Winners of the
Olympics-2001
Winners of the
Olympics-2000
Space Projects Competition
1. Sarah
Longest The Effects of a Non-Network Forming Polymer on
the Dissipation Curve of Its Dielectric System (84.94 points), Virginia state, the
USA.
2. Dmitry Golubtsov Simulation System of Control Motion for
Mechanical Caterpillar (82.94 points), Korolev, Russia.
3. Angela Kusaj The End of the Universe, Not the End
of Time
(81.13 points), Virginia state, the USA.
4. Lee Tessler Analysis of a Pulsed Detonation Wave
Engine
(80.75 points), Virginia state, the USA..
Winners of the Olympics-99
(1st round of Space Projects competition) 1. Alexander Goloborodko
"The Era of the Separated World, or The Unity as the Space Problem
in Russian Philosophy" (100 points), school No19, Korolev, Russia.
(2nd round of Space Projects competition) Anna MIHAILOVITCH
"The Mechanical Model of the Caterpillar" (83.4 points), the
Science & Engineering School, Korolev, Russia. |
The Effects of a Non-Network Forming Polymer on the Dissipation Curve of
Its Dielectric System
by Sarah Longest
Abstract:
The purpose of this experiment was to develop an in-situ dielectric
technique to monitor polymerization in microgravity and terrestrial
environments. This experiment investigated the dielectric response of the polymerization
of a non-network forming polymer. The capacitance and dielectric loss were
measured at different temperatures for the epoxy resin, a linear polymer formed
from epoxy 828 and an aniline curing agent. A dissipation curve can be found
from the dielectric loss. It was hypothesized that the dielectric spectrum of
the non-network forming polymer would be related to the build-up of the
molecular weight of the polymer, therefore producing a significant curve in the
dielectric spectrum instead of a flat line.
In the higher frequencies of the trials at 75° and 90° Celsius, a
significant dissipation curve was produced, which verified the hypothesis as
being true in the parameters of this experiment. The experiment at 60° Celsius
did not produce a dissipation curve, only an ionic curve, within the time
limit. The results disprove previous theories that the dielectric system was
directly related to the crosslinking in network forming polymers, showing
instead that the dielectric system is related primarily to either the molecular
weight build-up or the glass transition temperature. Future research should be
conducted to verify these results and determine if the dissipation curve is
related to the molecular weight or the glass transition temperature.
Introduction:
Studies in microgravity have become very popular recently among NASA
research
scientists in preparation for the upcoming “space age.” So far, scientists have
studied phenomena such as heat transfer, magnetohydrodynamics, and combustion
science in space to help them understand more about the effects of microgravity
on terrestrial physics laws which are taken for granted (Rosenberg 11-12).
Recently, space experiments have begun to include research on polymeric
phenomena such as crystal growth and fluid physics, but the research is very
limited (Rosenberg16).
Research on the polymerization process could be very beneficial to the
NASA Space Program. For example, new polymers could be produced to make space
shuttles safer and more cost efficient. New equipment could be made out of
these new materials to aid space exploration (i.e. sturdier machinery, more
efficient rover vehicles, etc.). Eventually, polymers may be able to be
manufactured in space as building materials for constructing and repairing space
stations. Already, astronauts have been able to produce latex pellets in space
used to calibrate scientific equipment on earth (Rosenberg 26). The
possibilities for uses of polymers in microgravity are endless.
However, a major drawback facing polymer research scientists involves how
polymers are formed. As of yet, scientists have not been able to monitor the
polymerization process in microgravity. All of the polymerization projects in
microgravity have involved scientists performing the preliminary setup on Earth
and then putting the polymer in a microgravity environment. Drop towers,
aircraft, rockets, and orbiting shuttles are the most common forms of
simulating microgravity (Rosenberg 3-7). Then the scientists analyze the
results after the polymerization process has taken place, hoping to recreate
the process from the data. A system that monitors the polymerization process as
it takes place would be a great benefit to the research of polymerization in
microgravity.
So far, scientists can only speculate how microgravity affects the
polymerization process. Scientists have known for along time that a polymer
forms when monomers, the “building blocks” of polymers, bond together in long
chains (Brown, Lemay, Burston 428). As the polymer chain grows, the molecular
weight of the polymer increases. On Earth, once the molecular weight becomes
too great, gravity can cause the polymer to precipitate out of the solution as
sediment (Brown, Lemay, Burston 101). Gravity also plays a role in determining
the weight and density of a monomer and the polymer it forms. However, in
microgravity, these relationships may not hold true anymore. Without gravity,
scientists speculate that polymers with large molecular weights would continue
to remain suspended in solution and the density of the polymer would not be as
significant in microgravity than on Earth. But because the polymerization
process cannot be monitored in microgravity, scientists have no way of knowing
for certain the effects of microgravity on polymers.
Epoxies and polymers are used everywhere. Plastics, glues, and resins are
just a few examples of products formed out of epoxy polymers. Epoxies are used
to make everything from pens to plastic wrap to airplanes. Because polymers and
epoxies are so widely used, it is essential to discover everything about the
polymerization process and how epoxies are made. The purpose of this experiment
was to develop an in-situ dielectric technique to monitor polymerization in
microgravity and terrestrial environments.
The in-situ dielectric spectroscopy provides a simple yet informative
technique of
monitoring the polymerization process. It involves using a parallel plate setup
or an
interdigitated electrode to record the capacitance and dielectric loss of the
epoxy's dielectric system. Although scientists know a lot about the capacitance
and dielectric constants, relatively little is understood about the origin of
the dielectric loss during the polymerization process. This experiment was
conducted to of learn more about dielectric loss in a polymeric system.
Polymers are constructed of monomers: smaller molecules, most of which
have a
backbone of carbon bonds (Brown, Lemay, Burston 428). When the epoxy
prepolymers are mixed with a curing agent, the prepolymers link up in long
chains to form polymers in a cured epoxy resin. This is the polymerization
process (Brown, Lemay, Burston 428). As the polymer chains grow, the molecular
weight also increases.
Some polymers form networks, or crosslink between each other so as to connect
many polymer chains together. (Brown, Lemay, Burston 435) These polymers can do
so because they have two amine groups on benzene ring of the curing agent,
which allows two monomers to connect to each other. (Fitz, Andejelic, Mijovic
5227) More crosslinking between polymers creates a more rigid epoxy resin
(Brown, Lemay, Burston 435). Forming networks between polymers also increases
the molecular weight of the epoxy resin. However, some polymers only have one
amine group in the curing agent, and cannot crosslink. Instead, they make only
long chains of polymers, and are not as rigid as the network forming polymers.
These polymers are called non-network forming polymers (Kennedy).
Temperature plays a significant role in the polymerization process of polymers.
As the temperature increases, the polymerization process speeds up (Brown,
Lemay, Burston 507). Also, the temperature hastens the glass transition phase,
or the Tg, which is the point that the epoxy mixture transforms from glass-like
solid to a viscous liquid (Carraher 47). Higher temperatures allow the
experiments to be conducted more quickly than lower temperatures.
In the dielectric system, two parallel plates, one positively charged,
one negatively charged, are used to measure the capacitance and the dielectric
loss (Halliday, Resnick 524-525). The capacitance is the ability to store
charge in the capacitor (Halliday, Resnick 525). Because some monomers have
permanent dipole moments, the charged ends of the monomers try to align
themselves with the opposite charges on the parallel plates (Halliday, Resnick
532). As the monomers align themselves, the charge on the monomer cancels the
charge on the plate, therefore reducing the charge on the plate (Halliday,
Resnick 533) The charges are noted as "missing" by the electrode, and
are replaced as soon as they are used. In this way, the HPLCR 4284A Meter
records how many charges are “taken away” from the plates. The units for
measuring these charges are picofarads, or pF (Halliday, Resnick 525).
This realignment process takes place continuously because the charges of
the plates switch sides back and forth (Halliday, Resnick 532). As the
frequencies change, the monomers settle into a rotation pattern for that
frequency (Kennedy). When the monomers are free, or are bound together in small
polymers called oligomers, they rotate very easily, keeping up to speed with
the different frequencies (Kennedy). However, as the monomers chain together,
the molecular weight increases, causing the polymer to become bigger and slower
to rotate. This changes the dielectric loss, or the loss of heat due to the
cancellation of charges (Kennedy). The dielectric loss forms a curve, called
the dissipation curve (Kennedy).
Typically, the in-situ dielectric measurements are only conducted on
network forming polymers to measure the gelation point of the polymer, the
point when the network begins to form. This has led many scientists to believe
that the dielectric loss is primarily related to the crosslinking between
network forming polymers (Kennedy). The data is usually measured from a network
forming polymer with a fixed molecular weight, leaving no room for other
theories about the origin of the dissipation curve (Kennedy). Very few, if any,
experiments have been conducted on non-network forming polymers or polymers
without fixed molecular weights.
Structure for Epoxy 828 Structure for Aniline
(illustration of molecular structure goes here)
In this experiment,
epoxy 828 with the curing agent aniline forms a non-network forming polymer.
This particular epoxy resin is being used to determine if the dissipation curve
is related to something other than crosslinking in network forming polymers.
Because a non-network forming polymer is used, the only relevant causes of the
dissipation curve, should there be one, would be the molecular weight and/or
the Tg. It is hypothesized that the dielectric spectrum of the non-network
forming polymer will be related to the buildup of the molecular weight of the
polymer, therefore producing a significant dissipation curve in the dielectric
spectrum.
Experimental Method:
In this experiment, dielectric measurements were performed on a mixture
of Epoxy 828 and aniline solution.
Determined as the optimum mixing ratio, 18.85g of Epoxy 828 were weighed
in a beaker to which 4.55mL of aniline were added. These compounds were stirred
thoroughly to create a homogenous mixture.
Dielectric measurements were taken over a frequency range of 100Hz to
1MHz using a vertical parallel plate cell with a capacitance between 124pF and
130pF. A beaker was attached to the parallel plate electrode and the
capacitance of the air was measured every 5 minutes for a 30-minute run. The
beaker was filled with the epoxy mixture via a syringe until the level of the mixture
exceeded the gold surface of the electrode. The beaker was placed in the oil
bath set at 60° Celsius, and the experiment was run for 6 hours. During this
time, capacitance and dielectric loss was recorded by a HPLCR 4284A meter and
stored in the computer every 5 minutes.
After the experiment was completed, the electrode and all instruments
that came in direct contact with the epoxy mixture were cleaned with toluene.
The epoxy mixture was labeled and stored in case further testing was needed.
Two trials were performed at 60° Celsius, 75° Celsius, and 90° Celsius.
Results:
Two trials at 90° Celsius produced sufficient dissipation curves as well
as several trends. One trial at 75° Celsius was only run for four hours
and, although the ionic curves appeared in both trials, the beginnings of a
dissipation curve only appeared in the 6 hour trial. However, the experiments
at 60° Celsius did not produce a dissipation curve.
For the trail runs at 90° (Table I), the variation between the peak
heights of both the ionic and dissipation curves of the two trials at each
frequency is very small. For example, the difference between the peak heights
of the dissipation curves at 100KHz was only .0001 units. The largest
difference between the peaks of the two trials is .0032 units at 1MHz. The
difference between the ionic peaks of the two trials is slightly larger,
ranging from .6 units to .0094 units.
The heights of the dissipation peaks for each trial increased as the
frequency increased. The peaks range from .0326 units to .0495 units between
100Hz and 1MHz respectively. Very little difference exists between the
dissipation peaks of both trials within the frequencies of 1KHz and 20KHz. The
height of the peaks leveled off slightly before increasing significantly in the
higher frequencies. However, the heights of the ionic peaks decrease as the
frequency increases. They range from 31.1units to .0219units. This is
expected because the ionic effects are more pronounced at the lower
frequencies.
The difference between the time to peak maximum of the two trials for
each frequency varies little. Except for 100Hz, the ionic curves peak at 50
minutes in both trials. In the dissipation curves, there are only 10 to 15
minute differences between times peak maximum for the trials. The time to peak
maximum for the dissipation curves decreases by 10 minutes as the
frequency decreases, until 1KHz. In the second trial, the dissipation peaks are
not as constant, but vary between a range of 5 to 15 minutes as frequency decreases
until 1KHz.
Several graphs are attached to display the ionic and dissipation curves.
In the graph depicting the experiment at 90° Celsius (Appendix I), a
significant dissipation curve appears towards the middle of the experiment at
1MHz. The ionic curve is the only predominant curve in the graph. The graph of
20KHz at 75° shows a very large ionic curve throughout most of the experiment,
but the dissipation curve is just beginning towards the end of the run
(Appendix II). In the second graph of 75°, the dissipation curve becomes very
prominent at 1MHz while the ionic curve has atrophied severely (Appendix III).
In the fourth and final graph, no dissipation curve is apparent in the 60°
Celsius run (Appendix IV).
Conclusion/Recommendation:
From the above results, it was determined that the trial at 90° Celsius
provided a better response than the trials at 60° and 75° Celsius. The
experiment at 90° Celsius provided the best results at the higher frequencies.
The dissipation curve appeared much sooner in the trial at 90° than at 60° or
75°. The length time provided for 90° Celsius run was appropriate for that
temperature. Also, at the higher frequencies, the dissipation curve appeared
more prominently than the ionic curves. At 75° Celsius, the dissipation curve
appeared near the end of the 6 hour run in the higher frequencies. The
experiment at 75° Celsius should also be run a little longer to produce a full
dissipation curve. The trial at 60° Celsius did not provide a dissipation curve
because the temperature was too low and the time period for the trial was too
short. Another experiment performed at 60° Celsius should be run for much
longer than 6 hours to produce a significant dissipation curve.
While the dissipation curves may be due to either the Tg or the molecular
weight, the ionic curves are due to a completely different phenomena. When some
epoxies are produced, the manufacturers include salts to aid in the production.
As the polymerization reaction proceeds, the salts break into ions and are
attracted to the charges on the parallel plates. These ions cancel with the
charges on the plates, and cause dielectric loss that has nothing to do with
the polymerization process itself (Kennedy).
A further study should be performed to verify the extent of the heat of
reaction at various temperatures and times. Also, experiments should be
conducted to determine the molecular weight build-up as the reaction proceeds
at different temperatures and frequencies. Other experiments should be
conducted to clarify whether the molecular weight build-up or the Tg is
producing the dissipation curve.
Acknowledgments:
The researcher would like to extend much appreciation to the dedication of the
following people and groups for making this experience the best that it could
be:
National Aeronautics and Space Administration (NASA), Quality Education for
Minorities (QEM), Dr. Alvin Kennedy, Ms. Rosemarie Agyei-Agyepong,
Dr. Vallie Guthrie, Dr. Dominic Clemence
References:
Brown, T. L., Lemay, Jr., H. E. & Bursten, B. E. (1997). Chemistry:
the Central Science. New Jersey: Prentice Hall.
Carraher, Jr., C. (1996). Polymer Chemistry. New York: Marcel Dekker.
Fitz, B., Andjelic, S., & Mijovic, J. (1997). Reorientation dynamics
and intermolecular cooperativity of reactive polymers. Macromolecules, 30,
5227-5238.
Halliday, D., & Resnick, R. (1970). Fundamentals of Physics. New
York: John Wiley and Sons.
Kennedy, A. (1999, June). “On the dissipation curve as it relates to the
molecular weights of both network forming and non-network forming polymers”
[Interview]. Greensboro, NC.
Koike, T., & Ishizaki, N. (1999). Dielectric properties above the
glass transition for a series of epoxide prepolymers. Journal of Applied
Polymer Science, 71, 207-214.
Koike, T., & Tanaka, R. (1991). Free volume and dipole mobility in an
epoxide oligomer before crosslinking. Journal of Applied Sciences, 42,
1333-1341.
Vogt, G. L., Wargo, M.
J., & Rosenberg, C. B. (1995). Microgravity: a Teacher’s Guide with Activities for Physical Science. Washington,
DC: NASA Headquarters.
Top
Simulation
System of Control Motion for Mechanical Caterpillar
by Dmitry
Golubtsov
At present it is necessary to make a universal highly maneuverable robot,
which does not need the high movement velocity. This robot is widely used: to
work on rocky and crossing terrain, to sort out the obstruction of destroyed
buildings, rescuing works, to transport cargoes and the other works on
the marshy and difficult terrain, to repair the space stations in orbit. For
this purpose the attempt was undertaken to make the mechanical analogue of
biological system (a caterpillar).
In this work the imitation model of robot-caterpillar was made and the control
algorithms of functioning were worked out for this system. The developed
control algorithms are implemented on computer.
The mechanical model of a caterpillar consists of consecutively added modules.
There are two versions of the basis element:
- A module is four-link kinematics chain with one onward pair and three
hinges. It is possible to replace the onward pair with a muscle from the
material which could lengthen, reduce and remain clamp in position; the
neighbouring modules have one common element and two hinges.
- A module can have any different shape (triangle, rectangle,
semicircle), connected to other modules within the hinge means through a
step-by-step motor.
In this paper the second version of the mechanical model is worked out in which
the links of different shape connect via the hinges with the
step-by-step motor.
Three-dimensional motion of robot-caterpillar can be separated in two
perpendicular planes (horizontal and vertical). In this paper the
robot-caterpillar’s plane motion was considered on any surface.
For this type of motion the robot control system was described which consists
of the mechanism of getting information and choice of the motion strategy.
Getting the information about two sections of the surface we can approximately
define its characteristic in the area of robot’s motion. The test prod
can get the information with definite frequency, consequently it can’t discern
completely all the surface. To get common notion of the whole surface, cube
spline algorithm of function interpolation of one variable can be used. This
method says that coefficients of cube polynomial are selected on each
area in such a way that it would pass through all known points of the surface.
In this paper we described the control algorithm of motion, having chosen more
suitable and universal strategy of motion (the strategy does not depend
on the forms of the relief).
The formulas for coordinate change of relative position of modulus and
surface were introduced for these algorithm. The angles between the modulus are
calculated on this data. On the real model this data must be sent on
step-by-step electric motors, which control the space motion of the robot.
The developed control algorithms are realized as a computer programme. In this
programme an optional surface is created and the motion of the robot with
prearranged parameters is shown on it. Initial data for the robot-caterpillar
is a number of segments, a length of one segment and also a minimal
possible angle between the modulus.
The initial surface can be created by three methods:
1 Automatic creation
The programme chooses by chance the coordinates of surface points on the
vertical axis at the definite interval on the horizontal axis. After that
the algorithm of cube spline interpolation works and the continuous
two-dimensional curve is created which signifies the surface.
2 Opening from a file
It is possible to save the created surface for the future work with them.
3 Tabular task
The user fills in the table consisting of two columns: A) horizontal
coordinate B) vertical coordinate ( It is not necessary to give this data
in increasing order of abscissa).
Only the first method is realized at the present time.
The result of this programme is the animation, representing the motion of
the robot caterpillar on the curve of two- dimensional surface. The
programme also calculates value of angles between the modulus of caterpillar,
really sent to step-by-step motors. The values of these angles and also the
activity condition of motors are represented as graphs in separate
windows.
The programme has a standard Windows interface - appendix that makes work with
it more easier. The program was written C++ for Visual C ++5 in the operating
system Windows 98. The Pentium with frequency of 166Mhz and higher is
needed to calculate this task. The necessary graphic resolution for
this programme is 800*600 pixels.
Top
The End of the Universe, Not the End of Time
By Angela Kusaj
The problem I will address is, “What is the most probable theory for the end of
the universe?”
Based on prior reading of
the subject, I predict that the closed model of the universe will be the most
viable and provide a basis for which I can elaborate my own theory.
There are six subjects I
will discuss. These are:
-why the Big Bang occurred at the beginning of the universe
-what happened immediately after the Big Bang
-why the universe is expanding
-current theory on the end of the universe
-my own models for the end of the universe
-importance of knowing the universal structure
Aleksandr Aleksandrovich Friedmann, is where it all started.
Einstein had proposed that the size of the universe was constant, and it
neither shrank nor grew. But, in 1922, Friedmann argued that space and time
have tendencies to be isotropic (all points traveled in uniformity in all
directions) and that it was possible for the average density and radius of the
universe to change over time.
In 1923, after initial controversy, Einstein reevaluated Friedmann’s solutions
and admitted that the solution was correct.
The Friedmann-Lemaitre Cosmological Model was formulated by Friedmann in 1922
and continued independently by Lemaitre in 1927. It assumes a homogeneous
and isotropic universe. The Big Bang theory developed from Friedmann's
theory of an expanding universe.
What happened immediately after the Big Bang
The universe cooled as it expanded. After about one second, protons formed. In
the following few minutes, combinations of protons and neutrons formed the isotope
of hydrogen known as deuterium as well as some of the other light elements,
principally helium.
From about 300,000 to about 1 million years after the Big Bang, the universe
cooled to about 3000° C (about 5000° F) and protons and electrons combined to
make hydrogen atoms.
Why the universe is
expanding
Redshifts of galaxies allow
astronomers to measure the distance from Earth to the galaxies. This
gives us an idea of how the universe is expanding.
The light of an object moving away from an observer is shifted toward a longer
wavelength, or toward the color red. The light from an object moving toward an
observer is shifted toward the color violet.
The redshift at a time with expansion parameter is defined as
z = (a0 / 1) – 1
The relationship between the redshift (and therefore velocity) and distance of
a galaxy is called Hubble’s Law, which was named after American astronomer
Edwin Hubble. Hubble’s Law states that galaxies farther away from Earth
are receding from Earth more quickly than nearer galaxies. The dots on this
balloon represent galaxies. As the balloon is inflated (representing the
universe’s expansion), each dot moves away from all the others. To a person
viewing the universe from a galaxy, all other galaxies seem to be receding. The
distant galaxies appear to be moving away faster than the near ones, which
demonstrates Hubble’s Law.
Current theory on the end
of the universe
Friedmann proposed three theories for the end of the universe. The
steady-state theory is no longer considered due to it basic
unconventionalism. The open and closed universe theories depend upon
whether or not a certain critical mass exists. I approach these theories
with a notion: “If the universe exploded, its unsteadiness must have been
caused as an effect to a reaction, what caused the universe to collapse.
If the universe had enough mass to explode, then it must have enough mass to
collapse again and again.” Then I will focus on Friedmann’s model of the
closed universe theory.
My own models for the end
of the universe
1st model
When reviewing my first model, I identified a basic error in how it would
be perceived. By placing the circles that represent the universe at
different points in time in different places in the illustration, I was
suggesting that the universe was curved. Space is not curved, but indeed
space-time is curved. I must then suggest a sense of the universe
pulsing, beating to the Big Crunches followed by the Big Bangs.
2nd model
My second model of a closed universe succeeds in portraying the universe
as stationary. In this model, time flows outward from the singularity and
inward to the Big Crunch. The model does indicate that the Big Bang and
the Big Crunch joined at one singularity, but it does not indicate whether the
universe is expanding or collapsing. A three-dimensional model is needed.
3rd model
My third model of a closed universe, also called my balloon model,
suggests a three-dimensional perfect model. To read my model, the time
flow direction must first be indicated. Unlike my second model, one can
track the progression and regression of the universe in this model as long as
time flow direction is indicated. It also illustrates what caused the Big
Bang. All of the mass in the universe may have once condensed in the Big
Crunch before the Big Bang. All of the mass of the universe was being
pushed through the point of infinite smallness, where Big Crunch meets Big
Bang. This would have caused an explosion of such cataclysmic proportions
as the Big Bang. According to my third model, time is infinite and has
neither a beginning nor an end.
What are the implications of this revised model? There is a strong controversy
over the possibility that something is outside of our universe. The
notion is simply dismissed by conservatists such as Robin Scagell, who stated
"nothing exists outside it (the universe), not even space." On
the contrary, for Plotinus, a third-century pagan, to exist in time is to exist
imperfectly. A perfect being must, therefore, not have any relation to
time. For Plotinus, time represents a prison for human beings, separating
us from the divine realm—the true and absolute reality. Because time is
not a physical thing, this would suggest that time passes due to physical
change. To be perfect would mean that one must not change. Change
for the worse would make a being imperfect, and change for the better would
signify that the being was imperfect to begin with. The universe
encompasses everything—everything which is constantly changing over time.
In accordance with Plotinus, this would imply that a Perfect Being must exist
outside of this universe.
Light cones
illustrate some consequences of relativity for the concept of time. In
relativity theory, time varies relative to the observer. The future light
cone represents events that must occur later than event 0 and the past light
cone represents events that must occur earlier. All points outside the
light cones represent events that may occur earlier or later than event 0,
depending on the frame of reference.
A perfect being's
frame of reference, without time, would cause it to witness the past and future
light cones at once, and the perfect being would witness any other events, or
events outside the light cones, simultaneously.
Relativistic time passage
(?t) equals
?t = ?to [1 -
(v/c)2]0.5
Notice the similarity
between my original explanation of the closed universe and the view of the
universe from the perfect being's frame of reference.
I could have stopped here,
but it seems too simple, and indeed it is for one who’s hardly a beginner, like
myself. I then perchance upon a book called Genesis and the Big Bang
written by Dr. Schroeder, applied physicist and applied theologian, his
research as reported in Newsweek and Jerusalem Post. His research added
one disturbing thought to my understanding of the events following the Big
Bang. Currently it is reasoned that, at the beginning of the universe,
conditions existed for a super black hole. Several hundred thousand years passed,
and then light separated from matter and emerged from the darkness of the
universe. Astrophysicists have no conventional explanation for what could
have started the outward flow of matter, because as we know, nothing can escape
a black hole, not even light. Instead, very early in universal
theory, scientists have called upon a one-time, new type of force. They
call it an “inflationary epoch.” You can call it a “fudge factor.”
It doesn’t compensate for our current understanding of gravity. I have
begun to revise my third model into a new model, which takes into account the
black hole at the beginning of the universe. I think that “the
inflationary epoch” could, in fact, be a side effect of the reaction between a
black hole and white hole. According to current thought, a white hole can
put out, whereas a black hole takes in. I realized the use of light cones in my
models weren’t entirely accurate, due to the lack of light at the beginning of
the universe. To compensate, I have added an intersection of the two
cones in my development of a fourth model.
Importance of knowing the
universal structure
As a scientific community, we should continue to try to find out what dark
matter consists of. We should also continue the studies of gravity.
We may discover properties that would provide insight as to its behavior in the
beginnings of the universe. Also, studying relatative time passage, such
as referred to in my third model, may prove time travel impossible, because it
seems as though to travel through time, or witness two times simultaneously,
one would have to be perfect.
Conclusion
One must understand that all current theories on the future of the universe are
based on one assumption or another. Whether one assumes that the
expansion of the universe is uniform or that the expansion of the universe is
slowing down, the validity of these assumptions seriously threatens even the
most expert theories. One can then see that this model I propose is no
more or less likely than current theories. It is only another
possibility.
Cosmology is a science we must continue to investigate. Our understanding
of it has only just begun with Friedmann’s model of the expanding universe in
1922. But cosmology is as vital to the exploration of space as knowing
how deep water is before saying you’ll reach the bottom.
Top
Analysis of a Pulsed Detonation Wave Engine
By Lee Tessler
This research effort was conducted during a mentorship program at NASA Langley
Research Center.
A computational model,
implementing primarily one-dimensional fluid dynamic approximations, has been
developed to analyze the performance potential of the pulsed detonation wave
engine cycle—specifically, an intermittent rocket cycle employing a
single-chamber, repetitive hydrogen-air fueled detonation process. The
multidisciplinary analysis that has been conducted incorporates the principles
of thermodynamics and the conservation of mass, momentum, and energy. Thrust
values, static pressure values, and relevant time scales have been calculated
and compare well with the existing experimental results of Dr. J. A. Nicholls
generated using bench-top class hardware. Nicholls conducted the experiment at
the University of Michigan in 1957. As anticipated, the analytic assessment,
albeit incomplete in engineering system details, yields a substantial increase
in performance compared to that of a "standard" rocket cycle; and
thus, confirms the potential performance benefits of the pulsed detonation wave
engine concept.
An idealized cycle of a
pulsed detonation wave engine is quite elegant and simple. A tube is filled
with a gaseous fuel-air mixture, and then subsequently mechanically closed-off
at one end (forming a dual thrust chamber and nozzle). Next, a detonation wave,
initiated near the close-off, traverses the tube producing very large static
pressure levels (in excess of the values typically obtained in comparable
steady-state combustion processes). Note that once the detonation wave exits
the tube, the static pressure ultimately returns to the ambient condition (via
a rarefaction wave initiated at the exit), and the combustion products are
expelled. Lastly, upon opening the close-off, the tube is replenished, and the
cycle is completed. Note that thrust is generated in an unsteady manner;
namely, it is only produced during the unsteady detonation wave and rarefaction
wave parts of the cycle.
A FORTRAN computer code has
been developed to conduct this analysis. In short, the program models a
hydrogen-air detonation, assuming immediate formation (after controlled
ignition), and yields results, for a twenty-cycles-per-second pulsed detonation
wave engine, indicating substantially improved performance compared to the
"standard" modern rocket cycle. The modeled pulsed detonation wave
engine cycle, generating comparable thrust levels as that of a
"standard" rocket cycle, requires approximately one-seventh the fuel.
Thus, if practical, this cycle potentially impacts both the design of
aerospace-class vehicles and the related cost of payloads. As previously
inferred, the practical aspects of implementing this cycle are non-trivial; for
example, the repetitive replenishment of the fuel is problematic, given the
thermal environment and the related pre-ignition problems. Additionally, issues
such as the design of practical and efficient inlets are significant design
problems.
In conclusion, an idealized
pulsed detonation cycle has been modeled, via first principles, and assessed,
via the development of a computational algorithm. Results indicate a significant
potential performance benefit and strongly suggest that research addressing
this engine cycle is warranted.
Top
|
WINNERS PROJECTS
1998 "DEEP IMPACT" by Shagufta
Tabassam, UK, winner of 1998 WINNERS PROJECTS
1997 "MEASUREMENT OF THE GRAVITY ACCELERATION
USING A COMPUTER" by Pantelis Ermilios, Greece |
"BLACK HOLES"
by
Timothy Lancashire, Mackworth College Derby, the UK (66.75 points)
winner 1999
Top
Black Holes
Black holes are still
quite a controversial area of astrophysics but there is more than one reason
for this. Obviously, the fact that black holes are difficult to prove is
the first reason why it is so controversial but if black holes were proven, all
sorts of questions would arise. What I plan to do is to give you a mix of
evidence and theories and then allow you to make your own mind up.
Einstein’s general
theory of relativity describes gravity as a curvature of space-time caused by
the presence of matter. If the curvature is fairly weak, Newton’s laws of
gravity can explain most of what is observed. For example, the regular
motions of the planets. Very massive or dense objects generate much
stronger gravity. The most compact objects imaginable are predicted by general
relativity to have such strong gravity that nothing, not even light, can escape
their grip.
Scientists today
call such an object a black hole. Why black? Though the history of
the term is interesting, the main reason is that no light can escape from
inside a black hole: it has, in effect, disappeared from the visible universe.
Black holes are
thought to form from stars and other massive objects if and when they collapse
from their own gravity to form an object whose density is infinite: in other
words, a singularity. During most of a star’s lifetime, nuclear fusion in
the core generates electromagnetic radiation, including photons, the particles
of light. This radiation exerts an outward pressure that exactly balances
the inward pull of gravity caused by the star’s mass.
As the nuclear fuel
is exhausted, the outward forces of radiation diminish, allowing the
gravitation to compress the star inward. The contraction of the core
causes its temperature to rise and allows remaining nuclear material to be used
as fuel. The star is saved from further collapse -- but only for a while.
Eventually, all
possible nuclear fuel is used up and the core collapses. How far it
collapses, into what kind of object, and at what rate, is determined by the star’s
final mass and the remaining outward pressure that the burnt up residue
(largely iron) can muster. If the star is sufficiently massive or
compressible, it may collapse to a black hole.
Scientists know that
black holes exist due to the effect of their gravity on other objects. A
prime example of this is something called an accretion disc. An accretion
disc is a ring of material surrounding a star or other object from which
matters spirals inward to fall into the object inside the disc. As the matter
gains energy by falling into the gravitational field, and the atoms collide
with one another in the disc, they can become so hot that they radiate
x-rays. Some scientists now believe that there are super-massive black
holes at the centres of most, if not all galaxies.
A wormhole is a
tunnel through space-time, a shortcut between two points. The most likely
solution to the riddle of the wormhole is that it connects two black holes or a
black hole and a white hole.
Before 1985
wormholes were not regarded as real features of the universe. It was also
believed that wormholes would open up very briefly and then snap shut again
before anything could traverse the tunnel, even light. It was generally
assumed that some law of nature prevented it.
In working with Carl
Sagan on his novel Contact, however, physicist Kip Thorne developed a scheme by
which wormholes might be made useful. Limited only by that, which is
explicitly proclaimed impossible by the laws of physics, Thorne imagined using ‘negative
pressure matter’. You see, the gravitational field of an object – how
much it attracts surrounding objects – is determined not only by its mass, but
also by its internal pressure. The pressures exerted by familiar matter
are invariably too small to contribute noticeably to a gravitational field,
rather than counteracting it. But matter can also exert a negative
pressure – the classic example of this is the rubber brick being stretched in
all directions. If this negative pressure is large enough, it can
overcome the gravitational field affected by the object’s mass, and you’ve got
matter that gravitationally pushes things away instead of attracting
them. If future space travellers could somehow manage to line a wormhole
with this negative pressure matter, the wormhole could be held open
indefinitely, offering a portal to other places and times.
One of my favourite
theories is that wormholes connect parallel universes. I agree with this
theory and think that it is highly likely that this theory will hold true in
years to come. The problem that would be encountered with a wormhole that
this served this type of function would be that the parallel universe may have
differing dimensions to our own. What I mean to say is that our world is
4-dimensional. There are three dimensions of space and one of time.
If we were to go through a wormhole and come out in a universe that was
7-dimensional or 2-dimensional we would quite simply cease to exist as it is
impossible for our bodies to sustain us in any other dimensions other than the
ones we are accustomed to.
One of my own
theories is a variant on black holes. I personally believe that
singularities are not present in black holes. I think that when a black
hole is created by a star, the material from the star burrows a whole through
space-time into another region of the universe or possibly into a new universe
in which case we could say that a black hole and wormhole were almost the same
thing. The only difference would be that wormholes are two-way whilst
with black holes you would only be able to go through it, you wouldn’t be able
to turn around and come back.
Not so long ago,
science fiction writers were also suggesting that black holes and wormholes
were the same thing but recently they seem to have gone off the idea. I
think this may have something to do with a lot of the authors being scientists
and the fact that scientists have recently decided that black holes have a
singularity at the centre.
If black holes and
wormholes are the same thing, this could have a great advantage to us. It
means we could have a way to travel through space and time without having to
worry about the speed of the ship. Some scientists find this unlikely
because they say that wormholes would just collapse the instant we entered
them. This does not mean we could not travel through them though because
this is only theory.
The main problem we have at
the minute is still speed. It would take way too long to get to the
closest black hole. Everybody onboard the ship would have died before
they got there. There are two main ways to deal with this problem.
Either freeze the people onboard or speed up the ship. We cannot freeze
people at the moment because we can’t defrost them without killing them and we
are trying to create faster ships but it is costing too much money, which is
slowing production.
What we need in
reality to achieve effective space travel is the entire world working together,
although it does not look likely that this will happen for quite a while yet.
|
"COMMUNICATION
WITH ANOTHER SENTIENT SPECIES" by Tomos Bell, Willam Farr
Comprehensive School, Lincoln, the UK (81 points) |
Communication with another
sentient species
The spacecraft Voyager
1 and 2, and Pinoeer 10 and 11, all carried certain payloads with the same
purpose - greetings and information designed to be decipherable by an alien
race. The Pioneers carried gold plaques showing a representation of a hydrogen
atom, a picture of a man and a woman, our sun's location relative to fourteen
pulsars, and a diagram of our solar system.
The theory behind the
inclusion of the hydrogen atom is that it is the most basic chemical element,
and any space-faring civilisation encountering the plaque would be
scientifically knowledgeable enough to recognise what the picture represents.
However, I do not believe that this diagram is as universal as its designers,
Sagan and Drake, hoped. The reality of an atom's structure is very strange,
with electron energy levels, wave particle duality, and other quantum
phenomena. When we represent it, such as in this diagram, we are imposing our
ways of thinking upon something which is far removed from our normal
experience. Hydrogen itself could be universally recognised, but as soon as we
try to reproduce it pictorially, we introduce ourselves and our prejudices as a
factor, and the message is no longer universal, because there is no reason to
assume that another species would think the same way as we do and thus imagine
a hydrogen atom similarly. The less we can include ourselves and our specific
ways of thinking, the better.
The Voyager
spacecraft carried much more information than the Pioneers: 115 images ranging
from scientific charts and diagrams, to photographs illustrating our world and
culture; greetings recorded in 55 languages; and 27 pieces of music, including
Eastern and Western classical pieces, a variety of ethnic music, and even
examples of blues, jazz and rock and roll.
This is one of the first
images in the Voyager collection. It is an attempt to define our number system
in a way that another species could understand. The definition begins with
lines of dots indicating numbers from one to six, and relates them to a binary
system, and arabic figures.
Any advanced sentient
race that can find this image will undoubtedly be able to count. The important
assumption here is that they will be able to recognise that these are
representations of the numbers one to six. This, unlike the same assumption for
hydrogenm us a lot safer, because the representation is more universal. The
problem with hydrogen is that, as its structure isn't directly familiar to
either us or any aliens, representations could vary wildly. However, the
closest any image could get to the abstract concept "five" is five
indeterminate objects - here, dots. Therefore, this attempt to explain our
number system overcomes the representation problem better than the hydrogen
image.
Considering the list
of data stored on the Voyager spacecraft, we can see that there were two
different intentions behind the choice of what to include. Some of the
information, such as the scientific images at the beginning of the collection -
numbers, unit definitions, astronomical, geological, chemical and biological
data - is a genuine attempt to meaningfully communicate. Other iage, such as
the picture of a mountain climber, or of Amish house construction, seems to
have been included more for sentimentality. Certainly, another race would be
able to learn something from these images, and in fact, photographs of people
and places have an advantage in that they do not suffer from the representation
problem I discussed earlier. However, they have little use in a serious attempt
to convey specific information.
The recorded
greetings in 55 languages must also have sentimental value only. A
previously-unencountered alien race will obviously not be able to understand
any human language, whether it is widely used, such as English; rare, like
Welsh, or even a dead language like Latin or Akkadian. It has been suggested
that binary code could be used, as the simplicity of binary makes it universal.
However, binary can only be used as a method of carrying a message, and the
problem of the message's language is still unsolved. Binary is the language of
computers, but this does not mean that information could therefore be read by
an alien computer, because although it is certain that a space-faring
civilisation will have a form of computer technology, there is no reason that
their computers will interpret and understand a pattern of noughts and ones in
the same way ours do. It is for these reasons that any attempt to communicate
in a language of the complexity of our spoken and written languages, such as
English or Russian, or of computer code, is inappropriate.
Lastly, I would like
to talk about the music recordings on board Voyager. Obviously, music cannot
convey a complex message. When listening to Stravinsky's Rite of Spring, an
alien will not realise its connection with a certain period in the Earth's
orbit; neither will it understand the specific ceremonial significance of the
Pygmy girls' inititation song. The music can only be itself. However, it has
been suggested that even at this level, music will not convey itself well. The
reason for this view is that alien music could be structured on different
principles to our own, so our music may mean nothing - or at worst, even be
offensive or intimidating. I disagree with this idea. The concern is valid for
musical styles such as heavy metal, or disharmonious modern classical pieces,
but most of the music included, such as Bach and Mozart, or the examples of
ethnic music, are based on harmony. Harmony of sounds has a strict mathematical
basis. If you pluck a taut string, you will hear a musical note. If you pluck a
similar string of exactly half the length of the first string, the note
produced will be an octave higher. Other simple fractions produce harmonious
notes such as thirds or fifths. This mathematical basis makes harmony a
universal concept. To see that this is true, we only have to look at the fact
that harmonious styles have been developed independently around the world in
ethnic music, as well as forming the staple of the western classical tradition.
This universality does not just cover the human race: numerous scientific
studies have shown that harmonious music has a positive effect on animals, from
increasing milk yield in cows, to improving maze performance in mice. We
therefore know that harmony has cross-species relevance, which is exactly what
we are looking for when we are considering what we should send out into the
stars.
|
"SPACE
PROPULSION SYSTEMS" by Trevor Golding,
Daventry Tertiary College, Northampton, the UK (67.5 points) |
Space propulsion systems
For many years mankind has
been physically active in space however major breakthroughs in space travel
have seemed few and far between. The most recent of which was
probably the use of a reusable shuttle with re-fillable booster rockets.
Experimental craft such as the X-craft and the Russian VTOL craft have been
recent projects, although not widely known by the public. Cost has been
the driving force behind most of these experimental craft trying to reduce the
amount of waste from a launch.
For the majority of the
ordinary public space travel has lost its appeal. New technologies and
ideas under development rarely make the news, or at least are very poorly
publicised. In its early years the space race pushed technology further
and further, from the German V-2 rocket in 1942 to the first artificial
satellite Sputnik 1 in 1957, Major Yuri Gagarins’ orbit of the Earth in 1961and
the ultimate goal, the 1969 moon landing. 27 years after rockets really
showed their potential, man had landed on the moon. Ordinary people had
become fascinated with space. In contrast, ask someone today a recent
event in space and an informed response is unlikely, some may say the success
of the Mir space station or even the construction of the international space
station. I wish to discuss some new concepts in space travel and how they
could make space travel far easier and possibly within reach of the ordinary
man.
Let us first look at how
conventional space craft work and how they are launched. A re-useable
shuttle is launched into space carried by its own three Oxygen-Hydrogen engines
and two ammonium perchlorate-aluminium based booster rockets. These
boosters are jettisoned after the launch and fall back to Earth by parachute
where they can be refilled, but the enormous external fuel tank used to fuel
the shuttles three engines is jettisoned and lost, eventually burning up in the
atmosphere. The engines work on the principle that every action has an equal
and opposite reaction. The high pressure gasses forced from the rear of
the engines, push the craft in the opposite direction. The shuttle
re-enters Earths atmosphere , protected by thick ceramic based shielding stuck
to the fuselage, and lands on an airstrip as a conventional aircraft
would. The first problem when planning the launch of a spacecraft
is the weight. Some 90% of the take off weight of a conventional shuttle
launch is the fuel and boosters required to get the craft out into space.
An ingenious way of
overcoming this inefficiency is being developed using lasers, named the “Light
Craft”. At present feasibility tests have been carried out on
models. The results of these tests appear to be very promising.
This craft works by shinning a laser beam onto a parabolic mirror at the base
of the craft. This beam is reflected onto a skirt around the base of the
craft which causes the air within the skirt to become very hot. This
instantaneously expands to several tens of atmospheres and is forced out pushing
the craft forwards. Once out of Earths atmosphere the craft can inject
its own gas, from its own internal fuel tank, into the absorption/propulsion
chamber to continue its flight. The laser beam is pulsed to allow a fresh
charge of gas to enter the chamber. The pulsing effect can be seen by the
flashes on the slide. The test model was 6 inches in diameter and was
launched to a height of 100 feet. The problem with this method
prevented it going any higher and was caused by the heat generated from the
laser. The skirt became so hot it began to burn up and fall off, even a
titanium skirt could not withstand the heat. On an actual spacecraft
there would be the possibility of its fuel tanks also becoming heated.
Research in metallurgy and composite materials is producing materials that
should be suitable for the light craft.
The benefits of this system
are obvious, only the weight of the spacecraft needs to be lifted. This
would mean more ambitious projects could be attempted as a far greater load
could be carried into space.
Another idea is to have a
fuselage with an airfoil section that provides lift instead of wings.
This craft is then flown to the upper atmosphere either attached to another
larger aircraft or even using its own engines. The shuttle can then break
off into space. The cost of this system is considerably cheaper than
using boosters and should be far safer, effectively being the same as a normal
passenger jet take off. The shuttle will be effectively a very advanced
aircraft, able to perform as a conventional aircraft except using rocket
engines instead of jets or pistons. Several individuals as well as big
business have shown interest in this system including parcel courier giants
UPS. The idea being long distance travel, England to Australia for
example, could be shortened by up to 13 times by flying around the Earth
instead of through its atmosphere. There is no reason why this system
could not also be used to transport people around the planet. The
American government have also been researching wingless shuttle and aircraft,
known as X-craft, with great success and with advances in engine technology the
craft may even be able to take off as a normal aircraft does and fly into space
on its own with no external fuel tanks or boosters. A recent breakthrough
has been the development of a heat resistant material that makes up the
fuselage, which is lighter, stronger and more versatile than the conventional
method of attaching heat resistant tiles to a metal fuselage.
Another method of transport
in space is by using ion engines. These were theorised in the fifties but
have only recently shown their potential being used on the long range probe
“Deep space 1.” This form of engine works on the principle that like charges
repel each other. In the case of deep space 1 Xenon gas is ionised by a
method of electron bombardment. An electric field is created to repel the
Xenon ions out the back of the engine at an amazing speed. Another
electron emitter is used, which is connected to the main ionising beam, that
sprays electrons back into the exhaust ions. This stops the craft
becoming charged and a potential between the exhaust and craft being
produced. This engine can potentially travel much faster than a
conventional oxygen-hydrogen engine, however it does take far longer to reach
this speed due to the comparatively low mass ejected from the engine. The ion
engine can run for extended periods of time compared with chemical engines
which only use short bursts in order to conserve fuel. Ion engines are
limited by the extent to which the xenon can be ionised and the amount of
energy required to do this, as progressive ionisation through the 6p subshell
requires an increasing amount of energy. It would be almost unthinkable
to ionise into the 5d subshell giving a maximum charge of 6+. The
electric field that repels the ions is limited to the energy required.
The engine must also switch off for the craft to de-ionise itself.
I would like to suggest a
system that incorporates all three systems. A craft that at its base has
the necessary parts for laser propulsion incorporated into the chemical-ion
engine. The idea being that the craft can be propelled into space via a
laser system, once in space the more conventional chemical engine takes over
but, with a difference, the exhaust gases could be ionised and repelled from
the craft at a greater speed. This system would enable space craft to
either carry a greater load or travel faster, both reasons have enormous
commercial and scientific benefits.
It is obvious that space
travel really will make this a small world. With the increase in interest
by big business in space travel and its associated technologies, the leaps in
development will increase which in the long run will benefit mankind and earn
our generation the name of space explorers as those before earned the name of
space travel pioneers.
|
"DEEP
IMPACT" |
|
Danger
Detected In December 1997, danger
was detected in our skies, as a mile-wide asteroid heading towards the earth,
codenamed "1997 xf11". The danger was detected
by Jim Scotti from the University of Arizona, America. The mile-wide asteroid
was found by Jim at the Kitt peak observatory using advanced technology.
There they run a spacewatch programme to spot and plot the courses of near
earth objects, which might threaten earth. (OHP slide of asteroid) After the discovery of
the asteroid xf11 in 1997 was reported, two Japanese astronomers calculated
its collision course, using brightness and trajectory data. NASA has
confirmed the existence of the asteroid. The calculations show that the
asteroid xf11 will descend to earth on Thursday 26 October 2028. Early calculations show that
this mile-wide asteroid would produce a "miss distance" from earth
for xf11 of 500 000 miles, which sounds like a long way away, but is far less
than any previous prediction for an asteroid. Further observations suggest
that this mile-wide asteroid is orbiting the sun at 17 000 miles per hour and
will pass within 26 000 miles of earth in the year 2028. Effects of the
asteroid (OHP of an asteroid
impact) If the asteroid were to
fall and hit the earth the effects would be devastating. If xf11 landed at sea -
the Atlantic Ocean for example - the coasts of America and Europe would be
devastated by monster tidal waves, hundreds of feet high, travelling at
tremendous speeds, destroying everything in its path. Where cities once stood
there would only be mud flats. On land the explosion
would leave a crater 15 miles across. Anything for hundreds of miles around
would be destroyed. Huge earthquakes would be triggered and the blast heat
would cause volcano- like meltdown. So much dust would be lifted up that the
sun would disappear for weeks, plunging the world into darkness and a
prolonged cosmic winter. Millions would die in a total collapse of society. In the worst case
scenario - a direct hit - the asteroid could flatten cities, side sweep a
continent, or churn up tidal ocean waves. In the best case scenario, xf11
will whiz by in a beautiful flash, with Europe getting front row seats. In
the intermediate scenarios, the asteroid could brush close enough to earth to
take out satellite systems and send communications systems, cell phones and
your favourite television programmes haywire. The history of
previous asteroids
In 1908 on the morning of
June 30th at 0717 hours an asteroid did fall to earth. It fell in a small
area called Tunguska in Siberia, Russia. A Russian scientist called William K
Hartman has reconstructed the impact from eyewitness accounts and so far, has
projected three series of paintings of the impact. A giant fireball was seen
racing across the night sky. Then it exploded with the force of 1000
Hiroshima bombs. Sensitive instruments recorded seismic vibrations as much as
1000 km (600 miles) away. At 500 km (300 miles), observers reported
"deafening bangs" and a fiery cloud on the horizon. About 170 km
(110 miles) from the explosion the object was seen in the cloudless daytime
sky as a brilliant, sun-like fireball. Probably the closest
observers were some reindeer herders asleep in their tents about 30 km from
the site; they were blown into the air. An eyewitness said, "everything
was shrouded in smoke and fog from the burning fallen trees". Even larger objects have
hit the earth, but they are more rare. For example, an iron asteroid fragment
perhaps 100 metres across hit Arizona about 20 000 years ago leaving the
kilometre wide "Arizona meteor crater", and a 10 kilometre asteroid
hit earth 65 million years ago ending the reign of the dinosaurs. The 10
kilometre asteroid caused massive damage. Those that were not killed by the
impact or by the earthquakes starved to death from lack of food and water. The path of the
asteroid The asteroid's orbit
around the sun takes it past the earth's orbit every two years. An asteroid
travels through the solar system, xf11 takes 21 months to complete an orbit
of the sun. It is tugged by the gravitational force of the planets and sun. (OHP of an orbit) The exact arrival time of
asteroid Armageddon is calculated to be at teatime on Thursday 26th October
2028. Luckily, the asteroid can
be prevented from descending to earth. If the asteroid looked set to hit the
earth, a space mission would be launched to deflect it. A nuclear rocket
could be fired at the asteroid to change its orbit. We have the technology to
do so. The more dramatic methods were illustrated in two Hollywood movies
released in mid-April 1998. "Deep Impact" tells the story of an
impending comet collision, while "Armageddon" focuses on an
asteroid threat. Fortunately. asteroid
1997 xf11 will pass beyond the moon's distance from earth in October 2028
with a zero probability of impacting the planet, according to astronomers at
the jet propulsion laboratory, Pasadena, California. The asteroid is
predicted to pass at a rather comfortable estimated range from 40 000 miles -
closer than the moon - to 600 000 miles. Data on the asteroid from March 1990,
well before its discovery in December 1997, was integrated into orbit
calculations to arrive at the distance the asteroid will pass earth. If these new factors and
calculations are incorrect, then the original odds of the asteroid hitting
the earth still stand. The odds of xf11 hitting
earth are 1000 to 1. The odds of winning the
National Lottery in Britain are 14 million to 1! |
|
"THE
DESIGN OF A SPACE STATION" |
|
There are
many different ideas and suggestions as to the future of Earth and its'
relationship with space, both in scientific communities and also in science
fiction. One of the more popular suggestions is that, as the Earth's
population continues to rise at an ever increasing rate, it will eventually
reach such a level where the needs of the population, both in space and
primarily food, will exceed that available in the Earth's resources. This view of the
increasing population is known as the `pessimistic' curve. If the needs of
the general population exceeds what is available then many would die,
primarily from starvation. One suggestion to counter
this is the development of human habitats away from the Earth i.e.- on different
planets or in space. This project is aimed at the development of a possible
design for such a facility in space, where a community could live in space,
either in transit or possibly as a permanent home. There are however, both practical
and health problems associated with humans spending prolonged periods of time
in space. Many of these problems stem from the fact that in space there is no
gravity. This can result in many health problems which have been demonstrated
in cosmonauts on various missions. In zero gravity the heart
muscles grow weaker and the heart steadily shrinks, muscles lose their tone
and gradually weaken. The worse effect though, of zero gravity is on the
human skeleton. On Earth bones renew themselves approximately every 6 months.
In zero gravity, while the calcium in an astronaut's bones disappears at the
same rate as it does on Earth, new bone growth dramatically slows down. The
result is that, over time, the skeleton becomes increasingly brittle. There are also many
practical problems, such as eating, which are created by a zero gravity
environment. Food and water would also need to be easily available to the
inhabitants. The design would also
need to be as resistant to radiation as is possible. This is because
radiation is always a hazard in space, particularly at the time of major
solar flares, as these release high energy protons capable of piercing simple
shield systems. During non-flare periods though, the annual radiation dosage
would be very much higher than is considered safe background radiation on
Earth. (20 times greater). The basic shape of the
space station will be a thin cylinder shape, resembling that of a doughnut,
which will continuously rotate, producing centrifugal force which would, to
some extent, produce a gravity mimicking that on Earth and also reducing some
of the problems, both practical and health related, which arise from being in
such an environment for prolonged periods of time. Within the Station there
would obviously be many rooms and facilities, including a medical bay
carrying complex medical equipment in case of any emergency. Persons residing
in the facility would have to be trained medically to cope with many
scenarios. Another room which would be very important to the health of the
residents would be a gymnasium. This would be vital as it is important that
the inhabitants exercise regularly to try to combat weakening of bones and
muscles caused by lack of gravity, particularly the heart muscle as any
significant weakening of the heart muscle could prove fatal. Another major problem
which would have to be overcome is that of food and water. It may be possible
to some extent to cultivate crops in an artificial, contained environment,
although it is not known how many species would react well to being grown in
that environment. It would, though, also help to regulate the atmosphere,
both taking in carbon dioxide and giving out oxygen (generally). Depending on
the location of the facility, light may be readily available. Water would have to be
recycled, using filtration plants, which along with the water would also
process urea and carbon dioxide from the inhabitants to produce purified
water and oxygen. An alternative method of producing water which could also
be used would be to produce water as a by-product of the fuel cells, which
would create electricity by combining hydrogen and oxygen. This would also
have a good availability of fuel, particularly as cultivated crops and plant
species, if successful, would give off oxygen from carbon dioxide. Most of the power used
within the facility though, would be generated from solar panels located on
the outside of the facility. The output of these would be greater than those
located on Earth as the time in which they are in sunlight would be much
longer, and there would be no obstacles (depending on position of facility)
to block the sunlight (i.e. cloud cover). One essential facility
would be a docking bay, by which ships could enter or leave quickly and
frequently bringing any supplies not available, and also providing the
inhabitants with the chance to commute to and from Earth if they needed to. If a large colony were
established then there are also many practical facilities which would have to
be established. One example of this would be sports facilities, such as
tennis courts, or possibly swimming pools could be included. Various
entertainment facilities, such as films would also be available. There would
also be portholes to allow the residents a view of the space which they are
inhabiting, but importantly to allow light (depending on location) to enter.
This would be particularly important for any plant or wildlife species living
there. It would be fundamental
to the facility to be adequately manned, initially set up with many experts.
Not only cosmonauts, but also botanists, doctors, psychologists etc. would be
required for the setting up of such a facility and also for the maintenance
and upkeep of the facility once it is up and running. It would be advisable
to introduce plant and wildlife species into the facility as soon as possible
so that the facility is not too reliant on supplies from Earth to continue
functioning. The initial setting up
and most of the building of the facility would have to be conducted in space,
with welding being used to construct trellis work beams, from materials such
as graphite/epoxy resin. An initial quantity of fuel which could be stored on
the facility, along with other supplies, would be required to initiate the
rotation of the facility, producing the centrifugal force essential to the
running of the facility, as well as for emergencies. There would have to be
many precautions taken on the facility to protect it from the hazards of
space such as debris and comets. If possible a radar system could be
installed to detect possible threats early and steps taken to ensure the
safety of the facility, such as trying to alter the course of the threat, or
in extreme cases, moving the whole facility. The material used would have to
be strong enough to protect against impact from minor debris. Although a facility, such
as I have described, would be as close to self sufficient as is possible,
many supplies may still be required from Earth, although as many as possible
would be stored, particularly food supplies and equipment needed to make any
repairs or corrections to the facility as would be required. Airlocks? My design for a facility
is done using current technology and, as space research is ongoing, it is
very likely that new methods and equipment will be produced which would
further aid the setting up of a space station, should it become necessary in
the future. Personally, I feel that
it is likely that such a facility, which is permanently manned and inhabited
would, in the future, become a reality, with children being born there
considering the facility their real home, as opposed to an Earth which they
would rarely, if ever visit. |
|
"COMMUNICATION,
HOW TO TACKLE THE DIFFICULTIES" |
|
For
thousands of years man has looked up to the stars with longing and questions.
In the last 40 years man has taken his first steps out into the universe with
Yuri Gagarin's first orbit in 1961 and Apollo 11's first lunar landing in
1969. Today we stand at the forefront of a new age of space exploration as in
the coming years we will see the launch of the first sections of a new
International Space Station. Now for the first time together, we will embark
into the vast and unknown universe. We should now make plans for the
possibility that as we travel off into space we may encounter other such
explorers from distant solar systems. In the past all of our
manned explorations have been within the earth's orbit. However we have sent
out numerous probes, such as the Pioneer and Voyager missions. Both of these
had preparations for the possibility that they could be our first
ambassadors. Both the Voyager 1 and Voyager 2 had an audio message on board.
This began with the 59 greetings in a range of languages, it also included
encoded pictures, various sounds and a collection of music dating back to a
3000 year old piece from the Chin dynasty. The Voyager 1 has now travelled
further than any other man made object and will soon reach terminal shock.
The Pioneer 10 and 11, however, chose to use a pictogram. This was of a man
and woman, our location according to 14 pulsars and within our solar system
and a representation of a hydrogen atom. Many people have
developed theories and designed formulas to determine the quantity of life
that exist outside of our planet. One such man was Frank Drake who designed
the formula: N=RxfpxnexflxfixfexL N = The number of
detectable civilisations in space. This is an estimate of
the number of extant technological communicating civilisations that might
exist in the universe. He made many variations on this formula, such as the
number of civilisations that would choose to communicate. Even after 37 years
this equation still creates conversation at SETI. I intend now to look at
the different methods of communication we would use and what their
probabilities are for confusion rather than understanding. There is a major flaw
when considering a verbal or written communication with extra-terrestrials in
the fact that we often speak in slang or phrases. So that even if they had
developed some sort of dictionary on their long journey here, they would not
be able to understand some of what we said and this would create confusion or
worst. For example, I have a Russian to English dictionary at home and if I
wished to write "how do you do?" to my Russian pen friend, I would
write"……!" which a Russia would no doubt understand. However if
that Russian was to write to me they would write "…..!" which I
would not understand without a phrase book. But consider for a moment
that they do have a perfect dictionary, the question still remains which ONE
of the hundreds of human languages do we use to represent our race for the
first time. Another possible form of
communication is sign language as suggested in the popular movie 'Close
Encounters of the Third Kind' where visiting aliens use sign and music to
communicate. Both of these however are impractical as there music could be
structured on different principles to our own and this again would lead to
confusion. Sign language adopts the same flaws as spoken language, because
that is what it is designed on. Using pictograms is a
favourite of many, but this could also be shown to have flaws. Take this
picture of a man running, for instance. We all know him to be running as we
have been brought up to recognise this position as being a man in mid stride.
However an alien unaware of our style of motion may see something quite
different. Michael Arbib agrees with
this theory and showed in a recent article in the SETI Quest magazine that if
you simply turn a pictogram over it can appear as something quite different
than that which it was designed to. This is a pictogram designed by Frank
Drake. It was designed to show us, our location, and various chemical
structures comment earth. But when it is turned the representation of a human
becomes a satellite with a link to Earth and four frequencies for
interstellar communication. The representations of the carbon and oxygen
atoms now become a six legged animal with a very large brain. Physiologists have looked
at the different ways people see things for years now. In the first year of a
physiology course, Advanced-level students are asked to investigate what
people see when they look at this picture. (Ask those around to say if
they see and old or a young women in the picture. ) This shows us how
pictograms and even photos are entirely up to how an individual personally
perceives things. Mathematics can also be
suggested as it is the language of science, something that anyone must have
discovered in order to travel the vast expanses of space that separate us
from our nearest neighbours. To communicate we would need to create a formula
on which we then encode our message. The advantage of this is that the lesson
on how to read the message is within the message itself. Carl Sagan used such
an idea in his film "Contact". He devised a simple equation. 2+2=4
TRUE, 2+3=4 FALSE. On this the rest of the message was based. Along the same
lines as this is the idea of binary, which is the simple language of the
computer in which there are only two symbols, 0 which means off and 1 which
means on. The use of binary code would allow us to transmit pretty much
anything that we wanted. Both binary and a mathematical
formula have a notable advantage in the fact there is verv little room for
confusion as in each instance it is either on or off, or true or false. They
can also be easily transmitted out into space at an on coming ship or a
planet we believe to be inhabited by intelligent life. For these reasons I find
that either binary or a mathematical formula would be a more practical method
of attempting first contact with an alien race. |
|
"MEASURMENT
OF THE GRAVITY ACCELERATION USING A COMPUTER" |
|
When I
started working on this project, the main purpose was to use an experimental
track, which existed in the physics laboratory of my school, for the
performance of experiments related with the motion of a mass on an inclined
plane i.e. experiments like those which Galilee performed in order to
investigate the free fall of masses to the earth surface. I used a computer
for the measurement of time as well as for the construction of the graphs of
distance, velocity and acceleration as functions of time. Soon I realized,
that the method I had followed and the program which I had created for the
computer could be easily used for the study of many other more complicated
forms of motion. The experimental
investigation of the motion a mass on a predefined path in the determination
of a sufficient number of points of the function S = S ( t ) For this purpose, we mark
n + 1 points (0, 1, 2, ..., n) ordered along the path of the mass and we
chose 0 as the initial point i.e. the point from which the motion starts.
Suppose s1, s2, ..., sn are the distance of
these points from 0, then the distance between two one another following
points is given by the relation delta Si = Si - Si-1
where i = 1, 2, 3, ..., n
(n distances). On the mass is fixed a pointer, which is shaped so that during
its motion we can clearly indicate the moment at which the mass passes
through each of the points that are marked along the path. If t1,
t2,..., tn, are the times which the mass needed to
cover the distances 51, 52,..., 5n then delta ti = ti - ti-1
(where i = 1, 2, 3, ...,
n and 10 = 0) are time intervals which the mass needed to cover
the distances delta Si.
Every couple of values (ti,
si) corresponds to a certain point of the function s = s ( t ),
which can now be approximated and described graphically with a sequence of
one another following linear sections (broken line), the ends of which are
defined by these points. The approximation of the function s = s ( t ) is as
better as smaller are the distances s between the points which are marked
along the path of the mass and of course as higher is the accuracy of the
measurement of t1, t2, t3 . The average velocity V of
the mass in an interval S can be calculated from the relation Vi = delta Si/ti Under the presupposition
that the distances S and the time intervals t are short enough, we can
approximately suppose that V is the value of the function v = v ( t ) in the middle of the time
interval delta ti
i.e. the instant velocity of the mass at the moment ti = ti+1
- delta ti/2 (where i = 1, 2, 4, ...,
n). We can now approximate the function v = v ( t ) with a broken line which
is defined by the points (ti, vi). In a similar way we
can then approximate the function of the acceleration of the mass a = a ( t ). The most difficult
problem in the experimental investigation of the motion of a mass on a
predefined path is the exact measurement of the time at the sequential
positions which it passes through. The measurement of time can be done with
high accuracy, if we use for this purpose appropriate methods which take into
account the capabilities of the electronic devices. The method which I
applied is the following: Along the path of the
mass and at the predefined positions s0, s1, s2,
..., sn are arranged photo gates which are suitable connected with
a special electronic circuit. The circuit sends an electric pulse to a
computer each time that the mass passes through a photo gate. The
identification of the pulses from the computer is achieved by using a second
electronic circuit (interface) which the computer must be equipped with. The
function of this circuit is to recognize voltage changes at the input of the
interface and to transmit them to the processor of the computer. With an
appropriate computer program the function of the interface is constantly
controlled, the entering pulses are recognized and the moments of their
arrival are registered to the computer memory. Then the program calculates
the time intervals that the mass needed to cover the distances delta si between the photo
gates. By processing the registered data the computer reconstructs the form
of the pulses, creates the tables with the values of the functions s ( t ), v
( t ) and a ( t ), constructs the corresponding graphs and presents them on
the monitor of the computer or prints them to a printer. The system
computer-interface-program does not only provide a high accuracy in the time
measurement (the accuracy depends on the quality of the interface - with the
interface I used the accuracy was of the order of 1/10000sec.) but also a
high speed and accuracy to the process of the experiment's data as well as by
the creation of the corresponding tables and graphs. Obviously, a system like
this can be used in many other analogous laboratory experiments which
investigate the motion of masses and especially when the duration of their
motion is very short. I have created the
computer program in the language Turbo Pascal v6.0 and it is available as a
source and as an executable code on a disk which can be used directly for the
performance of any experiments of this kind. |
|
"FUTURE
POSSIBILITIES OF THE MOON" |
|
The
inspiration for my presentation was thought up as a result of attending a
lecture on space given by Professor Heinz Wolf during the 1998 Easter Space
School at Brunel University, London, England. The Moon has proved to be
an accessible body in our Solar System but has not yet been exploited to its
full potential (the last manned mission was 1972). My presentation will open
up many possibilities the moon has to offer and give predictions as to
whether they will go ahead. KEY FEATURE The satellite "
Lunar Prospector " discovered the existence of water around the poles of
the Moon. This water is thought to remain in large blocks of ice after a
comet (carrying the water) collided with the Moon. This discovery is a bonus
and opens up many new possibilities such as rocket fuel as this consists of
mainly Hydrogen and Oxygen, the 2 main elements of water. The fact that we
need water to live is also important with this discovery as now food can be
grown making us more self sufficient. (OHP picture of base) For the Moon to be used
effectively a base would need to be constructed in a suitable location. The
position for the moon base would be carefully decided by its closeness to water,
closeness to metal ores (as many metals such as magnesium and aluminium, iron
and titanium exist on the moon) and a suitable land site. The land site would
be picked, preferably on flat ground with hills surrounding to protect from
meteorites. FEATURES OF THE SITE To utilise the Moon's
resources the technology needed would require an electric power supply. This
would be provided by the large number of solar arrays. The mine pictured will
use nuclear blasting to extract the metals and water. Due to the large number
of people needed to run the lunar base, buildings will be constructed to
house the crew, engineering, communications and food supplies. Small components, built
on the Moon, such as probes and satellites can be catapulted along a thin
shute to reach orbit. This will save money as rocket take off is avoided. BENEFITS One of the benefits the
lunar base has to offer is the lack of atmosphere. This will be favoured by
astronomers especially as they can view the stars without interference from
the atmosphere. But by far the biggest advantage the Moon has to offer is the
low gravity. Many beneficial features
come out of this like the way it can eliminate expensive multiple stage
rocket take offs, also future space ships intent on taking man to other solar
svstems can be built and launched . (OHP picture of floating
astronaut) The low (1/6th Earth)
gravity was said to be very pleasant by all 12 of the Apollo astronauts. This
is an important factor as the crew's attitudes will be improved if a pleasant
working environment is provided. (OHP picture of fuel
shipment) Rocket fuel produced on
the moon could be shipped to low Earth orbit to be used by facilities like
the International Space Station, future missions, satellites etc. "It seems paradoxical
that it's cheaper to ship fuel from the Moon 390,000 km away instead of
launching it just 480 km away from the Earth, but those are the economics
dictated by the relative strengths of gravitational fields " The following small
equation demonstrates an advantage which the Moon's low gravity gives when
launching objects into space, through rocket take off :- If the weight of a rocket
on Earth = 5000 Newtons (N) If the Rocket produces
25,000 N thrust Force = Mass *
Acceleration Therefore there is a
considerable saving on fuel and money. (OHP picture of safety) SAFETY A base on the Moon would
be exposed to many hazards that (on earth) would normally be filtered out by
the Earth's atmosphere e.g. micro-meteorites and radiation from the sun.
These dangers would need to be thoroughly analysed and preventative measures
taken to avoid deaths or equipment failure, so some form of underground home
for the crew should be considered. MONEY ISSUES The Moon project is
obviously going to need a large amount of money invested to initially build.
However many money saving assets are provided by the facility (OHP picture of tiles) Thermal Insulating tiles
are essential for space crafts during re-entry to Earth. However these are
very expensive and, due to large amounts of them being needed, are also very
heavy. These tiles will not be needed during re-entry to the Moon as there is
no atmosphere to generate the heat. Here on Earth the task of
sending even the smallest pieces of equipment into space is difficult and
requires many heavy and expensive multiple stage rockets. Billions of pounds
of money has been wasted due to rocket failure over the years, such as the
fairly recent Ariane 5 (European) and also Titan (American) rockets. The fact
that such rockets are no longer needed on the Moon means that a lot of money
will be saved with the lack of failure. To fund the project many
ideas have been looked into such as tourism. This would involve the public
being able to have short trips to the Moon but at a rather high cost,
nevertheless there has already been some enthusiasm from the Japanese. SOCIAL ISSUES If the project went ahead,
large numbers of people would be required to live on the Moon in order to
build, carry out tasks and maintain the base. The question is therefore
raised whether the families of the cosmonauts would also go along, due to the
journey time of the mission being many years. There would obviously be
large amounts of money needed to send a family, but if the general attitude
of the workers was greatly improved by the presence of their families then it
would be a serious issue to consider. CONCLUSION Using the Moon as a
resourceful object would be difficult. The project needs money, public
enthusiasm and has to exceed the benefits that alternative missions can
offer. However when those issues can be seen to be profitable or advantageous
then a similar project must surely happen one day. |
|
"THE
MILKY WAY" |
|
Project
Annotation: Research shows that the Milky
Way galaxy has characteristics which classify it as a normal spiral galaxy.
This knowledge is key in further understanding of our galaxy and solar
system. Thesis: For hundreds of years,
man has attempted to determine the shape of our galaxy and its resemblance to
other galaxies. Analogy with other galaxies having stellar populations
similar to that in our own galactic neighborhood suggests that our own galaxy
should be a spiral nebula with arms that extend 100,000 light years and over
100 billion stars. Thus, the Milky Way is usually classified as a normal
spiral galaxy. However, recent evidence has suggested to some astronomers
that it might be a barred spiral, although it is difficult to know for sure
because we can never see our galaxy from the "outside". A galaxy is a system of
stars that includes relatively large amounts of dust and rock, along with
other heavenly occurrences. The universe contains three primary types of
galaxy with a variation in one of the types. Spiral galaxies consist of a nucleus
or center of bright stars and flattened arms that spiral around the nucleus.
The spiral arms contain millions of stars. Some astrophysicists suggest that
tightly compacted nucleus is powered by the movement of matter toward a black
hole which will eventually emerge as a quasar, emitting prodigious amounts of
energy. The variation, the barred spiral galaxy, has the normal spiral
properties as well as having a bar of stars that runs through the center.
Elliptical galaxies vary in shape from nearly spherical to flattened disks.
They contain very bright centers and have no spiral arms. They contain very
little dust and gas and generally older than other types of galaxies. The
final type, irregular galaxies, have no particular shape. They tend to be smaller
and fainter than other types of galaxies. Some astronomers think that the
irregular shapes of these galaxies might have been caused by explosions at
their centers. The star forming an irregular galaxy are unevenly distributed
in the galaxy. Evidence identifying a
spiral galaxy is relatively recent. In 1951 W.W. Morgan and others recognized
this phenomenon. From the distribution of hot, bright stars and of regions of
ionized hydrogen, Morgan was able to identify portions of three spiral arms:
the Orion arm, the Perseus arm, and the Sagittarius arm. That was as
sophisticated as the models got until recently when the Cosmic Background
Explorer (COBE) space craft allowed researchers to construct the best model
to date. Astronomers have long
assumed that the Milky Way is a spiral galaxy, but direct visual evidence had
been extremely sparse. Although the sun orbits near the age of the Milky Way,
observation from Earth make it difficult to see through the dust that is
present throughout the arms and center of the galaxy. At visible wavelengths
only the relatively dust free parts can be seen. The new portraits of the
Milky Way combine images taken from free near-infrared wavelengths: 1.2
microns, 2.2 microns and 3.4 microns. They correspond to the wavelengths of
stars rather than dust particles, which absorb visible light. The only
drawback of the COBE system is the limitations of images of the arms. Information about
galaxies can be collected in two ways. First, telescopes such as the Infrared
Telescopes (IRT) and the Hubble, collect information on galaxies and provide
good photographs on the inside of galaxies. Second, the radio penetrates to
far greater distances than the optical methods and has led to fairly
extensive pictures of spiral inner structures. With each new discovery
and innovative invention, it becomes more apparent that additional
information is needed. The results of many investigations to this point in
time suggests that our galaxy is spiral nebula of E.P. Hubble's type Sb with
both spiral arms and nucleus well developed. |