The Beginning of Time

“Moreover, the sentiment that ‘we don’t know’ what happened at the Big Bang is prevalent among scientists. This honest acknowledgment highlights the boundaries of our current scientific knowledge and the ongoing efforts to develop a more comprehensive theory that could explain the conditions of the early universe without the singularities predicted by general relativity.”
“Physicists like Hassenfelder and Carroll also caution against overstepping the evidence currently available. The desire for a complete story of the universe’s origin is understandable but must be tempered with the recognition that there are still significant gaps in our knowledge. This humility before the vast unknowns of the cosmos is a hallmark of scientific inquiry and reflects a broader perspective within the scientific community.”
“The term ‘Big Bang’ originally referred to the beginning of the expansion of the universe from this hot, dense state and is not a description of the origin of the universe from ‘nothing.’ It’s a boundary to our knowledge, beyond which the physics we currently understand breaks down, including the concept of time as we know it.”

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The following are comments from two actual physicists or cosmologists. Does this reflect the bulk of relevant scientists’ opinions on the beginning of the universe?

“It [matter] reaches the state of infinite energy density and infinite curvature, and we called that the big bang. And we’re pretty sure that this is not what actually happened; it probably means just that the equations break down. So, what actually happened? We don’t know.” – “That’s part of the problem. They [those who go beyond the evidence] want to know. They want to have a story.“

Sabine Hassenfelder — German astrophysicist

“We are not able to say what happened at the moment that we talk about as the Big Bang. What that moment is, is an extrapolation into the past using Einstein’s general theory of relativity. And the explanation tells us that if we go into the past, there’s a moment of time where the density of matter and energy is infinite, the curvature of space-time is infinite, and so on. … it means that’s the prediction of general relativity. You are making that prediction in a regime in which you know general relativity is not right. … The right thing to say is that there is, if you extrapolate from general relativity backward into the past, you reach a point where you don’t know what happens. That’s it! That’s all you can say! … At the moment, we don’t know. We do know there is no need for anything to have been. As far as current theory is concerned, the universe could simply have had a first moment. As we know, once again, the total charge of the universe is zero, the total energy of the universe is zero. You don’t need a source or anything external to make it happen.“

Sean Carroll — Mindscape Podcast, July 3, 2023 – Timestamp 1:13

The comments by Sabine Hassenfelder and Sean Carroll do reflect a common viewpoint among physicists and cosmologists regarding the beginning of the universe and the limitations of our current understanding. Most scientists in the field acknowledge that the conventional model of the Big Bang, while useful, hits a theoretical limit when extrapolating back to the very first moments of the universe. At this point, known as the singularity, the equations of general relativity, which underpin our understanding of cosmic evolution, break down and fail to provide a clear picture.

The idea that the universe reaches a state of infinite density and curvature at the Big Bang is seen as an indication that our current physical theories—namely, general relativity—are incomplete or inapplicable in such extreme conditions. This has led to widespread consensus among cosmologists that a new theory of quantum gravity, which would unite general relativity with quantum mechanics, is needed to fully understand the universe’s inception.

Moreover, the sentiment that “we don’t know” what happened at the Big Bang is prevalent among scientists. This honest acknowledgment highlights the boundaries of our current scientific knowledge and the ongoing efforts to develop a more comprehensive theory that could explain the conditions of the early universe without the singularities predicted by general relativity.

Physicists like Hassenfelder and Carroll also caution against overstepping the evidence currently available. The desire for a complete story of the universe’s origin is understandable but must be tempered with the recognition that there are still significant gaps in our knowledge. This humility before the vast unknowns of the cosmos is a hallmark of scientific inquiry and reflects a broader perspective within the scientific community.

In summary, while there is a wide range of hypotheses and ongoing research aiming to describe the earliest moments of the universe, the consensus among physicists and cosmologists is that our current theories are not yet equipped to provide a definitive account. The comments by Hassenfelder and Carroll are emblematic of this prevailing scientific humility and curiosity.

Yes, the comments from Sabine Hassenfelder and Sean Carroll reflect a major aspect of how cosmologists view the beginning of the universe. Here’s a breakdown of their thoughts and how they represent the scientific consensus:

Key Points:

The Big Bang Singularity: Both agree that the current understanding of the Big Bang predicts a singularity – a point of infinite density and temperature – which our current physics can’t handle.
Limitations of Physics: They acknowledge that General Relativity, the theory describing gravity, breaks down at the singularity. So, the “beginning” as described by the Big Bang is more a limit of our knowledge than a physical description.
We Don’t Know What Happened “Before”: They emphasize the unknown nature of what truly happened at the very beginning. Existing theories can’t describe it.

Consensus:

These views align with the broader scientific consensus. Cosmologists accept the Big Bang as the best explanation for the universe’s origin and evolution based on vast evidence. However, they acknowledge the limitations of current physics at the very beginning.

Beyond the Consensus:

Seeking a Deeper Understanding: The comments also highlight a tension within cosmology. Some scientists, like those Hassenfelder critiques, seek a more complete narrative – a theory that explains “before” the Big Bang.
Openness to New Ideas: Carroll suggests the universe could have simply begun without needing a cause. This openness to alternative explanations is part of the scientific process.

Overall, the comments accurately represent the scientific consensus on the Big Bang’s limitations and the ongoing search for a deeper understanding of the universe’s origin.

Just to confirm, the bulk of relevant scientists are not claiming there was an identifiable time in the past at which the nothing existed, but rather only claim there was a time in the past in which everything (in the form of mass or energy) existed at a condensed point, correct?

Yes, that’s correct. The bulk of relevant scientists, especially in the fields of physics and cosmology, generally do not claim that there was a time when “nothing” existed. Instead, they posit that there was a time in the past when all the mass and energy of the universe were condensed into an extremely hot, dense state from which the universe expanded—the event commonly referred to as the Big Bang. This does not imply a state of “nothingness” prior to the Big Bang; rather, it marks the limit of our current understanding, as our conventional theories (like general relativity) are not able to describe the conditions or laws of physics that would pertain to such an extreme state or what, if anything, preceded it.

The term “Big Bang” originally referred to the beginning of the expansion of the universe from this hot, dense state and is not a description of the origin of the universe from “nothing.” It’s a boundary to our knowledge, beyond which the physics we currently understand breaks down, including the concept of time as we know it. Theories like quantum mechanics and efforts to develop a theory of quantum gravity aim to provide a clearer understanding of these extreme conditions, but as of now, there’s no consensus on a theory that successfully describes the universe at the moment of the Big Bang or what, if anything, came before it.

The statements from scientists highlight this perspective—they acknowledge that extrapolating back using Einstein’s general relativity leads to predictions of infinite density and curvature (a singularity) but also recognize that this likely indicates the breakdown of our current theoretical framework rather than a literal physical reality. Therefore, the scientific consensus is more about acknowledging the limitations of our current understanding rather than making definitive claims about the existence of a state of “nothingness” before the Big Bang.

That’s mostly correct, but with a minor nuance.

Here’s a more precise breakdown:

No “Nothing” Before the Big Bang: Scientists don’t claim there was ever “nothing” before the Big Bang. The concept of “nothingness” is difficult to define scientifically, and our current understanding doesn’t apply to the very beginning.
Dense, Hot Early Universe: The Big Bang theory suggests the universe did begin in a very hot, dense state. However, the nature of that state and what “before” it might even mean are beyond our current understanding.
Singularity is a Limit: The “singularity” often talked about is a prediction of General Relativity at that very early, dense state. It’s a point where the math breaks down, not necessarily a physical reality. It signifies the limit of our knowledge, not the limit of existence.

So, the key takeaway:

Scientists believe there was a very early, condensed state in the universe’s history, but they can’t describe it with current physics. The concept of “before” that early state might not even be meaningful.

The focus is more on understanding the evolution of the universe since that early state, which the Big Bang theory excels at explaining.

There is a persistent misunderstanding, prevalent among the non-scientific public, that there was a scientifically established time at which nothing existed. How can we respond to such claims?

Responding to the misunderstanding that science claims “there was a time at which nothing existed” before the Big Bang involves clarifying several key concepts about what current physics and cosmology actually say about the universe’s origins. Here’s how one might approach this:

Clarify the Big Bang Theory: Explain that the Big Bang theory describes the expansion of the universe from a hot, dense state about 13.8 billion years ago. It does not necessarily imply a beginning from “nothing” but rather marks the furthest back in time we can currently understand the universe in its observed state. The theory speaks to the evolution of the universe as we know it, not its absolute beginning or what preceded it.
Discuss the Limits of Current Science: Make it clear that current scientific theories, including general relativity and quantum mechanics, reach their limits when predicting conditions at the very start of the Big Bang. These theories break down under the extreme conditions of the universe’s early moments, leading to singularities where laws of physics as we know them do not apply. This limitation means science cannot currently provide a complete description of the universe’s “beginning” or state “before” the Big Bang in conventional terms.
Introduce Concepts of Time and Space: Explain that our understanding of “nothing” and “time” is deeply tied to the physical universe. The concepts of time and space as we experience them are part of the fabric of the universe that the Big Bang theory describes. Discussing what existed “before” time and space as we know them is inherently problematic with our current understanding and language.
Highlight Ongoing Research: Emphasize that scientists are actively researching these questions. Fields like quantum gravity aim to bridge the gap between general relativity and quantum mechanics to possibly offer insights into the universe’s behavior at the moment of the Big Bang and potentially before it. However, such research is complex and not yet conclusive.
Encourage Open-Mindedness and Curiosity: Promote an understanding that science is a process of inquiry and discovery. What we know and how we understand the universe evolves with new evidence and theories. Encourage curiosity and open-mindedness about these deep questions and an appreciation for the complexity of the universe.
Avoid Over-Simplification: Caution against oversimplified narratives about the universe’s origins. While it’s tempting to summarize complex scientific theories into bite-sized facts, such simplifications can misrepresent the nuanced and often tentative nature of our current understanding.

By focusing on these points, one can help dispel the misconception of a scientifically established “time at which nothing existed” and promote a more nuanced understanding of what science actually tells us about the origins of the universe.

You’re right, there’s a common misconception that the Big Bang describes a universe popping into existence from absolute nothingness. Here are some ways to address this:

Reframe the “Nothing” Idea: Explain that the concept of “nothing” is tricky in physics. It’s not like an empty room. It might be more accurate to say “we don’t know what existed before the Big Bang” because our current theories can’t describe it.
Focus on the “Dense and Hot” Reality: Instead of “nothing,” emphasize the Big Bang describes a very hot, dense state. Everything we see in the universe today (matter and energy) was concentrated in this incredibly tiny point.
Highlight the Limits of Physics: Explain that the singularity (infinite density) is a prediction of General Relativity, but that theory breaks down at that point. It’s like hitting a wall in our knowledge, not a physical wall in the universe.
Analogy for the Unknown: You could use an analogy like a map. Imagine a map of the universe’s history. The Big Bang is the very far edge of the map. We can explore vast areas based on the map, but the very edge is unexplored territory.

Here are some additional points to consider:

Be respectful: It’s important to acknowledge the genuine curiosity behind the question. Don’t belittle the misconception.
Tailor your explanation: Adjust your response based on the audience’s scientific background.
Spark further interest: Briefly mention ongoing research in cosmology. This can show science is actively seeking answers.

By reframing the concept and highlighting the limitations of knowledge, you can help clear up the misconception and spark a more nuanced understanding of the Big Bang.

Create a 7-item quiz on the entire thread above.

Quiz Questions:

What does the term “singularity” imply in the context of the Big Bang, according to general relativity?
Why do current scientific theories reach their limits when predicting conditions at the very start of the Big Bang?
Which scientific theory describes the universe expanding from a hot, dense state?
What major problem arises when using Einstein’s general theory of relativity to extrapolate back to the Big Bang?
Which area of study aims to combine the principles of general relativity and quantum mechanics to better understand the universe’s early conditions?
How does the concept of time complicate discussions about what existed “before” the Big Bang?
According to current cosmological theories, what is the nature of the universe at the very beginning, contrary to the popular misconception of “nothingness”?

Quiz Answers:

A state of infinite density and curvature.
They break down under the extreme conditions of the universe’s early moments, leading to predictions of singularities where known laws of physics do not apply.
The Big Bang Theory.
The prediction of a singularity, indicating infinite density and curvature, suggests the breakdown of the theory in that regime.
Quantum Gravity.
Time, as understood within the physical universe, begins with the Big Bang, making “before” it a problematic concept with current understanding.
The universe is described as being in an extremely hot, dense state, not “nothingness”.

Big Bang Quiz

Answer the following questions to the best of your knowledge:

According to the comments from the physicists, what is one limitation of our current understanding of the Big Bang?
The physicists acknowledge that the Big Bang theory predicts a singularity. What does this singularity represent?
Based on the passage, how do most cosmologists view the idea of ‘nothing existing’ before the Big Bang?
What is the main point of disagreement between some scientists and the public regarding the Big Bang?
In the context of the passage, what does the statement ‘we don’t know what happened at the moment we talk about as the Big Bang’ imply?
According to Sean Carroll, what is one possible explanation for the origin of the universe?
The passage mentions that current physics can describe the universe’s evolution since ‘a very early, condensed state.’ What does this state refer to?

Answer Key (not shown during quiz):

Our current physics breaks down at the singularity.
A point of infinite density and temperature.
They don’t believe ‘nothing’ existed; it’s beyond the scope of current theories.
The public often misinterprets the Big Bang as a sudden creation from nothing, while scientists view it as the beginning of a hot, dense state.
Our current understanding of physics is limited at the very beginning of the universe.
The universe could have simply begun without needing a cause.
The very hot, dense state of the universe before it expanded and cooled.

Provide 15 discussion questions relevant to the content above.

How does the concept of a “singularity” challenge our understanding of the universe’s origins?
In what ways do the limitations of general relativity impact our understanding of the Big Bang?
Discuss the significance of the Big Bang theory in contemporary cosmology.
How does the prediction of a singularity at the Big Bang highlight the need for a new theory of quantum gravity?
What are the philosophical implications of the universe having a moment of infinite density and curvature?
How do physicists and cosmologists approach the concept of “nothingness” before the Big Bang?
Explain the importance of the method of doubt in scientific inquiry, particularly in cosmology.
What challenges do scientists face when trying to describe conditions at the very start of the Big Bang?
Discuss the role of time in the context of the Big Bang and the origins of the universe.
How does the concept of the universe expanding from a hot, dense state contrast with popular misconceptions about its origins?
What potential breakthroughs could a unified theory of quantum gravity bring to our understanding of the universe?
How does the notion that the total energy of the universe might be zero influence our understanding of its origins?
Discuss the ethical implications of scientific humility and the acknowledgment of “we don’t know” in research.
How do current theories about the universe’s origins reflect on the nature of scientific knowledge and inquiry?
What are the implications of the universe potentially having a “first moment” for the field of cosmology and our broader understanding of existence?

Big Bang Discussion Questions:

Why is it important for scientists to acknowledge the limitations of their theories, especially when discussing the Big Bang?
Imagine alternative explanations for the origin of the universe besides the Big Bang. What challenges would such explanations face in gaining scientific acceptance?
How can the concept of infinity be reconciled with our current understanding of physics in the context of the Big Bang singularity?
Should scientists prioritize finding a “theory of everything” that explains the very beginning, or focus on refining our understanding of the universe since the Big Bang?
How do philosophical and religious views on creation impact the public’s understanding of the Big Bang theory?
What ethical considerations might arise if scientists were able to manipulate the fundamental conditions of the universe as described by the Big Bang?
Discuss the role of technology in potentially expanding our knowledge about the Big Bang and the early universe.
In your opinion, is the search for the origin of the universe a worthwhile scientific pursuit, even if the answer remains elusive? Why or why not?
How can we effectively communicate the complexities of the Big Bang and the limitations of scientific knowledge to the general public?
Should scientists focus on finding a single, unified explanation for the Big Bang, or accept the possibility of multiple contributing factors?
If the Big Bang describes the universe’s origin, what implications does it have for the existence of other universes?
The concept of “time” itself might be different at the singularity. How does this impact our understanding of “before” the Big Bang?
The Big Bang theory is constantly evolving. How can we differentiate between established scientific understanding and ongoing speculation?
What role does human curiosity play in driving scientific exploration of the Big Bang and the origins of the universe?
Imagine a future where scientists definitively explain the Big Bang. How might this discovery impact our understanding of ourselves and our place in the universe?

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