What is Inflation: Definition and 413 Discussions

In economics, inflation (or less frequently, price inflation) is a general rise in the price level of an economy over a period of time.
When the general price level rises, each unit of currency buys fewer goods and services; consequently, inflation reflects a reduction in the purchasing power per unit of money – a loss of real value in the medium of exchange and unit of account within the economy. The opposite of inflation is deflation, a sustained decrease in the general price level of goods and services. The common measure of inflation is the inflation rate, the annualised percentage change in a general price index, usually the consumer price index, over time.Economists believe that very high rates of inflation and hyperinflation are harmful, and are caused by excessive growth of the money supply. Views on which factors determine low to moderate rates of inflation are more varied. Low or moderate inflation may be attributed to fluctuations in real demand for goods and services, or changes in available supplies such as during scarcities. However, the consensus view is that a long sustained period of inflation is caused by money supply growing faster than the rate of economic growth.Inflation affects economies in various positive and negative ways. The negative effects of inflation include an increase in the opportunity cost of holding money, uncertainty over future inflation which may discourage investment and savings, and if inflation were rapid enough, shortages of goods as consumers begin hoarding out of concern that prices will increase in the future. Positive effects include reducing unemployment due to nominal wage rigidity, allowing the central bank greater freedom in carrying out monetary policy, encouraging loans and investment instead of money hoarding, and avoiding the inefficiencies associated with deflation.
Today, most economists favour a low and steady rate of inflation. Low (as opposed to zero or negative) inflation reduces the severity of economic recessions by enabling the labor market to adjust more quickly in a downturn, and reduces the risk that a liquidity trap prevents monetary policy from stabilising the economy. The task of keeping the rate of inflation low and stable is usually given to monetary authorities. Generally, these monetary authorities are the central banks that control monetary policy through the setting of interest rates, through open market operations, and through the setting of banking reserve requirements.

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  1. marcus

    Noncommutative geometry naturally includes inflation epoch

    In ordinary GR geometry, the Higgs field cannot play the rôle of the inflaton, so to imagine inflation one has to introduce some exotic field that is not part of the Standard Model. Something completely made up must be introduced to make it work. Not so in the context of non-commutative...
  2. F

    Calculating Air Bag Inflation Rate for Exhaust Powered Vehicle Jack

    I am designing an exhaust powered vehicle car jack air bag. I have calculated the mass flow rate and velocity of the exhaust gases leaving the vehicles exhaust pipe. I need to calculate the amount of time it will take to inflate an air bag of a particular size. What equations do I need to be...
  3. F

    Air Bag Inflation Rate: Calculating Time & Stress

    I am designing an exhaust powered vehicle car jack air bag. I have calculated the mass flow rate and velocity of the exhaust gases leaving the vehicles exhaust pipe. I need to calculate the amount of time it will take to inflate an air bag of a particular size. What equations do I need to be...
  4. S

    Inflation & Time: Exploring the FTL Expansion of the Early Universe

    The FTL expansion of the early universe is explained by the "stretching" of spacetime itself so that a meter stick would be uniformly "stretched". Two questions: 1. Is the stretching of the meter stick only in the direction of the expansion? Is it sensible to talk about the direction of...
  5. F

    Can Quantum Gravity Explain Inflation After the Big Bang?

    I wonder if quantum gravity effects can explain Inflation after the Big Bang? For example, in Loop Quantum Gravity, there are area and volume operators and eigenvalues, etc. Would there be jumps from one volume state to another with time? Thanks.
  6. M

    Calculating Real GDP Growth with Nominal GDP and Inflation Rates

    Homework Statement If nominal GDP grows with 7 % and the inflation is 2% What is the growth in real GDP The Attempt at a Solution is it 1.07/1.02 or ln(1.07) - ln(1.02) ?
  7. D

    Energy with inflation of Balloon problem

    Homework Statement A balloon is being inflated to its full extent by heating the air inside it. In the final stages of this process, the volume of the balloon changes from 4.00 x 106 L to 4.50 x 106 L by the addition of 1.3 x 108 J of energy as heat. Assuming that the balloon expands...
  8. wolram

    Cosmological Inflation: Theory and Observations

    arXiv:0810.3022 [pdf, other] Title: Cosmological Inflation: Theory and Observations Authors: Daniel Baumann (Harvard), Hiranya V. Peiris (Cambridge) Comments: 18 pages, 12 figures. Invited review to appear in Advanced Science Letters Special Issue on Quantum Gravity, Cosmology and Black...
  9. S

    Inflation Questions - Exploring Quantum Physics with Darcy

    Hello all, I'm new and this is my first Science forum I've ever joined. I got interested in Physics about 3 years ago after reading a book called What Remains to be Discovered. It opened my eyes to a lot of things, especially Quantum Physics. But, the most difficult thing to wrap my head...
  10. wolram

    Zimbabwe surviving with its massive inflation

    I know very little about the economics of countries, so i came here to ask, how is Zimbabwe surviving with its massive inflation and falling exports, i have seen reports of factories closing for lack of electricity and the lack of essential imported parts, also reports that the inflation rate...
  11. G

    Inflation & the Hubble Length: A Guide in cm

    I am presently reading a paper on Inflation. It uses the term Hubble length. Can someone provide the Hubble length in cm.
  12. H

    Inflation & the Speed of Light: Is It Possible?

    I have a question about inflation. I read that during inflation the speed which is expanding is greater than the speed of light, is that even possible? We know that nothing in the universe is faster than the speed of light.
  13. H

    Can Negative Energy Keep Wormholes Open in the Theory of Inflation?

    According to the theory of inflation, at least as I understand it, baby universes pop into existence and are connected to this one by a wormhole. That wormhole then shuts in a split second. Some also say that baby universes can be formed this way in particle accelerators. Is there any way to...
  14. I

    Can Higgs Particles Cause Universe Expansion Due to Negative Density?

    Please apologise to my poor English, and I am the bigginner in this field. I have recently read about The inflation of the universe. It said that The Higgs Particles causes universe expansion with acceleration because of its negative density. Does it mean it has a negative mass or a...
  15. S

    Perturbation spectrum after inflation

    The spectrum of perturbations at the end of inflation, which turns out to be flat and slightly red shifted, is calculated under the assumption that each perturbation mode crosses some initial time in the comoving coordinates with 'minimum energy allowed by the Heisenberg uncertainty principle'...
  16. G

    How is the Inflation theory going?

    Has it been debunked yet or is it still going strong?
  17. G

    Photon Energy vs. Red Shift, Inflation Theory, Acceleration

    Energy of Photon/Red-shift, inflation, acceleration I have a few questions (following a short premise) below. I have been reading medieval philospohy recently and also some about the "Big Bang." What I am struck by is number of assumptions made in both fields. There is a large amount of...
  18. K

    Dark matter and inflation - one and the same? [newscientist]

    New Scientist has a page on a new theory, proposed by Andrew Liddle, says that maybe one particle is responsible for inflation and dark-matter, its called the inflaton It goes on to say that Liddle and his colleagues realized that if some inflaton particles survived after the intense burst of...
  19. marcus

    Trying to relate string and inflation

    http://arxiv.org/abs/0709.0002 Searching for Inflation in Simple String Theory Models: An Astrophysical Perspective Mark P. Hertzberg (MIT), Max Tegmark (MIT), Shamit Kachru (Stanford), Jessie Shelton (Rutgers), Onur Ozcan (MIT) 24 pages, 5 figs (Submitted on 3 Sep 2007 (v1), last revised 3 Sep...
  20. M

    Condition for inflation presented by Liddle

    I can't understand the condition for inflation that Liddle presents in his book, Cosmological Inflation and Large-Scale Structure A.Liddle, Pg 51: \frac{d}{dt} \frac{H^{-1}}{a} <0 Because \frac{H^{-1}}{a} is the comoving Hubble length, the condition for inflation is that the comoving Hubble...
  21. George Jones

    Penrose, Carroll, and Inflation

    Without inflation, only extremely special conditions in the past produce the universe we now see. Or so the story goes. Penrose has long argued that conditions necessary for inflation are actually more special that the necessary past conditions without inflation. Its seems that Sean Carroll...
  22. A

    Nitrogen inflation of car tires

    A local garage has big advertizements featuring "free nitrogen inflation of all new tires fitted, as used in Formula I motorsport for the past 20 years". My cynicism assumes this is snake oil so far as normal road tires are concerned - can anybody confirm or deny this? It reminds me of a...
  23. F

    Discover the Best Book on Inflation Theory for Your Studies

    I need a good book on Inflation theory to start studying . Does anyone know a good book written on inflation theory? I really need a book advice...
  24. A

    Inflation System: Calculating Pressure & Volume

    (We are designing a portable pontoon with inflatable base, however neither of us has much knowledge of inflation systems or fluid mechanics) How can you calculate the internal pressure of an inflated bladder as it gets pushed under the water by the weight it supports? And how this pressure...
  25. B

    Inflation (The evolution of the Universe)

    Hello! I wanted to ask about the possible inflation era when considering the Big Bang model. Can someone explain me carefully but quite briefly what this inflation was? Thanks :)
  26. E

    SO(10) -> SU(3) x SU(2) x U(1) -inflation?

    I'm trying to learn some theory of inflation, and recently read a paper by Andrei Linde from 1982 where he suggested a scenario where inflation is driven by the phase transition SU(5) -> SU(3) x SU(2) x U(1). Now SU(5) is known to not be a good candidate as an extension of the standard model...
  27. S

    Inflation and pension plans

    Why is it that pension plans utilize the CPI when indexing for inflation and not the GDP deflator? Is this the preferable method in your opinion? Why? I know that both have their own pros and cons, so I'm not sure why the CPI for the purposes of pensions would be more favourable.
  28. O

    Tidal stresses during inflation

    Over in the Relativity forum, in the thread "Metrics and Forces", I have been brought (in fact dragged kicking and screaming, by Pervect) to the following view: In the FRW universe with matter, as gravity slows expansion, compressive tidal stresses develop in any entity that is bound by...
  29. K

    Inflation is the rapid acceration of space some time after the BB

    I know that inflation is the rapid acceration of space some time after the big bang, but are there theories that explain what cause inflation to happen?
  30. B

    Tire inflation to determine weight

    Tire inflation to determine weight - solved The problem goes as follows: he four tires of an automobile are inflated to a gauge pressure of 1.85E+5 Pa. Each tire has an area of 0.0237 m2 in contact with the ground. Determine the weight of the automobile. But I've applied the Pfluid = F/A...
  31. M

    Cosmological Event Horizon during Inflation

    The newly release WMAP data supports the Inflation model that the universe expanded from subatomic scales to Astronomic scales in a fraction of a second. If so, then what would have been the distance from each point where space would have been expanding at the speed of light, approximately? Thanks.
  32. I

    Time Dilation and Black Hole Inflation

    Here's the idea: As one approaches the event horizon of a black hole, gravity increases, and time slows. The outside universe appears to speed up. The rate of infalling matter increases, which is consumed by the black hole to increase it's mass. The Schwarzschild radius of the black hole...
  33. J

    Discussion/essay for uni on the Inflation proscess

    Hey, I'm doing a discussion/essay for uni on the Inflation proscess during the big bang. I'm not looking for facts/figures, that's what the uni wants me to do:smile: but I'd like to hear a little chat about other peoples views other than reading books. So who thinks its true/false or any better...
  34. M

    Did Inflation Solve the Problem of the Universe's Original Gravity?

    The gravity of the orginal singularity would make it a black hole. The original gravity of the universe would give it an escape velocity; the escape velocity of the Big Bang. In order to get the universe over its gravity there was an inflationary epoch that rapidly brought the strength of...
  35. M

    Solving Analysts' Inflation Prediction Problems

    the following problems i have trouble solving, please help: :smile: each member of a random sample of 15 analysts was asked to predict the rate of inflation for the coming year. assume that the predictions for the whole population of analysts follow a normal distribution with the standard...
  36. Loren Booda

    Entanglement instead of inflation

    Might quantum entanglement explain the cosmological constant, isotropy, flatness, magnetic monopole and horizon problems? Instead of inflation introducing a phase change that caused an exponential expansion in the early universe, perhaps entanglement has maintained a statistical causality...
  37. Z

    What are the physics behind parachute inflation?

    >>I'm trying to create a design for an improved, non-hesitationg pilot-chute, but going back through all my old textbooks I cannot find anything about the physics of inflation (which I understand are complex and chaotic). The only reference materials I've been able to find is a book called...
  38. S

    Finding God Through String Theory?

    I am not mathmatician and know little of string theory. But I am looking for God and I hear those of you who do know string theory may be hot on his trail. Years ago, when Hubble was still only a promise we were told it would allow us to see back in time nearly to the big bang. My concern...
  39. C

    About Eternal Inflation and Spacetime Bubbles

    I have read a lot about eternal inflation and as I understand it Guth and others are now arguing that once inflation has started, it is an ongoing process. However, my question is, once inflation had finished in one Universe and inflation had started somewhere else, wouldn't the expanding...
  40. mattmns

    Money and Inflation: How to Protect Your Finances

    I am no financial expert, but I keep hearing talk of inflation. Usually I would not care, but since I plan on taking advantage of the government, I thought I should look into it. So here is the scenario. I will be receiving as much as possible of $17,500 over the next two years in...
  41. B

    Newbie question about inflation

    Is it known which of the four fundamental forces drives inflation? If this is too stupid a question, feel free to flame me into the stone age. :)
  42. X

    Can Cosmic Inflation Explain the Accelerating Universe?

    If the hot Big-Bang model is accurate (and seems like it is), could cosmic inflation (maybe a further extension) explain why the universe is accelerating or will we have to retreat to extra-dimensions (superstring theory and leaking gravity)? There are other problems with this theory of...
  43. H

    Thermalization after inflation

    The fact that the black body distribution of the cosmic microwave background radiation is that of a black body, implies that during recombination the universe was in thermal equilibrium. My question is how this almost perfect thermal equilibrium was reached... During inflation, space was...
  44. marcus

    G.M. Hossain new paper on inflation

    G. M. Hossain posted a new Loop cosmology paper today. http://arxiv.org/gr-qc/0411012 Primordial Density Perturbation in Effective Loop Quantum Cosmology It suggests a way of testing LQG cosmology against standard scenarios by looking at details of the CMB power spectrum. A step in the...
  45. C

    Was All Matter Created During the Inflationary Period After the Big Bang?

    As I understand the inflationary cosmology states that at around 10^-35 seconds to 10^-32 seconds after the Big Bang all matter was created as what Alan Guth called the "ultimate free lunch". However, it is said that at 10^-43, the so-called Planck time, was when gravity became separated from...
  46. marcus

    LQG predicts inflation and solves horizon problem on its own

    Papers by a number of authors have shown that Loop Quantum Cosmology removes the big bang singularity. Loop Quantum Cosmology development leads that of the full LQG theory because in cosmology one is essentially quantizing the prevailing (Friedman) cosmological model, which is a deal simpler...
  47. O

    Are we entering an era of 'Penalty Shoot Out' for inflation?

    Here is a current paper:http://uk.arxiv.org/abs/hep-th/0406230 the authors can only be described as the 'premier-division' leaders, but the paper seems to be relaying a fundamental shift in Inflationary understandings, and this is having a direct consequence of the vast number of recent...
  48. H

    Particle horizon and inflation

    To calculate the size of the observable universe, one has to calculate the current distance to the particle horizon (t0: today, c = 1): \int_{0}^{t_0} \ dt / a(t) (1) To be able to calculate the integral one has to find an expression for a(t). With some assumptions one can take a(t) =...
  49. R

    Understand Inflation Theory: Scalar Field & Expansion/Supercooling

    Hi, I am trying to understand inflation from a pedagogical perspective and would like to ask if anyone has any lucid insights into the nature of the scalar inflation field and how/why the expansion/supercooling occurs. Any clear explanations extremely appreciated.
  50. R

    What caused inflation in the big bang theory?

    What caused inflation in the big bang theory? I've read a few things that seem pure speculation designed to give a cause for something thought to necessarily have happened such as an antigravity force that faded at the end of the inflationary period. It seems too contrived to me.
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