31 Aug 08
Originally posted by XZantothYour question is the ultimate question about the universe.
Possibly... but if so, then where did that come from?
a couple of theories that do NOT answer your question:
The universe is a cyclic universe. The big bang is followed by the big crunch which creates the initial singularity that triggers a new big bang, etc. This theory has been championed by some leading physicists such as M. Steinhart (co-creator of the inflationary universe theory) among others.
In another theory, there is no cycle, but eternal inflation in a "mega" or multi-verse. Our local universe (a pocket universe) is an infinetely small fraction of eevrything that exists, and big bangs can be seen as something similar to celular division. There is an infineltly large number of pocket universes, and the laws of physics may differ from one pocket to another.
In both theories, there is no beginning and no end. If the megaverse is infinite in both directions of time, the question of where the initial energy comes from does not belong to the realm of physics.
There is no "initial" as the megaverse is eternal.
31 Aug 08
There are any number of interesting theories as to the "origins" of the universe (including those origins which state that there has always been something in existence).
However, they fall outside the ability of science to observe or test with any confidence, and so they must remain theories.
31 Aug 08
1 edit
Originally posted by geepamoogleA "theory" is something that HAS been tested (when a scientist is speaking...not when those idiot ID people are talking). You want the phrase "unsupported model" or something like it.
There are any number of interesting theories as to the "origins" of the universe (including those origins which state that there has always been something in existence).
However, they fall outside the ability of science to observe or test with any confidence, and so they must remain theories.
31 Aug 08
Originally posted by AThousandYoungNot really. There are lots and lots of untested theories developed by the most prestigious scientists around. A theory can be right (i.e. it makes predictions that are confirmed by experiments and observation), wrong (i.e. it makes wrong predictions) and so bad that is not even wrong.
A "theory" is something that HAS been tested (when a scientist is speaking...not when those idiot ID people are talking). You want the phrase "unsupported model" or something like it.
31 Aug 08
7 edits
Originally posted by smaiaWhich 'theories' do you refer to specifically?
Not really. There are lots and lots of untested theories developed by the most prestigious scientists around. A theory can be right (i.e. it makes predictions that are confirmed by experiments and observation), wrong (i.e. it makes wrong predictions) and so bad that is not even wrong.
Theory, hypothesis are used in non-technical contexts to mean an untested idea or opinion. A theory in technical use is a more or less verified or established explanation accounting for known facts or phenomena: the theory of relativity.
http://dictionary.reference.com/browse/theory
As I said...in science, theories have been tested. For those ignorant of science (or are using the word casually or carelessly), the word 'theory' is used as you use it.
It is possible for a theory to be wrong in certain specific predictions, but that does not mean it has not been thoroughly tested otherwise! For example, Newton's theory of classical motion (whatever it's officially called) was shown to be incorrect at relativistic speeds, but NASA still used to to send a man to the moon!
If a scientist comes up with a testable but untested idea, it's a Hypothesis. If a scientist comes up with a general idea of how things work without making specific, testable predictions, he's describing a Model. The model suggests possible hypotheses. Testing the Hypotheses gives support for or against the Model. If the Hypotheses keep coming out to be correct based on the Model, then the Model is given Theory status.
- Joined
- 10 Dec 06
- Moves
- 8528
31 Aug 08
Every one is so worried about excluding the existance of a god from the universe, Why? Religion is the bad guy here.... Someone said that cavemen exclaimed "god" everytime they encountered the unknown, and if we think like that today we have not progressed...yadayada. Well, god is just an idea, a "goal" its been used since we first percieved ourselve's, and will continue to be used until "proven" to be false.....
31 Aug 08
2 edits
Originally posted by joe shmoGod is a possible explanation for any number of observations. Science has not been able to find support for God as the correct explanation on any occasion.
Every one is so worried about excluding the existance of a god from the universe, Why? Religion is the bad guy here.... Someone said that cavemen exclaimed "god" everytime they encountered the unknown, and if we think like that today we have not progressed...yadayada. Well, god is just an idea, a "goal" its been used since we first percieved ourselve's, and will continue to be used until "proven" to be false.....
That's why religion had to transform. Whenever it challenged science, it lost. F-16s are more useful in war than valkyries and angels! Biology cured smallpox, not laying on of hands! Secular nations are more powerful than those with highly religious governments, etc.
So, religion became limited to something used to interact with peoples' minds and emotions, whether to soothe and heal them, to control them, to inspire them, or to bring unity to a group, and it's still useful in that role today.
31 Aug 08
Originally posted by AThousandYoungFrom dictionary.com:
Which 'theories' do you refer to specifically?
Theory, hypothesis are used in non-technical contexts to mean an untested idea or opinion. A theory in technical use is a more or less verified or established explanation accounting for known facts or phenomena: the theory of relativity.
http://dictionary.reference.com/browse/theory
As I ...[text shortened]... keep coming out to be correct based on the Model, then the Model is given Theory status.
theory:
"a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein's theory of relativity. "
Based on the definition above, let me give you a couple of examples of recent untested or unverified theories:
1- Stephen Hawking's theory of black holes evaporation (Hawking radiation).
2- The Theory of Inflation (Alan Guth and others)
3- Super symmetry (various)
31 Aug 08
Originally posted by joe shmoIt is not that we want to exclude God from the universe. But when we do science, we search for explanations that result from the laws of nature. We want to believe that everything that exists results from these laws.
Every one is so worried about excluding the existance of a god from the universe, Why? Religion is the bad guy here.... Someone said that cavemen exclaimed "god" everytime they encountered the unknown, and if we think like that today we have not progressed...yadayada. Well, god is just an idea, a "goal" its been used since we first percieved ourselve's, and will continue to be used until "proven" to be false.....
But what determines the laws of nature? - an interesting subject that has been debated in the academia with the involvement of religious thinkers among others.
31 Aug 08
2 edits
Originally posted by smaiaHawking radiation was demonstrated to be consistent with the quantum mechanical uncertainty principal in Soviet Moscow in 1973. It also is necessary for both the Second Law of Thermodynamics and black holes to exist.
From dictionary.com:
theory:
"a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein's theory of relativity. "
Based on the definition above, let me give you a couple of examples of recent untested or unverified theories:
1- Stephen Hawking's theory of black holes evaporation (Hawking radiation).
2- The Theory of Inflation (Alan Guth and others)
3- Super symmetry (various)
I find the phenomenon only rarely described in a scientific context as a theory, by the way, but it looks like some people are calling it that. This is how it's typically talked about:
``The prediction that black holes radiate due to quantum effects is often considered one of the most secure in quantum field theory in curved space-time. Yet this prediction rests on two dubious assumptions ...''. This delightfully readable review paper does an excellent job of convincing the reader that Hawking radiation is still far from being an established prediction of the quantum physics of black holes. The paper gives the clearest exposition of Hawking radiation that I know of, emphasizing the physical concepts while simplifying the mathematics to its barest essentials (not that the mathematics is simple even in stripped form).
http://casa.colorado.edu/~ajsh/hawk.html
Quantum Field Theory is a theory, but there's no mention of Hawking Radiation Theory. Instead it's referred to as a prediction.
Take a look at this:
Claus Kiefer (1998) ``Towards a Full Quantum Theory of Black Holes'' (gr-qc/9803049) gives a pedagogical review of Hawking radiation and other quantum aspects of black holes.
There's a link on the above-linked page. Notice it refers to going towards a full theory of black holes, not that we already have one.
31 Aug 08
5 edits
Originally posted by smaiaAs a junior particle physicist, Guth first developed the idea of cosmic inflation in 1979 at Cornell after attending a Big Bang lecture by Robert Dicke, and gave his first seminar on the subject in January 1980.[1] Moving on to Stanford University Guth formally proposed the idea of cosmic inflation in 1981, the idea that the nascent universe passed through a phase of exponential expansion that was driven by a positive vacuum energy density (negative vacuum pressure). The results of the WMAP mission in 2006 made the case for cosmic inflation very compelling.
From dictionary.com:
theory:
"a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein's theory of relativity. "
Based on the definition above, let me give you a couple of examples of recent untested or unverified theories:
1- Stephen Hawking's theory of black holes evaporation (Hawking radiation).
2- The Theory of Inflation (Alan Guth and others)
3- Super symmetry (various)
http://en.wikipedia.org/wiki/Alan_Guth
I don't see the word theory, but that's just Wikipedia. Let's try to find Guth stating that Cosmic Inflation is a Theory.
MIT claims that Guth wrote this book:
The Inflationary Universe: The Quest for a New Theory of Cosmic Origins (Perseus Publishing, March 1998)
Note the phrasing - THE QUEST FOR A NEW Theory...
http://web.mit.edu/physics/facultyandstaff/faculty/alan_guth.html
31 Aug 08
Originally posted by AThousandYoung"Quantum Field Theory is a theory, but there's no mention of Hawking Radiation Theory. Instead it's referred to as a prediction."
Hawking radiation was demonstrated to be consistent with the quantum mechanical uncertainty principal in Soviet Moscow in 1973. It also is necessary for both the Second Law of Thermodynamics and black holes to exist.
I find the phenomenon only rarely described in a scientific context as a theory, by the way, but it looks like some people are calli ...[text shortened]... fers to going towards a full theory of black holes, not that we already have one.
Of course it is a prediction. A theory that does not make predictions is not a theory.
Alan wrote a book (accessible to the general public) called "The Inflationary Universe". In this book he explains the foundations of his idea of how the universe may have begun.
This idea is a coherent group of general propositions used as principles of explanation for a class of phenomena and is therefore, by definition, a theory.
I have a question for you: What do you think theoretical physiscists do?
31 Aug 08
Originally posted by XZantothI don't know. There is no satisfying answer. This chain of questioning is generally used by people trying to get the answer "God" but with comes the question "Who made God?" Religion fails to answer these questions too.
Possibly... but if so, then where did that come from?