As Bishop Berkeley noted, skeptics find us to be ignorant.
Berkeley could agree that we are blind to the true and real.
Everywhere and for anything, something there is that is beyond
the power of our comprehension. As Newton wrote - "what
the real substance of anything is we know not". Newton
in his Opticks felt gravity was of a manifest quality but that
its cause (Hume be damned) was of the occult. By use of the
occult he meant a hidden cause. For as far as others could go
on about a cause for gravity, they used attraction. A mechanical
cause, in other words, would suffice. This came down to ideas
causing ideas, but that didn't stop them.
Newton was uncomfortable about the linking of gravity and attraction.
Newton thought the cause of gravity was real but not material.
He wanted to avoid action at a distance. This inconsistently
necessitated, mechanically, an agent and that was the "aether".
How else to prevent a loss of affect? (How could you or I have
ideas, and think so that the thought could have an effect -
an action? If you read what Plato wrote and act on it, isn't
that action at a distance or, if you will, a contemporary writes
it, you read it, and then you act?) But Berkeley wanted causation,
in general, to go away. He replaced it with analogy and similarity.
He agreed gravity was universal but that it did not control
what did not yet exist. Newton agreed.
In regard to matter of whatever description, those
favoring attraction found matter proportional to gravity. Gravity
itself presupposed extension. If matter, extended, were to be
bound up with gravity, then matter needed a base, a support, something
to rest on. It couldn't just "be" but it couldn't have
Berkeley went so far as to find attraction to be of the human
world, a metaphor if applied to the inanimate. Things fall unaided.
Enough said. If we go on into causation, with attraction, we
(hello Hume) come to a lack of a sensible quality. It is of
the Newtonian occult, best not go there. Not by occult is meant
black magic but a hidden, unknowable agency. To remain in the
sensible is to have it as good as it gets and the skeptics can
be safely ignored. Stay clear of methodologically useful fictions.
They do try to reassert themselves via force and matter and
the magic vase of Circe so notes Berkeley in his comments on
Torricelli. The vase is matter and it contains force. It contains
the gravitational force which has momentum which requires velocity
which requires motion. Gravity is said to be in acting though
no motion be apparent. If suddenly motion appears then the conclusion
is formed that it had to be there at the time previously. How
far back in time must one go? How far back in spacetime? Newton
did not bring together time and space. For him attraction as
per gravity was a mathematical hypothesis. Einstein put gravity
on a geometric footing. Gravity, for him, was curvature, a curvature
of spacetime. Did spacetime via Einstein go beyond hypothesis?
It is today certainly not taken as other than a sensible quality
and gravitational waves are said to be warps in spacetime.
The warped Earth in spacetime is subject to a
force it applies to itself. So it weighs less than it should.
Putting the subject this way presupposes gravity and Earth are
one and the same. That is, as if Earth owned, so to speak, its
gravity. Rather odd, but the alternative is to have no connection
for Earth and gravity. The actual presupposition is for gravity.
Gravity comes first and always is in existence. Then comes Earth
and all else. Gravity is ubiquitous, Earth is not. If one says
"Earth's gravity" one must mean gravity as applied to
Earth. Gravity can get along quite well without Earth but Earth
can't do without gravity, or, can't exist without gravity.
Then the newer, compared to Berkeley and Newton's concerns,
bedrock for us is not ether but a spacetime - a spacetime that
is supportive because it is curved. It seems that a flatline
would represent no existence. Spacetime is nothing unless curved.
One occurrence involving spacetime is gravity. A further occurrence
thereafter is Earth. The Earth can be a familiar globe or the
teeming foam of the quantum stage. In the latter case, spacetime
provides no support. If one must have a support for the quanta,
then it can't have a size. The Earth and all other occurrences
for spacetime have a size as attribute. For the quanta, size
does not matter. Occurrences there do not partake of objects.
(Can these non-objects be related to us? We have quantum effects
at work for us every day. They are of the same Universe are
they not? Presumably, yes we are of the same Universe. Though
now, if of the quantum world, we can't safely speak about them.
Since there are quantum effects then there must be quanta. But
as far as we are concerned, now, they are functioning without
support, no bedrock. This could be all to the good to be able
to get away at long last from mechanics and into a quantum zone
that has no need of supports. But, then, it may be beyond our
Within our description are gravitational waves
that are changes in the pre-existing curvature of spacetime. No
one has detected gravitational waves (G waves). It has been argued,
and a Nobel Prize in Physics was awarded, on indirect evidence
of their reality in the Hulse-Taylor binary star system.
The Hulse-Taylor binary system is a special case
of stellar interaction and G waves themselves are special cases
of manifestations of change of position of objects in the Universe.
Gravity is everywhere; it is what "is" without question
anywhere and anytime. But G waves aren't all that common, they
are sometimes and somewhere present. With G waves one has found
an effect of acceleration of certain objects under certain conditions.
Earlier on, in Newton's time, the acceleration was a given. In
the realm of G waves it is a must. Finding G waves doesn't mean
J. Weber (I)
G waves were allegedly found in the 60s by Joseph Weber. He
found a great many G waves at what were rather high rates. His
devices are now called Weber bars. They are large solid bars
of metal isolated from any and all outside interference. At
least, it is asserted that they can be free of interference.
Joseph Weber became a pariah of the physics community because
of his adamant repeated declaration that his G wave detectors
were proving the reality of G waves. Others did not think this
to be the case and others did not find this to be the case.
His bars were to be strained by the passage of G waves. The
strain could cause the bar to resonant at a characteristic frequency
and then it could be amplified. His claims were violently disputed
in the 70s. The principal detractors were Richard Garwin and
David Douglas in 1974.
G waves and interferometry
Since the 70s the bars have been updated with cryogenics and
quantum devices. Only extremely large gravitational effects
can be recorded by these bars. Presumably lesser waves can be
noted by using laser interferometry involving objects of detection
that are far apart. A wide range of frequencies are detectable
as opposed to a Weber bar's resonant frequency. The wide ranges
are sought from equipment spread over miles. LIGO, for example,
has an interferometer at Livingston, Louisiana, and two more
at Richland, Washington. LIGO, Laser Interferometer Gravitational
Wave Observatory, is the most sensitive wave detection hopeful
among the world's interferometric G wave operations. Beyond
the world, in orbit, could be G wave detectors of the future.
Earth bound interferometry is beset by various problems like
shot noise that is random photons, thermal noise, seismic noise,
crackle and pop from electrical atmospheric storms, the groan
of stressed mechanical structures, and man-made activities that
generate occasional interference.
G waves do not propagate through spacetime, they are alterations
of spacetime, as oscillations. Einstein's general theory of
relativity has gravity not as a force. Spacetime can be distorted
or curved by the presence of massive objects. So is spacetime
prior to mass or simultaneous or synonymous? Note that "prior"
relies on time but we have spacetime. Can anything be prior
to spacetime? In the old sense, what is prior to time is like
asking what is prior to prior. When a person is writing about
"curved" spacetime, "ripples" in spacetime
and so on this is implied via imagery to be curvature or rippling
of space. How does one curve or ripple time? But of course the
error is to separate space and time. (But if spacetime is rippled
or curved then it has structure. A structure has support. But
then this way of thinking is erroneous and spacetime has no
structure, no support. No physicality, no reality. It is a mathematical
entity, an hypothesis. Existent only.) The ripples in spacetime
are very weak. They are a travelling distortion of the geometry
of space. Such ripples will jiggle any physical body it encounters.
This jiggling occurs in space. But spacetime, as a concept,
means time is jiggled too. What is jiggled time? Jiggled space
is easily enough made known. Weber was looking for jiggled space.
But G waves are jiggles in spacetime.
To detect jiggles in spacetime, Weber of the University of
Maryland in College Park used solid aluminum cylinders, about
2 meters long and 1 meter in diameter and suspended them on
steel wires. G waves would set one of these cylinders vibrating
at its resonant frequency - at about 1660 hertz and piezoelectric
crystals attached to the cylinder would convert that resonance
into an electrical signal. Weber claimed that his setup had
only one source of noise and that was from random thermal motion
of the aluminum atoms that made up his bar. This noise would
have made the bar vary in length by, at most the diameter of
a proton. This less than a proton diameter was a dimension he
said he had often found exceeding a threshold for occurrence.
This threshold was a moving target. Sometimes it was at one
level then another. Also, the threshold, once located, wasn't
precise. So a fuzzy threshold was a cross he had to bear.
That he was so afflicted would not be evident for some years.
He continued to time and again find an abundance of G waves.
In 1969, by then using 2 detectors separated by hundreds of
miles, he announced that both detectors were receiving G waves.
He noted such a plethora of signals should not usually come
about for thousands of years. In 1970 he was recording more
and more G waves and, more startling; they were coming from
the center of the Milky Way. To verify and validate Weber's
reports others built Weber bars and found nothing like what
Weber was getting. It was thought that Weber, since he was an
electrical engineer before he became a physicist, wasn't conducting
proper data analysis. As with his thresholds, the analysis wasn't
defined properly and allowed for subjectivity to enter. Also,
some theorists of the time were caught off guard by the signal
strength and the number of signals found. If Weber was correct,
then astrophysics, if not basic physics itself, would have to
be rewritten. In the hippie-dippy tenor of the times, such was
seen as a possibility.
As noted, the possibility of the experimental pursuit of G
waves began with Joseph Weber. The main account of his efforts
to establish the reality of G waves comes from Harry Collins's
book, "Gravity's Shadow, the Search for Gravitational Waves".
Mr. Collins also wrote of the opposition of Weber's discoveries.
Mr. Collins also wrote on sociological methods as they pertain
to the yes or no of G waves. Mr. Collins produced text that
has a sprawl derived from diversions that are perhaps feints
in regard to the subtitled search. One feint could be noting
that Weber's detection of G waves gained some traction from
being announced during an era of American physics when, in America,
soldiers returning from Nam were routinely spat upon. Pot smoke
floated thick around protests and demonstrations. Law and order
had no place in a promiscuous counterculture. The cultural boundaries
for literature, film, medicine, physics, politics and most other
expressions of thought were ended. There was at least a pseudo-youthful
feverish rush to many activities like into certain sections
Mr. Weber was already there and he was successful, at least
in his mind, about having found G waves. Until 1960, all was
theory. No one conceived of an apparatus that could find G waves.
He most certainly wasn't making it all out of thin air. But
what was it? G waves, per the Universe, should be abundant.
Well then they could be weakly, very weakly, abundant. Even
if very weak, still the Universe is rather formidable as to
number of objects in various categories. (But could G waves
found by Weber's unreliable detectors or otherwise vanish by
an effect akin to Olbers paradox?) In 1962 a Weber detector
in operation from 5:30 AM May 12 to 6:30 AM 48 hours later recorded
an off scale event. Another off scale event had happened on
May 8 to May 9. On the one hand such a detected magnitude meant
a momentous discovery of a stunningly great energy source. On
the other hand, it was concluded that it could be noise.
Either it was noise or it was something out there vastly asymmetric
that had happened. Neutron stars in binary format at the end
of their orbit could give rise to a powerful quiver. Unfortunately,
for Weber, many others over the years had come to think all
that he knew to be G waves were noise - be it experimental or
mental. There was a span of time in which he had the G wave
detector field to himself. Any and all of his detections later
became suspect and a chance of a once in 1,000 year possibility
might have been detected but that was before others pronounced
it impossible. If he found a lot of signals, his threshold of
detection could be said to be too low. If he raised the threshold,
fewer signals resulted and they were too few for too many of
the later researchers. Some had gotten positive results supporting
Weber but they did not want to be seen as backing the wrong
As criticism mounted, Weber came up with the idea
of having a time delay inserted into analysis of coincident signals
from two detectors. Also, his bars should have been preferential
in detection from differing directions. He found they were doing
so. Likely too, if they were G waves, they would produce data
reoccurring in sidereal time and not solar time. He found that
also. He did data analysis for delay, direction, and time with
differing statistical methods. One method could give better results
than another. If a still better outcome could be found, then that
method was used. Picking the best doesn't mean one is using the
best. This is known as statistical massage. Weber would not get
on the same page as others who used, for example, an amplitude
signal-processing algorithm while he continued to use an energy
algorithm. Others used electrostatics to put in false signals
to test their apparatus but Weber wouldn't do it.
To better understand Weber's battles and their outcome, Mr. Collins
wanted to resurrect à la Proust the combat down to the
level of skirmishes. At such a level, Mr. Collins could and did
participate in the action. Fully engaged, locked and loaded, he
found out about G waves through hearsay and socialization from
those prominent in G wave research. But without a doubt, Weber
was Mr. Collins's main man. Weber died September 31, 2000. He
was 81. Besides the U of Maryland and U of Cal at Irvine, he had
been at the Institute for Advanced Study at Princeton where he
was affected by Oppenheimer and Wheeler. Dyson had pushed him.
Weber's research flourished when it was a solitary or nearly
solitary game. Many potential researchers refused or at least
were very reluctant to get into the game since getting meaningful
results would be almost impossible. Perhaps they had read Epictetus
- "Men are harried, not so much by things, as by their
notions of things". Once the field of researchers engaging
in the detection of G waves got even a few entrants then competition
started. Competition was inevitable given that the object of
the game was to catch a faint signal, a ghostly one or a shadow
of a presence and to do so repeatedly or without question.
Weber was free at the beginning of the game to pick a threshold
for the signal. If that threshold was reached or surpassed then
he had an occurrence. The other early researchers came in the
game and picked other thresholds. All of them, freshly active,
could get along by doing it themselves and spending in the low
thousands. Later, they needed hundreds of people and spending
was in the millions. This transformation in quantity of personnel
and money altered the expectation of what results counted for
anything. The game of the ghost, find the ghost, or alternatively
let the recordable shadow fall across the apparatus had to be
repeated nor lack a question as to if it was fact, now altered.
Without the new facts, the merits of the data a researcher
could get were judged acceptable or not based on personal qualities
of the researcher or an opinion about that person's country
or institution. If the experimental outcome could not drive
the science, the theoretical aspect took control and then the
theoreticians asserted that only certain results were valid
or could become valid. To quality as acceptable came to mean
satisfying the theoretician, never mind what your apparatus
was doing. Scientific determinism, "causally constipated"
was brought to bear on Weber. This is a "democracy of physical
causes" that puts the execution of Caesar and the starting
of Brian the Bulb on the same footing.
Weber went beyond the apparatus to obtain the means by which
the apparatus could be supplying the data he was getting and,
later, what he expected. He thought his detectors were more
sensitive thanks to metastable states and multiplication factors.
No one bought this. Nevertheless some G wave researchers were
quite willing to release two sets of data, one of which was
false. Imagine Newton or Einstein adopting such a procedure.
Weber didn't knowingly publish papers having false data so as
to fake out others. The false data people gave the sets out
as a test. Post docs and full professors were being tested.
Did they get at least a passing grade? Some must flunk, as always,
lost and forgotten to science because the huge interferometer
projects had to have someone seen to fail in order for the project
to survive. It had become a Congressional funding matter in
the millions of dollars. A little old cryogenic bar simply must
not call into question the vast and primly proper enterprise
of interferometic detection of G waves.
This nefarious sort of activity is not science. If G waves
are under scientific discussion then such activity is unwarranted.
Mr. Collins relates how Garwin and Levine could pave the way
for the interferometer crowd by experimenting with apparatus,
on the scale of a toy some said, devised to most thoroughly
discredit Weber. Mr. Collins puts it in stronger terms but the
foregoing will suffice. A change in Weber's reality by Weber
acting upon himself was desired, to be imposed on him, if necessary,
by external controlling agents. Can you spell "revisionism"
as in the style of the Soviets?
How does science or its lesser but more virile
relation, scientism, proceed? Mr. Collins quotes Planck's dictum
of "science progresses funeral by funeral". Once the
Old Guard gives up the ghost, or shadow, we can get on with it.
Actually, the reputation for and activating of scientific demise
can proceed death- as it happened to Weber. It was aided by snobs
acting like high school kids and abetted by bullies acting like
grade school kids. Onward the scientists rocket with some caught
in research programs of institutions having their own "financial
and cognitive" agendas. In the G wave field they teeter into
disbelief and defenders have recourse to the implausible. Nevertheless,
was there any doubt that the "inferometeers" would prevail
against the "resonateers"? Meanwhile sideshows erupted
that maimed all concerned as in the Vogt-Drever nonsense (as related
by Mr. Collins) demonstrated in the LIGO scheme of things. Such
sober (?) scientists carried on most reprehensively.
Enough already. For heaven's sake, where are the G waves? They
haven't been found. The science, such as it is, has to be sifted
out of the personalities, money, politics, double-dealing, statistical
massages, scheming, and bad luck. An A for effort doesn't cut
Wo ist das spacetime?
All this is beside the point if spacetime isn't
real. Maybe it exists, as concept and mathematically useful. That
could be as far as it goes. In "A World Without Time"
by Yourgrau, with an emphasis on time in what follows, Yourgrau
states Einstein defined time in terms of its measurement with
clocks and so set a limit. Time became no longer an absolute;
it was limited to a frame of measurement. Einstein transformed
time into space. Many others maintain something similar.
Yet it has been noticed that Einstein in a review of Meyerson's
"La déduction relativiste" praised Meyerson
for not doing a spatialization of time. Time and space, said
Einstein, are fused into one continuum but the continuum is
not isotropic. The element of spatial distance and the element
of duration were to remain distinct in nature. Yourgrau, in
regard to time as space, stated Einstein was inconsistent for
a philosophical assessment of the mathematics of relativity.
Yourgrau also notes Einstein was in agreement with Meyerson
that the temporal component of spacetime was not a fourth spatial
dimension. However, there is the rigid 4-dimensional space of
special relativity. Einstein, Yourgrau further states, mentioned
that past, present, and future have only the significance of
a stubborn illusion and that "now" means something
which physics cannot speak to. (Aristotle, in the Nicomachean
Ethics, described an instant as not a part of time since it
is not extended, not an interval, and does not have duration.)
Kurt Gödel, the main subject of Yourgrau's
book, went on many walks with Einstein at the Institute. Gödel
had found that by relativity's lights, one could revisit the past.
But then if so, it has never "passed". A time that fails
to pass is not time at all. Kant, Einstein, and Gödel knew
space and time were the fundamentals of human experience. But
it was space that was the natural object of scientific inquiry.
There is also motion. This is change of position and position
could, in error, be said to be in space. But there is no place
to put the position (or as they came to be, points) in anything.
There is no supporting structure, no mechanical props. No ether,
no absolute space or absolute time, no spacetime - if they must
be real to support action at a distance or what have you.
Yougrau maintains that Einstein and Gödel well knew that
time, not space, poses the greater scientific challenge. The
dynamic nature of time, the fact that it flows, is its most
striking feature. Kant, thinking of time, made it into an analogy.
Science is geometrical in that it puts all it deals with subject
to space. Time, in order to be dealt with, is done by analogy.
So time, scientifically, becomes spatial. Einstein geometrized
(he could not timetrize) physics and time got into spacetime.
It became a fourth component. But then matter had to enter and
then came general relativity but the Universe was found to expand,
expanding over time. Special relativity has simultaneity as
not absolute. It is local and relative. So how could the Universe
be expanding, absolutely, over time? Einstein's metaphysics
has the speed of light in the definition of time and motion.
Time was relative to the motion of the observer and frames related
to the speed of light. For the formalism of physics Einstein
abandoned intuitions of space and time.
Yougrau finds that the advent of relativity enabled one for
the first time to question the reality of time into a theoretical
context amenable to formal mathematical methods. Are there the
ontological implications of relativity such as can one maintain
both the existence of intuitive time and the truth of relativity
theory? Special relativity was epistemologically (the speed
of light) inspired. Einstein had drawn ontological conclusions
from epistemological premises. Then Gödel wanted to answer
the question - is the temporal component of the fourth dimension
of spacetime really time?
Yougrau reports Gödel put together a world model for the
equations of general relativity that had a geometry so difficult
that the temporal component of spacetime could not reasonably
be seen as representing intuitive time. His spaceship, and he
calculated the fuel it needed, would travel so that B was before
A in time. So Gödel reasoned that the spacetime of his
world was a space and the time component of spacetime was another
spatial dimension. It was not the time of our ordinary experience.
Gödel found nothing wrong with relativity. It is intuitive
time that has the problems. Time is illusory if it is intuitive
Time, our time, is usually thought to have three
parts. Two of the three are illusory in that they are not real.
They are the past and the future. The third part is the present.
Just how real is spacetime? How much of the present does it partake?
Nothing. None of Einstein's calculations pertaining to spacetime
are real. That is so if your preoccupation is with intuitive time.
A horse of a different color comes into play if the concern is
with time as a fourth dimension integrated into 3-D space.
Clocks in Einstein's world aren't the ones on the mantelpiece
or those in towers like the one in Muri he gestured to as he
spoke to Besso. They are a starting point, finally they become
of a time "t" not like them. It is illusory that they
be the same. We are of the now or more properly we were "now".
We have been of the now. Einstein's time is one of measurement,
always of the past. How do we know this? Memory.
Memory is first, last, always. It is who we are, it is them,
and it is what is. It is it. Memory remembers. For a long time
we have known of short term and long term memory. What of the
fastest memory - of what we perceive constantly? The memory
of perception. But then memory is usually referred to in the
context of remembering. It is a memory that we have memory of.
Einstein's clocks and, to a lesser profundity for most of us,
time is of the perceived, the perceptive world. This perception
is a fleeting and fleeing memory. Memory is imposed on us. It
is involuntary. Undoubtedly one can suppress memory. One can
improve it too but it was there to start with.
Yourgrau's book portrays differences in philosophical
stances of some scientists. Realism and idealism are described
in his book. They are equivalent to differing degrees of consensus,
a consensus of memory. Having the most consensus is realism. Less
of a consensus is there for idealism. Any consensus is one of
individuals. All is subjective though consensus must be found
for Others, for objectivity and, thus, the real world. Motion,
such as it is, is memory. Memory it IT, there is no other. We
remember "change in position", we "perceive"
via memory. We have consensus via memory. Thus comes "reality."
We remember sounds and so comes language. We remember symbols,
letters and words, and we write. So we communicate. Many people
revel in how defective is our memory. Well then, we aren't "we".
Is this all too much a truism? We glide or bump along taking
it for granted that "it" is what is, given to us.
See, hear, touch - but it all comes from memory. Memory is extremely
pervasive. There is no getting outside it. It is involuntary.
It "comes with the territory" - however you twist
and turn, no other, no choice. If you have memory, this is it.
Without memory you are done. You aren't "you" and
you simply "are not". If our "objectivity",
your reality, is apart from memory (however that could be arranged)
then it is false.
We must have memory and then "remember"
in order to know we are thinking. Thinking doesn't require knowing,
"perceiving" - memory at its quickest. But to know we
are thinking is to remember. We recall the perception, we think
of it, with it, compose a memory, then we remember that.
Time itself isn't remembered. What was is remembered.
What is, is what we generalize (not conceptualize) as "space".
Occurrence is memory, remembering an occurrence is memory. There
is quick memory and another memory. The only route to reality
is through memory. Remembering memory, as it were, is time. There
is no "time" except as concept, nor is there "space"
unless as concept.
Unfound gravitational waves searched for diligently
by hundreds with millions of dollars at their disposal can produce
excursions into the weird. Such excursions come about because
hundreds are at it and millions go unrewarded and because the
waves are elusive and because theory says they must remain so.
JASON reported in 2008 on high frequency gravitational
waves. The abstract reads:
"JASON was asked by staff at the National MASINT Committee
of ODNI to evaluate the scientific, technological, and national
security significance of high frequency gravitational waves
(HFGW). Our main conclusions are that the proposed applications
of the science of HFGW are fundamentally wrong; that there can
be no security threat; and that independent scientific and technical
vetting of such hypothetical threats is generally necessary.
We conclude that previous analysis of the Li-Baker detector
concept is incorrect by many orders of magnitude; and that the
following are infeasible in the foreseeable future: detection
of the natural "relic" HFGW, which are reliably predicted
to exist; or detection of artificial sources of HFGW. No foreign
threat in HFGW is credible, including: Communication by means
of HFGW; Object detection or imaging (by HFGW radar or tomography);
Vehicle propulsion by HFGW; or any other practical use of HFGW.
For the relatively weak fields in the lab, on the Earth, or
indeed in the solar system (far from the cutting-edge science
of black holes of the Big Bang), the general theory of relativity
and its existing experimental basis are complete, accurate and
The report in its later sections touches on the
Li-Baker fractal membrane that is immersed in a Gaussian beam
of microwave energy. The optics used can be equivalent to "allowing
free divergence of the photons without optics at all". JASON
affirms that no magic is involved and that the calculations are
ridiculous or grossly wrong. They regard benefits and applications
as unlikely and submit that actually use of the word "unlikely"
is concluded to be "a totally inappropriate exaggeration".
Shadow ghosts can be dark gray to black. They
are earthbound. They are extremely evasive though cats and birds
easily sense them. Some shadow ghosts have hats. They can be found
with detectors powered by AA batteries that sound a tone when
detection is successful. The detectors come with instructions
about how to conduct a ghost hunt.