The Expansion of the Universe
The New interpretation of Moving Galaxies
Kishockkanthan Sivapragasam
Introduction
In the late 1920s, the American astronomer, Edwin Hubble, made probably the most important discovery in the history of astronomy. Hubble made observations that he interpreted as showing that distant stars and galaxies are moving away from Earth in every direction [1]. He knew this because the light coming from the galaxies exhibited redshift. Not only are they moving away, but the more distant galaxies appear to be moving away faster than the closer ones. The implication of these findings is that the universe is expanding. This is now the most widely accepted interpretation of the data. The other key point arising from the interpretation is that if we go back in time, galaxies must have been closer together; space was smaller. If you extrapolate back far enough, the Universe must have been concentrated at a point in space. A huge explosion, known as the Big Bang, then sent matter and energy expanding in all directions.
Many scientists, cosmologists, and popular science writers state recently that there are gaps in our fundamental understanding of the universe and suggest that something is wrong with the cosmological model itself. Some of them as follows.
· “It is tempting to think we may be seeing evidence of some ‘new physics’ in the cosmos.”
Dr. Adam Riess, the Johns Hopkins cosmologist. The expansion of the Universe is faster than expected. Nature [Online] December 2020. https://theweek.com/articles/889916/growing-crisis-cosmology
· “Cosmologists are perplexed. They believe they have a good understanding of the origins of the universe and how it has evolved since the beginning. However, two measurements of the speed at which the universe is currently expanding disagree and that could be the first signs that they will have to make significant changes to their understanding of the cosmos”.
Dr. Don Lincoln, the Senior Scientist at Fermi Lab, “Crisis in Cosmology Gets Worse”. Forbs [Online] January 2021.
https://www.forbes.com/sites/drdonlincoln/2021/01/05/crisis-in-cosmology-gets-worse/?sh=19ebe6882826
· The standard model of cosmology needs to be changed in some way using new physics to correct the discrepancy.
Dr. Chris Fassnacht, Professor of Physics at UC Davis says, “A crisis in cosmology”. phys.org [Online] October 2019. https://phys.org/news/2019-10-crisis-cosmology-universe-rapidly-believed.html
· A possibility is that the conflict points to undiscovered phenomena — “new physics.”
Nobody is suggesting that the entire standard cosmological model is wrong. But something is wrong — maybe with the observations or maybe with the interpretation of the observations, although each scenario is unlikely. This leaves one last option — equally unlikely but also less and less unthinkable: something is wrong with the cosmological m`1odel itself.
Richard Panek, American popular science writer. How a Dispute over a Single Number Became a Cosmological Crisis. Scientific American [Online] March 1, 2020.
· It could be a problem with the calibration of our measurement techniques — the standard candles and standard rulers we use to measure cosmic distances (more on those in a moment). It could be some unknown property of dark energy. Or perhaps our understanding of fundamental physics is incomplete.
Michelle Starr, Senior Journalist. This is the Most Exciting Crisis in Cosmology. sciencealert.com [Online] August 2020. https://www.sciencealert.com/we-can-t-figure-out-how-fast-the-universe-is-expanding-here-s-why
The current model of understanding the observation of moving galaxies falls into a picture of expansion that is happening in every direction. Since galaxies appeared to be moving away from each other in every direction, it seemed impossible for astronomers to grasp a model that could explain the motion of the galaxies as taking place only in one direction from a single point in space, in accord with all their observational data. As a result, astronomers came up with a model to interpret this effect of moving galaxies — Expansion. Since that picture abided by the results of the observation and there seemed to be no other logical explanation, the science world had accepted that model without further considerations.
The implication that galaxies appeared to be moving away from each other seems to have some great misinterpretations ever since the time of the first observation. This may be one of the reasons why the intelligent minds have been struggling to unify the reality of the submicroscopic world with the macroscopic world. Making some significant changes to our fundamental understanding of the structure and the mechanism of the universe may resolve the longstanding problems in cosmology and physics. Hence, this article.
The purpose of this article is to provide a new interpretation of the observation of moving galaxies and answer the most important questions that humans have been wondering about for centuries, such as: why do galaxies appear to be moving away from us in every direction? How did astronomers conclude that the universe is expanding? Where did the event of the Big Bang occur? Why is there no center in the universe according to the current model? Why does time flow in a predetermined direction, toward the future?
The History of the Expansion of the Universe
Edwin Hubble, Albert Einstein, and many other great minds had a fixed view of what the universe was like. But in 1929, in Mount Wilson, Edwin Hubble discovered something that changed everything.
Rockyworlds | Seeking rocky worlds, figuring out how planets form
Edwin Hubble seated at the Newtonian focus of the 100-inch telescope on Mount Wilson. Image Credit: Carnegie Institution for Science, San Marino, California.
During that year, scientists discovered something that turned the accepted model of the universe, on its head. The astronomer Edwin Hubble discovered that almost all the galaxies beyond our Milky Way were moving away from us. Therefore, he interpreted that the universe must be expanding [2]. This discovery was one of the greatest intellectual revolutions of the 20th century.
How did Hubble go about detecting the speed and direction of the galaxies billions of light-years away?
Think of how the sound of a siren changes as it moves toward and then away from you. As the sound waves from the siren move toward you, they are compressed into higher frequency sound waves. As the siren moves away from you, its sound waves are stretched into lower frequencies. This shifting of frequencies is called the Doppler Effect [3].
A similar thing happens to light waves. Light is made up of waves and each color has its own wavelength; blue light has a shorter wavelength and red light has a longer wavelength. But when an object moves in space, the wavelengths of light appear to change from our perspective. If the object is moving toward us, the wavelength gets squashed and appears to be more blue. If the object is moving away from us, the wavelength gets stretched out and appears to become more red. We call this effect “redshift” [4].
The speed and direction that a galaxy is traveling can be deduced simply by observing its color. In 1929, that is precisely what Edwin Hubble observed that the galaxies were moving away from us. He had measured the speed of galaxies at different distances from us, and discovered that the farther they were, the faster they were receding. This discovery of the expansion developed the idea of the universe and provided the first evidence for the Big Bang theory [5], which describes the birth and evolution of the universe. Even though the discovery was recognized as important, the notion that we could understand the Big Bang seemed steps too far at that time.
After a few decades during the 1960s, astronomers became aware of microwave background radiation [6] that was detectable from all directions. Known as the Cosmic Microwave Background, the existence of this radiation has helped our understanding of how the Universe began.
Arno Penzias and Bob Wilson in Holmdel, New Jersey, where the cosmic microwave background was first identified. Image Physics Today Collection
Cosmic Microwave Background implies that about 14 billion years ago, all matter was condensed onto a single point of infinite density and extreme heat. Due to the extreme heat and density of matter, the state of the Universe was highly unstable. Suddenly, this point began expanding, and the Universe as we know it began with a “Big Bang” and has been expanding ever since. Yet there is no known center to the expansion; rather, the whole universe is expanding, and it is doing so equally at all places, from any vantage point, as far as we can tell. As such, the standard theories of cosmology states that there is no center of the universe [7].
More recently, measurements of the redshifts of supernovae indicate that the expansion of the universe is, in fact, getting faster in its acceleration as it gets bigger. This is largely a result of the mysterious Dark Energy that pervades the universe. Dark Energy [8] s an unknown form of energy which is hypothesized to permeate all of space. The first observational evidence of its existence came from supernovae measurements, which showed that the universe does not expand at a constant rate, rather it is accelerating.
Lambda-CDM, accelerated expansion of the universe. The timeline in this schematic diagram extends from the Big Bang/inflation era 13.7 Byr ago to the present cosmological time. Credit: Coldcreation.
ACCELERATED EXPANSION OF THE UNIVERSE
There is something about this accelerating expansion of space that has extraordinary and unexpected consequences. What is crucial to understand is not simply that the universe is expanding, or the expansion is accelerating, but the unexpected way in which it does accelerate while expanding. From Hubble’s data, the observation of moving galaxies holds further secrets even after almost 100 years. The secret that this discovery holds is that the universe in 4-dimensional spacetime is expanding only in one direction: outward from the single point in space, where the event of the big bang occurred.
THE NEW PERSPECTIVE OF UNDERSTANDING THE MOVING GALAXIES
A simple way to help visualize the galaxies moving in space is to compare galaxies with cyclists riding at different velocities.
Imagine a small thought experiment that Ben, Alex, and you are riding bicycles on a straight road, in the same direction, at different velocities. Say Ben is riding his bicycle slower, and Alex a little faster than you. After a while if you notice them, Alex, who is riding faster than you, will look like he is moving away from you, and Ben, who is riding slower than you, will also look like he is moving away from you.
If you observe carefully, from your point of view, Ben will not only look like he is moving away from you, but also, he will look like he is moving in the opposite direction. When you observe Alex, you will feel as if you are moving away from him in the backward direction. It is bizarre to understand that while all of you are in motion in the same direction, from each of your points of view, everyone else appears to be moving away in different directions.
After a certain interval, Alex and Ben will look like they are receding away from you; so, the farther away they get from you, the faster they seem to travel. Which means the space between the three of you would be increasing at an accelerating rate. In other words, Ben and Alex will be redshifted from your perspective.
Now imagine the same thought experiment with a few more cyclists who are riding on the same road, in the same direction, but at different velocities proportional to their distance: the further away a cyclist is from the starting point, the faster they are moving. In other words, the cyclists riding in front of you are faster, and the cyclists behind you are slower. In this case, you will notice that each cyclist is moving away from you at an accelerating rate. In fact, this is true from everyone’s point of view. The farther away they are from you, the faster they appear to be moving away from you. In other words, the further away they are, the more their redshift would be.
The effect of light shift (Redshift) that one receives when galaxies are moving in the same direction with a velocity that is proportional to their distance from the starting point (the further away a galaxy is from the starting point, the faster it is moving), is the same effect of light shift that one would receive when the galaxies are moving away in all directions. In other words, it is indistinguishable whether a galaxy is moving in the same direction or moving away in a different direction, from the effect of light shift that we receive. This strange phenomenon made Hubble and other astronomers’ observations, even today, believe that the galaxies are moving away in all directions.
Based on the results of the above thought-experiment, it clearly alters the picture of our current understanding of the universe; the expansion of space is not taking place in every direction, but in fact it is taking place only in one direction in 3-dimensional space and 4-dimensional spacetime, outward from the Big Bang singularity, with a velocity that is proportional to the distance; the more distant space is from the point of origin, the faster it stretches. As a result, the further away a galaxy is, the faster it appears to be moving away. The different rate of the stretching of space is believed to be caused by the mysterious force of dark energy, which is getting stronger, relatively, as galaxies move apart from the point of singularity.
There is clear evidence to advocate that the universe began nearly 13.8 billion years ago, however, the location of the event of the Big Bang (the center of the universe) seems to be undefinable, up to now. Since galaxies appeared to be moving away from each other in all directions, it seemed impossible to comprehend that the universe is expanding only in one direction since Hubble’s time. As a result, astronomers had begun to accept the idea that the expansion of the universe has been happening in every direction without further arguments.
Since we now have a new way of understanding that the expansion of the universe is happening in one direction, if we run the picture of the expansion backward, it would imply that there had to be such a location as ‘the center of the universe’ in space, where everything in the universe today came from. However, the center of the universe did not exist only in space, but it existed also in time, therefore the center of the universe could be located if we travel back in time.
The Absolute Rest
Absolute Rest is a new idea which defines a point in space that a body would ultimately reach while traveling in the opposite direction to the expansion of space. Traveling in the opposite direction to the expansion of space means slowing down from the speed of being drifted in the direction of the expansion of space due to the expansion itself. The body would reach the specific point of absolute rest when it exactly reaches the speed of the expansion of space. That motion of the body equals the motion of the expansion of space and comes to the state of ultimate rest.
At this point, the so-called body would standstill against the force of expansion causing a total curvature in space. However, nothing could have ever become absolute rest since the event of the Big Bang; to occupy this point in space, a body must condense the total mass and energy of the universe together, at a single point in space. Nothing with mass travels or can travel backward toward the point of the Big Bang (the point of origin), or in other words, the opposite direction toward the direction of expansion. Everything, even if it seems to travel in the opposite direction, still travels in the same direction as the expansion. Anything that is forced to travel in the opposite direction cannot move beyond the point that it occupied at an earlier time, not even the point that it occupied a second before. That means, nothing with mass can occupy spacetime that it already occupied earlier. This is prevented from the point of the Absolute Rest.
The Absolute Rest is a point beyond which nothing with mass can travel. The certain point can also be termed as the mass particle’s Cosmic Space Boundary.
The Absolute Fast
Absolute Fast is the fastest or the maximum speed that anything in the universe can travel, including massless particles (e.g., the speed of light). This can also be termed as the massless particle’s Cosmic Speed Limit.
There is nothing such as an absolute rest in the universe, which means everything is in motion at some speed due to the expansion of space. The speed is between the Absolute Rest and the Absolute Fast. The velocity of the expansion of space itself, is the fastest in the universe; nothing can exceed it.
The slower a body travels relative to the speed of the expansion of space, the more it interacts with space. The more it interacts with space, the greater it acquires mass.
In other words, the greater the mass of the body, the slower it travels in space since the interaction of the body with space is greater. It is the same way a subatomic particle acquires mass when it interacts with the Higgs field [9]. Some particles do not interact with space (e.g., photons — the particles of light) are called massless particles. That is why it travels at a constant speed at the speed of light.
In an expanding universe, time that a body experiences depends on the speed and the direction in which it is traveling. As a body travels toward its absolute rest, the slower it moves in space, therefore, the faster it experiences the ticking of time. This could directly influence the measurement of velocity of the expansion of space. More about this will be discussed in the next presentation of The Unknown Universe: Nature of Spacetime.
The Mathematical Expression of the New Perspective of the Moving Galaxies
In Hubble’s Law, it shows the expansion of the Universe by showing how distant galaxies are moving away from us.
The following formula expresses the New Perspective of the Moving Galaxies. It shows how galaxies appear to be moving away from every other galaxy, while they are moving away in one direction, with a velocity that is proportional to the distance, from the point of origin. The derivation of the formula coincides with the linear equation and Hubble’s equation.
Conclusion
Astronomers observed galaxies were moving away in every direction from the point of their observations, and the further a galaxy was, the faster it appeared to be moving away, which is the same observation that would be made from any galaxy in the universe. As such, it seemed impossible for them to picture a model in a way that could define how space could be expanding only in a certain direction beginning from a single point in space, at the same time having the model agreed with all their observational data.
Unlike the observational interpretation from Edwin Hubble in 1927, that the universe is expanding in every direction, the concept concludes that the universe is expanding only in one direction in 4-dimensional spacetime, outward from the Big Bang Singularity, with a velocity that is proportional to the distance from the center point. As a result, the further away a galaxy is, the faster it appears to be moving away, regardless of the galaxy it is observed from. If the expansion were to run backward in space and time, it would take you to the location where the event of the Big Bang occurred, which would have been the center of the universe. An unexpected consequence of the expansion happening in one direction directly addresses the question of why time is flowing only in one direction, which is toward the future.
This new perspective of understanding the moving galaxies alters our current interpretation of the expanding universe and explains that the universe is expanding only in one direction. This new way of understanding the expansion of the universe may resolve the ongoing crisis in cosmology.
References:
[1] Deborah Byrd. Today in science: Edwin Hubble and the expanding universe. Earthsky [Online] 2018. Available from: https://earthsky.org/space/this-date-in-science-edwin-hubble-and-the-expanding-universe [Accessed November 20, 2018].
[2] Charles Q. Choi. Our Expanding Universe: Age, History & Other Facts. space.com [Online] 2017. Available from: https://www.space.com/52-the-expanding-universe-from-the-big-bang-to-today.html Accessed June 17, 2017]
[3] Doppler Shift. Imagine the universe. NASA. [Online] 2020. Available from: https://imagine.gsfc.nasa.gov/features/yba/M31_velocity/spectrum/doppler_more.html [Accessed June Sep 24, 2020]
[4] Elizabeth Howell. What Are Redshift and Blueshift?. Space.com [Online] 2018. Available from: https://www.space.com/25732-redshift-blueshift.html [Accessed March 16, 2018].
[5] Matt Williams. What is the Big Bang Theory?. PHYS.ORG. [Online] 2015. Available from: https://phys.org/news/2015-12-big-theory.html [Accessed DECEMBER 18, 2015].
[6] Elizabeth Howell. Cosmic Microwave Background: Remnant of the Big Bang. Space.com [Online] 2018. Available from: https://www.space.com/33892-cosmic-microwave-background.html [Accessed August 24, 2018
[7] Ethan Siegel. Ask Ethan: Where Is The Center Of The Universe?. Forbes [Online] 2019. Available from: https://www.forbes.com/sites/startswithabang/2019/08/24/ask-ethan-where-is-the-center-of-the-universe/?sh=6cd902645403 [Accessed Aug 24, 2019].
[8] Andy Briggs. What is dark energy?. Earth Sky [Online] 2020. Available from: https://earthsky.org/space/definition-what-is-dark-energy [Accessed March 31, 2020].
[9] The Higgs Boson. The Brout-Englert-Higgs mechanism. CERN [Online]. Available from: https://home.cern/science/physics/higgs-boson.
Written By,
Kishockkanthan Sivapragasam
(Original Writing: 2016, Completed 03/18/2021)
(+ 1 747 230 7032 | kishockkanthan@gmail.com) | Los Angeles, CA, USA.
