The loudest known sound, recorded in modern times, was the eruption in 1883 of the volcanic island of Krakatoa, located in the Dutch East Indies. The volcano erupted with such force that it could be heard in Australia, two thousand miles away. The explosions lasted for 36 hours, and blew off half the island. The final outburst had enough sound energy to circumnavigate the Earth 7 times before it eventually dissipated.
The softest sound which can be detected by the human ear occurs in the range of about 0 to 5 decibels, which is equivalent to the sound of air molecules moving inside the mouth of a drinking glass. By definition, the softest sound that can be detected by an acoustic sensor requires the minimum amount of energy which is necessary to produce a vibrating wave motion in a medium.
The highest sounds, known as hypersounds, are generated at frequencies which vibrate at billions of times per second. These microcycles include the oscillation of the tiniest known particles of matter.
The lowest sounds are produced by large objects, and are known as infrasounds. Infrasounds have very long wavelengths with a single vibration occurring within a period of millions of years. These include planetary, interplanetary, stellar, galactic, and intergalactic cycles. The very lowest sounds are generated in large intergalactic gas clouds caused by the galactic wind and stellar explosions.
Normal sounds propagate through the air at sea level at a speed of about 1100 feet per second, or 750 miles per hour. Sounds travel faster in liquids, faster still in solids, and fastest of all in hot gases known as plasmas. The fastest sounds propagate at supersonic speeds within a range of several thousand miles per second, to hypersonic speeds which approach the speed of light. The very fastest sounds are plasma waves which propagate in a low-density medium such as the upper atmosphere of a planet or the stellar wind, or high-density sounds which travel within the interior of stars, or are generated by chemical and nuclear reactions.
Slow sounds propagate at subsonic speeds, which range from several feet per second to several hundred feet per second. The slowest sounds form standing wave patterns in the place where they are generated. Standing waves do not travel through a medium like normal sound waves, but remain at or near their source, such as the wave patterns which are formed on the head of a drum. In a standing wave pattern, the frequency of the wave or waves is the same as its traveling speed. The frequency and the velocity of the wave are identical because the wave is traveling through space in a recurrent, orbital path. Global standing wave patterns include large-scale geological, ecological, biological, social and cultural cycles. The very slowest sounds include the spins, orbits, beats, and lifecycles of the largest astronomical bodies, such as galaxies, intergalactic gas clouds, galactic groups, clusters, and superclusters.
The shortest sounds are those which can generate enough energy from a sound source to form a wave pattern.
Sounds with the longest duration are known as solitons. Solitons form atypical waves such as a tidal bore, which may travel for miles down a narrow river or stream. Normally, sound waves spread-out then disperse very quickly as the distance from their source increases. However, when the dispersion of the wave is exactly balanced by the tendency of the wave to narrow, the sound will keep on going.
The most resonant sounds result from the perfectly regular rhythms of stars known as cepheid variables. Cepheid variables alternately expand and contract to as much as 30 percent of their normal size. These regular changes in size are accompanied by changes in brightness, temperature, and spectral type.
The most irregular rhythms belong to the complex sound waves which form so-called white noise. By definition, noise contains waves of different frequencies, any of which has no multiple or submultiple relationship to the others.
The most characteristic sounds are those which are uniquely expressive or familiar. Normally, an expressive musical pattern or phrase is underlined by psychological tensions which directly confront the emotions of the listener. The familiar childhood ridicule "Nah, Nah-Nah, Nah, Nah" or the most sublime melodies of Schubert or Mozart are extreme examples. Individual sounds with deep psychological associations will also create a strong impression, such as the sound of a crying baby, or the roar of a wild animal.
The least characteristic sounds are those which are void of emotional or intellectual tensions, or sounds that fail to engage our attention at all. These sounds may be physically soothing, such as the constant lapping of ocean waves on the beach, flat monotonic utterances of speech, or commercial ambient sounds.
The most intense sounds are shock waves. Shock waves travel at supersonic speeds and are produced by small disturbances such as the bursting of a balloon or small explosion, or by large disturbances such as a flash of lightning causing a thunderous sound, a foreign object such as an airship or meteorite traveling at supersonic speed, or by various chemical or nuclear explosions. The most intense sounds are standing shock waves, produced by the rotation of stars or galaxies, and by stellar explosions including supernovas.
The most reposed sounds are those which are least energetic. These may include slight ripples on a pond produced by a gentle breeze, the infinitesimal movement of molecules on a still day, or the slightest interaction of particles in a magnetic field.
The simplest sound is a pure tone, or so-called sine wave. Most sounds consist of many sound waves containing different vibrations, while a pure tone contains only a single vibration.
The greatest density of sound on Earth may occur in the tropical rain forest, where millions of sound-producing creatures are packed into a single listening environment. Although, rush-hour in any major city of the world will produce an impenetrable cacophony of sound.
Microacoustic waves are the smallest known sound waves. The smallest sounds on Earth are generated spontaneously by heat fluctuations of the trapped particles within a normal sound wave. In addition, microacoustic waves are generated by spontaneous vibrations within the bone structure of the middle ear, and in plasmas and superconductors.
The largest sounds are macroacoustic waves which are large-scale oscillations that are generated within, on, or near planetary bodies, stars, and galaxies, including large-scale disturbances of a planetary atmosphere, hydrosphere, or lithosphere. These oscillations include global weather patterns, ocean waves, and seismic waves, as well as solar waves, large-scale fluctuations of the solar wind and interstellar dust clouds, and galactic waves.
Imagine the very first sound on Earth. The first sounds used for the purpose of communication on Earth were probably made by insects.
Imagine the last sounds on Earth. Imagine the sounds of a collapsing solar system. Imagine the final sounds of an exploding or imploding universe.
J. H.
Sunrise on Mars
2.23.2009
2.21.2009
Procrastination (Week 2)
It is a curious phenomenon
that virtually all humans
procrastinate continuously,
in one form or another,
throughout their lifetimes.
It is equally puzzling when we try to imagine
the underlying reasons for this phenomenon.
Procrastination is as widespread as any behavior
that we observe. Yet from the view of evolution
what possible benefit does it provide?
It is clear enough what harm it can do
in slowing down efficiency
and disrupting the normal pattern of activity.
Perhaps it is a freak accident of genetics,
a mutated gene which persists
in causing the untimeliness of events
without causing enough harm to the species
to threaten its survival.
But what about its benefits?
One possibility is that
procrastination may act as a balance
against rapid efficiency, in order to maintain
a slower, steadier pace within the time demands
of our personal and social lives.
Another theory is that by putting something off
which needs doing,
we tend to focus more intently
on the thing in question
when we are ultimately confronted with the deadline.
J. H.
that virtually all humans
procrastinate continuously,
in one form or another,
throughout their lifetimes.
It is equally puzzling when we try to imagine
the underlying reasons for this phenomenon.
Procrastination is as widespread as any behavior
that we observe. Yet from the view of evolution
what possible benefit does it provide?
It is clear enough what harm it can do
in slowing down efficiency
and disrupting the normal pattern of activity.
Perhaps it is a freak accident of genetics,
a mutated gene which persists
in causing the untimeliness of events
without causing enough harm to the species
to threaten its survival.
But what about its benefits?
One possibility is that
procrastination may act as a balance
against rapid efficiency, in order to maintain
a slower, steadier pace within the time demands
of our personal and social lives.
Another theory is that by putting something off
which needs doing,
we tend to focus more intently
on the thing in question
when we are ultimately confronted with the deadline.
J. H.
Common Time (Week 2)
People often observe that each year of life
seems to pass more quickly than the last.
This appears to be a consequence of the fact
that each passing year becomes an increasingly
smaller fraction of a person's lifetime.
For example, for a one-year old infant,
a period of a year represents an entire lifetime,
while, for a person 80-years old, the same
period of a year occurs as a mere fraction,
or one-eightieth, of ones' lifetime.
With each succeeding year of life,
the period of a year represents
a constantly decreasing portion
of one's lifetime, creating the
perception that life itself
is speeding-up.
J. H.
seems to pass more quickly than the last.
This appears to be a consequence of the fact
that each passing year becomes an increasingly
smaller fraction of a person's lifetime.
For example, for a one-year old infant,
a period of a year represents an entire lifetime,
while, for a person 80-years old, the same
period of a year occurs as a mere fraction,
or one-eightieth, of ones' lifetime.
With each succeeding year of life,
the period of a year represents
a constantly decreasing portion
of one's lifetime, creating the
perception that life itself
is speeding-up.
J. H.
Time's Constant (Week 2)
Time is the rate of change of an event. Space is the extent of the
change, and is equal to the quantity of substance which it encompasses.
A space-time event refers to the combined rate and extent of the
incremental changes which constitute the event.
A planet, star, or galaxy moves through space at a specific velocity and
for a specified duration and distance, depending on the mass and
density of the body, the medium of travel, and the forces which act upon it.
In general, space-time is a continuum in which there is no spatial
volume or time interval that is void of substance or activity, only a
more or less coherent interaction of events occurring at various
orders of magnitude and scale and at different velocities and durations.
All objects and events are constituents of space, and evolve at time
durations and velocities which correspond to their changing states.
Space-time events are influenced by other events in varying degrees.
The more an event is influenced by another event, the less the degree
of difference in space and time between the events.
Space-time relations are the absolute or observed intervals which occur
between the beginnings and endings of events, or which separate
events, in space and time.
Observation is the ability to distinguish change within a range of
greatest and least occurrence of mass, energy, and lifespan.
The observation of events is affected by the relative motions of the
observer and the observed.
Relative values for space-time intervals are determined by the
observer's fixed or moving position in relation to the position of the
events which are being observed.
Variations in the observation of space-time intervals tend to alter the
observer's awareness of them.
Although distances and times vary for different observers, they form
an absolute space-time interval for all observers.
Both the process of observing events and the events themselves have
absolute time values.
The observation of events is a result of the function of sensory organs
which detect physical events in the outside world, and of the nervous
system which transmits sensory information to the brain where it is
recorded and processed in various ways.
The rates of reception and transmission in the nervous system produce
a time lag which prevents the brain from processing information
instantaneously.
The time required to make an observation depends upon the combined
rates of reception and transmission in the nervous system, along with
the feedback rates governing the processes of the brain.
By processing information which has been recorded in memory, the
brain is able to observe the continuity of present events, recognize
past events, and predict future events. Future events are predicted by
analyzing recurring patterns of information, and forming judgments
based on the causal relations which determine those patterns.
The ability to remember or predict events is due both to the causal
direction of events in time, and the functions of the brain which
process the events.
Two or more events which occur at the same time are simultaneous.
Events which are simultaneous occur at nearly the same time, but do
not necessarily begin or end at the same time or have equal time values.
Although the consequences of changing events may be observed over
time, such as the gradual buildup of a mountain chain or the lifecycle
of a star, the combined action of all events occurring in the universe
at any given moment is nearly instantaneous.
All events occur simultaneously in the present.
The instantaneous moment of time in which all events occur is equal to
the minimum length of time required to cause a change.*
The average time rate at which all events occur is equal to the sum of
the rates divided by the number of events.
The instantaneous moment of time in which all events occur, and the
average rate of the events are constant.
J. H.
* In quantum physics, the minimum amount of time which is meaningful is equal to the unit of time known as the Plank time, or 10-43 sec. The Plank time is calculated by combining the fundamental constants of gravity, the average speed of light, and Plank's constant. The Plank time is given by the square root of Gh/c5.
change, and is equal to the quantity of substance which it encompasses.
A space-time event refers to the combined rate and extent of the
incremental changes which constitute the event.
A planet, star, or galaxy moves through space at a specific velocity and
for a specified duration and distance, depending on the mass and
density of the body, the medium of travel, and the forces which act upon it.
In general, space-time is a continuum in which there is no spatial
volume or time interval that is void of substance or activity, only a
more or less coherent interaction of events occurring at various
orders of magnitude and scale and at different velocities and durations.
All objects and events are constituents of space, and evolve at time
durations and velocities which correspond to their changing states.
Space-time events are influenced by other events in varying degrees.
The more an event is influenced by another event, the less the degree
of difference in space and time between the events.
Space-time relations are the absolute or observed intervals which occur
between the beginnings and endings of events, or which separate
events, in space and time.
Observation is the ability to distinguish change within a range of
greatest and least occurrence of mass, energy, and lifespan.
The observation of events is affected by the relative motions of the
observer and the observed.
Relative values for space-time intervals are determined by the
observer's fixed or moving position in relation to the position of the
events which are being observed.
Variations in the observation of space-time intervals tend to alter the
observer's awareness of them.
Although distances and times vary for different observers, they form
an absolute space-time interval for all observers.
Both the process of observing events and the events themselves have
absolute time values.
The observation of events is a result of the function of sensory organs
which detect physical events in the outside world, and of the nervous
system which transmits sensory information to the brain where it is
recorded and processed in various ways.
The rates of reception and transmission in the nervous system produce
a time lag which prevents the brain from processing information
instantaneously.
The time required to make an observation depends upon the combined
rates of reception and transmission in the nervous system, along with
the feedback rates governing the processes of the brain.
By processing information which has been recorded in memory, the
brain is able to observe the continuity of present events, recognize
past events, and predict future events. Future events are predicted by
analyzing recurring patterns of information, and forming judgments
based on the causal relations which determine those patterns.
The ability to remember or predict events is due both to the causal
direction of events in time, and the functions of the brain which
process the events.
Two or more events which occur at the same time are simultaneous.
Events which are simultaneous occur at nearly the same time, but do
not necessarily begin or end at the same time or have equal time values.
Although the consequences of changing events may be observed over
time, such as the gradual buildup of a mountain chain or the lifecycle
of a star, the combined action of all events occurring in the universe
at any given moment is nearly instantaneous.
All events occur simultaneously in the present.
The instantaneous moment of time in which all events occur is equal to
the minimum length of time required to cause a change.*
The average time rate at which all events occur is equal to the sum of
the rates divided by the number of events.
The instantaneous moment of time in which all events occur, and the
average rate of the events are constant.
J. H.
* In quantum physics, the minimum amount of time which is meaningful is equal to the unit of time known as the Plank time, or 10-43 sec. The Plank time is calculated by combining the fundamental constants of gravity, the average speed of light, and Plank's constant. The Plank time is given by the square root of Gh/c5.
2.17.2009
Genes and Synesthesia
Since it did come up in class just now, here is an article about synesthesia that I happened to read just a week ago.
Feynman, Liszt and Nabokov are among its celebrity vessels.
Feynman, Liszt and Nabokov are among its celebrity vessels.
2.14.2009
Speculations On The Shape Of The Universe (Week 1)
Space is everywhere. Energy and matter are continuously in motion.
Energy and matter change and conform to the forces that direct them, giving them duration, coherence, shape, and form. These forms eventually decay, devolving back into space.
Standard models in physics and astronomy predict that the universe is expanding, that space is flexible, perhaps even multidimensional. We have compiled sliced images of the large scale structure of space.* There are proposed universe’s with boundaries, without boundaries, with holes like Swiss cheese, elastic models, rigid models, etc.
Since the time of Galileo, the scientific method has been employed to interpret and describe the external world. Yet, as individuals, we inhabit the center of a unique perspective. We experience the world in proportion to our sensory and perceptual limitations. Still, scientists have learned to collect data in reliable and elegant fashion, in the service of truth, despite their profound perceptual biases.
And yet we can easily visualize an expanding universe as having a spherical shape, simply because of our knowledge of physics. Or perhaps because the planet we live on is spherical. We also know that our solar system and galaxy are spinning, orbiting systems.
The regions of our brain that are responsible for comprehending whole to parts relationships may have evolved as an adaptation to this primary form. Or maybe our brains simply make the jump from a spinning planet to a spherical universe by association.
However, that doesn’t mean that the shape of the universe is necessarily spherical or egg-shaped, or is even limited by a boundary.
Perhaps we can be sure of only one thing: that the shape of the universe is the shape of space. And the shape of space is matter and energy everywhere, ongoing.
J. H.
* see Margaret Geller and John Hukra, Smithsonian Observatory, Harvard University
Energy and matter change and conform to the forces that direct them, giving them duration, coherence, shape, and form. These forms eventually decay, devolving back into space.
Standard models in physics and astronomy predict that the universe is expanding, that space is flexible, perhaps even multidimensional. We have compiled sliced images of the large scale structure of space.* There are proposed universe’s with boundaries, without boundaries, with holes like Swiss cheese, elastic models, rigid models, etc.
Since the time of Galileo, the scientific method has been employed to interpret and describe the external world. Yet, as individuals, we inhabit the center of a unique perspective. We experience the world in proportion to our sensory and perceptual limitations. Still, scientists have learned to collect data in reliable and elegant fashion, in the service of truth, despite their profound perceptual biases.
And yet we can easily visualize an expanding universe as having a spherical shape, simply because of our knowledge of physics. Or perhaps because the planet we live on is spherical. We also know that our solar system and galaxy are spinning, orbiting systems.
The regions of our brain that are responsible for comprehending whole to parts relationships may have evolved as an adaptation to this primary form. Or maybe our brains simply make the jump from a spinning planet to a spherical universe by association.
However, that doesn’t mean that the shape of the universe is necessarily spherical or egg-shaped, or is even limited by a boundary.
Perhaps we can be sure of only one thing: that the shape of the universe is the shape of space. And the shape of space is matter and energy everywhere, ongoing.
J. H.
* see Margaret Geller and John Hukra, Smithsonian Observatory, Harvard University
2.06.2009
Two books
Many of you have probably heard of Flatland, by Edwin A. Abbott, a fun story about dimensions. The book I was referring to the other day in class is called The Hidden Dimension, by Edward T. Hall and examines cultural reasons for different understandings of space.
2.04.2009
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