Houston, we have a problem
While most cosmologists agree that the big bang is the most reasonable explanation for the origin of the universe, it is not without its problems.
One principle problem is that the universe is too big by several orders of magnitude. The age of the universe is estimated at 13.7 billion years (I am using billion in the American sense of thousand-million, not the British sense of million-million). It is assumed to have a naïve radius of 13.7 billion light years or a diameter of 27.4 billion light years. However, based on current understanding of how energy, particles and fundamental forces interact, this is too big - 300 million light years would be much more reasonable.
To resolve this, it has been proposed that shortly after coming into existence, the universe underwent a period of extreme inflation where it expanded exponentially rapidly.
Introducing the concept of hyperinflation also resolves a number of other issues such at the universe having too uniform a horizon. If the universe had expanded normally, scientists would expect a much greater temperature variation at the horizon as local effects took place cooling and heating various regions. If the universe inflated, then there would have been no time for these effects to take place and consequently the fairly uniform shell of the universe would have stretched into place.
Another issue it resolves is the apparent lack of magnetic monopoles, which, according quantum physics, should have been created during the early universe. A lack of magnetic monopoles would occur if the universe rapidly inflated thus not permitting their formation.
Some scientists believe the universe may be larger than we observe, since we cannot observe beyond the horizon. Alternatively, some scientists believe the visible universe may be as large as 156 billion light years in diameter if one factors in space-time expansion.
The 5 Second Origins of the Cosmos Lesson
While there are numerous propositions for the origins of the universe, the current rage is that it arose from a perturbation in the quantum field. Quantum physics allows for the spontaneous creation of energy out of the quantum field. This does not violate conservation of energy, since the sum of the energy created is zero and typically collapses quickly back on itself. In the case of our universe, for some reasons, the energy did not collapse back in on itself, but continued to expand, eventually coalescing out as the matter in our universe - however, the net energy in our universe is zero (i.e. it does not exist). IT is theorizd that the universe cam into existence with a radius 10-35 metres (this is the size of the Planck Length - the theorized smallest dimension).
Why the Universe may be Bigger than it is Old
Given that Einstein fixed the speed of light as a constant in the universe, some might complain that it is impossible for the universe to be 156 billion light years, since it implies faster than light travel. This is not the case. Light is limited to travelling a 3x108 m/s in time-space (what is colloquially known as space). However, there is no current limit on the expansion rate of time-space (the medium through which light travels). So, you not only have light travelling through space, but you also have space (the medium) expanding stretching.
One misconception is that the universe (the matter and energy) is expanding and filling space. This is wrong. Prior to the big bang, there was no space. Space, energy and matter are a consequence of the big bang. Matter and energy are embedded in space. It is the expansion of space that fundamentally drives the expansion of matter and energy. There are local gravitational effects which cause matter to gather and coalesce, but it is all done within the space-time fabric.
Universe as a Balloon Analogy
A two dimensional view of the universe can be had by imagining an uninflated balloon. Draw a bunch of spots on the balloon. This represents the early universe where everything was together. As you blow up the balloon, it is not the spots that are moving apart, but rather the expansion of the surface of the balloon is moving the spots apart. Our universe is the same way, except in three dimensions and the spots (matter and energy) are free to interact with one another.
Just as there is no centre of the balloon surface, there is no centre of the universe - it is a closed continuous surface. In fact, if traveled in a straight line through the universe, you would eventually get back to where you had begun (imagine tracing a straight line on the surface of the balloon, eventually, you would return to where you had started from). This leads to the interesting effect, that with a powerful enough telescope, you could see the back of your head.
For the Curious
It is theorized that particles called inflatons were responsible for the inflation of the early universe.
For the Really Curious
While I am no expert on quantum physics, it seems to be getting increasingly complex with too many fudge factors being added in. I believe that quantum physics is getting ripe for an overhaul and there will likely be a new revolution in physics (as there was about a century ago). So, I think physics is a good place to go now (notwithstanding Stephen Hawkins belief that physics is a dead end since most everything has been worked out and all that is left is tidying up a few odds and ends).
Again, I note that I am no expert in this area, but things looks similar to the way they did a century ago (including the pronouncements that physics is just about all wrapped up).
For those who were not so curious
Some people don't really care for so much detail. When asking, "How does it work?", all they really want to know is, "Where is the on / off switch?". And that is fine too. After all, not everyone wants to know how a television works deep down inside, or its manufacturing origins.
For many people knowing that you can pick up the TV at Joe's TV Emporium and where the power switch is, is all they want to know.
One principle problem is that the universe is too big by several orders of magnitude. The age of the universe is estimated at 13.7 billion years (I am using billion in the American sense of thousand-million, not the British sense of million-million). It is assumed to have a naïve radius of 13.7 billion light years or a diameter of 27.4 billion light years. However, based on current understanding of how energy, particles and fundamental forces interact, this is too big - 300 million light years would be much more reasonable.
To resolve this, it has been proposed that shortly after coming into existence, the universe underwent a period of extreme inflation where it expanded exponentially rapidly.
Introducing the concept of hyperinflation also resolves a number of other issues such at the universe having too uniform a horizon. If the universe had expanded normally, scientists would expect a much greater temperature variation at the horizon as local effects took place cooling and heating various regions. If the universe inflated, then there would have been no time for these effects to take place and consequently the fairly uniform shell of the universe would have stretched into place.
Another issue it resolves is the apparent lack of magnetic monopoles, which, according quantum physics, should have been created during the early universe. A lack of magnetic monopoles would occur if the universe rapidly inflated thus not permitting their formation.
Some scientists believe the universe may be larger than we observe, since we cannot observe beyond the horizon. Alternatively, some scientists believe the visible universe may be as large as 156 billion light years in diameter if one factors in space-time expansion.
The 5 Second Origins of the Cosmos Lesson
While there are numerous propositions for the origins of the universe, the current rage is that it arose from a perturbation in the quantum field. Quantum physics allows for the spontaneous creation of energy out of the quantum field. This does not violate conservation of energy, since the sum of the energy created is zero and typically collapses quickly back on itself. In the case of our universe, for some reasons, the energy did not collapse back in on itself, but continued to expand, eventually coalescing out as the matter in our universe - however, the net energy in our universe is zero (i.e. it does not exist). IT is theorizd that the universe cam into existence with a radius 10-35 metres (this is the size of the Planck Length - the theorized smallest dimension).
Why the Universe may be Bigger than it is Old
Given that Einstein fixed the speed of light as a constant in the universe, some might complain that it is impossible for the universe to be 156 billion light years, since it implies faster than light travel. This is not the case. Light is limited to travelling a 3x108 m/s in time-space (what is colloquially known as space). However, there is no current limit on the expansion rate of time-space (the medium through which light travels). So, you not only have light travelling through space, but you also have space (the medium) expanding stretching.
One misconception is that the universe (the matter and energy) is expanding and filling space. This is wrong. Prior to the big bang, there was no space. Space, energy and matter are a consequence of the big bang. Matter and energy are embedded in space. It is the expansion of space that fundamentally drives the expansion of matter and energy. There are local gravitational effects which cause matter to gather and coalesce, but it is all done within the space-time fabric.
Universe as a Balloon Analogy
A two dimensional view of the universe can be had by imagining an uninflated balloon. Draw a bunch of spots on the balloon. This represents the early universe where everything was together. As you blow up the balloon, it is not the spots that are moving apart, but rather the expansion of the surface of the balloon is moving the spots apart. Our universe is the same way, except in three dimensions and the spots (matter and energy) are free to interact with one another.
Just as there is no centre of the balloon surface, there is no centre of the universe - it is a closed continuous surface. In fact, if traveled in a straight line through the universe, you would eventually get back to where you had begun (imagine tracing a straight line on the surface of the balloon, eventually, you would return to where you had started from). This leads to the interesting effect, that with a powerful enough telescope, you could see the back of your head.
For the Curious
It is theorized that particles called inflatons were responsible for the inflation of the early universe.
For the Really Curious
While I am no expert on quantum physics, it seems to be getting increasingly complex with too many fudge factors being added in. I believe that quantum physics is getting ripe for an overhaul and there will likely be a new revolution in physics (as there was about a century ago). So, I think physics is a good place to go now (notwithstanding Stephen Hawkins belief that physics is a dead end since most everything has been worked out and all that is left is tidying up a few odds and ends).
Again, I note that I am no expert in this area, but things looks similar to the way they did a century ago (including the pronouncements that physics is just about all wrapped up).
For those who were not so curious
Some people don't really care for so much detail. When asking, "How does it work?", all they really want to know is, "Where is the on / off switch?". And that is fine too. After all, not everyone wants to know how a television works deep down inside, or its manufacturing origins.
For many people knowing that you can pick up the TV at Joe's TV Emporium and where the power switch is, is all they want to know.
Comments
kaymac: thank you. When I was growing up, the 3 predominant theories where (1) steady state universe (Einstein's prefered notion - in fact, he introduced constants into his equations to make the universe static), (2) oscillating universe (where the universe alternately expands and contracts), (3) big bang (this term was introduced by Fred Hoyle back in 1950 as a dismissive term - something along the lines of "Oh, and we are supposed to belive in what? A big bang?")
A marriage of sorts occured betwen quantum physics and cosmology in the 1980s and has resulted in our current cosmological understanding.
Who knows, maybe in 20 years time the prevalent cosmological idea will change.
One alternate theory is that our universe exists as the intersection between two or more higher dimensional universes.
I also think creationists are not looking at making sense of science.
Some people get hung up on ideology. Protestantism brought about the idea of sola scriptura and this tends to be pushed as a false and dangerous dichotomy of "it is either all true or not at all".
Now, such ideological obstinacy is not the sole purview of religious fundamentalists. Fred Hoyle, the astronomer who derisively coined the term big bang, was also ideologically opposed to the idea of the big bang because he was an atheist. He did not want to admit a theory which allowed the possible existence of God (if the big bang originated the universe, then where did it come from? What was its beginning?). He maintained until his death the notion of a steady state universe - one which has always existed.
Personally, I think God gave us a brain and we should use it - in a moral manner. For me, knowledge is nothing to be afraid of; knowledge does not diminish the grandeur and glory of God.