
However,
there is a totally different way of programming that is often used, a
quick-and-dirty way of programming. This way of programming is
sometimes called cowboy coding.
Cowboy coding is what happens when a single developer produces some code,
typically in a quick-and-dirty method. The cowboy coder isn't
interested in any quality guidelines that will slow him down. He
typically grinds out some software without doing much to document it.
He may make no use of version control. He may then release his work
without having had anyone check it other than himself. Typically the
cowboy coder just kind of says, “It seems to work well when I try
it – let me know if you find anything wrong with it.” A typical
cowboy coder makes little or no attempt to produce written
documentation for his software, and may take no care to document
different versions or to document exactly which bugs were fixed.
Now
cowboy coding certainly has its place. Lots of programs are not
mission critical, and need not be developed using best practices. It
would be overkill to follow the best practices listed above when
creating some little graphic utility for doing something like
allowing a user to add text to an image.
However,
it must be noted that cowboy coding is a severe danger if it is used
for some critical part of a hugely important scientific study. This
is because cowboy coding isn't very reliable. Maybe it does the right
thing, and maybe it doesn't. It can be hard for anyone to tell except
the original cowboy coder, and probably he doesn't even know. This is
no exaggeration. Poorly documented software code is very hard to
read, even if you are the original developer. Countless cowboy coders
simply don't know whether their cowboy-coded projects work correctly.
I've cowboy-coded quite a few little projects, and then when I went
back to them much later, I could often hardly figure out any more
what exactly they were doing.
The Huge Problem of Cowboy Coding in Scientific Studies
There is a very big problem that modern scientific studies often rely on dubious software solutions that have been cowboy-coded. Modern science involves incredibly high amounts of specialized data processing. Scientists cannot buy off-the-shelf software to handle these specialized needs. This is because each scientific specialty requires its own specific type of software, and the market for such software is so small that few software publishers will cater to it.
What very often happens is that scientists will often write their own software programs to handle their own specialized needs. Such efforts are often one-man cowboy-coded efforts that do not come anywhere close to meeting the best practices of modern software development. We have many scientists writing amateurish code that any full-time software developer would be ashamed to put his name on. But such code might become a critical linchpin in some scientific study that uses up millions of federal dollars.
We need new standards to minimize this problem. One possibility is to include software professionals as part of the peer review process for scientific studies. There are major scientific studies that are 30% science and 70% data processing. But in the peer review process, only scientists review the study. This makes no sense. Software professionals should be included in the process, to a degree that depends on how much data processing was done by the study.
Tuesday, March 18, 2014
BICEP2 Study Has Not Confirmed Cosmic Inflation
The
BICEP2 study was released yesterday, and found some evidence of
something called b-mode polarization in the early universe. Advocates
of the theory of cosmic inflation were quick to trumpet these
results, with many of them claiming that the study had finally
confirmed the theory of cosmic inflation. This theory maintains that
the universe underwent a period of exponential inflation during a
fraction of its first second.
But
there are several reasons why the BICEP2 study does not confirm cosmic inflation or even provide substantial evidence for it.
The
first reason is that a single scientific study rarely proves
anything. Having followed scientific developments closely for more
than four decades, I have lived through many a case of scientific
announcements that did not stand the test of time. I remember back
around 1980 an announcement in which scientists announced a fate for
the universe (collapse) that is the exact opposite of the fate they
now predict for it (unending expansion). I also remember the famous
“life on Mars” announcement in the 1990's which did not pan out.
At this web site a scientist says that there is only a 50% chance that the results
from this BICEP2 study will hold.
Another
reason for doubting this BICEP2 study is that it makes an estimate
for an important cosmological ratio called the tensor-to-scalar ratio,
and that estimate is about twice the maximum possible value, according to
the estimate from a very definitive source on the topic, the Planck team of scientists (larger than the BICEP group). Apparently some group of
scientists are in serious error in regard to this matter, and there
is a 50% chance that it is the team that made yesterday's BICEP2
study. If they are the ones who are wrong, it throws much of their
study into doubt.
A
third reason why the BICEP2 study does not confirm the theory of
cosmic inflation is that BICEP2's results do not match well with the
predictions of that theory.
The
supporters of the inflation theory are citing the graph below from
the BICEP2 study. The black dots are the BICEP2 observations, with
the vertical lines being error bars (representing uncertainty in the
data). The bottom red dashed line is what we expect from the cosmic
inflation theory.
Considering
just what is predicted from the theory of cosmic inflation, the
results do not match well at all. The little black dots show a rise
in the line exactly where the cosmic inflation theory predicts a fall
in the line.
What
is interesting, however, is that even if you accept as gospel truth
this estimate of the amount of gravitational lensing, the data from
BICEP2 ends up strongly diverging from the expected results produced
from the estimated amount of gravitational lensing and cosmic
inflation.
It
is very hard to tell how big this discrepancy is from the graph shown
above, because it uses two sneaky data presentation techniques to
make the discrepancy look much smaller than it is. The techniques
are: (1) the graph unnecessarily includes a whole load of irrelevant
data in the top half of the graph, causing the scale of the graph to
be unnecessarily large; (2) the graph uses a logarithmic scale (a
type of scale that often tends to make two data items look closer
than they are).
I
can use exactly the same techniques to make a graph that makes it
look like a dishwasher makes almost the same amount of money as a
Wall Street bond trader.
But,
thankfully, buried within the BICEP2 scientific paper is a nice
simple non-logarithmic graph that shows just how great the difference
is between the BICEP2 results and the results predicted from the
cosmic inflation theory. The graph is below.
In
the graph above the black dots are the new BICEP2 observations. The
vertical lines are uncertainties in the data. The bottom red dotted
line is the prediction from the theory of cosmic inflation. The
solid red line is the estimated gravitational lensing factor. The
upper red dashed line is the result predicted given a combination of
the gravitational lensing factor and the theory of cosmic inflation.
Notice
the big difference between the observed results and the expected
result. Even if we include this highly uncertain gravitational lensing
fudge factor, the predicted results from the cosmic inflation theory
do not closely match the observed results. Note that the sixth and
seventh black dots are way above the top dashed red line.
Therefore
these results are far from being a confirmation of the theory of
cosmic inflation. They can't even be called good evidence for cosmic
inflation.
I
may also note that there are numerous non-inflationary cosmological
models that might produce the type of polarization observations that
BICEP2 has produced. If there is currently a shortage of such
models, it is largely because cosmic inflation speculations have
almost monopolized the activities of theoretical cosmologists during
recent decades.
The
BICEP2 observations can be explained by the decay of exotic
particles, or by some noninflationary exotic phase transition. Or it
could be that all of the observed effect is produced by gravitational
lensing and none of it produced by cosmic inflation. Scientists are
already assuming that most of the observed effect is being produced
by gravitational lensing; it's a short jump from “most” to “all”
(particularly given the many uncertainties involved in estimating the
amount of gravitational lensing).
If
cosmologists spend as much time producing non-exponential
non-inflationary models of the early universe as they do producing
models that involve inflationary exponential expansion, they will
probably find that non-exponential non-inflationary models are able
to explain the observed BICEP2 results just as well, and perhaps even
better.
Because
the effect observed by the BICEP2 study can be produced by
gravitational lensing, and because we will for many decades be highly
uncertain about how much gravitational lensing has occurred in the
past, it is very doubtful that any study like the BICEP2 will ever be
able to provide real evidence for a theory of cosmic inflation. Just
as UFO photographs rarely prove anything (because there are so many
ways in which lights in the sky can be produced), a study like BICEP2
doesn't prove cosmic inflation (because there are other ways, such as
gravitational lensing, that the observed polarization effect can be
produced).
The
case for the theory of cosmic inflation theory is much weaker than
many think. In a nutshell the standard sales pitch for the theory is
that it solves two cosmological problems: one called the flatness
problem and the other called the horizon problem. The flatness
problem is an apparent case of cosmic fine-tuning, and the horizon
problem is an example of cosmic uniformity. The weakness in trying to
solve these problems with a theory of cosmic inflation is that we
have many other apparent cases of cosmic fine-tuning and many other
cases of astonishing cosmic uniformity (including laws of nature and
constants that are uniform throughout the universe). Inflation theory
claims to solve only one of these many cases of apparent cosmic
fine-tuning, and only one of the many cases of cosmic uniformity.
That puts it in not a very good position, rather like a theory of
the origin of species that only explains the origin of lions and
tigers without explaining the origin of any other animals. I will
explain this point more fully in a later blog post.
What
is particularly ironic is that the theory of cosmic inflation claims
to help in getting rid of some cosmic fine-tuning, but the theory
itself requires abundant fine-tuning of its own to work, as many
parameters in the theory have to be adjusted in just the right way to
get a universe that starts exponentially inflating and stops inflating in a way
that matches observations.
Postscript: The chart below (in which I have added a green line) shows one way we can explain the BICEP2 observations without requiring any cosmic inflation. We simply imagine a slightly higher amount of gravitational lensing (shown in the green line). The shape of this line matches the shape of the gravitational lensing estimated by the BICEP2 study (solid red line). Because the green line passes through all of the vertical error bars, it is consistent with the BICEP2 observations.
Post-postscript: at this link cosmologist Neil Turok says, "I believe that if both Planck and the new results agree, then together they would give substantial evidence against inflation!"
Post-post-postscript: See the post here for a discussion of wishful thinking and cherry picking involved in the main graph shown above.
Post-post-post-postscript: See this link for a National Geographic story on how the BICEP2 results may be caused by dust, not cosmic inflation.
Yet another postscript: see this post for a discussion of a talk at Princeton University in which a scientist gives a presentation that gives a devastating blow to the inflated claims of the BICEP2 study. The scientist gives projections of dust and gravitational lensing which show how such common phenomena (not from the Big Bang or cosmic inflation) can explain the BICEP2 observations.
Postscript: The chart below (in which I have added a green line) shows one way we can explain the BICEP2 observations without requiring any cosmic inflation. We simply imagine a slightly higher amount of gravitational lensing (shown in the green line). The shape of this line matches the shape of the gravitational lensing estimated by the BICEP2 study (solid red line). Because the green line passes through all of the vertical error bars, it is consistent with the BICEP2 observations.
BICEP2 graph with an added trend line (green)
Post-postscript: at this link cosmologist Neil Turok says, "I believe that if both Planck and the new results agree, then together they would give substantial evidence against inflation!"
Post-post-postscript: See the post here for a discussion of wishful thinking and cherry picking involved in the main graph shown above.
Post-post-post-postscript: See this link for a National Geographic story on how the BICEP2 results may be caused by dust, not cosmic inflation.
Yet another postscript: see this post for a discussion of a talk at Princeton University in which a scientist gives a presentation that gives a devastating blow to the inflated claims of the BICEP2 study. The scientist gives projections of dust and gravitational lensing which show how such common phenomena (not from the Big Bang or cosmic inflation) can explain the BICEP2 observations.
Yet another postscript: In this article in the scientific journal Nature, it is explained that two recent scientific papers have concluded that there is no significant evidence the BICEP2 signals are from cosmic inflation or gravitational waves, with dust and cosmological lensing being an equally plausible explanation.
Sunday, March 16, 2014
Teenage World Savior: A Science Fiction Story
All attempts to defeat
the hostile extraterrestrial invasion had failed utterly. A meeting of
military officers was convened at the house of Jonas MacDonald, a
physicist who specialized in high-energy physics. The officers were
there to ask the physicist if he knew of any high-tech way that the
invading extraterrestrials could be attacked, perhaps with something
such as lasers or electromagnetic pulse weapons.
“So far our military
efforts have been a complete disaster,” said General Curtis. “After
the aliens landed in New Jersey, and wiped out many people, we've hit them with every
conventional weapon we had. We've dropped countless bombs. We've
strafed them with our jets again and again. We've shelled the hell
out of them with our best artillery. But we're getting nowhere. The
alien stronghold keeps growing larger and larger.”
“Why aren't such
attacks working?” asked MacDonald.
“They seem to have some
kind of strange energy bubble around their landing area,” explained
Curtis. “It's some kind of super-strong energy field that is able
to vaporize incoming bombs and bullets. Whenever we shoot something
at the alien stronghold, our bombs and bullets just kind of melt as
soon as they touch the protective energy bubble.”
“Have you thought about
using nuclear weapons?” asked MacDonald.
“No, that's out of the
question,” explained General Curtis. “The prevailing winds would
cause radioactive fallout to drift on to New York City.”
“Do you have a picture
of what these extraterrestrials look like?” asked MacDonald.
General Wheeler produced
a photograph, and put a picture on the table.
“Let me think,” said
MacDonald. “There might be some kind of high-energy proton beam we
could use to attack these things.”
MacDonald's 13-year-old
son Artie walked into the room. Artie should have been at school, but
he had got suspended for starting a big food fight in his high school
cafeteria.
“Is that what the
aliens look like?” asked Artie. “Cool.”
“This meeting is
classified,” said MacDonald. “Artie, clear out of here.”
The men continued to
discuss MacDonald's ideas for a high-energy proton beam. Twenty
minutes later Artie came back into the room.
“Dad, I know I'm not
supposed to be here,” said Artie. “But I've got an idea. I've got
an idea about how you might defeat the aliens.”
“Artie, have you lost
your senses?” asked MacDonald. “Nobody wants to hear a teenager's
ideas on saving the world from an alien invasion.”
“But, Dad, it's a
really good idea,” said Artie.
“Let the boy speak,”
said General Curtis. “Right now, we're desperate for new ideas.”
“I got the idea from
the cafeteria food fight I got suspended for,” said Artie. “We
can fight the aliens with food.”
“Very funny,” said
MacDonald. “Now go to your room, and don't bother us again.”
“I'm not kidding, Dad,”
said Artie. “There's a way to do it. Look at that picture of the
alien. He has no real nose. Just a kind of a slit for a nose. So my
guess is these aliens are probably sensitive to particles in the air.
If we bombard them with fine particles, it may kill them. The easiest
way to bombard them with fine particles is by using spices.”
“Spices of what type?”
asked General Wheeler.
“Any type of spice that
is a very fine powder,” explained Artie. “Cinnamon or curry
powder would probably do the job.”
“That's the craziest
idea I've ever heard,” said MacDonald. “The aliens are protected by an energy bubble that would
make it so that the powder couldn't even fall into the alien
stronghold.”
“But it just might
work,” said General Wheeler. “Who knows – maybe their
protective energy bubble was only designed for things like bombs and
bullets. Maybe a fine powder could get through that thing. Let's give
it a try.”
So the conventional
high-explosive bombs were taken out of a military jet. Two giant vats
of cinnamon and curry powder were loaded into the jet. The jet made a
bombing run of the alien stronghold, dumping the curry powder and
cinnamon on to the strange alien structures.
The protective
energy bubble of the aliens had been designed to destroy only incoming objects
larger than about a millimeter. The curry powder and cinnamon fell
right through the protective bubble.
The aliens breathed in
the curry powder and cinnamon, and all died instantly. They came
from a dustless planet, and had never evolved any apparatus for
protecting their lungs from fine particles.
And so the teenage boy
who had started a food fight at his high school cafeteria became
known as the unlikely world savior who started a food fight that
saved planet Earth.
Friday, March 14, 2014
The Lesson From Arthur C. Clarke's Predictive Errors
The television show Prophets
of Science Fiction liked to portray science fiction writers as
latter-day visionaries with great predictive powers. One of the
writers profiled on this show was the late Arthur C. Clarke. Clarke
was both a science fiction writer and a nonfiction writer who wrote
about space exploration and the future. I greatly enjoyed his work,
particularly when I was a teenager. Clarke first proposed
communication satellites, and made some very prescient predictions
about that technology.
Clarke's predictions about the immediate effects of space travel varied in accuracy. Clarke predicted that an age of manned space exploration would produce a new Renaissance, and judging from this argument the 1970's (directly following the 1969 moon landing) should have been a decade of immortal art. Anyone who remembers the music and television shows of the 1970's may chuckle at that concept.
But what about Clarke's record in making predictions about our century -- how accurate was he?
If fiction can be taken as a form of prediction, Clarke's record in regard to predicting our century was not very good. His most famous fictional work (co-authored with director Stanley Kubrick) was the screenplay for 2001: A Space Odyssey. Although it was a great artistic success (and one of my favorite movies), that movie predicted that the year 2001 would see a manned mission to Jupiter, a giant-sized lunar colony housing more than 100 residents, computers that could have conversations with a human and understand our language, and a giant space station with artificial gravity and very roomy interiors. None of those things actually occurred by 2001. It is now 2014, and no one is living on the moon. We haven't even made it to Mars, and probably won't get there for many years. Although there are “chat bot” computer programs that might fool you (for a while) into thinking you're talking with some one, there is no computer that even has the intelligence of a 1-year-old. The only space station is a small station in which a few astronauts live in cramped conditions, without artificial gravity.
But what about Clarke's nonfiction predictions about our century – how well do they hold up? In 1999 Clarke wrote for the London Sunday Telegraph an article called “The Twenty-First Century: A (Very) Brief History.” Below are some of the predictions he made, along with comments about their accuracy.
Clarke predicted that the year 2002 would see “the first commercial device producing clean, safe power by low-temperature nuclear reactions,” causing the inventors of cold fusion to get a Nobel Prize in physics in that year. Serious misfire.
Clarke predicted that the year 2004 would see the first example of a human clone. Misfire.
Clarke predicted that the year 2005 would see the first return of a soil sample from Mars. Misfire.
Clarke predicted that in the year 2006 the last coal mine would be closed. Very serious misfire.
Clarke predicted that in the year 2009 (because of a nuclear accident) all nuclear weapons would be destroyed. Serious misfire.
Clarke predicted that in the year 2010 “quantum generators (tapping space energy)” would be deployed, and that electronic monitoring would all but eliminate professional criminals from society. Both predictions were complete misfires.
Clarke predicted that in the year 2011 a space probe to Jupiter's moon Europa would discover life on that moon. Misfire.
Clarke predicted that in the year 2014 construction of a Hilton Orbiter Hotel would begin. Misfire.
These misfires are not hand-picked from a list of predictions including quite a few successes. As far as I can tell from his 1999 forecast , pretty much nothing that Clarke predicted to happen between the year 2000 and 2014 actually happened (except for the arrival of a space probe to Saturn, which was already due to arrive in the year Clarke predicted).
These predictions were from one of the twentieth century's leading futurists, who had written a widely-read book entitled Profiles of the Future. My purpose here is not to belittle Clarke, who I regard highly. My purpose is merely to suggest the lesson that no matter how highly regarded a particular futurist may be, you should remember that his predictions are just educated guesses.
So the next time you see Ray Kurzweil predict that highly intelligent computers are just around the corner, take it with a grain of salt.
You should also pay very little attention to the prediction in today's news, from the SETI Institute's senior astronomer Seth Shostak. Shostak predicts that if intelligent life exists in space, we will find it within twenty years. Although there is every reason to suspect that there is very much intelligent life outside of our planet, there is fairly little reason to conclude that if it exists we will find it in twenty years.Whatever reasons have prevented us from finding such intelligent life for the past fifty years may well also prevent us from finding it in the next fifty years.
Clarke's predictions about the immediate effects of space travel varied in accuracy. Clarke predicted that an age of manned space exploration would produce a new Renaissance, and judging from this argument the 1970's (directly following the 1969 moon landing) should have been a decade of immortal art. Anyone who remembers the music and television shows of the 1970's may chuckle at that concept.
But what about Clarke's record in making predictions about our century -- how accurate was he?
If fiction can be taken as a form of prediction, Clarke's record in regard to predicting our century was not very good. His most famous fictional work (co-authored with director Stanley Kubrick) was the screenplay for 2001: A Space Odyssey. Although it was a great artistic success (and one of my favorite movies), that movie predicted that the year 2001 would see a manned mission to Jupiter, a giant-sized lunar colony housing more than 100 residents, computers that could have conversations with a human and understand our language, and a giant space station with artificial gravity and very roomy interiors. None of those things actually occurred by 2001. It is now 2014, and no one is living on the moon. We haven't even made it to Mars, and probably won't get there for many years. Although there are “chat bot” computer programs that might fool you (for a while) into thinking you're talking with some one, there is no computer that even has the intelligence of a 1-year-old. The only space station is a small station in which a few astronauts live in cramped conditions, without artificial gravity.
The Roomy Space Station in 2001: A Space Odyssey
But what about Clarke's nonfiction predictions about our century – how well do they hold up? In 1999 Clarke wrote for the London Sunday Telegraph an article called “The Twenty-First Century: A (Very) Brief History.” Below are some of the predictions he made, along with comments about their accuracy.
Clarke predicted that the year 2002 would see “the first commercial device producing clean, safe power by low-temperature nuclear reactions,” causing the inventors of cold fusion to get a Nobel Prize in physics in that year. Serious misfire.
Clarke predicted that the year 2004 would see the first example of a human clone. Misfire.
Clarke predicted that the year 2005 would see the first return of a soil sample from Mars. Misfire.
Clarke predicted that in the year 2006 the last coal mine would be closed. Very serious misfire.
Clarke predicted that in the year 2009 (because of a nuclear accident) all nuclear weapons would be destroyed. Serious misfire.
Clarke predicted that in the year 2010 “quantum generators (tapping space energy)” would be deployed, and that electronic monitoring would all but eliminate professional criminals from society. Both predictions were complete misfires.
Clarke predicted that in the year 2011 a space probe to Jupiter's moon Europa would discover life on that moon. Misfire.
Clarke predicted that in the year 2014 construction of a Hilton Orbiter Hotel would begin. Misfire.
These misfires are not hand-picked from a list of predictions including quite a few successes. As far as I can tell from his 1999 forecast , pretty much nothing that Clarke predicted to happen between the year 2000 and 2014 actually happened (except for the arrival of a space probe to Saturn, which was already due to arrive in the year Clarke predicted).
These predictions were from one of the twentieth century's leading futurists, who had written a widely-read book entitled Profiles of the Future. My purpose here is not to belittle Clarke, who I regard highly. My purpose is merely to suggest the lesson that no matter how highly regarded a particular futurist may be, you should remember that his predictions are just educated guesses.
So the next time you see Ray Kurzweil predict that highly intelligent computers are just around the corner, take it with a grain of salt.
You should also pay very little attention to the prediction in today's news, from the SETI Institute's senior astronomer Seth Shostak. Shostak predicts that if intelligent life exists in space, we will find it within twenty years. Although there is every reason to suspect that there is very much intelligent life outside of our planet, there is fairly little reason to conclude that if it exists we will find it in twenty years.Whatever reasons have prevented us from finding such intelligent life for the past fifty years may well also prevent us from finding it in the next fifty years.
Wednesday, March 12, 2014
Bouncing Black Holes May Cause the Sun to Suddenly Vanish
The sun has been shining for
billions of years, and scientists say that in all probability it will
continue shining brightly for billions of additional years. We assume
that there is 100% probability that the sun will continue to shine
throughout our lifetimes. But surprisingly enough, there is a very
small chance that the sun will suddenly disappear at any time --
perhaps a thousand years from now, perhaps ten years from now, or
perhaps even tomorrow.
The sun might vanish at any time because there is a very small chance that a particular theory I will now describe is true. If this theory is true, the sun might instantly disappear at any time.
The theory I mention is a theory involving black hole collapses. To explain that theory, I must first discuss why scientists think that black holes are formed. Scientists say that black holes are formed when very massive stars begin to collapse, with the collapse being caused by the enormous gravity of the star. A star that is more than five times more massive than the sun has a tremendous gravity many times higher than the gravity of our planet. But such a star emits lots of energy through thermonuclear fusion, and that causes an outward force that balances the inward force caused by the star's gravity.
But when the star nears the end of its lifetime and runs out of hydrogen and usable helium to burn as nuclear fuel, then there is no longer any outward force to counteract the force of gravity. The star's enormous gravity causes the star to suddenly shrink in size. Gravity crushes the mass of the star in a mighty collapse. Scientists think this causes a supernova explosion, along with the formation of a black hole. Much of the star's mass is blasted off into space, but the remaining mass then collapses into a state of infinite density called a black hole.
What happens to all that matter once this black hole forms? This is a matter for speculation; no one knows for sure. There are many exotic speculations. One speculation advanced by more than one scientist is that when black holes are formed, they create a spacetime wormhole. The idea is that the matter lost in a black hole travels through a wormhole, and then suddenly appears elsewhere in the universe. Such a sudden appearance has been called a white hole. Of course, this idea is pure speculation, and there is no evidence for white holes. But let us consider what the consequences might be if white holes were to be created from the creation of a black hole.
If a white hole were to be created, one possibility is that we might suddenly see a gushing of matter coming out from some point in space, perhaps some point in interstellar space. But we've never observed anything like that happening. So let's consider another possibility.
Another possibility is that once a white hole is created from a black hole, the white hole then immediately collapses to become a black hole again. This would make sense from a gravitational standpoint. Imagine if a star of 10 solar masses were to collapse, causing 7 solar masses to collapse into a black hole. That might cause the appearance of a white hole elsewhere in the universe. But an instant after that white hole appeared, you would then have 7 solar masses suddenly existing in some small area. Gravity would then probably cause all that matter to collapse in a process similar to the process that produced the original black hole.
We are led, then, to a fascinating possibility – the possibility of “ever-bouncing” black holes. The creation of a black hole might be the beginning of a process that works like this:
Because many black holes have been created in the history of the universe, if this “ever-bouncing” black hole theory is true, then white holes could be appearing at various points in the universe millions of times every second.
At this point the reader may well be thinking: well, that's a fascinating idea, but it is no reason for thinking that the sun may suddenly vanish – because the sun is not a supermassive star of the type that becomes a black hole.
It is true that the sun will never become a black hole purely because of its own gravity. But if this wild theory of “ever-bouncing” black holes is correct, then the sun still might be in danger. This is because when a white hole appears from the creation of a black hole, the white hole could randomly appear within the volume of the sun.
If we assume that a white hole appears at a random position in space, it is overwhelmingly likely that the white hole would appear in interstellar space, the space between stars. But there is a very small but nonzero chance that the white hole could appear in the worst possible place – right in the very volume of space that the sun occupies. Who knows, there could be some strange relativistic reason why a white hole is more likely to appear where there is already matter, perhaps something along the lines of matter being attracted to matter.
If such a white hole were to suddenly appear within the volume of the sun, it would be as if the sun were to suddenly acquire a mass many times greater. Most of that mass would be material that could not be used for nuclear fusion. So rather than suddenly becoming much brighter, the sun would suddenly be like a super-massive star at the end of its lifetime, about to collapse into the super-density of a black hole. Shortly thereafter, the sun would presumably collapse to become a black hole. There might or might not be the flash of a supernova explosion. Then the sun would vanish.
Imagine what it would like for you if this were to happen. You might go to work one day at the office. Then in the middle of the day, people would suddenly start shouting, as they noticed that it was inexplicably dark outside. Some people would say: “Wow, I didn't know there was a total eclipse today.” People would wait for the supposed eclipse to end. But the sunlight would never return.
People would gradually realize that the sun was gone forever. There would then be a desperate struggle, as everyone tried to gather up food, clothing, and generators that might allow them to survive as long as possible in the cold. It would soon become colder than the North Pole. Crops would stop growing. Remnants of the human race would probably be able to survive for a few months longer until the food and fuel ran out. A few lucky ones might even be able to survive for a few years.
Of course, the chance of this happening is extremely remote, but it is interesting to realize that there are theoretical reasons why the sun might suddenly vanish at any time. I don't know what effect such speculation has on you, but I, for one, am going to take serious measures to protect myself from this theoretical cosmic menace.
I am going to go out right now and buy myself a nice pair of wool mittens.
The sun might vanish at any time because there is a very small chance that a particular theory I will now describe is true. If this theory is true, the sun might instantly disappear at any time.
The theory I mention is a theory involving black hole collapses. To explain that theory, I must first discuss why scientists think that black holes are formed. Scientists say that black holes are formed when very massive stars begin to collapse, with the collapse being caused by the enormous gravity of the star. A star that is more than five times more massive than the sun has a tremendous gravity many times higher than the gravity of our planet. But such a star emits lots of energy through thermonuclear fusion, and that causes an outward force that balances the inward force caused by the star's gravity.
But when the star nears the end of its lifetime and runs out of hydrogen and usable helium to burn as nuclear fuel, then there is no longer any outward force to counteract the force of gravity. The star's enormous gravity causes the star to suddenly shrink in size. Gravity crushes the mass of the star in a mighty collapse. Scientists think this causes a supernova explosion, along with the formation of a black hole. Much of the star's mass is blasted off into space, but the remaining mass then collapses into a state of infinite density called a black hole.
What happens to all that matter once this black hole forms? This is a matter for speculation; no one knows for sure. There are many exotic speculations. One speculation advanced by more than one scientist is that when black holes are formed, they create a spacetime wormhole. The idea is that the matter lost in a black hole travels through a wormhole, and then suddenly appears elsewhere in the universe. Such a sudden appearance has been called a white hole. Of course, this idea is pure speculation, and there is no evidence for white holes. But let us consider what the consequences might be if white holes were to be created from the creation of a black hole.
If a white hole were to be created, one possibility is that we might suddenly see a gushing of matter coming out from some point in space, perhaps some point in interstellar space. But we've never observed anything like that happening. So let's consider another possibility.
Another possibility is that once a white hole is created from a black hole, the white hole then immediately collapses to become a black hole again. This would make sense from a gravitational standpoint. Imagine if a star of 10 solar masses were to collapse, causing 7 solar masses to collapse into a black hole. That might cause the appearance of a white hole elsewhere in the universe. But an instant after that white hole appeared, you would then have 7 solar masses suddenly existing in some small area. Gravity would then probably cause all that matter to collapse in a process similar to the process that produced the original black hole.
We are led, then, to a fascinating possibility – the possibility of “ever-bouncing” black holes. The creation of a black hole might be the beginning of a process that works like this:
- A super-massive star
collapses to become a black hole.
- The black-hole creates a
spacetime wormhole, which causes the appearance of a white hole
somewhere else in the universe, as the mass from the star collapse
reappears elsewhere.
- The matter coming from
that white hole is so dense and concentrated that it very soon
collapses to become another black hole.
- That black-hole creates
a spacetime wormhole, which causes the appearance of a white hole
somewhere else in the universe.
- These steps keep
repeating over and over again endlessly, ad infinitum, forever and
ever.
Theory of ever-bouncing black holes
Because many black holes have been created in the history of the universe, if this “ever-bouncing” black hole theory is true, then white holes could be appearing at various points in the universe millions of times every second.
At this point the reader may well be thinking: well, that's a fascinating idea, but it is no reason for thinking that the sun may suddenly vanish – because the sun is not a supermassive star of the type that becomes a black hole.
It is true that the sun will never become a black hole purely because of its own gravity. But if this wild theory of “ever-bouncing” black holes is correct, then the sun still might be in danger. This is because when a white hole appears from the creation of a black hole, the white hole could randomly appear within the volume of the sun.
If we assume that a white hole appears at a random position in space, it is overwhelmingly likely that the white hole would appear in interstellar space, the space between stars. But there is a very small but nonzero chance that the white hole could appear in the worst possible place – right in the very volume of space that the sun occupies. Who knows, there could be some strange relativistic reason why a white hole is more likely to appear where there is already matter, perhaps something along the lines of matter being attracted to matter.
If such a white hole were to suddenly appear within the volume of the sun, it would be as if the sun were to suddenly acquire a mass many times greater. Most of that mass would be material that could not be used for nuclear fusion. So rather than suddenly becoming much brighter, the sun would suddenly be like a super-massive star at the end of its lifetime, about to collapse into the super-density of a black hole. Shortly thereafter, the sun would presumably collapse to become a black hole. There might or might not be the flash of a supernova explosion. Then the sun would vanish.
Imagine what it would like for you if this were to happen. You might go to work one day at the office. Then in the middle of the day, people would suddenly start shouting, as they noticed that it was inexplicably dark outside. Some people would say: “Wow, I didn't know there was a total eclipse today.” People would wait for the supposed eclipse to end. But the sunlight would never return.
People would gradually realize that the sun was gone forever. There would then be a desperate struggle, as everyone tried to gather up food, clothing, and generators that might allow them to survive as long as possible in the cold. It would soon become colder than the North Pole. Crops would stop growing. Remnants of the human race would probably be able to survive for a few months longer until the food and fuel ran out. A few lucky ones might even be able to survive for a few years.
Of course, the chance of this happening is extremely remote, but it is interesting to realize that there are theoretical reasons why the sun might suddenly vanish at any time. I don't know what effect such speculation has on you, but I, for one, am going to take serious measures to protect myself from this theoretical cosmic menace.
I am going to go out right now and buy myself a nice pair of wool mittens.