pulsar gravity-wave data search einstein at home written by jamaal johnson aka jjohn
TRANSCRIPT
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
1/39
PULSAR GRAVITY-WAVE DATA SEARCH at SOUTHERN UNIVERSITY:
EINSTEIN@HOME
____________________
A THESIS
Presented to the
Honors College at Southern University
Baton Rouge, Louisiana
____________________
In Partial Fulfillment of the Requirements for the
Honors College Degree
____________________
By
Jamaal N. Johnson
May 2006
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
2/39
Honors College
Southern University
Baton Rouge, Louisiana
CERTIFICATE OF APPROVAL
____________________
HONORS THESIS
____________________
This is to certify that the Honors Thesis of
Jamaal N. Johnson
has been approved by the examining committee for the thesis requirement for theHonors College degree in Computer Science.
___________________________________
Advisor
___________________________________Chairman, Honors Advisory Committee
___________________________________
Dean, Honors College
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
3/39
ACKNOWLEGEMENT OF RESEARCH
This research was supported by the National Science Foundation Grant
No. PHY-0101177.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
4/39
PULSAR GRAVITY-WAVE DATA SEARCH at SOUTHERN UNIVERSITY:
EINSTEIN@HOME
____________________
An Abstract of a Thesis
Presented to the
Honors College at Southern University
Baton Rouge, Louisiana
____________________
In Partial Fulfillment of the Requirements for the
Honors College Degree
____________________
By
Jamaal N. Johnson
May 2006
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
5/39
ABSTRACT
And God said Let there Be Light and it was so. However, before light there
were large bodies of Masses created and science suggests that the creation of these
landforms emitted gravitational radiation. According to Einsteins General Theory of
Relativity, gravity waves do in fact exist but as of date they have not been detected.
The LIGO research project has implemented three interferometers with the
capability to detect a gravitational wave, should one exist. With the implementation of
these interferometers and the constant tweaking of the instruments components, the
LIGO project has had and will have a profound impact on the world of science. This
impact will occur whether a gravity-wave signal is ever detected or not. This holds true
not only because of the improvements it has made in science but also on the view on
science as we know it. If a wave is not detected, then this will cause scientists to go back
hundreds of years and research the validity of many scientific principles that are being
taught in curriculums around the world.
v
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
6/39
ACKNOWLEDGEMENTS
First and foremost I would like to give reverence and thanks to my personal Lord
and Savior Jesus Christ for giving me strength, a sound mind, and the thirst for
knowledge to complete my years of study. I want to also thank him for blessing me with
a loving mother who was strong and who instilled principles of research and learning
inside of me at a young age. I love you MOM and I want to thank you for always taking
care of and loving hard for your children. You have done an excellent Job. I want to also
thank my Father for providing me with a home environment suitable for obtaining a good
education. You have always worked hard to provide for us and I will always remember
that. You helped me to become the man I am and I want to thank you for that. Also,
thanks Torie and Brittany, my two loving sisters who will do anything that they can for
me. I love you both dearly.
Next, I want to thank my Dear Aunt Beulah J. Clark. My Aunt Beulah has been
my mentor from the moment I moved to Baton Rouge, LA at the age of 12. There is
nothing I have asked of her that she hasnt done for me. Thanks so much Auntie. You
are wonderful!
Next, I want to thank the Honors College for your assistance in obtaining my
degree. Your funding and guidance have allowed me to focus on my books and get a
jump start on understanding what I was in college to do. I want to also thank the
Department of Computer Science. I prefer to call it the Family of Computer Science
vi
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
7/39
because I feel you all truly care about your students and I feel that I can come talk to
anyone of you about anything. Especially Mrs. Betz, Mrs. Roquemore, Mrs. Johnson,
and Mrs. Ricard. I love you all.
Last but certainly not least, I want to thank my advisor Dr. McGuire. You helped
to open up my mind in areas of Science that I never knew existed. You are a very
knowledgeable person and I truly appreciate the knowledge that you have allowed me to
obtain through this project. Thanks.
vii
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
8/39
TABLE OF CONTENTS
Page
ABSTRACT.v
ACKNOWLEDGEMENTSvi
LIST OF APPENDICES..x
LIST OF FIGURES....xi
CHAPTER
I. BACKGROUND OF STUDY...........1
Introduction.. 1
Overview of LIGO: Purpose of Study 2
Significance of Study3
II. LITERATURE REVIEW..6
High Sensitivity Accelerators for Gravity Experiments6The Computational and Storage Potential of Vol. Computing..7
High Performance Task Distribution for Volunteer Computing...8BOINC..9
III. METHODS AND MATERIALS/METHODOLOGY.10
Einstein@Home Begins...10
Implementation of the Software...12
What Are Pulsars..13
The LIGO Screensaver.14
IV DATA.. 16
Search For Data16
Pulsar Gravity Radiation..17
Southern Universitys Search Credit...18
viii
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
9/39
V. CONCLUSION/SUMMARY..................................................................20
BIBLIOGRAPHY..............................................................................................................22
APPENDIX 1.....................................................................................................................26
APPENDIX 2.....................................................................................................................29
APPROVAL FOR SCHOLARLY DISSEMINATION....................................................30
VITA31
ix
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
10/39
LIST OF APPENDICES
Appendix Page
1. An Interview With Dr. Stephen C. McGuire 26
2. Interferometer Diagram 29
x
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
11/39
LIST OF FIGURES
Figure Page
1. SETI Dish Radio Telescope.... 102. Order Phase of Two Neutron Stars Colliding. 11
3. Jocelyn Bell and Pulsar Signals.. 13
4. Diagram of A Pulsar14
5. Einstein@Home Screensaver..156. Rotating Pulsar18
7. Southern Universitys Cobblestone Credits19
xi
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
12/39
Pulsar Gravity-Wave Data Search at Southern University: Einstein @Home
Chapter 1Background of Study
Introduction
Albert Einstein was one of the greatest scientific minds in world history. Einstein
is known as a brilliant physicist who contributed more to the scientific world than any
other person. His theories on relativity paved the way for how science currently views
time, space, energy, and gravity. Einstein was so advanced in his thinking that his studies
and work set the standards for the control of scientific energy and space explorations
currently being studied in the field of astrophysics.
Albert Einstein predicted the existence of gravitational waves in 1916 as part of
the gravitational theory of general relativity. However, it is only now through The Laser
Interferometer Gravitational-Wave Observatory (LIGO), that this investigation has begun
to take place. As an experiment, LIGO seeks to make the first direct detections of the
elusive gravity waves predicted by Einstein.
According to the general theory of relativity, space and time are two different
aspects of reality in which matter and energy are ultimately the same. Space time can be
thought of as a fabric defined by the measuring of distances by rulers and the
measuring of time by clocks. The presence of large amounts of mass or energy distorts
this fabric and causes it to warp. This warpage of space-time is called gravity. Freely
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
13/39
2
falling objects (satellites, soccer balls, beams of starlight) simply follow the most direct
path in this curved space-time.
Overview of LIGO: Purpose of Study
So, what exactly is LIGO? Well, as indicated above, the acronym itself stands for
Laser Interferometer Gravitational Wave Observatory. However, the project itself is a
great deal more complex. The LIGO project deals with the detection of astrophysical
sources of Gravitational Waves. There are four types of events that would emit these
waves: The collision of extremely dense objects such as neutron stars and black holes;
the violent explosion and collapse of stellar systems via supernovae; pulsars which are
currently being searched for in the Einstein@Home Project; and gravity-wave remnants
of the event that scientists believed started the physical universe (1).
When large masses move suddenly, some of this space-time curvature propagates
outward, very similar to ripples of a pond struck by a rock. So we can take a closer look
at the neutron star theory. A neutron star is the burned out core often left behind after a
star explodes. It is very dense and can carry as much mass as the sun. Yet, it is only
about a two or three mile diameter sphere. When two objects this dense orbit each other,
space-time is stirred and gravitational energy ripples throughout the universe.
In order to detect these ripples, scientists must have the techniques and the
technologies to do so. This capability is managed in LIGO. The first detectors designed
to detect gravity-waves were built in the 1960s by J. Weber of the University of
Maryland (2). A second generation gravity-wave detector, the LIGO interferometer, will
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
14/39
3
detect the ripples through the universe using a device called a laser interferometer. The
Interferometer measures the time it takes for light to travel between suspended mirrors by
using controlled laser light (see appendix 2). Two mirrors hanging a far distance from
each other make up one arm of the interferometer and a perpendicular make up forms the
other arm. The shape of the interferometer is an L. Laser light enters the arms through
a beam splitter located at the corner of the L, dividing the light between the arms. The
light can bounce between the mirrors many times before it returns to the beam splitter. If
there is any difference between the lengths of the arms, some light will travel where it
can be recorded by a photo detector. The space-time ripples cause the distance measured
by a light beam to change as the gravitational wave passes by, and the amount of light
falling on the photo detector to vary. This distance is exceedingly small, 10-18m, so that
laser interferometry is needed in order to perform the measurement. The photo detector
then produces signals that define the variation of light falling on it over time. The laser
interferometer converts gravitational waves into electrical signals much like a
microphone converts sound waves into electrical signals. However, there is a catch.
There must be at least two widely separated detectors, operated in unison, to rule out
false signals and to confirm that a gravitational wave has in fact passed through Earth.
Thus, three interferometers of the same kind were built two near Richland, Washington,
and another near Baton Rouge, LA (see Appendix 2). The idea is that because these
gravity waves travel at a finite speed, 3.0 * 108m/s (speed of light), there is only a short
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
15/39
4
amount of time allowed between an occurrence in one interferometer and a showing in
the other. This time frame is about 10 milliseconds.
Now one may ask: what else will these interferometers and photo detectors see.
Well, given their sensitivity to vibrations, they will pick up a variety of signals. These
signals may be anything from earth quakes to earth tides. So, with this in mind, how will
the LIGO detectors identify and differentiate these signals and those of gravitational
wave ripples caused by the crashing and merging of neutron stars? The following
paragraph will explain how.
Along with the development and implementation of the interferometers,
theoretical expressions have been calculated that describe the signal of a gravitational
wave caused by such astrophysical changes in mass distributions. With the density, size,
and speed of these neutron stars, specifications or detailed features of the event can be
theoretically predicted so as to produce the types of signals that we expect to see. To
even further distinguish these signals, they can be compared to supernova stars and
quasars which produce periodic wave signals. It is expected that the signals produced by
the gravitational wave ripples will in theory be much more a-periodic and irregular (3).
Significance of Study
In order to find such signals in gravitational wave data, a huge capacity of
computing power must be used. Estimates indicate that searching gravitational data
with the maximum possible sensitivity would require many times the computing capacity
of even the most powerful supercomputer. This is where the Einstein @ Home Project
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
16/39
5
becomes a major player in the scope of the LIGO Project. Einstein @ Home searches
data from the three observatories for any type of signal that may come from dense,
rapidly rotating quark and neutron stars (4). According to Einsteins theory, if these stars
are not perfectly spherical, they should continuously emit gravitational waves (4). The
three observatories now contain enough sensitivity where they would detect signals if the
signals were close enough to earth.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
17/39
Chapter 2
Literature Review
The LIGO project is a very new project so the types of Literature wont be found
in the traditional places where one may be accustomed to researching information. Most
of the material that is out for research will be in the form of theses, scholarly journals,
and magazine articles.
High Sensitivity Accelerators for Gravity Experiments
This thesis paper was written by Alessandro Bertolini and it talks about the first
detection of a gravity wave signal as the main goal in this gravitational experiments;
more specifically the LIGO project. He tells how the LIGO project uses three large laser
interferometers to obtain data that could possibly be from gravitational waves and how
there are many research and development groups who are constantly working to improve
the components of the lasers, the antennas, the optical scheme, the quality of the mirror
and their suspension system. The proper functionality of all these components is
essential in order to properly detect a wave source from the explosion of pulsars.
This thesis is divided into seven chapters. Chapter one gives an introduction of
the gravitational wave principles and an overview of the possible sources where a
gravitational wave can be detected. In Chapter two, the LIGO interferometers are
reviewed. Here, he discusses about the principles of their operation, the components of
the interferometers, and their limitations to sensitivity. Chapter three describes the
Seismic Attenuation Systems attenuator design and operation. It is estimated that a
typical gravity wave event will shake masses a few kilometers apart by a distance of .
000000000000000001 meters or less. The aim of the earth based interferometers
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
18/39
7
antennas is to detect this displacement in the frequency range of a few Hz and a few kHz.
This is so it can be distinguished from the low frequency fluctuations of the gravity field
of the Earths crust. This very important concept is discussed in chapter three. Chapters
four and five discuss the horizontal accelerometer. A horizontal accelerometer is able to
read accelerations which occur in a longitudinal direction. These chapters go into detail
about the design features, the physics of the instrument, the materials and machining
issues, the electronics of the accelerometer, the capacitance position sensor (determines
the position between two opposed electrodes), the feedback system and the noise feature.
In chapter six, preliminary applications of the accelerator are presented and in chapter
seven, a new tunneling displacement sensor is introduced (5).
The Computational and Storage Potential of Volunteer Computing
This is a paper submitted for publication by David P Anderson and Gilles Fedak
about the positive potential of a phrase they termed Volunteer Computing. It says that
Volunteer Computing uses internet-connected computers as a source for computing
power and storage. The computers are volunteered by their owners and they are used to
compute large quantities of data and information to an ongoing research project. The
paper studies the potential capacity of volunteer computing and during their research they
analyzed measurements of over 330,000 hosts participating in a volunteer computing
project. The measurements included processing power, memory, disk space, network
throughput, host availability, user specified limits on resource usage, and host churn.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
19/39
8
They show that volunteer computing can support applications that are significantly more
data intensive and have larger memory and storage requirements.
High Performance Task Distribution for Volunteer Computing
This is a paper written by David P. Anderson, Eric Korpela, and Rom Walton. It
discusses the task server power that is involved in Volunteer Computing (6). Volunteer
Computer projects use a task server to manage work. Participants PCs will periodically
communicate with the server to report completed tasks and to get new tasks. In the LIGO
project, tasks are basically bits of information that need to be inputted and analyzed. The
rate at which the server can dispatch tasks may limit the computing power available to
the project. This paper discusses the design of the task server in the Berkeley Open
Infrastructure for Network Computing (BOINC), which is the software used for volunteer
computing in the LIGO Project (see p. 12).
In this paper, they show measurements of the CPU time and the disk input and
output used by a BOINC server. They show that a server used by a single inexpensive
computer can distribute about 8.8 million tasks per day. With two additional computers,
this increases to 23.6 million tasks per day.
BOINC: A System for Public-Resource Computing and Storage.
LIGO uses the BOINC software for Volunteer Computing. David P Andersons
Paper on the BOINC software talks about how it makes it easy for scientist to create and
operate public-resource computing projects. It tells how the software supports diverse
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
20/39
9
applications, including those that have large storage or communication requirements,
such as the LIGO project.
The BOINC software allows participants to be active in various BOINC projects
and it allows them to specify how their computer resources are allocated. The paper
describes the goals of BOINC, the design issues they confronted, and their solutions to
these problems.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
21/39
Chapter 3
Methods and Materials/Methodology
Einstein @ Home Begins
Einstein @ Home is a project developed to search for the gravitational waves
predicted by Einsteins Theory. It relies upon the donation of idle computer time from
potential users around the world. The Einstein @ Home project was made available to
the public on Saturday February 16, 2005 (7). It is a home based program that uses the
same basic platform as SETI @ Home (8), which had about 5 million users who shared
their computers to search for data that contained signs of extraterrestrial intelligence.
Figure 1 World's largest single dish radio telescope. Site where the SETI info is collected.
(www.myurl.net)
According to Einstein, the universe is full of gravitational waves. He suggested
that the movement of heavy objects (dense stars and black holes); create waves that
change space and time. This idea is shown in figure 2 below.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
22/39
11
Figure 2: Order phase of two neutron stars colliding (http://www.ligo-wa.caltech.edu).
Einstein @ home allows users to search through data from the LIGO
observatories that detect the possible emission of these waves. The program searches for
faint signals that could possibly be coming from dense rapidly rotating compact quark
stars and neutron stars which are very likely to emit continuous gravitational waves (9).
http://www.ligo-wa.caltech.edu/http://www.ligo-wa.caltech.edu/http://www.ligo-wa.caltech.edu/ -
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
23/39
12
The basic idea behind the software, which was in beta testing for a period of time, is to
download information from a central computer directly onto the hosts home CPU. The
data is then automatically analyzed while the persons computer is idle and then
uploaded directly back into the central computer. The data is chunked into 12-megabyte
pieces and it is analyzed three times by the software for a possible gravitational signal.
The signals that prove to be most intriguing are flagged and then sent to the project
scientists to be further analyzed.
Implementation of the Software
Implementation of the software is quite simple and anyone with a PC is able to do
it. The name of the software is BOINC and its acronym stands for: Berkley Open
Infrastructure for Networking Computing. There are many other projects similar to
Einstein @ Home which use this same software. Some of these projects include:
Climateprediction.net, which studies the change of climate in different areas; Predictor @
Home, which studies protein related diseases; Rosetta @ Home, which helps researches
find cures for human diseases; and SZTAKI Desktop Grid, which searches for
generalized binary number systems.
The first step in downloading the software is finding out which platform you will
be using. The BOINC software can be downloaded onto Mac, Windows, and Linux
operating systems. The Southern University Physics Department - LIGO IT uses the
Windows operating system for its contribution to the project. Once you have figured out
what platform you will be running the software on, you simply go to the Einstein@Home
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
24/39
13
homepage (http://einstein.phys.uwm.edu/), and follow the instructions under Join
Einstein@Home. As mentioned before, the main purpose of BOINC in the scope of
LIGO and Einstein@Home is to search for gravitational wave signals generated by
pulsars.
What are Pulsars?
Pulsars are what scientists believe to be the fastest-spinning stars in the universe.
They were first discovered by Anthony Hewish and Jocelyn Bell in 1967 (10). One
summer while Bell was pursuing her PhD, they observed an unusual wavelength signal at
3.7m on a radio telescope that was specifically designed to observe the twinkling
(scintillation) of stars.
Figure 3 Jocelyn Bell at the Cambridge site where the first Pulsar Signals were recorded.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
25/39
14
She found the reading to be regular every 1.3373011 seconds and it synchronized with
star time. Their discovery was the first known in existence and the pulsing signal became
known as Pulsars.
We now know that a pulsar is a neutron star that emits beams of radiation that
cover the earths line of site. Or at least we know this in theory. The pulses of this high
energy radiation come from a misalignment of the neutron stars rotation axis and its
magnetic axis. Pulsars give off a pulse because of the rotation of the neutron star causes
the radiation generated within the magnetic field to sweep in and out of our line of sight
with a regular period (11). An illustration of this concept is shown below in figure 4.
Figure 4 A diagram of a pulsar showing its rotation axis, its magnetic axis, and its magnetic field.
The LIGO Screensaver
The Einstein@Home Screensaver is a real time display that consists of many of
the elements related to the LIGO project. The screensaver primarily consists of a rotating
celestial sphere that contains the known constellations and the three geographic positions
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
26/39
15
of the three gravity wave detectors involved in the project. The positions of the detectors
change over a period of one earth rotation and the change in position is relative to the
stars positions in space. A picture of the screensaver can be seen below in figure 5.
Figure 5 Einstein@Home Screensaver
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
27/39
Chapter 4
Data
Search For Data
The whole purpose of the Einstein@Home LIGO experiment is to search for
signals matching that of a pulsar gravity wave. Once this is done, the project is a success
and the study can then continue on into other areas of exploration. However, there is one
problem with identifying that signal. With the LIGO detectors being as sensitive as they
are, the most sensitive made to date it is hard to distinguish a pulsar gravity wave
signal from signals that arise from many different sources. These sources include:
seismic ground motion, thermal vibrations of the atoms making up the detector and
suspensions, and the particle like quantum behavior of the laser light (12). The problem
of finding a pulsar signal amidst these other signals has been described as trying to hear a
flute in the middle of a heavy metal concert. All of the other signals can be considered
noise and the purpose of LIGO is to identify a known wave form among this noise of the
detector.
The method that LIGO will use to search for this data in noise is called matched
filtering or optimal filtering. It can be proven mathematically that this is the best
technique to search for a known signal that is mixed up in unwanted noise. This idea is
not very hard to comprehend. If the exact waveform of the signal is known, then it can
be multiplied times the output of the detector and averaged over a period of time called T.
The resulting integral will have two terms. One has an expected value which grows like
the square root of time T, coming from the random noise that comes from the detector.
This process is also known as the random walk process (13). The random walk process
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
28/39
17
can be described as having a starting point, moving from one point in the path to the next
at a constant distance, and the direction from one point to the next is picked at random.
The other term from the matched filtering technique will grow in proportion to time T
and is due to the pulsar signal. Since T is limited to the amount of time that data is
actually collected, the pulsar signal must have a minimum signal strength to be detectable
in that finite amount of time (14).
Pulsar Gravity Radiation
So why would a pulsar emit gravity radiation? As stated before, Pulsars are the
fastest spinning stars in the universe and in almost all cases these stars are not perfect
spheres so as they spin, they continue to rip through space and emit waves of radiation.
According to News Office, in association with The Massachusetts institute of technology,
Gravitational radiation waves are ripples in the fabric of space which was predicted by
Albert Einstein in his Theory of Relativity.
In an article entitled Einsteins gravitational waves may set speed limit for pulsar
spin, an explanation was given as to why pulsars are capable of emitting gravitational
waves. Pulsars are defined as the core remains of exploded stars. They are so dense that
they contain the mass of the Earths sun yet they are only about 10 miles across. Imagine
this compared to the suns radius of about 432 163.664 miles. Pulsars are known to gain
speeds of about one revolution per millisecond or almost 20 percent that of the speed of
light which is about 299,792,458 meters per second (15). To get an understanding of
how astronomical these speeds are, a comparison of a pulsars rotation time with the
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
29/39
18
earths. It takes the earth about 24 hours to make a full rotation. Compared to a pulsars
millisecond rotation, it is easily seen how fast these pulsars are spinning. Even though a
pulsar has a significantly shorter radius, it is about 333000 times denser than the earth.
With that said, scientists believe that the faster a pulsar spins, the more it will emit
gravity waves because of its constant deformation and warping (16)
Figure 6 Image by Dana Berry of a rotating pulsar. This image is displayed on web.mit.edu website.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
30/39
19
Southern Universitys Search Credit
As stated before, the goal of the BOINC software is to aid LIGO in the search for
gravitational waves. Because there is so much information to be processed, the more
people that are connected to LIGO through the BOINC software, the more likely we will
be able to detect a gravitational wave at a faster rate. As seen the figure below, Southern
University has received and processed 63,969 cobblestones of credit. A cobblestone is
1/100 day of CPU time on a BOINC computer. It received the name cobblestone after
Jeff Cobb of SETI@Home.
Figure 7 Southern University's Cobblestone Credits
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
31/39
Chapter 5
Summary/Conclusion
Summary and Conclusions
This Honors College thesis comprises the first implementation of the LIGO
distributed data analysis program known as Einstein@home within the Southern
University System. Thus, a major outcome has been the initiation of Southern
Universitys contribution to the search for gravitational radiation produced by pulsar
astrophysical sources. At present the software is operating on several desktop computers
within the department of physics, which serves as the academic home of the Southern
University-LIGO Research Group, led by Dr. Stephen C. McGuire, Professor of Physics
and Department Chair. We can anticipate that as other departments become involved
with LIGO, they, too, will apply resources to the project and thereby increase our
contribution to the quest to detect gravity waves.
Further, the work of this thesis complements our pre-existing collaboration with
the LIGO Science Education Center (SEC) co-located with the Observatory in nearby
Livingston, Louisiana. In particular, the department of physics is revamping its physics
education courses to help better prepare middle and high school science teachers for the
future. As of this writing Southern University is further distinguished by being the only
Historically Black College/University (HBCU) that is a member of the LIGO Scientific
Collaboration (LSC), the body that recommends the research and development agenda for
the LIGO experiment.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
32/39
21
Because LIGO is pushing the limits of technology in making the measurement of
gravity waves a reality it is not unreasonable to expect that there will practical spin-offs
from this project in the future. One only has to look to modern day health care to see the
manifestations of basic physics research in our every day lives. Examples include
nuclear magnetic resonance imaging (MRI), diagnostic nuclear medicine based on the use
of radioisotopes, radiation therapy, laser surgery and arthroscopic surgery. These are just
a few examples where discoveries in basic science have led to major advances in
medicine. We also note that even as LIGO evolves as an experiment, improvements in
science and engineering are occurring. Examples include innovations in real-time data
acquisition and analysis hardware and software systems, advances in the production and
maintenance of high vacuum systems, operation of electromechanical systems, as well as
improvements in high laser power optical systems and vibration isolation engineering.
What will we learn about our universe from LIGO? What practical applications
will stem from LIGO, exactly? Well, well have to wait and see, but they probably will
be full of surprises. For future generations of students and faculty at Southern
University, a foundation has been laid for them to answer these questions by making their
contributions.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
33/39
Bibliography
1. McGuire, Dr. Stephen C. Personal interview. 11 Apr. 2006.
2. "Einstein@Home." University of Southern Indiana Department of Physics. 14 Mar.
2005 .
3. Bartusiak, Marcia. "Laser Interferometer Gravitational-Wave Observatory - an
Astronomical Tool of the 21st Century, a Detector Like No Other Before It."
Online Magazine of the Israel Physical Society 01 Jan. 2005. 20 Feb. 2006
.
4. "Einstein@Home." University of Southern Indiana Department of Physics. 14 Mar.
2005 .
5. Berolini, Alessandro. High Sensitivity Accelerators for Gravity Experiments. Diss.
Universita di Pisa, 2001. .
6. David P. Anderson, Eric Korpela, Rom Walton, "High-Performance Task Distribution
for Volunteer Computing," e-science, pp. 196-203, First International Conference
on e-Science and Grid Computing (e-Science'05), 2005.
7. Boyle, Alan. "Software Sifts Through Gravity's Mysteries." MSNBC. 19 Feb. 2005
.
8. "SETI@Home." SETI@Home. University of California. 16 Feb. 2006
9. "Einstein@Home." University of Southern Indiana Department of Physics. 14 Mar.
2005 .
10. Bell, Jocelyn. "Petit Four." Annals of New York Academy of Science 1977: 685-689.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
34/39
11. "Pulsars." NASA Goddard Space Flight Center. NASA. 15 May 2005
.
12. Gonzalez, Gabriela. Suspensions Thermal Noise in the LIGO Gravitational Wave
Detector. Diss. Pennsylvania State Univ., 2000. .
13. Weisstein, Eric W. "Random Walk-1-Dimensional." Math World. 05 Dec. 2005
.
14. Saulson, Peter. "10 Years in Gravitational Wave Detection." 09 July 2001. Syracuse
University. 06 Jan. 2006 .
15. "Pulsars." NASA Goddard Space Flight Center. NASA. 15 May 2005
.
16. "Einstein's Gravitational Waves May Set Speed Limit for Pulsar Spin." News Office.
Massachusetts Institute of Technology. 7 Apr. 2006
.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
35/39
24
Appendix 1. An interview with Dr. Stephen C. McGuire
Dr. Stephen C. McGuire is Professor and Chair of the department of physics atSouthern University and A&M College. His research interests are in the areas of
experimental materials physics and the integration of research with teaching and
learning. Dr. McGuire is the Principal Investigator and Director of the NationalScience Foundation (NSF)-funded project, Materials Science, Astronomy and
Educational Outreach. The project is a collaboration between Southern University at
Baton Rouge (SUBR) and the Laser Interferometer Gravitational-Wave Observatory(LIGO). LIGO is a major NSF experiment designed to detect and measure gravity-
waves reaching earth from space and promises to create the entirely new field of
gravitational astronomy (See, for example, www.ligo.caltech.edu). Dr. McGuire is theSouthern University delegate to the LIGO Scientific Collaboration and leads the Southern
University LIGO Physics Group. He is the Honors Thesis advisor to Mr. Jamaal N.
Johnson, undergraduate computer science major.
1. JNJ To what other areas of science is LIGO contributing?
SCM -- As a forefront physics effort LIGO pushes the limits of bothastrophysics and the physics of the technology that is needed to perform the
experiment. It is in this second area that LIGO has made and continues to make
contributions to science and technology. Specific examples includeimprovements in high laser power optical systems, advances in the production and
maintenance of large volume, high vacuum systems, innovations in real-time
data acquisition and analysis hardware and software systems, operation of
electromechanical systems, as well as mechanical vibration isolation engineering.These spin off areas are a direct result of the need to bring online an instrument
that has never existed before in the history of mankind, the LIGO Observatory
2. JNJ - Can you comment on the stabilization of the instrumentation involvedin the LIGO experiment?
SCM -- If by stabilization you mean the ability to continuously operate the
interferometer in the mode in which science is being done, there has been great
progress in this area. The most significant improvement, however, has been the
implementation of an active vibration dampening system known as the HydraulicExternal Pre-Isolator, or HEPI, system. With the implementation of HEPI the
duty cycle for daytime operation, for example, when there noise levels from
human activity is the greatest, has improved significantly.
http://www.ligo.caltech.edu/http://www.ligo.caltech.edu/ -
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
36/39
3. JNJ - Please comment on the types of events that are expected to produce
signals in the interferometer. That is, what types of astrophysical events are
expected to be seen with LIGO?
25
SCM -- There are basically four types of astrophysical events that are predicted
to generate gravity waves that may be observable with LIGO. They include the
collision of extremely dense objects such as neutron stars and black holes, theviolent explosion and collapse of stellar systems via supernovae, pulsars such
as that being searched for in the Einstein@home project -- and gravity-wave
remnants of the event theorized to have started the physical universe, known as
the big bang. All involve rapid asymmetrical redistributions of astronomicalamounts of matter and therefore are thought to be big producers of gravitational
radiation.
4. JNJ - If gravity waves are conclusively not observed by LIGO what otherresearch directions might result from this finding?
SCM -- As an experiment, LIGO is part of the process of the scientific method
wherein a theory, the general theory of relativity in this case, is tested. The test,
for us, is the existence of gravity waves. There is much indirect evidence that thisphenomenon is real. We know that Newtons Universal Law of Gravitation
doesnt explain all of what we observe. Should it be determined that gravity
waves do not exist, then gravitational radiation theory and its interpretation will
be revisited by the scientific community. In either case, I believe it will be asignificant find for science and will surely help point us in the direction of a more
accurate view of our physical universe.
5. JNJ - Do you see LIGO contributing
in some way to the improvement of
healthcare through advances in diagnosis and/or treatment?
SCM -- On the one hand improvements in health care is not a goal of LIGO, it
would not be unusual for applications of the new knowledge gained to eventuallyfind applications in that field. Notable past examples of the practical
manifestation of pure science include nuclear magnetic resonance, or MRI as its
called, diagnostic nuclear medicine, radiation therapy, laser surgery, arthroscopicsurgery, etc. New knowledge almost always leads to some practical uses and as
your question suggests health care is an ongoing concern for our society. Well
just have to wait to see over time where the applications of the new materialsscience, laser physics, and computer technology will occur.
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
37/39
6. JNJ -What type of results have been
obtained so far from the five scienceruns
that have taken place?
SCM Lots. You are referred to the LIGO web site for many examples of
papers and presentations that describe results from the approximately 500
researchers that work worldwide on the LIGO project. 'Happy surfing!26
APPENDIX 2.
Interferometer Diagram
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
38/39
APPROVAL FOR SCHOLARLY DISSEMINATION
The author grants to the Honors College the right to reproduce, by appropriate
methods, upon request, any or all portions of this thesis.
It is understood that request consists of agreement, on the part of the requesting
party, that said reproduction is for his personal use and that subsequent reproduction will
not occur without the written approval of the author of the thesis.
The author of this thesis reserves the right to publish freely, in the literature, at
any time, any or all portions of this thesis.
Author______________________________
Date________________________________
-
8/8/2019 Pulsar Gravity-Wave Data Search Einstein at Home written by Jamaal Johnson aka Jjohn
39/39