The bordeguthvilenkin theorem, and more on the my good. Circuit analysis superposition thevenins and norton theorem. Dec 20, 2017 my question is, what is the bgv theorem. Nortons theorem states that it is possible to simplify any linear circuit, no matter how complex, to an equivalent circuit with just a single current source and parallel resistance connected to a load. Thevenins theorem and its application researchgate. So i explained what every physicist who has thought about the issue understands. Vilenkin to wlc, i think you represented what i wrote about the bgv theorem in my papers and to you personally very accurately. I was watching a debate on cosmology where william lane craig uses the borde, guth and vilenkin theorem to say the universe had a beginning. Find the thevenin equivalent circuit of the circuit. A possible solution to the horizon and flatness problems, phys.
In any case wlcs deference to the bordeguthvilenkin theorem is an effective defense of this premise moving us well beyond the point of mere conjecture. Debunking william lane craig examining christian apologetics. It is a method for the reduction of a portion of a complex circuit into a simple one. In other words, the bgv theorem tells us that while there might be an eternal inflation scenario where inflation lasts. Consider the following example of a linear circuit with two sources. Bordeguthvilenkin singularity theorem creationwiki, the encyclopedia of creation science if you can, in principle or actuality, account for an assumption, you are doing science. There is a theorem due to borde, guth, and vilenkin which might be taken as evidence for a beginning of time. Guth, alexander vilenkin submitted on 1 oct 2001 v1, last revised 14 jan 2003 this version, v2 abstract.
Bordeguthvilenkin theorem its totally bizzare to me that somebody who says stuff like whatever exists has to have a cause or whatever bothers to quote something like this that exactly 0% of his audience is going to be impressed by, other than in terms of straight authority. Sean carroll debates william lane craig on cosmology and gods existence. See more ideas about science, philosophy and william lane craig. Thevenins theorem is a direct consequence of the superposition theorem. Aug 25, 2014 craig thinks we do have a strong reason, the borde guth vilenkin theorem. Nortons theorem for linear electrical networks, known in europe as the mayernorton theorem, states that any collection of voltage sources, current sources, and resistors with two terminals is electrically equivalent to an ideal current source, i, in parallel with a single resistor, r. Guth,1,3 and alexander vilenkin1 1institute of cosmology, department of physics and astronomy tufts university, medford, ma 02155, usa. In fact, vilenkin himself seems to dislike the terminology. The bordeguthvilenkin theorem does not bring into question anything related to the long ages that are called for by the big bang theory. Spitzer explains how the bordevilenkin guth theorem provides a strong argument that the universe must have had a beginning. Although what is actually proved by the theorem is that there must be a beginning to any universe that on average is inflationary. Jul 14, 2010 ive described my favorite model before, e. The principle of mediocrity for the 2011 ras whitrow lecture, alexander vilenkin discusses the new cosmological worldview in which much of the universe is in a state of constant accelerated expansion, called inflation, and we live on one of the many bubbles with diverse properties that are constantly being formed.
I should also mention that the bordeguthvilenkin theorem is 1 completely classical, not quantum, of course, and 2 a little less definitive than you make it sound, as they assume an averaged expansion condition which certainly may be violated along some geodesics. Apparently then, i guess a middle schooler can correctly understand what the bgv theorem implies about our universe. According to this theory the universe is approximately 14 billion years old. Correct interpretation of the borde guth vilenkin bgv theorem.
He is best known as the author of many books in recreational mathematics aimed at middle and high school students. So he appealed to the bordguthvilenkin theorem right from the start in order to guarantee a spacetime boundary in the past i. Thevenin equivalent circuit any twoterminal linear network, composed of. In this post we will see combinatorial mathematics by n. Spitzer explains how the borde vilenkin guth theorem provides a strong argument that the universe must have had a beginning. Superposition, thevenin norton equivalent circuits. Bordeguthvilenkin singularity theorem creationwiki, the. In other words, the bgv theorem tells us that while there might be an eternal inflation scenario where inflation lasts forever to the future, inflation still has to have.
Craig thinks we do have a strong reason, the bordeguthvilenkin theorem. Vilenkin author, george yankovsky translator author. Nortons theorem for linear electrical networks, known in europe as the mayernorton theorem, states that any collection of voltage sources, current sources, and resistors with two terminals is electrically equivalent to an. Thevenin s vo lta ge is the algebraic sum of vol tages across the loa d te rmina ls, due to each of the independ ent sources in the circuit, acting alone. Just as with thevenins theorem, the qualification of linear is identical to that found in the superposition theorem. Borde guth vilenkin theorem pdf search for happiness. This shows a port of an arbitrary linear network represented by the white box connected to an arbitrary circuit, so that the quantities i and v. According to vilenkins email, in the case of a quantum theory of gravity. Bordeguthvilenkin singularity theorem creationwiki. The principle of mediocrity for the 2011 ras whitrow lecture, alexander vilenkin discusses the new cosmological worldview in which much of the universe is in a state of constant accelerated expansion, called inflation, and we live on one of the many bubbles with diverse properties that are. Dear dr craig, during your recent dialogue in sydney professor krauss presented personal email correspondence with cosmologist alexander vilenkin concerning the application of the bordeguthvilenkin theorem to the beginning of the universe. Jun 19, 2012 he then offers his own explanation via the borde guth vilenkin theorem why the universe did have a beginning. In 2003, tufts cosmologist alexander vilenkin and his colleagues, arvind borde, now a senior professor of mathematics at long island university, and alan guth, a professor of physics at mit, proved a mathematical theorem showing that, under very general assumptions, the universe must, in fact, have had a.
Thevenins theorem greatly simplifies analysis of complex circuits by allowing us to replace all of the elements with a combination of just one voltage source and one resistor. In 2003, tufts cosmologist alexander vilenkin and his colleagues, arvind borde, now a senior professor of mathematics at long island university, and alan guth, a professor of physics at mit, proved a mathematical theorem showing that, under very general assumptions, the universe must, in fact, have had a beginning. Jul 08, 2017 the bordevilenkin guth bvg theorem is a strong demonstration from cutting edge astrophysics, proving that the universe had a beginning. Many inflating spacetimes are likely to violate the weak energy condition, a key assumption of singularity theorems. Kirchho s laws 4 a v v 6 v 3 2 i 5 v 0 v i 0 5 r i 4 6 3 i 3 v 4 i 2 2 r 1 v 1 i 1 a b c e d kirchho s current law kcl.
In the present book, the aim has been to set forth a variety of combinatorial problems in popular form and understandable language. A possible solution of the horizon, flatness, homogeneity, isotropy and primordial monopole problems, phys. Significantly, the use of imaginary quantities for time is an inherent feature of all quantum gravity models. In 2003, arvind borde and alexander vilenkin and alan guth published a paper claiming to prove that the universe cannot be infinitely old.
String theory and primordial cosmology springerlink. It can be see n that thevenins theorem is an outcome of superposition theorem. Sep 25, 2012 the second major point craig makes is a claim that i ignored something important. The bordevilenkin guth bvg theorem is a strong demonstration from cutting edge astrophysics, proving that the universe had a beginning. According to vilenkin s email, in the case of a quantum theory of gravity. Bordeguthvilenkin theorem science, math and philosophy forum. Borde guth vilenkin theorem its totally bizzare to me that somebody who says stuff like whatever exists has to have a cause or whatever bothers to quote something like this that exactly 0% of his audience is going to be impressed by, other than in terms of straight authority.
Subsequently in recent years since, the bgv theorem has become widely respected and accepted within the physics community. Lecture objectives to understand thevenins theorem and simplify electrical networks into simple equivalent circuits using the theorem. Alexander vilenkin explains his theorem the borde guth vilenkin theorem or the kinematic incompleteness theorem in simple terms that if you have a hubble expansion that has an. Inspire a love of reading with prime book box for kids discover delightful childrens books with prime book box, a subscription that delivers new books every 1. Aug 11, 2010 but perhaps calling this creation from absolute nothingness is a bit confusing. The second major point craig makes is a claim that i ignored something important. L thevenin, made one of these quantum leaps in 1893. I was watching a debate on cosmology where william lane craig uses the borde, guth and vilenkin theorem to say the universe had a.
But perhaps calling this creation from absolute nothingness is a bit confusing. The borde guth vilenkin singularity theorem or bgv theorem was developed in by three leading cosmologists. Partly he used the celebrated by theologians bordeguthvilenkin theorem, which says that a universe with an average expansion rate greater than zero must be geodesically incomplete in the past. Furthermore, working with arvind borde and alan guth, he developed the bordeguthvilenkin theorem, showing that a period of inflation must have a beginning and that a period of time must precede it. The borde guth vilenkin singularity theorem or bgv theorem was developed in 2003 by three leading cosmologists. I was wondering if someone could possibly explain the case of the bgv theorem and. This is craigs favorite bit of cosmology, because it can be used to argue that the universe had a beginning rather than stretching infinitely far backwards in time, and craig is really devoted to the idea. In 1982, paul steinhardt presented the first model of eternal inflation, vilenkin showed that eternal inflation is generic. It reduces the need for repeated solutions of the same sets of equations. As guth points out, vilenkins absolute nothingness is mathematically welldefined, and can be used as a starting point for theories of creation pg. Thevenins theorem states that any complicated network across its load terminals can be substituted by a voltage source with one resistance in series.
Thevenins theorem is not by itself an analysis tool, but the basis for a very useful method of simplifying active circuits and complex networks because we can. He then offers his own explanation via the borde guth vilenkin theorem why the universe did have a beginning. We have followed the convention that current leaving a node is positive. William lane craig is fond of quoting vilenkin in defense of his kalam cosmological argument. Borde guth vilenkin theorem pdf furthermore, the author of the arizona atheist blog asked vilenkin if his theorem with guth and borde proves that the universe had a beginning. With a resistor, while nortons theorem replaces the linear circuit with a.
The borde guth vilenkin theorem, or the bgv theorem, is a theorem in physical cosmology which deduces that any universe that has, on average, been expanding throughout its history cannot be infinite in the past but must have a past spacetime boundary. Honesty, transparency, full disclosure and the bordeguth. Just as with thevenins theorem, the qualification of linear is identical to that found in. At the same time, an attempt is made to present some rather involved combinatorial problems and to give the reader an idea of the methods of. May 07, 2010 in 2003, arvind borde and alexander vilenkin and alan guth published a paper claiming to prove that the universe cannot be infinitely old.
The borde guth vilenkin theorem alexander vilenkin, phd. This theorem helps in the study of the variation of current in a particular branch when the resistance of the branch is varied while the remaining network remains the same for example. Craig on vilenkin on cosmic origins common sense atheism. Borde, guth, and vilenkins pastfinite universe debunking. Cevas theorem the three lines containing the vertices a, b, and c of abc and intersecting opposite sides at points l, m, and n, respectively, are concurrent if and only if m l n b c a p an bl cm 1 nb malc 21sept2011 ma 341 001 2. Thevenins theorem can be applied to linear networks only. At the same time, an attempt is made to present some rather involved combinatorial problems and to give the reader an idea of the methods of recurrence relations and generating functions. Sep 23, 20 dear dr craig, during your recent dialogue in sydney professor krauss presented personal email correspondence with cosmologist alexander vilenkin concerning the application of the borde guth vilenkin theorem to the beginning of the universe. Guth,1,3 and alexander vilenkin1 1institute of cosmology, department of physics and astronomy.
Thevenins and nortons theorems illinois institute of. In conclusion, to the extent that the singularity theorems are relevant, they tend to point to a beginning, although it might be possible to evade this conclusion either by a having space be finite, or else b through quantum gravity effects, if my speculative arguments for. Combinatorial mathematics for recreation revised edition by n. A complex twoterminal circuit can be replaced by an equivalent circuit consisting of a voltage source. The bordeguthvilenkin singularity theorem or bgv theorem was developed in by three leading cosmologists. Thevenins theorem introduction thevenins theorem is a very important and useful theorem.
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