Lambda-CDM theory - Woo or not?

[Michael Mozina]

Indeed so.

You really should refrain from the cheap shots. It's beneath you. I'll note for the record that my explanation of "pressure" was consistent with the images and explanations of *FORCE* on Wiki, not that Wiki is always the best source of scientific info. In this case however, it was great, right down to the detailed images. There is no "negative pressure" in a vacuum.

I find it to be the only alternative to fits of insane rage . I use my posting opportunities to review what I know, consult my books & papers, and either remind myself of the relevant physics, refine my own knowledge, or learn it for the first time. I have no false illusions about miraculous conversions, but at least I get something out of it for my time.

I note that while I have been in this forum since Dec 2008, this will be, I think, my 59th post (we'll see if I remember well enough), while Mozina, who has been in this form since Feb 2009 has already amassed over 700 posts. And all that time I have posted 2 or 3 messages on other boards, and have been active only here, while Mozina has been active evidently on multiple boards, and busy on all of them. How can there be any time at all for consideration, thought, or even eating & sleeping, with a post rate so high?


Emphasis mine, and I could not agree more. It is really the only reason I bother at all.

I've had to pretty much give up posting anywhere else, and I've had to abandon the EU conversations almost entirely just to keep up with this one thread. The number of active posters here is rather amazing and utterly overwhelming at times.

I regret not continuing our conversation about coronal loops in the EU theory, but perhaps I should try to start a thread on that topic, and we can go from there. After reading that first paper on idea of "magnetic reconnection", I'm curious if you would agree or disagree that "magnetic reconnection" and "circuit reconnection" are interchangeable terms?

 

[Michael Mozina]

Question about source ...

MM - or anyone else - what is the source of the image of the Sun (right-hand of the two)? And what are the details of the image?

http://solar.physics.montana.edu/sol_phys/century.html

There are of course many other high energy wavelength images you could choose from include the iron ion wavelengths from SOHO or STEREO. The coronal loops show up in many images.

http://antwrp.gsfc.nasa.gov/apod/ap981221.html
http://www.plasma-universe.com/images/3/3b/Fig-248.jpg

Notice the "bands" in both the Yohkoh images and the bands we find in the second and third Birkeland images? Pure coincidence? Here are some more Yohkoh images you might consider as well.

http://antwrp.gsfc.nasa.gov/apod/ap990316.html
http://antwrp.gsfc.nasa.gov/apod/ap980629.html

We know that nature visually demonstrates "electrical discharges" in our own atmosphere. Why wouldn't we look to the obvious "explanation" for high energy discharges in the solar atmosphere?

http://www.plasma-universe.com/images/8/8b/Fig-260.jpg
http://sohowww.nascom.nasa.gov/data/realtime/eit_195/512/

 

[Reality Check]

It's comments like this one that make it hard not to appreciate your level headed rational thinking Tim, even when we disagree on issues.

Now if we can just agree that "magnetic reconnection" and "circuit reconnection" are the same process, things would proceed rather quickly. http://www.internationalskeptics.com/forums/images/smilies/biggrin.gif

I would say that we can agree that magnetic reconnection is the well known and researched process that you want to call "circuit reconnection" for some reason. If you want to be the only person in the world to use this term feel free.

Of course no one will know what you are talking about - but maybe that is usual for you !

 

[Reality Check]

I Well, that's not exactly a mystery now is it? The whole thing has been a "curve fitting exercise" from the very start. Guth curve fit the inflation thing into place, and Lambda-CMD filled in the "gaps" rather liberally (75%) with "dark energy" and more gap filler in the form of "dark matter". How could it not fit the postdicted observations with almost 96% metaphysical "gap filler"?

Totally wrong as usual MM.

1. Guth proposed the inflationary period of the early universe as a solution to a couple of problems with BBT (e.g. the horizon problem). His original "model was problematic because the model did not reheat properly ^WP". This was solved by Linde, Albrecht and Steinhardt.
2. Inflation has predictions in addition to solving the problems. These have been verified, e.g.
   

   Inflation predicts that the observed perturbations should be in thermal equilibrium with each other (these are called adiabatic or isentropic perturbations). This structure for the perturbations has been confirmed by the WMAP satellite and other cosmic microwave background experiments, and galaxy surveys, especially the ongoing Sloan Digital Sky Survey. These experiments have shown that the one part in 10,000 inhomogeneities observed have exactly the form predicted by theory.^WP

   FYI: Guth proposes inflation in 1980. WMAP, SDSS collected data 20 years later. Looks like a prediction to me. What do you think?
3. Dark matter was first suggested by Fritz Zwicky from his observations in 1933. Confirmation was obtained 40 years later.
   We now have actual observations of dark matter (see my signature).
   Any theory that ignores this fact is flawed from the start.
4. Dark energy is another physical observation.
   Any theory that ignores this fact is flawed from the start.

The Lambda-CMD theory does not ignore the actual observations that we make about the universe. Any replacement for Lambda-CMD theory will also include the effects of dark matter, dark energy and inflation (unless a plausible replacement for it is found).

One more time:

Where is your list of postdicted observations?​

I mentioned previously as an aside that I suspected that you had no such list. Your repeated assertion of the "postdicted observations" in the Lambda-CMD theory is getting close to lying (or maybe a delusional obsession or maybe just lazy researching or maybe an inability to read).

 

[Guybrush Threepwood]

Pour encourager les autres

To Tim Thompson, Sol Invictus, DeiRen Dopa and any others who are posting analyses of current cosmology theories for lurkers. Speaking as a lurker with a Physics background but little knowledge of cosmology, keep up the good work. I've learned a lot and the information I've gained has been worth speed reading through MM's diatribes.

I also agree with Tim's suggestion not to pick on Michael for use of colloquial meanings for terms like acceleration, it's usually clear what he meant and jumping on him for it doesn't advance the discussion.

 

[Dancing David]

Welcome Guy!

The thing you will find is that about 75% of the discussion on these forums is exactly about the usage of words. The defintions are crucial to clear communications, the construction of false arguments and analogies follows from the defintions.

So yes the quippy one liners may detract from the conversation (but those same people have answered some really stupid questions I have asked) but they also provide some outlet for the frustration felt by those who do know what they are talking about.

Part of the issue is exactly the colloquial concepts being used to advance arguments about very specific theories best described in specific jargon.

Welcome to the Forum!

 

[Guybrush Threepwood]

Welcome Guy!

The thing you will find is that about 75% of the discussion on these forums is exactly about the usage of words. The defintions are crucial to clear communications, the construction of false arguments and analogies follows from the defintions.

So yes the quippy one liners may detract from the conversation (but those same people have answered some really stupid questions I have asked) but they also provide some outlet for the frustration felt by those who do know what they are talking about.

Part of the issue is exactly the colloquial concepts being used to advance arguments about very specific theories best described in specific jargon.

Welcome to the Forum!

Thanks for the welcome.
I take your point about the precise meaning of words being important when discussing something like cosmology, however in this case where everyone (I think) has been using the term 'acceleration of space expansion' to mean that the expansion of space is getting faster, it doesn't seem to me constructive to jump on MM for using this interpretation without qualification, particularly when he has shown throughout several hundred posts that he is unlikely to suddenly start using terms in the same way as everyone else.

 

[Michael Mozina]

Naturally, since all forces, energy, momentum, pressure and even acceleration must be positive is his imaginary 'kinetic' universe there can be no negative acceleration or a conservation of energy and Newton’s third law.

I swear you folks must be required to minor in strawman creation.

There is no "imaginary world of kinetic energy", and those blue arrows demonstrate that there is *less kinetic pressure* (from the force of the EM carrier particles) between the plates than outside of the plates, and no area of the vacuum chamber experiences "negative pressure".

The term "negative acceleration" is a totally different term and argument. FYI, the plates are *accelerated* from the *outside* due to the *greater force* outside the plates than between them.

Notice the direction of the little blue arrows between the plates?

 

[Michael Mozina]

FYI: Guth proposes inflation in 1980. WMAP, SDSS collected data 20 years later. Looks like a prediction to me. What do you think?

I think he *postdicted* this idea from the start because he *already knew* what he was trying to achieve, namely a solution to problems 1 and 2. How is that a "prediction" when he named it as the the "number 1 problem" he was trying to "explain"? From his abstract:

The standard model of hot big bang cosmology requires initial conditions which are problematic in two ways: (1) the early universe is assumed to be highly homogeneous, in spite of the fact that separated
regions were causally disconnected (horizon problem); and (2) the initial
value of the Hubble constant must be fine tuned to extraordinary accuracy
to produce a universe as flat (i.e., near critical mass density) as‘the
one we see today (flatness problem). These problems would disappear if,.....

He "assumed" homogeneity from the start and 'postdicted' a "fit".

Dark matter was first suggested by Fritz Zwicky from his observations in 1933. Confirmation was obtained 40 years later.

Back then "dark matter" could have related to any sort of "missing mass", including MACHO forms of "dark matter", and neutrinos, etc. He didn't propose SUSY particles as composing the vast majority of "dark matter". The concept of "dark matter" is actually the least of your worries in the sense that at least the SUSY theory *might* be something that can be falsified in a lab. When you folks start *assuming* that "dark mater" emits x-rays, etc, then I want to hurl.

Dark energy is another physical observation.

No, acceleration is a rational "interpretation" derived from observation. "Dark energy" is a mythos and it does not exist in nature.

Any theory that ignores this fact is flawed from the start.

Even this idea is technically flawed. Nobody has to *assume* things exactly the same way that you do. In other words, all that is important is that the theory *address* the observations in question. Redshifted photons may be due to a lot of things, not necessarily "superluminal expansion".

The Lambda-CMD theory does not ignore the actual observations that we make about the universe.

Nobody ever claimed otherwise. It does however "curve fit' these observations using 3 different *hypothetical entities*. That's the rub, not the idea you "ignored" anything, other than perhaps alternative ideas related to expansion theories.

http://arxiv.org/abs/astro-ph/0601171

Where is your list of postdicted observations?

See Guth's primary motives in the abstract, items 1 and 2. His motive in introducing inflation was based upon these *assumptions* based on what was already "popular" based on observations from that time. His third stated "goal" was to explain his 'missing monopole' problem and don't even get me started on that one.

Guth's theory is DOA for two reasons apparently. First it failed to "reheat" properly after the supercooling phase, and secondly it is based on a physical impossibility, namely "negative pressure" in a vacuum. Instead of it dying a natural death based on it's flaws, "new and improved" dead inflation deities with new lipstick emerge to prop up the otherwise dead pig of a theory. If his model was already falsified, what exactly will it take to convince you "inflation didn't do it"? How many different brands of "inflation" are there to choose from now? Guth's inflation? Linde's inflation? Hairy inflation? Some new exotic brand I haven't heard of yet? Is Linde's inflation dependent upon the need for "negative pressure in a vacuum" as well?

 

[ben m]

After reading that first paper on idea of "magnetic reconnection", I'm curious if you would agree or disagree that "magnetic reconnection" and "circuit reconnection" are interchangeable terms?

A few posts ago you were back to claiming that magnetic reconnection violates Maxwell's Equations. What gives?

• I gave you an example of magnetic reconnection in a vacuum, far from the nearest actual current-carrying wires.
• I put an infinitesimal charge into the magnetic field and allowed it to follow a field line
• You acknowledged that the particle's path "reconnects"
  • The particle's path is exactly mathematically identical to the "field lines" that you've insisted cannot possibly reconnect. If the paths reconnect, the field lines reconnect. If A=C and A=B, then A=C.
  • You also insisted that since the test particle is a moving charged particle, it itself is responsible for creating the magnetic field. This was a simple mistake on your part; the test charge can be zero coulombs, and carry zero current, and create zero magnetic field, and its path is still well-defined and still reconnects.

The only reason I can think of to call this "circuit reconnection" rather than "magnetic reconnection" is because you want to continue ignoring the next-to-last bullet, and exploiting the confusion and ambiguity in the last bullet.

 

[Michael Mozina]

A few posts ago you were back to claiming that magnetic reconnection violates Maxwell's Equations. What gives?

Maxwell's equations treat the magnetic field as a full and complete continuum, without beginning and without end, not a discrete "lines" that "reconnect". When I've really sat down and looked at the mathematical presentation by Birn et all, it was clear there were no mathematical errors, and only the label he chose to call this process was "self conflicted". I'm willing to accept that electrons pass between "circuits" and from Tim's first paper on this topic, that is clearly what they are proposing just as Birn's presentation proposed this same idea. Yes, "circuit reconnection" happens. Magnetic field lines however form as a full and complete continuum. Calling this "magnetic reconnection" is like calling a short circuit between two wires "magnetic reconnection". It's not the magnetic fields that physically reconnect, it's the electrons and ions that "reconnect" and flow into different "circuits". What makes the term "circuit reconnection" superior to "magnetic reconnection" is that it conveys the importance of the circuit energy in *both circuits*, and it accurately describes what actually "reconnects", namely the electrons and ions.

I gave you an example of magnetic reconnection in a vacuum, far from the nearest actual current-carrying wires.
* I put an infinitesimal charge into the magnetic field and allowed it to follow a field line
* You acknowledged that the particle's path "reconnects"

The *particles* are simply "changing direction". Current flows "in a new direction". It is still a "current flow" and a "particle" that do the "reconnecting" at the level of real physics.

* The particle's path is exactly mathematically identical to the "field lines" that you've insisted cannot possibly reconnect.

The particle's path is related directly to the 'current flow' in the vacuum. The magnetic lines can have some influence of the movement of the particles to be sure, but at the level of kinetic energy it is a form of "particle reconnection", and at the level of "current flow', it is a form of "circuit reconnection", particularly as described by Tim's first paper reference where electrons are literally "jumping circuits".

The only reason I can think of to call this "circuit reconnection" rather than "magnetic reconnection" is because you want to continue ignoring the next-to-last bullet, and exploiting the confusion and ambiguity in the last bullet.

The terms "circuit reconnection" and "particle reconnection" are both consistent with particle physics theory and electrical engineering. The term "magnetic reconnection" is not consistent with either of these two branches of physics and it "hides" the fact that the "particles" and "circuits" are doing all the 'reconnecting' inside the plasma. The term "circuit reconnection" is best IMO because it immediately conveys the importance of the *total circuit energy* of both circuits when trying to figure out a "rate of reconnection".

 

[ben m]

The terms "circuit reconnection" and "particle reconnection" are both consistent with particle physics theory and electrical engineering. The term "magnetic reconnection" is not consistent with either of these two branches of physics and it "hides" the fact that the "particles" and "circuits" are doing all the 'reconnecting' inside the plasma.

Still wrong, MM. Forget about the plasma for a second. I gave you an example with two wires---remember? We measured their magnetic fields in a vacuum---remember? I had placed you at X=1 Z=1 and handed you a magnetometer to wave around. You measured a changing magnetic field---and that was a real physical field. You measured changes in a simple and well-defined parameter of this field---a real magnetic field in a vacuum, remember, into which we have not yet put any free charged particles, plasma, currents, or circuits. Remember? We weren't talking about particles and circuits at all----we were talking about fields. You keep putting particles into them because you don't know enough vector math to talk about fields.

 

[Michael Mozina]

My question was:
How do the photons get inside the chamber? It's not too terribly difficult to block EM radiation.

Evidently it is more difficult than you imagine, particularly at the level of quantum mechanics, inside a universe that is filled with flowing kinetic energy.

 

[Ziggurat]

FYI, the plates are *accelerated* from the *outside* due to the *greater force* outside the plates than between them.

FYI, the plates are not generally accelerated at all during a measurement. Rather, a counter-balancing force is applied, and this force is measured.

Oh, and you can get a pressure from that force by dividing by area. You know, pressure: that thing you still don't know how to define.

 

[Tubbythin]

I swear you folks must be required to minor in strawman creation.

Well. Let's see who made up the following strawmen:

Oh look, inflation elves *did it*, and here's the math to prove it.

"Inflation Elves did it and killed the monopole clan" is not a "theory", it's a bizarre postdicted dogma thingy

You could never show evidence that "inflation or dark energy did it".

Lambda theory has dead inflation elves, dark energy acceleration leprechauns, and big fat invisible dark matter fairies doing all the work, and it *includes math*! Wheeeeeeee!

What I most resent is the notion that Lambda-PureMakeBelieve theory is somehow superior to all other cosmology theories.

One of the many problems with sol and this crew is that they hold the (delusional) belief that astronomers should have a "free pass" when it comes to empirically supporting their beliefs. Somehow it's "ok" to posit hypothetical entities like "dark energy" and "inflation" and SUSY particles galore and call the whole thing a "physics theory". Only 4% of this theory is based on actual "physics" and 96% of it is purely "made up" stuff that nobody can empirically demonstrate.

There's plenty more where that came from...

 

[Michael Mozina]

Still wrong, MM. Forget about the plasma for a second.

Hoy. Why? The notion of "light plasma" applies here, particularly in the solar atmosphere where the "density" is rather low, and high speed movement of charged particles through the medium is continuous.

I gave you an example with two wires---remember?

Actually, no. Sorry, I've been busy at work and I've had a lot of ideas tossed my way this month.

We measured their magnetic fields in a vacuum---remember?

Unless there is current flow in the wire, or the wire is magnetized, there is no magnetic field in or around the wire.

I had placed you at X=1 Z=1 and handed you a magnetometer to wave around. You measured a changing magnetic field---and that was a real physical field.

If there is a real "magnetic field" around the wire it is due to the fact that current flows inside the wire, or because the wire is actually a magnet of some sort, in which case it's electrons resonate in concert inside the wire.

You measured changes in a simple and well-defined parameter of this field---a real magnetic field in a vacuum, remember, into which we have not yet put any free charged particles, plasma, currents, or circuits. Remember? We weren't talking about particles and circuits at all----we were talking about fields. You keep putting particles into them because you don't know enough vector math to talk about fields.

Your words don't make sense to me Ben. If we start with two "wires", then we have two "circuits". If we cross them over one another, then they "short circuit". In Tim's first paper, they literally discuss "electrons" traversing the two circuits. This is simply "particle flow" that eventually results in a change of the topology of the current carrying threads inside the plasma. It's "circuit reconnection", or "particle reconnection", but as Alfven said, not a single magnetic line disconnects or reconnects to any other magnetic line.

The absolutely irrational part of this whole conversation IMO is the fact that we *KNOW* with absolute certainty that nature uses "electrical discharges" to release gamma and x-rays in the Earth's atmosphere.
http://www.nasa.gov/vision/universe/solarsystem/rhessi_tgf.html

We know with absolute certainty that nature uses "electrical discharges" to release high energy photons in Saturn's atmosphere at even greater strengths. The only *logical* first option at an "explanation" for these high energy gamma and x-ray discharges that we observe in the solar atmosphere would be "electrical discharges inside the plasma". That is why a single coronal loops reaches millions of degrees, and how the Sun discharges itself through the Earth in huge current carrying "magnetic ropes". It's irrational that you folks would not turn to the obvious logical option that nature demonstrates in every electrical discharge we observe in our own atmosphere.

 

[Michael Mozina]

There's plenty more where that came from...

I suppose I deserved that.

 

[Michael Mozina]

FYI, the plates are not generally accelerated at all during a measurement. Rather, a counter-balancing force is applied, and this force is measured.

Oh, and you can get a pressure from that force by dividing by area. You know, pressure: that thing you still don't know how to define.

Oh the irony. You have "pressure" on both sides of the plates! There is no "negative pressure" in the chamber, just more "force" on one side of the plate than the other. These experiments are not even usually done in a vacuum at zero Kelvin in the first place, so there is no way it can demonstrate "negative pressure"! There is no such thing as "negative pressure" in a vacuum, and your citation of the Casimir effect has nothing whatsoever to do with "negative pressure in a vacuum".

 

[Ziggurat]

Oh the irony. You have "pressure" on both sides of the plates! There is no "negative pressure" in the chamber, just more "force" on one side of the plate than the other.

If you had paid any attention, you would have noticed that I never actually said anything about the sign of the pressure in the Casimir effect. But it's funny that you refuse to call it a pressure, even a positive one.

These experiments are not even usually done in a vacuum at zero Kelvin in the first place, so there is no way it can demonstrate "negative pressure"!

Now that's just stupid. Zero temperature isn't a requirement of negative pressure. Certainly isn't in liquids. Yes, yes, I know liquids aren't the same thing as a vacuum. But this gets back (once again) to the definition of pressure. And pressure is never defined in terms of temperature, even if temperature affects it. Nor is it defined differently for liquids, gasses, vacuums, etc.

There is no such thing as "negative pressure" in a vacuum, and your citation of the Casimir effect has nothing whatsoever to do with "negative pressure in a vacuum".

That's not actually why I brought up the Casimir effect. I brought it up to show how laughably wrong your attempt to use the ideal gas law to define pressure was. And you still haven't figured out how to define pressure. You're failing at the most basic level of comprehension, unable to form a definition for a term that even grade-school students can understand. You refuse to demonstrate that you can do even simple math. And you expect us to take your challenges seriously? No, Michael. Nobody takes you seriously because you have yet to demonstrate that we should take you seriously.

 

[Reality Check]

I think he *postdicted* this idea from the start because he *already knew* what he was trying to achieve, namely a solution to problems 1 and 2. How is that a "prediction" when he named it as the the "number 1 problem" he was trying to "explain"? From his abstract:

He "assumed" homogeneity from the start and 'postdicted' a "fit".

In other words he did what all other scientists since Newton and before have done: Created a hypothesis to fit the existing data.

Homogeneity is the standard assumption of cosmology and the observed state of the large scale universe.

Back then "dark matter" could have related to any sort of "missing mass", including MACHO forms of "dark matter", and neutrinos, etc. He didn't propose SUSY particles as composing the vast majority of "dark matter". The concept of "dark matter" is actually the least of your worries in the sense that at least the SUSY theory *might* be something that can be falsified in a lab. When you folks start *assuming* that "dark mater" emits x-rays, etc, then I want to hurl.

Once again your ignorance is showing - dark matter is an observation. The fact that we do not know what it is does not effect the fact that it exists.

No, acceleration is a rational "interpretation" derived from observation. "Dark energy" is a mythos and it does not exist in nature.

Once again your ignorance is showing - dark energy is the observed acceleration.

Even this idea is technically flawed. Nobody has to *assume* things exactly the same way that you do. In other words, all that is important is that the theory *address* the observations in question. Redshifted photons may be due to a lot of things, not necessarily "superluminal expansion".


Nobody ever claimed otherwise. It does however "curve fit' these observations using 3 different *hypothetical entities*. That's the rub, not the idea you "ignored" anything, other than perhaps alternative ideas related to expansion theories.

http://arxiv.org/abs/astro-ph/0601171

See Guth's primary motives in the abstract, items 1 and 2. His motive in introducing inflation was based upon these *assumptions* based on what was already "popular" based on observations from that time. His third stated "goal" was to explain his 'missing monopole' problem and don't even get me started on that one.

More ignorance - "3 different *hypothetical entities" when it is 2 actual observations of physical facts and one hypothetical event that gives falsifiable predictions that have been verified.

Guth's theory is DOA for two reasons apparently. First it failed to "reheat" properly after the supercooling phase, and secondly it is based on a physical impossibility, namely "negative pressure" in a vacuum. Instead of it dying a natural death based on it's flaws, "new and improved" dead inflation deities with new lipstick emerge to prop up the otherwise dead pig of a theory. If his model was already falsified, what exactly will it take to convince you "inflation didn't do it"? How many different brands of "inflation" are there to choose from now? Guth's inflation? Linde's inflation? Hairy inflation? Some new exotic brand I haven't heard of yet? Is Linde's inflation dependent upon the need for "negative pressure in a vacuum" as well?

Your ignorance is showing again, MM.

Firstly there is a reason why Guth's model is known as the "old inflation" - it had been replaced by the current model. See below for the Wikipedia text (following links and reading web pages also seems beyond you ).

Secondly you can have negative pressure in a vacuum, e.g. the Casimir effect. Repeating your ignorance of physics is not impressive.

Have you found your definition of pressure that excludes negative pressure yet?

Where is your list of postdicted observations?

Guth
Guth was the first to assemble a complete picture of how all these initial conditions problems could be solved by an exponentially expanding state.

The physical size of the Hubble radius (solid line) as a function of the linear expansion (scale factor) of the universe. During cosmic inflation, the Hubble radius is constant. The physical wavelength of a perturbation mode (dashed line) is also shown. The plot illustrates how the perturbation mode grows larger than the horizon during cosmic inflation before coming back inside the horizon, which grows rapidly during radiation domination. If cosmic inflation had never happened, and radiation domination continued back until a gravitational singularity, then the mode would never have been outside the horizon in the very early universe, and no causal mechanism could have ensured that the universe was homogeneous on the scale of the perturbation mode.Guth proposed that as the early universe cooled, it was trapped in a false vacuum with a high energy density, which is much like a cosmological constant. As the very early universe cooled it was trapped in a metastable state (it was supercooled) which it could only decay out of through the process of bubble nucleation via quantum tunneling. Bubbles of true vacuum spontaneously form in the sea of false vacuum and rapidly begin expanding at the speed of light. Guth recognized that this model was problematic because the model did not reheat properly: when the bubbles nucleated, they did not generate any radiation. Radiation could only be generated in collisions between bubble walls. But if inflation lasted long enough to solve the initial conditions problems, collisions between bubbles became exceedingly rare. In any one causal patch, it is likely that only one bubble will nucleate.

Linde, Albrecht and Steinhardt
The bubble collision problem was solved by Andrei Linde[5] and independently by Andreas Albrecht and Paul Steinhardt[6] in a model named new inflation or slow-roll inflation (Guth's model then became known as old inflation). In this model, instead of tunneling out of a false vacuum state, inflation occurred by a scalar field rolling down a potential energy hill. When the field rolls very slowly compared to the expansion of the universe, inflation occurs. However, when the hill becomes steeper, inflation ends and reheating can occur.^WP