Astronomy

What happened just before the Big bang?

What happened just before the Big bang?


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Does the CMB contain any clues to what caused the Big Bang? Does a mathematical model theorize it?


Caveat: I'm not a cosmologist, so this answer may not reflect the forefront of scientific knowledge/accuracy, but I have some knowledge so thought I'd share it and hopefully someone can correct me if I'm wrong.

The Big Bang theory states that everything is moving away from everything else, so it must have started closer together. We know from the Cosmic Microwave Background that everything was very dense and hot and small.

You may have heard that the universe started in a singularity. This means one point at which all matter was in the same place. In this state, all information in matter is lost. No particle can be labelled as having a position or size or spin, because every particle is in the same state as every other particle. This means we lose all possibility of having any information about what happened before this. There are many theories of what could have been before this, but no matter how simple/beautiful/mathematically rigorous the theory, it is physically impossible to know anything about it so they are impossible to test. In some definitions this makes these theories not actually science, as the scientific method involves making testable predictions.


We don't really know what happened before the big bang, but it is logical to think that just like the the mass was released when the big bang happened, it also got crushed to that single point, and since energy can't be created or destroyed, there was also mass before the big bang. And this is also a lot similar to a black hole, leading us to think that the big bang might have been a black hole


Most everybody is familiar with the Big Bang — the notion that an impossibly hot, dense universe exploded into the one we know today. But what do we know about what came before?

In the quest to resolve several puzzles discovered in the initial condition of the Big Bang, scientists have developed a number of theories to describe the primordial universe, the most successful of which — known as cosmic inflation — describes how the universe dramatically expanded in size in a fleeting fraction of a second right before the Big Bang.

But as successful as the inflationary theory has been, controversies have led to active debates over the years.

Some researchers have developed very different theories to explain the same experimental results that have supported the inflationary theory so far. In some of these theories, the primordial universe was contracting instead of expanding, and the Big Bang was thus a part of a Big Bounce.

Some researchers — including Avi Loeb, the Frank B. Baird, Jr. Professor of Science and chair of the Astronomy Department — have raised concerns about the theory, suggesting that its seemingly endless adaptability makes it all but impossible to test.

“The current situation for inflation is that it’s such a flexible idea … it cannot be falsified experimentally,” Loeb said. “No matter what result of the observable people set out to measure would turn out to be, there are always some models of inflation that can explain it.” Therefore, experiments can only help to nail down some model details within the framework of the inflationary theory, but cannot test the validity of the framework itself. However, falsifiability should be a hallmark of any scientific theory.

That’s where Xingang Chen comes in.

Xingang Chen is one of the authors of a new study that examines what the universe looked like before the Big Bang. Jon Chase/Harvard Staff Photographer

A senior lecturer in astronomy, Chen and his collaborators for many years have been developing the idea of using something he called a “primordial standard clock” as a probe of the primordial universe. Together with Loeb and Zhong-Zhi Xianyu, a postdoctoral researcher in the Physics Department, Chen applied this idea to the noninflationary theories after he learned about an intense debate in 2017 that questioned whether inflationary theories make any predictions at all. In a paper published as an Editor’s Suggestion in Physical Review Letters, the team laid out a method that may be used to falsify the inflationary theory experimentally.

In an effort to find some characteristic that can separate inflation from other theories, the team began by identifying the defining property of the various theories — the evolutionary history of the size of the primordial universe. “For example, during inflation, by definition the size of the universe grows exponentially,” Xianyu said. “In some alternative theories, the size of the universe contracts — in some very slowly and in some very fast.

“The conventional observables people have proposed so far have trouble distinguishing the different theories because these observables are not directly related to this property,” he continued. “So we wanted to find what the observables are that can be linked to that defining property.”

The signals generated by the primordial standard clock can serve this purpose.

That clock, Chen said, is any type of massively heavy elementary particle in the energetic primordial universe. Such particles should exist in any theory, and they oscillate at some regular frequency, much like the swaying of a clock’s pendulum.

The primordial universe was not entirely uniform. Quantum fluctuations became the seeds of the large-scale structure of today’s universe and one key source of information physicists rely on to learn about what happened before the Big Bang. The theory outlined by Chen suggests that ticks of the standard clock generated signals that were imprinted into the structure of those fluctuations. And because standard clocks in different primordial universes would leave different patterns of signals, Chen said, they may be able to determine which theory of the primordial universe is most accurate.

“If we imagine all the information we learned so far about what happened before the Big Bang is in a roll of film frames, then the standard clock tells us how these frames should be played,” Chen explained. “Without any clock information, we do not know if the film should be played forward or backward, fast or slow — just like we are not sure if the primordial universe was inflating or contracting, and how fast it did that. This is where the problem lies. The standard clock put time stamps on each of these frames when the film was shot before the Big Bang, and tells us what this film is about.”

The team calculated how these standard clock signals should look in noninflationary theories, and suggested how to search for them in astrophysical observations. “If a pattern of signals representing a contracting universe were found,” Xianyu said, “it would falsify the entire inflationary theory, regardless of what detailed models one constructs.”

The success of this idea lies in experimentation. “These signals will be very subtle to detect,” Chen said. “Our proposal is that there should be some kind of massive fields that have generated these imprints and we computed their patterns, but we don’t know how large the overall amplitude of these signals is. It may be that they are very faint and very hard to detect, so that means we will have to search in many different places.

“The cosmic microwave background radiation is one place,” he continued. “The distribution of galaxies is another. We have already started to search for these signals and there are some interesting candidates already, but we still need more data.”

This research was supported with funding from the Black Hole Initiative at Harvard University and the Center of Mathematical Sciences and Applications, Harvard University.


Glimpse of Time Before Big Bang Possible

It may be possible to glimpse before the supposed beginning of time into the universe prior to the Big Bang, researchers now say.

Unfortunately, any such picture will always be fuzzy at best due to a kind of "cosmic forgetfulness."

The Big Bang is often thought as the start of everything, including time, making any questions about what happened during it or beforehand nonsensical. Recently scientists have instead suggested the Big Bang might have just been the explosive beginning of the current era of the universe, hinting at a mysterious past.

To see how far into history one might gaze, theoretical physicist Martin Bojowald at Pennsylvania State University ran calculations based on loop quantum gravity, one of a number of competing theories seeking to explain how the underlying structure of the universe works.

Past research suggested the Big Bang was preceded by infinite energies and space-time warping where existing scientific theories break down, making it impossible to peer beforehand. The new findings suggest that although the levels of energy and space-time warping before the Big Bang were both incredibly high, they were finite.

Scientists could spot clues in the present day of what the cosmos looked like previously. If evidence of the past persisted after the Big Bang, its influence could be spotted in astronomical observations and computational models, Bojowald explained.

However, Bojowald also figures some knowledge of the past was irrevocably lost. For instance, the sheer size of the present universe would suppress precise knowledge of how the universe changed in size before the Big Bang, he said.

"It came as a big surprise that some properties of the universe before the Big Bang may have only such a weak influence on current observations that they are practically undetermined," Bojowald said of findings detailed online July 1 in the journal Nature Physics.

One implication of this "cosmic forgetfulness," as Bojowald calls it, is that history does not repeat itself&mdashthe fundamental properties of the current era of the universe are different from the last, Bojowald explained. "It's as if the universe forgot some of its properties and acquired new properties independent of what it had before," he told SPACE.com.

"The eternal recurrence of absolutely identical universes would seem to be prevented by the apparent existence of an intrinsic cosmic forgetfulness," he added.

These findings differ from a cyclic model of the cosmos from cosmologist Paul Steinhardt at Princeton and theoretical physicist Neil Turok at Cambridge, which envisions an infinite series of Big Bangs preceding our universe caused by additional membranes or "branes" of reality perpetually colliding and bouncing off each other. Steinhardt said he felt Bojowald's calculations were concrete, but needed further elaboration to include the interplay of different kinds of matter and radiation.

Cosmologist Carlo Rovelli at the Center of Theoretical Physics in Marseilles, France, found it "remarkable" that the new work could delve past the Big Bang. He added the work had to lead to predictions that could be compared to cosmological observations "in order to become credible."


New Proposal for Probing What Came Before the Big Bang

Most everybody is familiar with the Big Bang — the notion that an impossibly hot, dense universe exploded into the one we know today. But what do we know about what came before?

In the quest to resolve several puzzles discovered in the initial condition of the Big Bang, scientists have developed a number of theories to describe the primordial universe, the most successful of which — known as cosmic inflation — describes how the universe dramatically expanded in size in a fleeting fraction of a second right before the Big Bang.

But as successful as the inflationary theory has been, controversies have led to active debates over the years.

Some researchers have developed very different theories to explain the same experimental results that have supported the inflationary theory so far. In some of these theories, the primordial universe was contracting instead of expanding, and the Big Bang was thus a part of a Big Bounce.

Some researchers — including Avi Loeb, the Frank B. Baird, Jr. Professor of Science and chair of the Astronomy Department — have raised concerns about the theory, suggesting that its seemingly endless adaptability makes it all but impossible to test.

“The current situation for inflation is that it’s such a flexible idea … it cannot be falsified experimentally,” Loeb said. “No matter what result of the observable people set out to measure would turn out to be, there are always some models of inflation that can explain it.” Therefore, experiments can only help to nail down some model details within the framework of the inflationary theory, but cannot test the validity of the framework itself. However, falsifiability should be a hallmark of any scientific theory.

That’s where Xingang Chen comes in.

A senior lecturer in astronomy, Chen and his collaborators for many years have been developing the idea of using something he called a “primordial standard clock” as a probe of the primordial universe. Together with Loeb and Zhong-Zhi Xianyu, a postdoctoral researcher in the Physics Department, Chen applied this idea to the noninflationary theories after he learned about an intense debate in 2017 that questioned whether inflationary theories make any predictions at all. In a paper published as an Editor’s Suggestion in Physical Review Letters, the team laid out a method that may be used to falsify the inflationary theory experimentally.

In an effort to find some characteristic that can separate inflation from other theories, the team began by identifying the defining property of the various theories — the evolutionary history of the size of the primordial universe. “For example, during inflation, by definition the size of the universe grows exponentially,” Xianyu said. “In some alternative theories, the size of the universe contracts — in some very slowly and in some very fast.

“The conventional observables people have proposed so far have trouble distinguishing the different theories because these observables are not directly related to this property,” he continued. “So we wanted to find what the observables are that can be linked to that defining property.”

The signals generated by the primordial standard clock can serve this purpose.

That clock, Chen said, is any type of massively heavy elementary particle in the energetic primordial universe. Such particles should exist in any theory, and they oscillate at some regular frequency, much like the swaying of a clock’s pendulum.

The primordial universe was not entirely uniform. Quantum fluctuations became the seeds of the large-scale structure of today’s universe and one key source of information physicists rely on to learn about what happened before the Big Bang. The theory outlined by Chen suggests that ticks of the standard clock generated signals that were imprinted into the structure of those fluctuations. And because standard clocks in different primordial universes would leave different patterns of signals, Chen said, they may be able to determine which theory of the primordial universe is most accurate.

“If we imagine all the information we learned so far about what happened before the Big Bang is in a roll of film frames, then the standard clock tells us how these frames should be played,” Chen explained. “Without any clock information, we do not know if the film should be played forward or backward, fast or slow — just like we are not sure if the primordial universe was inflating or contracting, and how fast it did that. This is where the problem lies. The standard clock put time stamps on each of these frames when the film was shot before the Big Bang, and tells us what this film is about.”

The team calculated how these standard clock signals should look in noninflationary theories, and suggested how to search for them in astrophysical observations. “If a pattern of signals representing a contracting universe were found,” Xianyu said, “it would falsify the entire inflationary theory, regardless of what detailed models one constructs.”

The success of this idea lies in experimentation. “These signals will be very subtle to detect,” Chen said. “Our proposal is that there should be some kind of massive fields that have generated these imprints and we computed their patterns, but we don’t know how large the overall amplitude of these signals is. It may be that they are very faint and very hard to detect, so that means we will have to search in many different places.

“The cosmic microwave background radiation is one place,” he continued. “The distribution of galaxies is another. We have already started to search for these signals and there are some interesting candidates already, but we still need more data.”

This research was supported with funding from the Black Hole Initiative at Harvard University and the Center of Mathematical Sciences and Applications, Harvard University.


“Pop Goes the Cosmos” –Mystery of the Universe Before the Big Bang

On March 21, 2013, the European Space Agency held an international press conference to announce new results from a spacecraft called Planck that mapped the cosmic microwave background (CMB) radiation, light emitted more than 13 billion years ago just after the Big Bang revealing some of the greatest mysteries of cosmology.

The new map, ESA scientists told the journalists, confirmed a 35-year-old theory that the universe began with a bang followed by a brief period of hyperaccelerated expansion known as inflation. This expansion smoothed the universe to such an extent that, billions of years later, it remains nearly uniform all over space and in every direction and “flat,” as opposed to curved like a sphere, except for tiny variations in the concentration of matter that account for the stars, galaxies and galaxy clusters around us.

Although cosmic inflation is well known for resolving some important mysteries about the structure and evolution of the universe, other very different theories can also explain these mysteries. In some of these theories, the state of the universe preceding the Big Bang – the so-called primordial universe – was contracting instead of expanding, and the Big Bang was thus a part of a Big Bounce.

A team of scientists has proposed a powerful new test for inflation, the theory that the universe dramatically expanded in size in a fleeting fraction of a second right after the Big Bang. Their goal is to give insight into a long-standing question: what was the universe like before the Big Bang?

To help decide between inflation and these other ideas, the issue of falsifiability – that is, whether a theory can be tested to potentially show it is false – has inevitably arisen. Some researchers, including Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA), have raised concerns about inflation, suggesting that its seemingly endless adaptability makes it all but impossible to properly test.

“Falsifiability should be a hallmark of any scientific theory. The current situation for inflation is that it’s such a flexible idea, it cannot be falsified experimentally,” Loeb said. “No matter what value people measure for some observable attribute, there are always some models of inflation that can explain it.”

The debate about the falsifiability of inflation started in 2017, when Loeb — along with Princeton professor Paul J. Steinhardt and then-Princeton postdoctoral fellow Anna Ijjas — wrote an article in Scientific American, Pop Goes the Universe, in which they challenged the dominance of the inflationist theory.

In the years since the 2013 ESA news conference, wrote Loeb and colleagues, “more precise data gathered by the Planck satellite and other instruments have made the case only stronger. Yet even now the cosmology community has not taken a cold, honest look at the big bang inflationary theory or paid significant attention to critics who question whether inflation happened. Rather cosmologists appear to accept at face value the proponents’ assertion that we must believe the inflationary theory because it offers the only simple explanation of the observed features of the universe. But, as they explain, the Planck data, added to theoretical problems, have shaken the foundations of this assertion.”

In Pop Goes the Universe, the authors make the case for a bouncing cosmology, as was proposed by Steinhardt and others in 2001. They close by making the extraordinary claim that inflationary cosmology “cannot be evaluated using the scientific method” and go on to assert that some scientists who accept inflation have proposed “discarding one of [science’s] defining properties: empirical testability,” thereby “promoting the idea of some kind of nonempirical science.

“One of the inevitable consequences of inflation is the notion of the multiverse. Anything that can happen will happen an infinite number of times,” Loeb said. “So is inflation really falsifiable? We think that a scientific theory is one that you can falsify. If inflation can accommodate anything, it’s a problem.”

The 2017 piece provoked what Loeb characterized as a “odd” response from Massachusetts Institute of Technology Professor Alan H. Guth — a letter co-signed by 32 of Guth’s colleagues, including Stephen Hawking and five Nobel Prize Laureates. “People — especially people that invented inflation — got really upset, and said that it cannot be falsified, it must be true, it should be true, and therefore there is no need to test it because it must be true,” Loeb said.

Guth wrote in an email to Loeb and team that he has never argued that inflation “cannot or should not be tested.” Loeb said Guth’s letter prompted them to search for a way to test the theory of inflation, leading them to publish their most recent paper.

Now, a team of scientists led by the CfA’s Xingang Chen, along with Loeb, and Zhong-Zhi Xianyu of the Physics Department of Harvard University, have applied an idea they call a “primordial standard clock” to the non-inflationary theories, and laid out a method that may be used to falsify inflation experimentally.

In an effort to find some characteristic that can separate inflation from other theories, the team began by identifying the defining property of the various theories – the evolution of the size of the primordial universe.

“For example, during inflation, the size of the universe grows exponentially,” Xianyu said. “In some alternative theories, the size of the universe contracts. Some do it very slowly, while others do it very fast.

“The attributes people have proposed so far to measure usually have trouble distinguishing between the different theories because they are not directly related to the evolution of the size of the primordial universe,” he continued. “So, we wanted to find what the observable attributes are that can be directly linked to that defining property.”

The signals generated by the primordial standard clock can serve such a purpose. That clock is any type of heavy elementary particle in the primordial universe. Such particles should exist in any theory and their positions should oscillate at some regular frequency, much like the ticking of a clock’s pendulum.

The primordial universe was not entirely uniform. There were tiny irregularities in density on minuscule scales that became the seeds of the large-scale structure observed in today’s universe. This is the primary source of information physicists rely on to learn about what happened before the Big Bang. The ticks of the standard clock generated signals that were imprinted into the structure of those irregularities. Standard clocks in different theories of the primordial universe predict different patterns of signals, because the evolutionary histories of the universe are different.

“If we imagine all of the information we learned so far about what happened before the Big Bang is in a roll of film frames, then the standard clock tells us how these frames should be played,” Chen explained. “Without any clock information, we don’t know if the film should be played forward or backward, fast or slow, just like we are not sure if the primordial universe was inflating or contracting, and how fast it did so. This is where the problem lies. The standard clock put time stamps on each of these frames when the film was shot before the Big Bang, and tells us how to play the film.”

The team calculated how these standard clock signals should look in non-inflationary theories, and suggested how they should be searched for in astrophysical observations. “If a pattern of signals representing a contracting universe were found, it would falsify the entire inflationary theory,” Xianyu said.

The success of this idea lies with experimentation. “These signals will be very subtle to detect,” Chen said, “and so we may have to search in many different places. The cosmic microwave background radiation is one such place, and the distribution of galaxies is another. We have already started to search for these signals and there are some interesting candidates already, but we need more data.”

Loeb told the Harvard Crimson’s Juliet E. Isselbacher that he hopes the data needed to complete the test will come within the next decade.

Many future galaxy surveys, such as US-lead LSST, European’s Euclid and the newly approved project by NASA, SphereX, are expected to provide high quality data that can be used toward the goal.


BBC Horizon: What happened before the Big Bang?

Have you read A Briefer History of Time? I found that to be the best science book I ever read, and The Grand Design seemed to build off of it and discuss more abstract ideas.

It's should be noted that your link only works in the UK.

i hate michio i've made it my mission to tell the world he's a worthless to the scientific community.

I haven't forgiven him for trying to stop the Cassini mission.

He's actually very good when not pariticipating in this popularized speculative papp.

It's too bad they only produce shows about grandiose speculation with the whizz bang and neato factor turned way up (ahem Bryan Greene and the Elegant Universe) but neglect any real scientific education by instructing in the basics of physics and the scientific method. They should just label those programs 'Imagination Time with PhDs' they are so useless and contribute to scientific ignorance and the spread of fantasy rather than prevent it.

Anyway, I have actually seen really very good interview with Michio Kaku when he was speaking to an intelligent audience when he gets on one of these flashy useless programs, he just says fancy words in sound bites without conveying any actual information.

Ok, after looking at his Wikipedia page, he is a complete nut - Art Bell? Nukes and the New World Order? Guh.


Before, During, and After the Big Bang

Neatorma is proud to bring you an excerpt from the book NOTHING: Surprising Insights Everywhere from Zero to Oblivion,from the magazine New Scientist. It features thoughts from 21 different writers and scientists on subjects from the nature of nothingness to the cosmos to the inner workings of the human mind. They harness the latest ressearch to explain complicated concepts in ways we can understand. For example:

Why does the placebo effect&mdashessentially, feeling better after taking nothing&mdashwork?
Can meditation&mdashclearing the mind of everything&mdashcause structural changes in the brain?
What was happening immediately after the big bang, and, even more mysterious, what came before?
Is the appendix&mdasha body part that supposedly does nothing&mdashtruly a vestigial organ?
Why was it so hard to invent the number zero?
How might cooling elements down to nearly absolute zero solve our energy crisis?

This excerpt on the big bang is from New Scientist cosmology consultant Marcus Chown.

Beginnings
&ldquoAstronomy leads us to a unique event, a universe which was created out of nothing,&rdquo said Arno Penzias, the American physicist and Nobel laureate. He was talking about the mother of all beginnings, the big bang. It&rsquos the obvious place for us to start. To add some variety, we&rsquoll bounce you to ancient Babylon and then to the most modern of brain-scanning laboratories. You&rsquoll find out about the birth of a symbol that you almost certainly take for granted and discover that your head is home to an organ you&rsquove probably never heard of. Along the way, we&rsquoll look at the fruits of an infant scientific field&mdashthe mind&rsquos power to heal the body.

The big bang
Our universe began in an explosion of sorts, what&rsquos called the big bang. The $64,000 question is how the cosmos emerged out of nothing. But before we tackle that, we need to understand what the big bang entailed. Here&rsquos Marcus Chown.

In the beginning was nothing. Then the universe was born in a searing hot fireball called the big bang. But what was the big bang? Where did it happen? And how have astronomers come to believe such a ridiculous thing?

About 13.82 billion years ago, the universe that we inhabit erupted, literally, out of nothing. It exploded in a titanic fireball called the big bang. Everything&mdashall matter, energy, even space and time&mdashcame into being at that instant.

In the earliest moments of the big bang, the stuff of the universe occupied an extraordinarily small volume and was unimaginably hot. It was a seething cauldron of electromagnetic radiation mixed with microscopic particles of matter unlike any found in today&rsquos universe. As the fireball expanded, it cooled, and more and more structure began to &ldquofreeze out.&rdquo

Step by step, the fundamental particles we know today, the building blocks of all ordinary matter, acquired their present identities. The particles condensed into atoms and galaxies began to grow, then fragment into stars such as our sun. About 4.55 billion years ago, Earth formed. The rest, as they say, is history.

It is an extraordinarily grand picture of creation. Yet astronomers and physicists, armed with a growing mass of evidence to back their theories, are so confident of the scenario that they believe they can work out the detailed conditions in the early universe as it evolved, instant by instant.

That&rsquos not to say we can go back to the moment of creation. The best that physics can do is to attempt to describe what was happening when the universe was already about 10&ndash35 seconds old&mdasha length of time that can also be written as a decimal point followed by 34 zeroes and a 1.

This is an exceedingly small interval of time, but you would be wrong if you thought it was so close to the moment of creation as to make no difference. Although the structure of the universe no longer changes much in even a million years, when the universe was young, things changed much more rapidly.

For example, physicists think that as many important events happened between the end of the first tenth of a second and the end of the first second as in the interval from the first hundredth of a second to the first tenth of a second, and so on, logarithmically, back to the very beginning. As they run the history of the universe backward, like a movie in reverse, space is filled with ever more frenzied activity.

This is because the early universe was dominated by electromagnetic radiation&mdashin the form of little packets of energy called photons&mdashand the higher the temperature, the more energetic the photons. Now, high-energy photons can change into particles of matter because one form of energy can be converted into another, and, as Einstein revealed, mass (m) is simply a form of energy (E), hence his famous equation E=mc2, where c is the speed of light.

What Einstein&rsquos equation says is that particles of a particular mass, m, can be created if the packets of radiation, the photons, have an energy of at least mc2. Put another way, there is a temperature above which the photons are energetic enough to produce a particle of mass, m, and below which they cannot create that particle.

If we look far enough back, we come to a time when the temperature was so high, and the photons so energetic, that colliding photons could produce particles out of radiant energy. What those particles were before the universe was 10&ndash35 seconds old, we do not know. All we can say is that they were very much more massive than the particles we are familiar with today, such as the electron and top quark.

As time progressed and temperature fell, so the mix of particles in the universe changed to a soup of less and less massive particles. Each particle was &ldquoking for a day,&rdquo or at least for a split second. For the reverse process was also going on&mdashmatter was being converted back to radiant energy as particles collided to produce photons.

What do physicists think the universe was like a mere 10&ndash35 seconds after the big bang?

Well, the volume of space that was destined to become the &ldquoobservable universe,&rdquo which today is 84 billion light years across, was contained in a volume roughly the size of a pea. And the temperature of this superdense material was an unimaginable 1028 ºC.

At this temperature, physicists predict, colliding photons had just the right amount of energy to produce a particle called the X-boson that was a million billion times more massive than the proton. No one has yet observed an X-boson, because to do so we would have to recreate, in an Earth bound laboratory, the extreme conditions that existed just 10&ndash35 seconds after the big bang.

How far back can physicists probe in their laboratories?

The answer is to a time when the universe was about one-trillionth (10&ndash12) of a second old. By then, it had cooled down to about 100 million billion degrees&mdashstill 10 billion times hotter than the center of the sun. In 2012, physicists at CERN, the European center for particle physics in Geneva, recreated these conditions in the giant particle accelerator called the Large Hadron Collider. They conjured into being a particle that resembles the Higgs boson, a particle that vanished from the universe a trillionth of a second after the big bang.

(Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

The gulf between 10&ndash35 seconds and a trillionth of a second is gigantic. We know that for most of this period, matter was squeezed together more tightly than the most compressed matter we know of&mdashthat inside the nuclei of atoms. And, as the temperature fell, so the energy level of photons declined, creating particles of lower and lower masses.

At some point, the hypothetical building blocks of the neutron and proton&mdashknown as quarks&mdashcame into being. And by the time the universe was about one-hundredth of a second old, it had cooled sufficiently to be dominated by particles that are familiar to us today: photons, electrons, positrons and neutrinos. Neutrons and protons were around, but there weren&rsquot many of them. In fact, they were a very small contaminant in the universe.

About one second into the life of the universe, the temperature had fallen to about 10 billion ºC, and photons had too little energy to produce particles easily. Electrons and their positively charged &ldquoantimatter&rdquo opposites, called positrons, were colliding and annihilating each other to create photons. However, because of a slight and, to this day, mysterious lopsidedness in the laws of physics, there were roughly 10 billion + 1 electrons for every 10 billion positrons. So, after an orgy of annihilation, the universe was left with a surplus of matter, and with about 10 billion photons for every electron, a ratio that persists today.

The next important stage in the history of the universe was at about one minute.

The temperature had dropped to a mere 1 billion ºC&mdashthe temperature in the hearts of the hottest stars. Now the particles were moving more slowly. In the case of protons and neutrons, it meant that they stayed close to each other long enough for the strong nuclear forces, which bind them together in the nuclei of atoms, to have a chance to take hold. In particular, two protons and two neutrons could combine to form nuclei of helium.

Solitary neutrons decay into protons in about 15 minutes, so any neutrons left over after helium formed became protons. According to physicists&rsquo calculations, roughly ten protons were left over for every helium nucleus that formed. And these became the nuclei of hydrogen atoms, which consist of a single proton.

This is one of the strongest pieces of evidence that the big bang really did happen. For much, much later, when the temperature had cooled considerably, the hydrogen and helium nuclei picked up electrons to become stable atoms. Today, when astronomers measure the abundance of elements in the universe&mdashin stars, galaxies and interstellar space&mdashthey still find roughly one helium atom for every ten hydrogens.

(Image credit: NASA, Hubble Space Telescope, ESA)

The point at which it was cool enough for electrons to combine with protons to make the first atoms was about 380,000 years after the big bang. The universe was now cooling very much more slowly than in its early moments, and the temperature had reached a modest 3,000 ºC. This also marked another significant event in the early history of the universe.

Until the electrons had combined with the hydrogen and helium nuclei, photons could not travel far in a straight line without running into an electron. Free electrons are very good at scattering, or redirecting, photons. As a consequence, every photon had to zigzag its way across the universe. This had the effect of making the universe opaque. If this happened today and light from the stars zigzagged its way across space to your eyes, rather than flying in straight lines, you would see only a dim milky glow from the whole sky rather than myriad stars.

We can still detect photons from this period. They have been flying freely through the universe for billions of years, and astronomers observe them as what&rsquos called the cosmic microwave background. Whereas these photons started their journey when the temperature was 3,000 ºC, the universe has expanded about 1100 times while they have been in flight. This has decreased their energy by this factor, so that we now record the signals as just 2.725 degrees above absolute zero.

The temperature dropping to about 3,000 ºC also signalled another event&mdashthe point at which the energy levels of the radiation, or photons, in the universe fell below that of the matter. From then on, the universe was dominated by matter and by the force of gravity acting on that matter.

The building of elements, which had begun when the universe was about one minute old, had stopped by the time it had been in existence for ten minutes, and the protons and neutrons had formed the nuclei of hydrogen and helium. For elements such as carbon and oxygen to form, hotter and denser conditions were needed, but the universe was getting colder and more rarefied all the while. The heavy elements in the planets and in your body were created, billions of years later, in the nuclear furnaces of stars.

(Image credit: NASA,ESA, and E. Perlman, Florida Institute of Technology)

Instead, as the universe continued to expand, gravity caused clumps of matter to accumulate in large islands. Those islands were to become the galaxies. The galaxies continued their headlong rush into the void, fragmenting into smaller clumps which became individual stars, producing heat and light by nuclear reactions deep in their cores. At one point, about 9 billion years after the big bang, a yellow star was born toward the outer edge of a great spiral whirlpool of stars called the Milky Way. The star was our sun.

How do we know there was a big bang?
Our modern picture of the universe is due in large part to an American astronomer, Edwin Hubble. In 1923, he showed that the Milky Way, the great island of stars to which our sun belongs, was just one galaxy among thousands of millions of others scattered throughout space.

Hubble also found that the wavelength of the light from most of the galaxies is &ldquored shifted.&rdquo Astronomers initially interpreted this as a Doppler effect, familiar to anyone who has noticed how the pitch of a police siren drops as it passes by. The siren becomes deeper because the wavelength of the sound is stretched out. Similarly with light, the wavelength of light from a galaxy which is moving away from us is stretched out to a longer, or redder, wavelength.

Hubble discovered that most galaxies are receding from the Milky Way. In other words, the universe is expanding. And the farther away a galaxy is, the faster it is receding.

One conclusion is inescapable: the universe must have been smaller in the past. There must have been a moment when the universe started expanding: the moment of its birth. By imagining the expansion running backward, astronomers deduce that the universe came into existence about 13.82 billion years ago.

This idea of a big bang means that the red shifts of galaxies are not really Doppler shifts. They arise because in the time that light from distant galaxies has been traveling across space to Earth, the universe has grown, stretching the wavelength of light.

The picture of a universe that is expanding need not have been a surprise to anyone. If Albert Einstein had only had faith in his equations, he could have predicted it in 1915 with his theory of gravity, known as the general theory of relativity. But Einstein, like Newton before him, hung on to the idea that the universe was static&mdashunchanging, without beginning or end. He can be forgiven because, at the time, he did not even know about the existence of galaxies.

The vision of a static universe also appealed strongly to astronomers. In 1948, Hermann Bondi, Thomas Gold and Fred Hoyle proposed the steady-state theory of the universe. The universe was expanding, they said, but perhaps it was unchanging in time.

Their theory said that space is expanding at a constant rate but, at the same time, matter is created continuously throughout the universe. This matter is just enough to compensate for the expansion and keep the density of the universe constant. Where this matter would come from, nobody could say. But neither could the proponents of the big bang.

The steady-state theory held its own as the principal challenger to the big bang theory for two decades. Then, in the 1960s, two astronomical discoveries dealt it a fatal blow.

The first discovery came from Martin Ryle and his colleagues at the University of Cambridge. They were studying radio galaxies&mdashenormously powerful sources of radio waves. In the early 1960s, the Cambridge astronomers found that there were many more radio galaxies at large distances than nearby.

The radio waves from these distant objects have taken billions of years to reach us. Ryle and his colleagues, therefore, were observing our universe as it was in an earlier time. The excess of radio galaxies at great distances had to mean that conditions in the remote past were different from those today. A universe which changes with time ran counter to the steadystate theory.

Then in 1965, Arno Penzias and Robert Wilson, two scientists at the Bell Telephone Labs in Holmdel, New Jersey, detected an odd signal with a radio horn they had inherited from engineers working on Echo 1 and Telstar, the first communication satellites.

The signal did not come from Earth or the sun. It seemed to come from all over the sky, and it was equivalent to the energy emitted by a body at about 3 degrees above absolute zero (&ndash270 °C).

There could be no doubt. Penzias and Wilson had discovered the &ldquoafterglow&rdquo of the big bang fireball&mdashthe cosmic microwave background. For their proof of the big bang, they shared the 1978 Nobel prize in physics.

Looking backward in time
Physicists can run the expansion of the universe backward. In this way, they can watch it get hotter as it gets smaller, just as the air in a bicycle pump heats up as it is compressed. But theory proposes that, at the big bang itself, the temperature was infinite. And infinities warn physicists that theories are flawed.

At the moment, the theories which take us furthest back in time are the Grand Unified Theories. These GUTs are an attempt to show that three of the basic forces that govern the behavior of all matter&mdashthe strong and weak nuclear forces and the electromagnetic force&mdashare no more than facets of a single &ldquosuperforce.&rdquo

Each force of nature arises from the exchange of a different &ldquomessenger&rdquo particle, or boson. The messenger transmits a force between two particles, just as a tennis ball transmits to a player the force of an opponent&rsquos shot. At high enough temperatures&mdash such as those when the universe was 10&ndash35 seconds old&mdashphysicists believe the electromagnetic and strong and weak nuclear forces were identical, and mediated by a messenger dubbed the X-boson.

Physicists want to show that gravity, too, is a facet of the superforce. They suspect that gravity split apart from the other three forces at about 10&ndash43 seconds after the big bang. But before they can &ldquounify&rdquo the four forces, they must describe gravity using quantum theory, which is hugely successful for describing the other forces. To say that physicists are finding this difficult is an understatement.

When they have their unified theory, physicists believe that they will be able to probe right back to the moment of creation and explain how the universe popped suddenly into existence from nothing 13.82 billion years ago.

Excerpt from NOTHING: Surprising Insights Everywhere from Zero to Oblivion, copyright © New Scientist, 2014. Reprinted by permission of the publisher, The Experiment. Available wherever books are sold.​


What Happened Before the Big Bang? The New Philosophy of Cosmology

Last May, Stephen Hawking gave a talk at Google's Zeitgeist Conference in which he declared philosophy to be dead. In his book The Grand Design, Hawking went even further. "How can we understand the world in which we find ourselves? How does the universe behave? What is the nature of reality? Where did all this come from? Traditionally these were questions for philosophy, but philosophy is dead," Hawking wrote. "Philosophy has not kept up with modern developments in science, particularly physics."

In December, a group of professors from America's top philosophy departments, including Rutgers,* Columbia, Yale, and NYU, set out to establish the philosophy of cosmology as a new field of study within the philosophy of physics. The group aims to bring a philosophical approach to the basic questions at the heart of physics, including those concerning the nature, age and fate of the universe. This past week, a second group of scholars from Oxford and Cambridge announced their intention to launch a similar project in the United Kingdom.

One of the founding members of the American group, Tim Maudlin, was recently hired by New York University, the top ranked philosophy department in the English-speaking world. Maudlin is a philosopher of physics whose interests range from the foundations of physics, to topics more firmly within the domain of philosophy, like metaphysics and logic.

Yesterday I spoke with Maudlin by phone about cosmology, multiple universes, the nature of time, the odds of extraterrestrial life, and why Stephen Hawking is wrong about philosophy.

Your group has identified the central goal of the philosophy of cosmology to be the pursuit of outstanding conceptual problems at the foundations of cosmology. As you see it, what are the most striking of those problems?

Maudlin: So, I guess I would divide that into two classes. There are foundational problems and interpretational problems in physics, generally --say, in quantum theory, or in space-time theory, or in trying to come up with a quantum theory of gravity-- that people will worry about even if they're not doing what you would call the philosophy of cosmology. But sometimes those problems manifest themselves in striking ways when you look at them on a cosmological scale. So some of this is just a different window on what we would think of as foundational problems in physics, generally.

Then there are problems that are fairly specific to cosmology. Standard cosmology, or what was considered standard cosmology twenty years ago, led people to the conclude that the universe that we see around us began in a big bang, or put another way, in some very hot, very dense state. And if you think about the characteristics of that state, in order to explain the evolution of the universe, that state had to be a very low entropy state, and there's a line of thought that says that anything that is very low entropy is in some sense very improbable or unlikely. And if you carry that line of thought forward, you then say "Well gee, you're telling me the universe began in some extremely unlikely or improbable state" and you wonder is there any explanation for that. Is there any principle that you can use to account for the big bang state?

This question of accounting for what we call the "big bang state" is probably the most important question within the philosophy of cosmology.

This question of accounting for what we call the "big bang state" -- the search for a physical explanation of it -- is probably the most important question within the philosophy of cosmology, and there are a couple different lines of thought about it. One that's becoming more and more prevalent in the physics community is the idea that the big bang state itself arose out of some previous condition, and that therefore there might be an explanation of it in terms of the previously existing dynamics by which it came about. There are other ideas, for instance that maybe there might be special sorts of laws, or special sorts of explanatory principles, that would apply uniquely to the initial state of the universe.

One common strategy for thinking about this is to suggest that what we used to call the whole universe is just a small part of everything there is, and that we live in a kind of bubble universe, a small region of something much larger. And the beginning of this region, what we call the big bang, came about by some physical process, from something before it, and that we happen to find ourselves in this region because this is a region that can support life. The idea being that there are lots of these bubble universes, maybe an infinite number of bubble universes, all very different from one another. Part of the explanation of what's called the anthropic principle says, "Well now, if that's the case, we as living beings will certainly find ourselves in one of those bubbles that happens to support living beings." That gives you a kind of account for why the universe we see around us has certain properties.

Is the philosophy of cosmology as a project, a kind of translating then, of existing physics into a more common language of meaning, or into discrete, recognizable concepts? Or do you expect that it will contribute directly to physics, whether that means suggesting new experiments or participating directly in theoretical physics?

Maudlin: I don't think this is a translation project. This is a branch of the philosophy of physics, in which you happen to be treating the entire universe --which is one huge physical object-- as a subject of study, rather than say studying just electrons by themselves, or studying only the solar system. There are particular physical problems, problems of explanation, which arise in thinking about the entire universe, which don't arise when you consider only its smaller systems. I see this as trying to articulate what those particular problems are, and what the avenues are for solving them, rather than trying to translate from physics into some other language. This is all within the purview of a scientific attempt to come to grips with the physical world.

There's a story about scientific discovery that we all learn in school, the story of Isaac Newton discovering gravity after being struck by an apple. That story is now thought by some to have been a myth, but suppose that it were true, or that it was a substitute for some similar, or analogous, eureka moment. Do you consider a breakthrough like that, which isn't contingent on any new or specialized observations to be philosophical in nature?

Maudlin: What occurred to Newton was that there was a force of gravity, which of course everybody knew about, it's not like he actually discovered gravity-- everybody knew there was such a thing as gravity. But if you go back into antiquity, the way that the celestial objects, the moon, the sun, and the planets, were treated by astronomy had nothing to do with the way things on earth were treated. These were entirely different realms, and what Newton realized was that there had to be a force holding the moon in orbit around the earth. This is not something that Aristotle or his predecessors thought, because they were treating the planets and the moon as though they just naturally went around in circles. Newton realized there had to be some force holding the moon in its orbit around the earth, to keep it from wandering off, and he knew also there was a force that was pulling the apple down to the earth. And so what suddenly struck him was that those could be one and the same thing, the same force.

That was a physical discovery, a physical discovery of momentous importance, as important as anything you could ever imagine because it knit together the terrestrial realm and the celestial realm into one common physical picture. It was also a philosophical discovery in the sense that philosophy is interested in the fundamental natures of things.

Newton would call what he was doing natural philosophy, that's actually the name of his book: "Mathematical Principles of Natural Philosophy." Philosophy, traditionally, is what everybody thought they were doing. It's what Aristotle thought he was doing when he wrote his book called Physics. So it's not as if there's this big gap between physical inquiry and philosophical inquiry. They're both interested in the world on a very general scale, and people who work in the foundations of physics, that is, the group that works on the foundations of physics, is about equally divided between people who live in philosophy departments, people who live in physics departments, and people who live in mathematics departments.

In May of last year Stephen Hawking gave a talk for Google in which he said that philosophy was dead, and that it was dead because it had failed to keep up with science, and in particular physics. Is he wrong or is he describing a failure of philosophy that your project hopes to address?

Maudlin: Hawking is a brilliant man, but he's not an expert in what's going on in philosophy, evidently. Over the past thirty years the philosophy of physics has become seamlessly integrated with the foundations of physics work done by actual physicists, so the situation is actually the exact opposite of what he describes. I think he just doesn't know what he's talking about. I mean there's no reason why he should. Why should he spend a lot of time reading the philosophy of physics? I'm sure it's very difficult for him to do. But I think he's just . . . uninformed.

Hawking is a brilliant man, but he's not an expert in what's going on in philosophy, evidently.

Do you think that physics has neglected some of these foundational questions as it has become, increasingly, a kind of engine for the applied sciences, focusing on the manipulation, rather than say, the explanation, of the physical world?

Maudlin: Look, physics has definitely avoided what were traditionally considered to be foundational physical questions, but the reason for that goes back to the foundation of quantum mechanics. The problem is that quantum mechanics was developed as a mathematical tool. Physicists understood how to use it as a tool for making predictions, but without an agreement or understanding about what it was telling us about the physical world. And that's very clear when you look at any of the foundational discussions. This is what Einstein was upset about this is what Schrodinger was upset about. Quantum mechanics was merely a calculational technique that was not well understood as a physical theory. Bohr and Heisenberg tried to argue that asking for a clear physical theory was something you shouldn't do anymore. That it was something outmoded. And they were wrong, Bohr and Heisenberg were wrong about that. But the effect of it was to shut down perfectly legitimate physics questions within the physics community for about half a century. And now we're coming out of that, fortunately.

And what's driving the renaissance?

Maudlin: Well, the questions never went away. There were always people who were willing to ask them. Probably the greatest physicist in the last half of the twentieth century, who pressed very hard on these questions, was John Stewart Bell. So you can't suppress it forever, it will always bubble up. It came back because people became less and less willing to simply say, "Well, Bohr told us not to ask those questions," which is sort of a ridiculous thing to say.

Are the topics that have scientists completely flustered especially fertile ground for philosophers? For example I've been doing a ton of research for a piece about the James Webb Space Telescope, the successor to the Hubble Space Telescope, and none of the astronomers I've talked to seem to have a clue as to how to use it to solve the mystery of dark energy. Is there, or will there be, a philosophy of dark energy in the same way that a body of philosophy seems to have flowered around the mysteries of quantum mechanics?

Maudlin: There will be. There can be a philosophy of anything really, but it's perhaps not as fancy as you're making it out. The basic philosophical question, going back to Plato, is "What is x?" What is virtue? What is justice? What is matter? What is time? You can ask that about dark energy - what is it? And it's a perfectly good question.

There are different ways of thinking about the phenomena which we attribute to dark energy. Some ways of thinking about it say that what you're really doing is adjusting the laws of nature themselves. Some other ways of thinking about it suggest that you've discovered a component or constituent of nature that we need to understand better, and seek the source of. So, the question -- What is this thing fundamentally? -- is a philosophical question, and is a fundamental physical question, and will lead to interesting avenues of inquiry.

One example of philosophy of cosmology that seems to have trickled out to the layman is the idea of fine tuning - the notion that in the set of all possible physics, the subset that permits the evolution of life is very small, and that from this it is possible to conclude that the universe is either one of a large number of universes, a multiverse, or that perhaps some agent has fine tuned the universe with the expectation that it generate life. Do you expect that idea to have staying power, and if not what are some of the compelling arguments against it?

Maudlin: A lot of attention has been given to the fine tuning argument. Let me just say first of all, that the fine tuning argument as you state it, which is a perfectly correct statement of it, depends upon making judgments about the likelihood, or probability of something. Like, "how likely is it that the mass of the electron would be related to the mass of the proton in a certain way?" Now, one can first be a little puzzled by what you mean by "how likely" or "probable" something like that is. You can ask how likely it is that I'll roll double sixes when I throw dice, but we understand the way you get a handle on the use of probabilities in that instance. It's not as clear how you even make judgments like that about the likelihood of the various constants of nature (an so on) that are usually referred to in the fine tuning argument.

Now let me say one more thing about fine tuning. I talk to physicists a lot, and none of the physicists I talk to want to rely on the fine tuning argument to argue for a cosmology that has lots of bubble universes, or lots of worlds. What they want to argue is that this arises naturally from an analysis of the fundamental physics, that the fundamental physics, quite apart from any cosmological considerations, will give you a mechanism by which these worlds will be produced, and a mechanism by which different worlds will have different constants, or different laws, and so on. If that's true, then if there are enough of these worlds, it will be likely that some of them have the right combination of constants to permit life. But their arguments tend not to be "we have to believe in these many worlds to solve the fine tuning problem," they tend to be "these many worlds are generated by physics we have other reasons for believing in."

If we give up on that, and it turns out there aren't these many worlds, that physics is unable to generate them, then it's not that the only option is that there was some intelligent designer. It would be a terrible mistake to think that those are the only two ways things could go. You would have to again think hard about what you mean by probability, and about what sorts of explanations there might be. Part of the problem is that right now there are just way too many freely adjustable parameters in physics. Everybody agrees about that. There seem to be many things we call constants of nature that you could imagine setting at different values, and most physicists think there shouldn't be that many, that many of them are related to one another. Physicists think that at the end of the day there should be one complete equation to describe all physics, because any two physical systems interact and physics has to tell them what to do. And physicists generally like to have only a few constants, or parameters of nature. This is what Einstein meant when he famously said he wanted to understand what kind of choices God had --using his metaphor-- how free his choices were in creating the universe, which is just asking how many freely adjustable parameters there are. Physicists tend to prefer theories that reduce that number, and as you reduce it, the problem of fine tuning tends to go away. But, again, this is just stuff we don't understand well enough yet.

I know that the nature of time is considered to be an especially tricky problem for physics, one that physicists seem prepared, or even eager, to hand over to philosophers. Why is that?

Maudlin: That's a very interesting question, and we could have a long conversation about that. I'm not sure it's accurate to say that physicists want to hand time over to philosophers. Some physicists are very adamant about wanting to say things about it Sean Carroll for example is very adamant about saying that time is real. You have others saying that time is just an illusion, that there isn't really a direction of time, and so forth. I myself think that all of the reasons that lead people to say things like that have very little merit, and that people have just been misled, largely by mistaking the mathematics they use to describe reality for reality itself. If you think that mathematical objects are not in time, and mathematical objects don't change -- which is perfectly true -- and then you're always using mathematical objects to describe the world, you could easily fall into the idea that the world itself doesn't change, because your representations of it don't.

If you think that mathematical objects are not in time, and mathematical objects don't change, you could easily fall into the idea that the world itself doesn't change, because your representations of it don't.

There are other, technical reasons that people have thought that you don't need a direction of time, or that physics doesn't postulate a direction of time. My own view is that none of those arguments are very good. To the question as to why a physicist would want to hand time over to philosophers, the answer would be that physicists for almost a hundred years have been dissuaded from trying to think about fundamental questions. I think most physicists would quite rightly say "I don't have the tools to answer a question like 'what is time?' - I have the tools to solve a differential equation." The asking of fundamental physical questions is just not part of the training of a physicist anymore.

I recently came across a paper about Fermi's Paradox and Self-Replicating Probes, and while it had kind of a science fiction tone to it, it occurred to me as I was reading it that philosophers might be uniquely suited to speculating about, or at least evaluating the probabilistic arguments for the existence of life elsewhere in the universe. Do you expect philosophers of cosmology to enter into those debates, or will the discipline confine itself to issues that emerge directly from physics?

Maudlin: This is really a physical question. If you think of life, of intelligent life, it is, among other things, a physical phenomenon -- it occurs when the physical conditions are right. And so the question of how likely it is that life will emerge, and how frequently it will emerge, does connect up to physics, and does connect up to cosmology, because when you're asking how likely it is that somewhere there's life, you're talking about the broad scope of the physical universe. And philosophers do tend to be pretty well schooled in certain kinds of probabilistic analysis, and so it may come up. I wouldn't rule it in or rule it out.

I will make one comment about these kinds of arguments which seems to me to somehow have eluded everyone. When people make these probabilistic equations, like the Drake Equation, which you're familiar with -- they introduce variables for the frequency of earth-like planets, for the evolution of life on those planets, and so on. The question remains as to how often, after life evolves, you'll have intelligent life capable of making technology. What people haven't seemed to notice is that on earth, of all the billions of species that have evolved, only one has developed intelligence to the level of producing technology. Which means that kind of intelligence is really not very useful. It's not actually, in the general case, of much evolutionary value. We tend to think, because we love to think of ourselves, human beings, as the top of the evolutionary ladder, that the intelligence we have, that makes us human beings, is the thing that all of evolution is striving toward. But what we know is that that's not true. Obviously it doesn't matter that much if you're a beetle, that you be really smart. If it were, evolution would have produced much more intelligent beetles. We have no empirical data to suggest that there's a high probability that evolution on another planet would lead to technological intelligence. There is just too much we don't know.

Images: 1. NASA 2. Ross Anderson. 3. NASA. 4. Cambridge Digital Gallery Newton Collection. 5. NASA. 6. NASA.

*Updated: This piece has been amended to include Rutgers in the list of participating universities.


What was before the Big Bang

I’ve been thinking about this more and more lately and trying to wrap my head around what was before the bing bang. People say nothing, well what exactly is “nothing”. Even the idea of nothing. is something. it’s an idea. If the Big Bang started history and “time”, what was before that. Something has to initiate the Big Bang and I’m trying to think of what that space looked like. and how THAT space was created

The real answer here is that no one knows. The Big Bang is as far back as we (currently) have any ability to find evidence of. It may even be that it is “impossible” for anything in this universe to perceive beyond (or before) the space/time in which we exist.

Or to put it another way, if we (in this universe) experience existence in terms of space/time and space/time began with the Big Bang, then that means that we have no way of experiencing anything before it. but that isn’t the same “nothing”. nothing doesn’t exist.

Or to put it another way, if we (in this universe) experience existence in terms of space/time and space/time began with the Big Bang, then that means that we have no way of experiencing anything before it.

I agree, nothing doesn’t exist.

My undergrad thermo professor talked about this in one of his lectures on the 2nd Law. His thoughts were that this is where you leave the realm of science and mathematics and start into metaphysics, philosophy, and even theology. Any idea conceived about this is pure conjecture. From his experience, those holding to positions explaining any pre-Big Bang condition held said positions in an almost religious-like manner, even though most would bristle at such a description due to their agnostic or even atheistic insistence. His conclusion was that they operated in (for lack of a better term) faith in their positions -- no different than he did that there was an Originator to the Big Bang (he was a theist). I discussed with him in office hours once, and he said most of his colleagues (not all) were really bad at holding their positions since they would posit, claim, and even publish ideas about pre-Big Bang conditions but when pressed to explain further would almost always pivot to speak equivocally.

Among other things, he writes:

Despite the fact that almost every popular description of the universe’s history says that “The Universe began with a Big Bang”, it has been known for decades that this statement is highly ambiguous, misleading, and in some ways wrong.

I've heard it said as an analogy, consider going outside and walking north. Eventually you'll get to a point where you're walking south, at which point you'll have to turn around and go north again. If you do this, you'll find yourself stuck at the North Pole, because you can't go any further north that's the definition of "the northmost". Time is the same way you can go back in time, but either you go back in time infinitely (which does not appear to support the evidence) or you go back to the point where time began. Your question is, what happened to kick it all off. Well, that implies something caused time to begin, and "what happened before time began?" is a nonsense question. It's like asking "what's north of the North Pole?".

Perhaps some day we'll figure out a better reason than that, because "it just did" is very unsatisfactory. Until then, we must place it in the "we don't know" bin, and keep doing science.

Now you're getting into space time. That is deep, high.

Wait, when in space, North means nothing.

Hmmm I understand what you are saying

As Stephen Hawking puts it it, what is north of the North Pole ? The real answer here is that we'll probably never know. Even if we discover what was before the big bang then there's another question, ok where did that come from ? With every answer we'll raise another question going deeper into the rabbit hole.

E.g. : What was before the big bang ? Well an event we call Proto Big Bang. Ok, where did that came from ? From two universes colliding. Ok, so where did the other universe come from ? From a cereal box you bought as a kid !

The problem with answering this question is that we'll get more and more layers until maybe (or maybe not) we'll reach an end where there was literally nothing and then our minds will not be able to comprehend what nothing is.

Isn’t that crazy though? Just interesting

What I think about, thinking about the size of the universe, is how small we really are.

We just don't know cause we can't go back in time, our brains find it hard to grasp certain concepts.

I'm not accepting the usual reasons of "nothing was there" "time didn't exist" type posts.

If it was a singularity, something would have been on the outside of it. We use science very well but our little sums and equations simply cannot account for the unknowns, and we can't say for certain that nothing was there cause time didn't exist. Frustrating!

Not a theoretical mathematician: If the singularity contains everything, then there is no outside for anything to exist. The error lies in assuming that the singularity is a small object located somewhere in a void. Probably because that's how it is usually represented in videos. This is the same issue that people get tripped up on with the expansion of the universe. They always make the assumption that there's something outside of the universe to expand into. This is a false assumption. The singularity and the universe are the same thing. For everyday purposes, there is nothing and nowhere outside of it. Not even a void. Nothing.

Outside of theoretical mathematics, there just isn't a way to simulate either the singularity, or the whole of the universe. The best we can do is analogy, and simplifications. One excellent example is the analogy of space-time as a rubber sheet. If you put a weight on it, the sheet warps under the weight. This is gravity. Send a small ball rolling in a straight line past the object, and it will curve because space-time is bent. From the objects perspective, it has continued in a straight line, but space was curved. Put two weights on it and stretch the sheet. The distance between the objects increases. This is the expansion of the universe. Person on planet A sees planet B receding at a given velocity. Person on planet B sees planet A receding at the same velocity. In fact, if that's the only measurement you have, then both are correct. Neither object has an intrinsic velocity, only the expansion of space.

Now, there may be additional dimensions, but I'm not well enough read up on those to even consider discussing them.


One Big Bang, or were there many?

The universe is at least 986 billion years older than physicists thought and is probably much older still, according to a radical new theory.

The revolutionary study suggests that time did not begin with the big bang 14 billion years ago. This mammoth explosion which created all the matter we see around us, was just the most recent of many.

The standard big bang theory says the universe began with a massive explosion, but the new theory suggests it is a cyclic event that consists of repeating big bangs.

"People have inferred that time began then, but there really wasn't any reason for that inference," said Neil Turok, a theoretical physicist at the University of Cambridge, "What we are proposing is very radical. It's saying there was time before the big bang."

Under his theory, published today in the journal Science with Paul Steinhardt at Princeton University in New Jersey, the universe must be at least a trillion years old with many big bangs happening before our own. With each bang, the theory predicts that matter keeps on expanding and dissipating into infinite space before another horrendous blast of radiation and matter replenishes it. "I think it is much more likely to be far older than a trillion years though," said Prof Turok. "There doesn't have to be a beginning of time. According to our theory, the universe may be infinitely old and infinitely large."

Today most cosmologists believe the universe will carry on expanding until all the stars burn out, leaving nothing but their cold dead remains. But there is an inherent problem with this picture. The Cosmological Constant - a mysterious force first postulated by Albert Einstein that appears to be driving the galaxies apart - is much too small to fit the theory. Einstein later renounced it as his "biggest blunder".

The Cosmological Constant is a mathematical representation of the energy of empty space, also known as "dark energy", which exerts a kind of anti-gravity force pushing galaxies apart at an accelerating rate.

It happens to be a googol (1 followed by 100 zeroes) times smaller than would be expected if the universe was created in a single Big Bang. But its value could be explained if the universe was much, much older than most experts believe.

Mechanisms exist that would allow the Constant to decrease incrementally through time. But these processes would take so long that, according to the standard theory, all matter in the universe would totally dissipate in the meantime.

Turok and Steinhardt's theory is an alternative to another explanation called the "anthropic principle", which argues that the constant can have a range of values in different parts of the universe but that we happen to live in a region conducive to life.

"The anthropic explanations are very controversial and many people do not like them," said Alexander Vilenkin a professor of theoretical physics at Tufts University in Massachusetts. Rather than making precise predictions for features of the universe the anthropic principle gives a vague range of values so it is difficult for physicists to test, he added.

"It's absolutely terrible, it really is giving up," said Prof Turok, "It's saying that we are never going to understand the state of the universe. It just has to be that way for us to exist." His explanation by contrast is built up from first principles.

But if he's right, how long have we got until the next big bang? "We can't predict when it will happen with any precision - all we can say is it won't be within the next 10 billion years." Good job, because if we were around we would instantly disintegrate into massless particles of light.


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