Reasoning behind the big bang theory

In summary, the Big Bang theory proposes that the universe originated from a tiny, high-density particle and expanded rapidly during its first fraction of a second. This concept has been supported by data such as red shifting of galaxies, the cosmic microwave background, and the relative abundancies of elements in the universe. While the term "theory" in science may imply a proven hypothesis, it is based on empirical data and can be subject to change. Some argue that the logical thought of a created universe is flimsy, and many physicists continue to explore what may have preceded and caused the Big Bang. However, the Big Bang model remains the most comprehensive and supported explanation for the origin of the universe.
  • #1
Will
[SOLVED] Reasoning behind the big bang theory

Is there are way to qualitativly explain this, or is the math beyond most people? I understand that according to this model, the universe expanded from an unimaginably tiny particle with unimaginable mass desity, and that during the first fraction of a second, the expasion was substanstial.
The concept is hard for me to accept, it seems so unreal, but many physicists subscribe to this model, and physicists are the most resonable people, so there must be some logic behind this. What experiments were carried out that confirmed this theory? Does one require a background in modern physics to grasp this logic? I only know some classical physics myself, so maybe I am just to ig'nant to be asking this!
 
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  • #2
The Big Bang theory is based on a certain number of data that point to this hypothesis.

(1) Red shifting of galaxies, increasing with distance, suggest the expansion of the universe. Extrapolate back and... ta da!
(2) Cosmic Microwave Background anistrophy. Basically, we can detect microwaves in space that may be explained as remnants of the BB. Further, study of the distribution of the radiation suggests a source, or major event.
(3) Relative abundancies of certain elemenst in the universe. The large amount of lighter elements, particularly hydrogen, suggest a reasonably young universe that probably was hence created.
(4) Logical thought that the universe must have been somehow created. Yes, pretty flimsy.

There may be others.
 
  • #3
Will, "a theory" in science mean PROVEN hypothesis. Newtonian theory. Einstein special relativity theory. Maxwell theory. Quantum theory. Evolution theory. Big Bang theory.

Unlike in layman terminology where word "theory" may mean anything but proven thing: "...my theory...", "Conspiracy theory", "In theory yes but in practice - no..." , "...this is just a theory", and so on.

By the way, in Europe usually even in everyday language "theory" is referred to as verified by observation hypothesis. I don't know why in US they frequently mix theory with hypothesis.
 
  • #4
Originally posted by FZ+
The Big Bang theory is based on a certain number of data that point to this hypothesis.

(1) Red shifting of galaxies, increasing with distance, suggest the expansion of the universe. Extrapolate back and... ta da!


(3) Relative abundancies of certain elemenst in the universe. The large amount of lighter elements, particularly hydrogen, suggest a reasonably young universe that probably was hence created.
There may be others.

(1)Does this involve the doppler effect? Does the term red shift mean that because the object is moving away from us,( because of the expansion) the lowest visible frequency emmited from the source is perceived as having a lower frequency and not visible? If the universe was contracting, would we observe a "violet shift"


(3)Does this imply that as the universe gets older, there will exist even heavier elements than those known?
 
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  • #5
Originally posted by Will
(1)Does this involve the doppler effect? Does the term red shift mean that because the object is moving away from us,( because of the expansion) the lowest visible frequency emmited from the source is perceived as having a lower frequency and not visible? If the universe was contracting, would we observe a "violet shift"


Yes on both counts!

(3)Does this imply that as the universe gets older, there will exist even heavier elements than those known?

Not exactly, but more that as the universe gets older, the heavy elements will become more abundant as stars fuse hydrogen and supernovae make, well, everything heavier than iron, basically.
 
  • #6
Originally posted by Alexander
Will, "a theory" in science mean PROVEN hypothesis. Newtonian theory. Einstein special relativity theory. Maxwell theory. Quantum theory. Evolution theory. Big Bang theory.

I must disagree. No physics can be CONCLUSIVELY proven like a mathematical theorem. The best one can do is provide experimental data to SUPPORT the theory. But empirical data is not precise in the absolutel sense; it is possible that you may perform an experiment tomorrow which contradicts your theory.

As for evolution theory.. Not really a theory, when it doesn't make predictions that may be experimentally verified or refuted. I believe it's true, purely on blind faith and "it sounds reasonable, a hell lot more reasonable than that bible stuff."


Now, about the Big Bang... If we run the clock backwards, the beginning of the universe resembles the creation of a sigularity inside the black hole, which leads me to ask...
Is the known, observable universe contained inside the event horizon of a black hole with its time axis reversed?

(It is pointless to ask "is something really really true, in reality?" I meant are the mathematical frameworks equivalent.)
 
  • #7
Originally posted by FZ+
The Big Bang theory is based on a certain number of data that point to this hypothesis.

..
(4) Logical thought that the universe must have been somehow created. Yes, pretty flimsy.

That point isn't logical. It would have been more "logical" if the universe exist in time without begin or end. A "begin of time" is incomprehensible.
Most theoretical models that try to explain the Big Bang therefore try to figure out what preceded and caused the Big Bang.
 
  • #8
Originally posted by Alexander
Will, "a theory" in science mean PROVEN hypothesis. Newtonian theory. Einstein special relativity theory. Maxwell theory. Quantum theory. Evolution theory. Big Bang theory.


Not to get of topic here, but what is the difference between "theory" and "law".
 
  • #9
"Law" was considered hip terminology a couple hundred years ago; now "theory" is in. No real difference.
 
  • #10
If you read Steven Weinberg's excellent book "The First Three Minutes" you will walk away with a strong understanding of the Big Bang.

Also, you can debate theory vs. law vs. hypothesis all day long, the end result is that the Big Bang model provides a level of detail of explanation for observed phenomena which is noticably missing from its competitors (i.e. biblical creation, steady state, etc.). Anyone seeking to displace the Big Bang has some very big shoes to fill. The BB theory neatly plays back in time to when the universe was less than a second old.
 
  • #11
Originally posted by vshiro Now, about the Big Bang... If we run the clock backwards, the beginning of the universe resembles the creation of a sigularity inside the black hole, which leads me to ask...
Is the known, observable universe contained inside the event horizon of a black hole with its time axis reversed?


Yes, universe always was (and still is) a black hole.
 
  • #12
Originally posted by Will
Not to get of topic here, but what is the difference between "theory" and "law"?

Law is what we observe (bunch of related facts). Theory is a mathematical explanation of why facts are related the way we see them.

Say, Faraday law of e/m induction (bunch of facts about induced voltage in coils and motion of magnets around). Maxwell theory (= special relativity applied to electric charge) is the explanation.

Or, say, facts: human and chimp genes are 98.5% identical (call it law: all primates have similar genes). Explanation: branching from common ancestor (=evolution theory).
 

1. What is the Big Bang Theory?

The Big Bang Theory is a scientific explanation for the origin and expansion of the universe. It suggests that the universe began as a singularity, a point of infinite density and temperature, around 13.8 billion years ago. This singularity then rapidly expanded, creating all matter and energy in the universe.

2. What is the evidence for the Big Bang Theory?

There are several lines of evidence that support the Big Bang Theory. One is the observation of the cosmic microwave background radiation, which is a faint glow of energy that permeates the universe and is thought to be a remnant of the early universe. Other evidence includes the observed expansion of the universe, the abundance of light elements, and the large-scale structure of the universe.

3. What is the role of scientific reasoning in the Big Bang Theory?

The Big Bang Theory is based on scientific reasoning and evidence-based thinking. Scientists use observations, experiments, and mathematical models to understand and explain the natural world. The Big Bang Theory was developed through a combination of observations, calculations, and predictions, making it a strong and well-supported scientific theory.

4. How does the Big Bang Theory explain the origins of the universe?

The Big Bang Theory suggests that the universe began as a singularity and expanded rapidly, creating all matter and energy. As the universe cooled, particles began to form and eventually clumped together to form galaxies and stars. Over billions of years, stars and galaxies continued to form and evolve, leading to the diverse and complex universe we see today.

5. Are there alternative theories to the Big Bang Theory?

While the Big Bang Theory is the most widely accepted scientific explanation for the origins of the universe, there are alternative theories that have been proposed. These include the Steady State Theory, which suggests that the universe has always existed and is continuously creating new matter, and the Oscillating Universe Theory, which suggests that the universe goes through cycles of expansion and contraction. However, these theories have not been supported by the same amount of evidence as the Big Bang Theory and are not currently widely accepted among scientists.

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