By Sing H. Lin, Ph.D., E-Mail: SINGHLIN@GMAIL.COM
Original appeared on January 3, 2007, Latest Revision on December 7, 2014
Mysteries in Astronomy: Many astronomers and scientists all over the world have been struggling with
the strange and puzzling phenomena of dark energy and dark flow based on astronomical observations. These
astronomical observations on the inter-galactic scale found the surprising phenomena of (a) the accelerated
expansion of universe caused by an unknown dark energy, (b) the dark energy appears to be weak in earlier
years of our expanding universe, but becomes much stronger in recent 7 or 8 billion years, and (c) strange
huge flow of hundreds of galaxy clusters in certain direction. These strange phenomena imply the existence of
huge amount of unknown dark energy in the universe, but our scientific knowledge still does not understand
that "dark side of the cosmos" well yet.
By applying Theory of Parallel Universes, String theory and M-Theory, I found that the dark energy that is
causing the accelerated expansion of our universe can be explained by the inter-universe coupling gravity from
matters residing in other parallel universes surrounding our universe. From my viewpoint, Dark Energy is
inter-universe coupling gravity. This model, based on the concept of parallel universes and inter-universe
coupling gravity, can explain all the three observed surprising phenomena (a), (b) and (c).
For about 21 years since my tour of The Mystery Spot in Santa Cruz, California, USA in 1993, of Oregon
Vortex in Gold Hill, Oregon, USA in 2004 and of the Magnetic Hill in eastern Canada in 2005, I have been
thinking about and investigating on the issue of whether such strange gravity hill effects and gravity mysteries
are real or illusion and searching for a possible scientific explanation for such strange gravity phenomena and
mysteries. Such search enables me to keep up with the advances by many scientists all over the world
working on experiments and research on the exciting frontier of science on dark matters, dark energy and dark
flow. Such thinking and research lead me into my proposed model of inter-universe coupling gravity for dark
energy. I started presenting this web page on January 3, 2007 soon after my Travelogue website (
WWW.SHLTRIP.COM ) was established in December 2006. I have been revising and updating this web page
from time to time as I gain more insight and relevant information since 2005. After 8 years, the original web
page had become too long. So, in early 2014, I divided the lengthy web page into several related, but shorter
web pages so that each web page is more focused on certain aspects, is shorter and is easier for many
readers to read.
The highlights of this web page are summarized in the following PowerPoint Presentation (PPP).
Click the following links to see the PowerPoint Presentation.
Dark Energy is Inter-Universe Coupling Gravity
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Figure 1 - Concept of Parallel Universes with Inter-Universe Coupling Gravity among our universe and many
other parallel universes surrounding our universe.
In this way, the matters in other parallel universes are exerting their inter-universe coupling gravity to pull
outward on all matters in our Universe A. In other words, the inter-universe coupling gravity from other
parallel Universes is causing accelerated expansion of our Universe A.
Therefore, from my viewpoint, Dark Energy is just the plain old gravity, that is the inter-universe coupling
6. My Explanation for Time Varying Dark Energy
In early years, our universe was smaller. The matters and galaxies in our universe were crowed in the
smaller earlier universe. Therefore, the inward gravity pulls among all matters and all galaxies in our universe
were stronger in those early years of smaller universe with shorter distances among the galaxies. Such
stronger inward gravity pull inside our small universe acts against the outward gravity pull from those matters
in other parallel universes. With such strong inward gravity pull, the dark energy appears to be weaker in
earlier years of our universe.
However, in recent 7 or 8 billion years, our universe has expanded to become much larger universe with
greater distances among all galaxies in our universe. The dark energy becomes stronger in recent 7 or 8
billion years due to two factors: (1) The inward gravity pull among all galaxies in our universe becomes
weaker because of the greater distances among galaxies in the larger universe. (2) As our universe become
larger, many galaxies in our universe are getting closer to neighboring parallel universes and are experiencing
stronger outward gravity pull because of the shorter distance to neighboring parallel universes. With
weakening inward gravity pull, and stronger outward gravity pulling from other parallel universes, the outward
gravity pull becomes the dominant force. Therefore, the dark energy becomes stronger in recent 7 or 8 billion
7. Dark Flow
There is no reason that the distribution of other parallel universes must be perfectly symmetrical with respect
to the center of our Universe A. Then the inter-universe coupling gravity from all those parallel universes on
our Universe A is not perfectly symmetrical. Therefore, the accelerated expansion of our Universe A is not
perfectly symmetrical, not perfectly uniform, and not perfectly homogeneous. This may be the reason for the
"Dark Flow" discovered in 2008 by Alexander “Sasha” Kashlinsky of NASA’s Goddard Space Flight Center.
Dark Flow represents the movement of hundreds of galaxy clusters at about two million miles per hour in the
direction of a patch of sky between the constellations Centaurus and Vela.
Since the inter-universe coupling gravity between Universe A and other parallel universes is not perfectly
symmetrical, the shapes of our Universe A and of other parallel universes may not be perfectly spherical
8. Concluding Remark
The String Theory, M-Theory and Theory of Parallel Universe indicate that gravity can "leak" from one
universe into other parallel universes. Therefore, parallel universes are not totally independent of each other,
but are coupled to each other through such inter-universe coupling gravity. The accelerated expansion of our
universe is caused by such inter-universe coupling gravity from other parallel universes. The Dark Flow
detected in our universe is also caused by such inter-universe coupling gravity.
Since the sources of this inter-universe coupling gravity are matters residing in other parallel universes, we
cannot see and cannot touch those matters in other parallel universes. Therefore, the effects of this inter-
universe coupling gravity show up in our universe as very strange phenomena, namely: (8-1) accelerated
expansion of our universe by strange unknown dark energy, and (8-2) Dark Flow of hundreds of galaxy
clusters in certain direction.
It turns out that these two major mysteries at the frontier of modern physics and astronomy are all caused by
the same plain old gravity - that is the inter-universe coupling gravity.
9. Technical Background of the Author of This Web Page
Dr. Sing H. Lin is a retired Telecommunication engineer and manager with technical expertise in the area of
radio/wireless communication technologies and systems. He received his Ph.D. Degree in Electrical
Engineering from the University of California at Berkeley, California, USA in 1969 and BSEE degree from
National Taiwan University in 1963. He joined Bell Laboratories in New Jersey, USA in 1969. He has 68
technical publications and presentations in various technical journals and conferences, 3 patents, and a
Chinese certificate of a copyright on a mapping table for Chinese Spelling Code.
He had been a member of the US Delegation to International Telecommunication Union (ITU) for many years
in developing the global standards and recommendations for radio/wireless communications systems
including the Third Generation (3G) mobile wireless communications systems and beyond. In 1998, this
international team of wireless technology experts, including Dr. Sing Lin, completed the development of ITU
standard for 3G mobile wireless communication system. This 3G wireless mobile system standard provides
the platform that spawned the rapidly growing smart phone industry with many useful applications attracting
huge number of users all over the world. The total global annual sales of smart phones is about 500 million
units in 2011 and is growing very fast. The smart phone industry is now moving forward into the international
4G system standard which is also known as LTE (Long Term Evolution).
Dr. Sing H. Lin and his colleagues in the old Bell Laboratories had conducted many years of experiments on
effects of multipath radio propagation and rain attenuation on the performance of terrestrial and earth-
satellite microwave communication radio links. Such experiments and huge amount of data were collected
from numerous microwave radio links in USA and in some foreign countries such as Saudi Arabia. Results
from such experimental data, analyses and developed theories are important for engineering microwave
communication radio links to meet performance objectives. Some of these results were published in the
following technical papers:
S. H. Lin, H. J. Bergman and M. V. Pursley, "Rain Attenuation on Earth-Satellite Paths - Summary of 10-year
Experiments and Studies," The Bell System Technical Journal, Vol. 59, No. 2, February 1980, pp 183 to 228.
S. H. Lin, "Statistical Behavior of a Fading Signal," The Bell System Technical Journal, Vol. 50, No. 10,
December 1971, pp. 3211 - 3270.
S. H. Lin, "Statistical Behavior of Deep Fades of Diversity Signals," IEEE Transaction on Communications,
Vol. COM-20, No. 6, December 1972, pp. 1100 - 1107.
By using Statistical Theory of Extremes, Dr. Sing H. Lin has also developed a theory and a method to obtain
nationwide long term (25 to 50 years) distributions of rain rate at more than 200 locations in USA. Such
theory and method are published in the following technical papers:
S. H. Lin, "Statistical Behavior of Rain Attenuation", The Bell System Technical Journal, Vol. 52, No. 4, April
1973, pp. 557 - 581.
S. H. Lin, "Rain Rate Distributions and Extreme Value Statistics," The Bell System Technical Journal, Vol. 55,
No. 8, October 1976, pp. 1111 - 1124.
S. H. Lin, "More on Rain Rate Distributions and Extreme Value Statistics," The Bell System Technical
Journal, Vol. 57, No. 5, May-June 1978, pp. 1545 - 1568.
Note: The technical papers in Bell System Technical Journal (BSTJ) from 1922 to 1983 are available online in
the following BSTJ website:
A complete list of his 68 technical publications and presentations in various technical journals and
conferences and of his patents is in his web page at:
When he was a Ph.D. student in the University of California at Berkeley, he did take and enjoyed the
graduate course on Radio Astronomy. As a radio engineer in Bell Laboratories, in New Jersey, USA, he
participated in a team project on radiometer measurements and experiments as related to satellite
communication technologies. He learned the Dickie radiometer technologies from a team of radio
astronomers, including Robert W. Wilson, in Bell laboratories at Crawford Hill in Holmdel, New Jersey.
His interest in astronomy continues from his student life through his professional engineering life and into his
retiree life. In his retiree sightseeing trips, he enjoyed touring the Very Large Array (VLA) site operated by
the National Radio Astronomy Observatory near Socorro, New Mexico and the National Solar Observatory
and Apache Point Observatory on Sacramento Peak in New Mexico, USA in February 2006. More
information on and a picture of Dr. Sing H. Lin are available at the following web page:
His e-mail address is: SINGHLIN@GMAIL.COM
He has retired from his professional Telecom engineer job and is living in New Jersey, USA.
1. Introduction on Issue of Dark Energy
1.1 Discovery of Expanding Universe
In about 1929, Edwin Hubble and several other scientists discovered that the spectral lines in the light received
from distance galaxies are all shifted toward red light end of the spectrum. Edwin Hubble further discovered
that the amount of red-shift is proportional to the distance of galaxy from us. A red-shift can occur when the
light source is moving away from an observer, similar to the Doppler shift that changes the perceived
frequency of sound waves. The observed red-shift implies that: (1A) Galaxies are running away from us, (1B)
The receding speed of a galaxy is proportional to its distance from us, and (1C) Universe is not static, but is
1.2. Surprising Discovery of Accelerated Expansion of Universe
Since all matters have gravity pulling on each other, such gravity pull is expected to slow down the expansion
of universe. In 1998, two independent teams of scientists did two independent astronomical measurements to
try to measure the rate of slowing down of expanding universe (i.e. to measure the ultimate fate of our
universe). These two teams are the Supernova Cosmology Project at the Lawrence Berkeley National
Laboratory and the High-z Supernova Search Team.
However, these two teams of scientists and the whole world were all surprised in 1998 to find that the
expansion of universe is NOT slowing down, but is accelerating. These two independent teams of scientists
were scared and thought that they might have some errors in their measurements. But their careful checks
found no errors in their two independent sets of measurements. All scientists and astronomers have been in a
state of collective bewilderment since this surprising discovery in 1998.
The key question is what is causing such accelerated expansion of universe? For the time being, scientists
have to postulate a “Dark Energy” that is a hypothetical form of energy that permeates all of space and tends
to increase the rate of expansion of the universe.
1.3. Time Varying Dark Energy
More astronomical observations subsequent to the 1998 experimental discovery found that the dark energy for
the accelerated expansion of universe is NOT “constant”. In the 14 billion years of history of expansion of
universe, the dark energy appeared to be weak in earlier years but becomes stronger in recent 7 or 8 billion
years. It is NOT constant. Such subsequent discovery of time variation adds to the great mystery of dark
1.4 Discovery of Huge Dark Flow
"Dark Flow" was discovered in 2008 by Alexander “Sasha” Kashlinsky of NASA’s Goddard Space Flight
Center. Dark Flow represents the movement of hundreds of galaxy clusters at about two million miles per hour
in the direction of a patch of sky between the constellations Centaurus and Vela.
2. Some Preliminary Evidences for Multiverse
Several aspects at the cutting edge of science are relevant and important to the understanding of dark energy
and dark flow. They include String Theory, M-Theory and Multiverse or Parallel Universe. They are briefly
introduced in this Section.
One of the current cutting-edge fields of research by many scientists all over the world is multiverse or parallel
universes and the related String Theory/M-Theory. It is driven by several surprising and uncomfortable
discoveries from astronomy scale and from sub-atomic scale of quantum physics (i.e., from very large scale
and from very small scale). For almost a hundred years science has been haunted by a dark secret: that there
might be mysterious hidden worlds beyond our human senses. Recent advances in investigations and studies
of these strange discoveries are all pointing consistently to the possible existence of parallel universes
(multiverse) and to the development of String Theory, M-Theory and Big Bang Inflation Theory.
3.1. Some preliminary evidences for multiverse are:
3.1.1. Observation from BICEP Experiment in South Pole
The announcement on March 18, 2014 of the results of the 3-year observation at South Pole of the BICEP
(Background Imaging of Cosmic Extragalactic Polarization) experiment provides a strong validation of the Big-
Bang Inflation Theory. According to Professor Alan Guth in MIT and Professor Andrei Linde in Stanford
University, the two main contributors to the inflation theory, inflation, once started, is eternal in the sense that it
created not only our universe, the rest of the cosmos will continue blowing up, spinning off other bubbles
endlessly, a concept known as the Multiverse with many parallel universes. In other words, our universe is one
of many inflationary universes in a vast Multiverse. Some descriptions of BICEP experiment and its important
discovery are in the following websites:
3.1.2 Signatures of Collision of our universe with other universes
In studying CMB (Cosmic Microwave Background), a team of scientists have identified disc shaped signatures
on CMB as preliminary evidences of collisions of our universe with other parallel universes in the past. Some
descriptions of this discovery of collision signatures are in the following websites:
3.1.3 1998 Discovery of Accelerated Expansion of Our Universe
A brief description of the surprising 1998 discovery accelerated expansion of our universe is in Section 1 of this
web page. According to my theory, such accelerated expansion of our universe is due to inter-universe
coupling gravity from other parallel universes surrounding our universe as explained in Section 5 on this web
page. In other words, Dark Energy is inter-universe coupling gravity from other parallel universes surrounding
3.1.4 Discovery of Huge Dark Flow in 2008 by Alexander “Sasha” Kashlinsky of
NASA’s Goddard Space Flight Center
"Dark Flow" was discovered in 2008 by Alexander “Sasha” Kashlinsky of NASA’s Goddard Space Flight
Center. Dark Flow represents the movement of hundreds of galaxy clusters at about two million miles per hour
in the direction of a patch of sky between the constellations Centaurus and Vela. According to my theory, this
dark flow is due to the inter-universe coupling gravity from the asymmetrical distribution of parallel universes
surrounding our universe as explained in Section 5.
Admittedly, these evidences are preliminary and controversial at this early stage because science has not
been doing extensive work on multiverse yet. But it is a very exciting, challenging and fertile ground for many
scientists to explore in the future. Human scientific research is now venturing out beyond our familiar universe
and into much more challenging and exciting parallel universes or mulltiverse.
4. Some Key Characteristics of Parallel Universes
The following team of leading scientists and professors in physics and astronomy in prestigious universities
jointly provides detailed in-depth explanations of this cutting-edge field of research on parallel universes, String-
Theory and M-Theory in a series of documentary TV programs which are often shown on educational TV
channels such as Science Channel or History Channel:
NIMA ARKANI-HAMED, Professor of Physics, Harvard University,
MICHAEL DUFF, Professor of Physics, University of Michigan, and Imperial College (London),
ALEX FILIPPENKO, Professor of Astronomy, University of California, Berkeley
ALAN GUTH, Professor of Physics, Massachusetts Institute of Technology,
MICHIO KAKU, Professor of Theoretical Physics at the City University of New York
BURT OVRUT, Professor of Physics, University of Pennsylvania,
LISA RANDALL, Professor of Physics, Harvard University,
PAUL STEINHARDT, Professor of Physics, Princeton University,
NEIL TUROK, Professor of Mathematical Physics, Cambridge University
The transcript of this series of video programs on Parallel Universes is also available at:
These science documentary TV programs are very helpful and educational to many people, including me.
According to the preliminary theory of parallel universes, there are many, infinitely many, universes that exist in
parallel to our known universe, we are not alone!
4.1. Gravity Coupling Among Parallel Universes
According to the String Theory, most forces are based on open strings that are attached to a brane (i.e., a
universe) such that most forces are confined within their own universe. But gravity is different and is based on
a closed-loop string that is not attached to a given brane. The close-loop string based gravity can float from
one brane to another brane such that gravity can "leak" from one universe into other parallel universes
Since gravity can leak from one universe into other parallel universes, it means that the parallel universes are
not totally independent of each other, but are coupled through gravity. I, therefore, propose that (4.1A) the
inter-universe coupling gravity is the dark energy that is causing accelerated expansion of our universe as
explained in Section 5, (4.1B) the inter-universe coupling gravity is causing the Dark Flow in our universe as
explained in Section 7.
The effects of this inter-universe coupling gravity show up in our universe as very strange gravity phenomena
and gravity mysteries because their sources in other parallel universes cannot be seen and cannot be touched
from our universe.
5. Dark Energy is Inter-Universe Coupling Gravity
With the concept of parallel universes, our universe is NOT the only universe that is going through the big bang
expansion. There are other parallel universes that are out there surrounding our universe. For discussion
purpose, let our universe be the Universe A and other parallel universes be Universe B, universe C, universe D,
universe E, etc. as illustrated in the following Figure 1.