"Either dead or not dead, existed or did not,
universe would end for some observers and not for others"
If you believe in the Big Bang theory, you must agree that we and everything in the universe were closer together in the past. The sequence is like big bang ( beginning)- now- and then big crunch (the end). From nothing to nothing. It sounds very simple, but in astronomy and cosmology, which categorized as branch of science, everything has to be proven. Oftentimes, mathematically. And it's getting more challenging because the objects you observe are far far away, you can only see them through a lens of telescope. Oftentimes too, the object comes from the past. Million years of the past. So, it's like an advanced History with lights, nebulae, or microwave radiation background as fossils to examine. And it requires scientists from generation to generation to pass the work. From Galileo to Albert Einstein. From Roger Penrose to Stephen Hawking.
To be accepted, theory should explain current condition consistently and also predict the future. For example, once Einstein made a calculation about his theory of relativity- that gravity is a bent of space-time caused by mass, so when light passes near a massive thing in the universe (like our sun, of course) it will be bent. Several years later by observation, astronomer found it's true. There was a solar eclipse so it was possible to see that light from a faraway star bent when it passed near our sun.
Predicting the future is always a fun thing to do. Is the Big Crunch theory true in explaining the fate of universe in the future? Or are there any other theory?
Scientists have been in attempt to understand and figure out the fate of the universe. Will it be there always, will there be an end? If ends, will it be in a one big explosion or in more slowly pace, star dies one by one peacefully. We still try to understand too whether universe is open or close/ finite of infinite? What is the shape of the universe? If we fly far enough to one direction, will we see the start line again from the opposite direction? Or we'll just fly forever to never ending sea of stars.
Stephen Hawking, in his book, A brief History of Time, mentioned that universe began in one explosion sometime in the past from singularity. Singularity describes one condition that cannot be explained; when physic laws (like time and space itself) don't exist. So there's no point considering it. It's the "nothing". Stephen had this idea when he was attending one course about black holes by Roger Penrose in 1960's.
If black holes can suck everything and disappear in to singularity, considering that universe is expanding now, if we turn back time, so everything is closer and closer and very dense, it'll disappear into a singularity too.
But that's when we don't consider the quantum effect.
It's not a secret that general relativity and quantum mechanics don't mix. That's one of the reason why we haven't found that "Theory of Everything" yet. Because general relativists don't quite like the idea of quantum mechanics, even though it is considered as a very strong branch of physics and make sense mathematically, if not by observation.
The other reason is that in the heart of quantum mechanics, lies the uncertainty principle. Popularized by Werner Heisenberg, it says that you can't measure two parameters in precise number for both. For instance, the more you measure a position of an object, the more you won't get precise measurement of its velocity, and vice versa. You've got to lose one. So there has to be more than one condition of something: there or not there, die or live, jump or not jump. There's no certainty until we do the observation. Nothing is certain until we do the measurement. It's like a present box that contains thing that always changes form; we don't know what's in it until we unwrap it. That sounds like a crazy ghost theory if we see in a larger scale, but in quantum scale, you know it's true.
Back to the big bang and black holes, singularity behind both can be dismissed if quantum effect is taken into account. And it was observed in mini black holes from twin stars. If in regular black holes everything went into it would be swallowed into singularity with nothing left, not with mini black holes. Because based on the thermodynamics theory, there's radiation leaking out of it.
"
If singularity actually applied to any kind of black holes, the radiation couldn't be leaking because there was no matter. In the black hole, whatever went in was crushed out of existence at the singularity. A black hole was empty curved space. How could particles rain out of empty space? (Overbye, 1991)
That's when the Uncertainty Principle plays.
"
One of the strange implications of the Uncertainty Principles, Hawking knew, was there was no such thing as absolute nothing: space could never be completely empty. The reason was because the amount of mass- energy in some volume, say in a box, was always uncertain no matter how carefully it was measured. That's a vacuum fluctuation. (Overbye, 1991)
Have you learnt in school how an electron can be seen as an X ray form by hitting it with some energy?
Vacuum fluctuations manifested itself in the form of elementary particles, dancing briefly into existence. These so called virtual particles were created in complimentary pairs, like electron with its antiparticle, positron. They lived on borrowed energy for an infinitesimal fraction of second and then met, cancelling each other out of the existence, and paying back the debt of the energy to the universe- in this case, in the form of radiation (Overbye, 1991)
Crazy as it sounded, physicist, W.F. Lamb, Jr. had won Nobel Prize for measuring the effect of these ghost particles on atomic transition in hydrogen atoms. The vacuum was really an invisible fountain of creation (Overbye, 1991).
Inflation Theory
Astronomers in 1920's found out that many stars in other galaxies were redshifted. It means they shifted away from each other. It's like seeing black dots on a balloon being blown to move apart from each other. This observation concludes that our universe is expanding.
Edwin Hubble, that time, wanted to prove that our galaxy isn't the one. There must be more galaxies out there, he suggested. So, he measured distance to other faraway galaxies which looked constant (doesn't move), unlike the nearer ones by comparing luminosity data.
... (Hawking, 1988)
Furthermore, many scientists in the 20th century were trying to find a Hubble Constant, which would explain the age of the universe. And whether the universe is open ( will expand forever ) or close ( in one time, in a certain number of mass, will turn back to contract and get closer again and end in a Big Crunch). There was also one theory mentioned that maybe our universe came in pulses. It began in a Big Bang, and in one scene, it would stop, and then contract to itself to the Big Crunch, and then to bear again another Big Bang.
That's what astronomers like Allan Sandage, G.A Tammann, Beatrice Tinsley, and particle physics theorists like Jim Peebles and Yakov B Zeldovich did in the 2nd half of the 20th century, searching ways to get the Hubble constant as correct as possible. From using conventional way; charting the stars and galaxies using telescope, making the list of lights and examine the red shifts, to the more advanced way using computer to do the charting, calculation and map the sight shifting. Some used different approach, e.g. using physics, measuring percent gas in the early big bang and calculating it to see whether it matches percent gas in today universe.
Jim Peebles was one who did that in the 1960's. Beside seeing the universe as a different problem (physics way, oftentimes), he and his physics club (who gathered in a little cottage after did skiing together) wanted to prove one of George Gamow's idea about cosmic microwave background, which is a leftover from the Big Bang.
But fortune apparently came to another who didn't even try to find it. It's Arno Penzias and Robert Wilson, young astronomers from Bell Labs.
"
The discovery of the cosmic background radiation was partly accident. Wilson and Penzias had been recruited in early sixties to modify a special horn-shaped antenna built to bounce signal off the "Echo" satellite so that it could send and receive microwave transmission from "Tellstar" communication satellite. Attempting to finish the work soon, something annoying bothered them. There was a constant unexplained signal when they tried to calibrate the antenna no matter how the antenna was positioned. That hum was always present (Overbye, 1991)
Turned out, it was the Big Bang's cosmic background radiation.
The temperature of it was about 3 degree above absolute zero and it is uniform in all direction of the sky. There is no special spot in the universe. If we look up from one part of the universe cosmic background's no different from another part.
That makes us think again, about the smoothness of the universe, why is it so uniform in all direction.
In the end of 1970's, Alan Guth who studied at MIT came with inflation theory. The theory explained why the universe is so uniform and so smooth.
Inflation theory begins with the idea of the forming universe. That everything exists now comes from a symmetry breaking, little time after the Big Bang. Symmetry breaking is something like the spinning pencil that fallen. Another example is liquid-solid phase transition. A water molecule of two hydrogen atoms attached to an oxygen atom is shaped like a shallow V. Above the freezing point (0 degree Celcius), an individual water molecule can point in any direction it wants to- all directions are equal- space to the molecule is symmetric.
Below 0 degree Celsius, the molecules hook up into crystalline structure of ice. A molecule is no longer free. Symmetry was broken.
The change from liquid to solid is called phase transition. Steven Weinberg (Alan's classmate) suggested that the universe underwent phase transitions as it went from high energy (seconds after Big Bang) to low energy now. Only in this case what froze was the Higgs Field (Overbye, 1991)
Higgs Field is the field separates "observable universe" and the "real universe" in inflation theory. Observable universe is universe that currently we can observe, which lights from the edge of it can be received. Real universe contains false vacuum that we cannot observe because lights cannot reach us due to it was being flattened/ ironed out in the seconds of inflationary phase, seconds after Big Bang.
"
The idea of inflation was that the current observable universe -- a sphere roughly 10 billion light years in radius was about the size of a grapefruit in the beginning. And when Higgs Energy- false vacuum which include "real universe that out of our sphere", the universe blew up.
Different from Hubble Expansion where it was 1 foot across when it was 1 second old, 2 feet across when it was 4 seconds old, then 3 feet in 10 seconds, universe with false vacuum in it, it expanded exponentially. With every tick of the cosmic clock (a tick in this case is 10^-34 second), the size of the universe doubled. If it started 1 foot across, by the second it would be 4 feet, by the tenth tick it would be 1028 feet across. The bigger it got, the faster it would grow to keep doubling. In no time at all, the universe would double in size 100 times becoming a trillion trillion trillion times larger. The more false vacuum energy there was, the faster the universe would push itself apart (Overbye, 1991)
"
It's like a dot size balloon with very very tiny picture on it that blown into a mountain sized balloon. It creates cosmological horizon that separates observable and real universe. The blow irons and smoothens, dilutes, and hides the original spec in the dots to a very very big smooth balloon. We'd never know what's the original picture on it because it was blown in a very rapid rate.
"Two widely separated regions of the observable universe cannot exchange information because they moved apart faster that the speed of light- no interaction in the early universe" *
Based on inflation theory, the universe would have grown so fast during this exponential doubling that in only an eyeblink the entire realm visible to telescopes today could have burst forth from a piece of the big bang that was no larger than a proton. Guth was so content with this "basement universe" idea. If you could compress 25 pounds of matter into a 10^-24 cm, making a mass around 10^75 times the density of water and certain conditions were met, a bubble of a false vacuum or "child universe" would be formed *. From the outside it would look like a black hole. From the inside, it would look like an inflating universe. The child universe would slip sort of sideways to our own and expand into its own space-time (Overbye, 1991)
The Shape of The Universe
Knowing there are galaxies other than where we live, understand the beginning through big bang, and searching black holes to get a deeper look in singularity are daily dose of cosmology works, but cosmologists nowadays taking this task to another level by trying to figure out the shape of the universe. It is called cosmic topology.
In the last two decades, when computer modelling gets more and more advanced, many researchers suggest many theories and models of the universe. One amongst the popular is tiling method. Not quite different with what we do in school when we want to measure the area of irregular shapes. It depends in how big the universe itself. If universe was finite, we would see a ghost image of ourselves, because some light would hit us again after winding around and create a ghost images in several places. It would trick our mind when applied in a bigger scale because light might take longer route. Says the ghost image of Milky Way could be mistakenly recognized as other distant galaxy.
Remember classic astronomy says that when we look up at the sky, we see the past? because light from faraway object needs time to reach us, what we see now might be things that happened in million years ago.
So when we see that ghost image, it might be us seeing ourselves or our home (Milky Way) but the older version. Because light that sent from older "us" needs time to reach us again after winding around the finite space of universe (if the universe is indeed finite).
"
The tiling reveals that a finite space looks like a hall of mirrors and the kaleidoscope of images can reveal how the tiles fit together. The farther away the tile, the longer it takes light to get to observers and so the older the image they'd see. "
The smallest spaces are the most important to cosmology. If the volume of space is huge, then we won't be able to see far enough into the universe to perceive the topology. If instead the volume of space is small, then we just may be able to see far enough into the universe to discover the shape of space."
(Levin, 2002)
The tiling would be like this:
A guy sees images of himself, says 6 images in different places, in this case he suspects he lives in a finite space. So he starts to blow up a balloon and sees all of his ghosts images blow up balloons too. Eventually the balloon begins to collide with itself (and its ghost images) at six places around each image of his.
As the balloon continues to expand, a hexagon is traced out by the pressing edges. And then, we'll figure out the shape of the universe.
"If nature had made space as small as a room, we'd always have known the world was finite. If I stand in the middle of a compact universe with a light bulb that never burns out and spaces is so small as a room, the light from bulb will transit around the space. Some will make it back to me after winding once around the space, some won't get back until winding a few times, some will take nearly forever just to happen to scratch past me again. If I wait long enough, I'll see a copy of myself in all directions, so that the space is filled and bright with ghost images of me and my light bulb at different ages. I could watch myself growing up and growing old. There'd be no need for photo album, I could watch my own life before me beyond the images of my own (Levin, 2002)
"We wouldn't have to rely on memories or stories of History. We could use binoculars or telescopes to look back, point it to the right direction and watch that history plays itself out (Levin, 2002)".
The thing is, we wouldn't be there long enough to see that happen,
"We would see no copies of ourselves but we could see many copies of our solar system, which has been around for million years"
Old enough to see several ghost images of itself.
"We could watch the solar system in different ages, when it's formed from dust and coagulate into the star with collection of planet"
But if the space were so huge that not even galaxies are ancient enough for the ghost images to wrap around the cosmos, we'd have to look back to the beginning (Big Bang). (Levin, 2002)
So, the Big Bang is still the very important source of information. Anything happen in that seconds of Big Bang will be carefully studied.
Recent Study
HoloQosmos (Holographic Quantum Cosmology)
Current Big Bang Theory lets limitless number of possibilities of multiverses.
In a paper published in the "Journal of High Energy Physics", Stephen Hawking and Thomas Hertog from KU Leven present a model that reduces the boundless multiverse to a more manageable range of possible universe using holography, based on String Theory (Cordis, 2018).
No Big Bang Model
The new theory proposed by Ali and Saurya Das from University of Lethbridge in Alberta Canada, in which the cosmos is filled with a quantum fluid suggests that there was no Big Bang. The new theory suggests the universe was much smaller in the past but it was never a singularity. Instead, the universe appears to have existed forever (Zeeya, 2015)
Cosmic Topology and Gravitational Wave
Proposals had been made by researchers about the shape of the universe in the expanding field of cosmic topology; include tetrahedral and octahedral spaces, flat doughnut, and an infinite horn shaped universe. The popular one was universe that is shaped like a football/ dodecahedron. In that scenario, an object that travels away from earth in a straight line will eventually return from the other side of the universe, having been rotated by 36 degree. Space might therefore act like a cosmic hall of mirrors and creating multiple images of faraway light source.
However, the best way to determine the shape of our universe is to go back to its beginning, just after the Big Bang. The infant universe is thought to have been crossed by acoustic waves that would have caused tiny density fluctuations in the primordial plasma. After about 380,000 years, however, the universe had expanded and cooled enough to allow matter and antimatter to decouple. This meant that photons could travel unhindered through space, carrying with them vital information about the primordial density fluctuations (which are now thought to have been the seeds for galaxies and clusters of galaxies to form). Today, 13.7 billion years after the Big Bang, this radiation has cooled to a temperature of about 2.7 K, which is in the microwave region. And the fluctuations are imprinted as hot and cold spots in this cosmic microwave background (Luminet, 2015)
Just recently in September 2015, gravitational wave that carried information from the clash of two black holes was observed. According to Einstein, an object with enormous mass that accelerated will form a ripple that spread away across the universe. That ripple what we call as gravitational wave. This gravitational wave carries information about what caused it. Using gravitational wave, we might know detail/ information from just a little time after the Big Bang (Nugraha, 2016)
In remembrance of Stephen Hawking
I was feeling so sad when I heard the news that Stephen Hawking had passed away. Just earlier this year I’d searched and read again his work like Universe in a Nutshell and The Grand Design, just hoped that he will make another ones, so when in that March the news came, it hit me quite hardly. It was one of my saddest day .
Stephen was good at explaining difficult matters, that's what I love most about him. This writing is partly because of my admiration to him. If you read one of the reference books of this writing entitled "Lonely Hearts of The Cosmos", you'll find him described as a witty and very funny guy, despite of his brilliant works and ideas.
"
As a student, Hawking was bright but lazy. He impressed his professors and fellow students as the sort who would rather point out the mistakes in the textbook than do the problems at the end of the chapter. He grew long-haired and famous for not studying, being smart enough to do the work without cracking the books. He rarely took notes. He fell asleep in classes and made a show of tossing his own papers contemptuously in the wastebasket. Hawking was free spirit.
"
His life has been adapted to a 2014 film “Theory of Everything” which was nominated in 2015 Academy Award.
This writing can also be read at my personal blog https://hapsaririana.wordpress.com/2018/09/30/closer-look-at-our-universe-big-bang-singularity-microwave-radiation/
References
Hawking, Stephen. 2013. Sejarah Singkat Waktu. Gramedia: Jakarta (From original: A Brief History of Time, 1988)
Levin, Janna. 2002. How The Universe Got Its Spot. Anchor Books: New York
Overbye, Dennis. 1991. Lonely Hearts Of The Cosmos: The Story Of The Scientific Quest For The Secret Of The Universe. Back Bay Books: USA
Community Reasearch and Development Information (Cordis). 2018.A new cosmological theory points to a smaller, simpler, finite universe. European Commission's primary public repository and portal.
Jean-Pierre Luminet. 2005. A cosmic hall of mirrors. Plysics World, IOP Publishing.
Merali, Zeeya. 2015. New origin of universe model pours water on Big Bang theory. Nature Middle East comprehensive portal site for information on scientific and medical research.
Nugraha, Rukman. 2016. Terdeteksinya Gelombang Gravitasi dari Penggabungan Dua Lubang Hitam. Langit Selatan, Media Astronomi Indonesia
The Theory of Everything - Official Trailer
Image Source:
NASA in NASA's planet-hunting TESS spacecraft captures 'first light' image by Mariella Moon
He Lives on as All Great Philosophers Do': Readers Mourn Stephen Hawking
There was one mystery which Stephen Hawking admits he couldn’t solve
Keywords: Singularity, Uncertainty Principle, Vacuum Fluctuations, Cosmic Topology
Follow Instagram @kompasianacom juga Tiktok @kompasiana biar nggak ketinggalan event seru komunitas dan tips dapat cuan dari Kompasiana
Baca juga cerita inspiratif langsung dari smartphone kamu dengan bergabung di WhatsApp Channel Kompasiana di SINI
