Mystery of the Coldest Spot In the CMB Solved

StartsWithABang writes: The cosmic microwave background is a thing of beauty, as not only does its uniform, cold temperature reveal a hot, dense past that began with the hot Big Bang, but its fluctuations reveal a pattern of overdensities and underdensities in the very early stages of the Universe. It's fluctuations just like these that give rise to the stars, galaxies, groups and clusters that exist today, as well as the voids in the vast cosmic web. But effects at the surface of last scattering are not the only ones that affect the CMB's temperature; if we want to make sure we've got an accurate map of what the Universe was born with, we have to take everything into account, including the effects of matter as it gravitationally grows and shrinks. As we do exactly this, we find ourselves discovering the causes behind the biggest anomalies in the sky, and it turns out that the standard cosmological model can explain it all.

Comments

But why is there only one spot like this?

[ceview]

Isn't the whole point of this area is that is anomalous? at least in comparison to all the other areas of the CMB? yes there are other 'cooler' areas but this seems to be the only one of this magnitude. If this was a common feature across the whole CMB then the cold spot could be considered as part of the standard cosmological model surely?

Re:But why is there only one spot like this?

[wonkey_monkey]

Well, it's medium.com. You can't analyse it too much.

I think it comes down to this: why there is a big cold spot in the CMB? Because there's a big void. Mystery solved!

Except there's still the mystery of why there is such a big void in the first place.

Re:But why is there only one spot like this?

[narcc]

Medium.com explains it all.

It's essentially blogspot disguised as a news site.

Look forward to my article explaining how the CMB cold spot is the result of CFC's breaking down galactic ozone. Also, aliens.

Re:But why is there only one spot like this?

[Gavagai80]

If you actually bothered to read the article, you would not be claiming that's a mystery. The article explains that the void is not a big void, it's actually a fairly normal 20% less dense than average area. It just so happens to be on top of what's already a cool spot in the CMB. A a normal less dense area on top of a normal cool spot in the CMB = an appearance of an extraordinarily cold spot which is not really extraordinary at all but just a coincidence of that combination.

Re:But why is there only one spot like this?

[careysub]

...

I think it comes down to this: why there is a big cold spot in the CMB? Because there's a big void. Mystery solved!

Except there's still the mystery of why there is such a big void in the first place.

That is true, but it is a much lesser mystery. The previous record-holder was the Canes Venatici Supervoid at 1.3 billion light years, and an Eridanus Supervoid has been the preferred explanation for the Eridanus Cold Spot (or, humorously, CAOE: "Cosmic Axis Of Evil) for years ("parallel universe collisions" was always an exotic explanation), but the existence of such a supervoid had not been confirmed. Dr. István Szapudi of the Institute for Astronomy at the University of Hawaii at Manoa has has just announced findings that measures this supervoid at 1.8 billion light years. This is moderately bigger than the previous record-holder (40% wider), but there are quite a few that are 400-800 million light years across. This looks rather like a power law distribution, often found in nature.

The Canes Venatici Supervoid is closer as than the Eridanus Supervoid (red shift z=0.118 vs 0.22, or 1.5 vs 2.5 billion light years) as well as being smaller so there are two reasons for the Integrated Sachs-Wolfe Effect to be weaker, but apparently there is no anomalous cooling for that void at all. I would like to see someone address that.

Re:But why is there only one spot like this?

[Paradise Pete]

Medium.com explains it all. It's essentially blogspot disguised as a news site.

I don't think Medium has ever purported to be a news site. It's doesn't look like one, it doesn't cover the news. It's a collection of stories. Not news stories, just stories. Thinking otherwise "explains it all".

Re:But why is there only one spot like this?

[bill_mcgonigle]

If slashcode had ever evolved beyond 2001, we'd be selecting comments like this to replace the summary.

Re:But why is there only one spot like this?

[buchner.johannes]

You make it sound like the temperature of the (empty) region averages down the background, making it colder. But something way more awesome actually happens: Photons enter one side of the Void (empty region) at an early time and travel through it. During that time, the Void expands. To escape the Void, the photon then has to lose more energy than it received when it entered. It is the slow light speed relative to these enormous scale, evolving structures that causes this effect!

Re: But why is there only one spot like this?

[Anonymous Coward]

That must be where God lives... we have to go there!

Re:But why is there only one spot like this?

[serviscope_minor]

If slashcode had ever evolved beyond 2001, we'd be selecting comments like this to replace the summary.

Slashdot Beta was evolved since 2001. Personally, I use slashdot classic and prefer it over other commenting systems.

Re: But why is there only one spot like this?

[Anonymous Coward]

He needs us to bring him a starship.

Re:But why is there only one spot like this?

[Agent0013]

But the cool spot in the CMB says it should be an extra dense region of space. How do we have a void in an area where we should have extra density. It seems the two things are saying the opposite should occur and they reinforce each other to make the spot appear even colder. Ok, you explained how it got colder than what it actually is, but you skipped over how the two results are opposite of each other.

"that the standard cosmological model can explain"

[devent]

Aw, boring. I was hoping that everyone was wrong and we get some new physics. Misconception of scientists number one, scientists (and me) like to be shown wrong so we can go and investigate and discover new knowledge. The day it turns out that we know everything will be a very sad day indeed.

Summary is contradictory

[Anonymous Coward]

The cosmic microwave background is a thing of beauty, as not only does its uniform, cold temperature reveal a hot, dense past that began with the hot Big Bang, but its fluctuations

So, is the CMB uniform, or not? I propose that it is not.

Re:Summary is contradictory

[Anonymous Coward]

Something can be uniform and fluctuating at the same time. All that's required is that the fluctuations follow the same, regular pattern everywhere.
I have no idea whether this is true for the CMB, however.

Re:Summary is contradictory

[careysub]

Something can be uniform and fluctuating at the same time. All that's required is that the fluctuations follow the same, regular pattern everywhere. I have no idea whether this is true for the CMB, however.

It is true. Further, the fluctuations are tiny - at the parts per million level. It took 28 years after the CMB was discovered to detect any fluctations at all, requiring a sophisticated space probe (COBE) to do it.

Asserting that the CMB is "not uniform" because of these fluctuations is rather like saying the Bonneville Salt Flats are not really flat at all since the surface has millimeter scale irregularities, or your polished marble dining room floor isn't flat since it has micron sized irregularities.

Re:Summary is contradictory

[Anonymous Coward]

Nothing can be perfectly uniform, but CMB is uniform to 1 in 10,000. Pretty much the most uniform thing in the Universe.

There should be less than one

[grimJester]

Before the void was found, a cold spot that large should have been rare enough that it seemed odd we had even one in our sky. With the void explanation it's no longer rare enough in the models that it seems odd we have one.

StartsWithABang writes

[Anonymous Coward]

I see what you did there

also-known-as-the-wet-spot

[Anonymous Coward]

I see what you did there

Ghosts

[Culture20]

That cold spot will require a big salt ring.

Kludgy Mess Requires Kludgier Foundation

[eyepeepackets]

The standard cosmological model sits on top of the concept of cosmological inflation, a well known kludge adopted to explain away serious problems with the standard cosmological model, thus suggesting that it is indeed turtles all the way down.

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

a well known kludge adopted to explain away serious problems

I think you just summed up all of science, as the whole process amounts to find problems, make a kludge to fix it, look for new problems. Sometimes someone finds a way to make a kludge look prettier later, but if you look at the papers that establish the some of the more well established principles in various fields, the original papers are a lot uglier than the versions later people did a better job of explaining in a textbook.

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

Except inflation explains structure formation, give a good accounting of why the spectral index is almost 1, explains the smallness of omega_k, gives a great match to data observed by WMAP/Planck, solves the horizon problem, and appears well motivated by simple matter lagrangians...

But yeah, a kludge.

Clues are handed out at your local physics dept. Please take one before you come back.

Re:Kludgy Mess Requires Kludgier Foundation

[eyepeepackets]

"A recurrent criticism of inflation is that the invoked inflation field does not correspond to any known physical field, and that its potential energy curve seems to be an ad hoc contrivance to accommodate almost any data obtainable. Paul J. Steinhardt, one of the founding fathers of inflationary cosmology, has recently become one of its sharpest critics. He calls 'bad inflation' a period of accelerated expansion whose outcome conflicts with observations, and 'good inflation' one compatible with them: "Not only is bad inflation more likely than good inflation, but no inflation is more likely than either.... Roger Penrose considered all the possible configurations of the inflaton and gravitational fields. Some of these configurations lead to inflation ... Other configurations lead to a uniform, flat universe directly – without inflation. Obtaining a flat universe is unlikely overall. Penrose's shocking conclusion, though, was that obtaining a flat universe without inflation is much more likely than with inflation – by a factor of 10 to the googol (10 to the 100) power!"[106][107]"

Source: http://en.wikipedia.org/wiki/I...

Personal insults are not adequate replacements for knowledge, asshole.

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

Personal insults are not adequate replacements for knowledge, asshole.

Which is why there was the whole first 75% of the comment, which you completely disregard and just copy paste a quote and comment on the other 25%. There are well founded criticism, but that doesn't make it any more of a kludge than any other succinct theory in physics that can cover a wide variety of observations.

Re:Kludgy Mess Requires Kludgier Foundation

[lgw]

Inflation was cooked up to explain most of that after the fact, though, so it's unsurprising that it does. The fundamental problem with inflation is that too much is tunable. Penrose's cyclic cosmology explains all the same stuff, and at least has the decency to make some bizarre (and very likely false) predictions outside of the early universe.

Theories of the very early universe that require new fields that there's a way to detect today are interesting. Certainly there are ideas to explain dark energy as an extension of inflation that fit that bill. But theories that propose a bunch of cool new physics that all conveniently vanished early on are a bit sketchy, at least until we can somehow make an equivalent of WMAP for the neutrino background radiation, and observe the very early universe directly. I hope I live to see that!

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

"Personal insults are not adequate replacements for knowledge, asshole."

Oh, the irony.

You're quoting Wikipedia. Again, go in search of a clue. To answer lgw's comment here, inflation was first posited as a solution to the flatness problem and gained traction because it explained also the lack of magnetic monopoles. Then later it was seen to explain the spectral index, fit ridiculously well with observations of the CMB, gives rise to the early universe structure and a whole host more.

Here's a scientific paper on the subject by the Planck collaboration, not a Wikipedia article:

http://arxiv.org/abs/1303.5082

there are (quite literally) hundreds more of these. As for the Steinhardt quote, well, he's a /long/ way out in terms of measures of probability for inflation - see anything by Wald, Gibbons, Turok, Corichi or any of the other serious measure papers.

Or you could stick to insults and half-assed bullshit. Your choice.To say that inflation is a kludge is a massive insult to people who have investigated the models thoroughly. You, I suspect from your serious lack of a clue, have not.

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

And after complaining about personal insults, you make a whole post of them still without responding to the points previously made. Maybe you should shoot down that with reasoning if it is so easy to do, instead of trying to act like Slashdot should magically filter out certain people from AC posting.

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

Allowing AC posts like yours have ruined this site for years now. The owners and operators of Slashdot should have fixed this by now, severely restricting who has access to AC posting.

Maybe you haven't looked at many science stories on here, but there are numerous named accounts that will make wildly inaccurate and wrong on nearly every science story of various topics. They get modded up faster than coherent replies can be made pointing out how wrong they are, and often retain a net positive mod even after a dozen replies pointing out how wrong they are, letting them post the exact same mistakes again at a later time. And not just subtle mistakes, but stuff that directly contradicts the first sentence or two of a wikipedia lede.

The root of problems around here with science topics has very little to do with what name people post under.

Would you have made your original reply to my post if you had had to use your real account name?

Quite a few actual scientists post here and elsewhere anonymously as possible. It takes one whack job with too much free time getting upset over the stupidest things then using your easy to find department listing to spam or harass you. I've had it happen over stuff as benign as trying to explain intro level electrical circuits, while a colleague had it happen over what amounted to a west-vs-easy difference in name of an effect. Most researchers just end up stopping to answer questions online once their enthusiastic youth wears thin, while a smaller number just drops their name from things, and fewer bother to actually try weathering the storms.

And besides, I've found when you have a point to make, it makes no difference whether done here as an AC or with some pseudo-anonymous name. The only people who seem to care are those that have no actual counter point.

If you had bothered to read the first sentence of the quote -- and were able to comprehend it in context -- then you would not have posted this grammatically-challenged reply.

That is a rather crappy context, and you can far better understand it by reading some of Penrose's, among other's, actual papers. But it doesn't contradict that inflation can neatly package up a lot of things in a unified idea, usually something considered the opposite of a kludge in physics. It is not the only explanation with some traction these days and there is a lot to be said about criticism of inflation, but just ranting about what name a person posts under doesn't amount to anything in that regard. Maybe if you are going to complain about people using personal attacks in place of knowledge, you should lead by example.

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

I don't know why the idea that the inflation field doesn't match any other fields within easy reach of current particle physics experiments seems like such a big issue, considering the situation it is needed. However, it is a rather simple change to the Lagrangian that produces a lot of useful results. It is not the first time a new term gets added, and of course the new ones will look nothing like any previously known field.

Re:Kludgy Mess Requires Kludgier Foundation

[Anonymous Coward]

Slashdot does restrict AC posts from any IP or user account that has a history of being modded down.

But all you're done is copy from Wikipedia, then go off on a tangent of personal attacks and wishing Slashdot would protect you from those with counterpoints. If you wanted to discuss the actual topic, you would have done so. Instead, you seem to be one of the large number of people here more interested in arguing and bashing each other than actually trying to learn about a topic. If you're going to complain about trash, at least don't be littering when you do so.

Yawnity

[Anonymous Coward]

Linkspam to unreadable sites not worth the effort.

Re:"that the standard cosmological model can expla

[Anonymous Coward]

It depends in what way you are wrong. As a thought experiment, imagine all the equations would work perfect but there has somehow been an extra 2pi somewhere it shouldn't be. No one is going to like to be shown wrong in that way, in fact most will never admit it. Instead, I think you want to be shown "almost right".

Re:"that the standard cosmological model can expla

[rabbin]

How will we know that we know everything?

What is the other 95%

[Anonymous Coward]

Gotta love the arrogance of this statement: "that the standard cosmological model can explain it all." when 95% of what composes the Universe is a complete mystery :-)

Re:What is the other 95%

[Anonymous Coward]

"complete mystery" isn't the best description of dark matter, considering it has a long list of measured properties based on a rather small number of assumptions. Dark energy is not in the same ball park, but still isn't a complete unknown. It is also not like it is the only field where an equation is found to work well, but lacks a more fundamental description of where those equation terms come from.

Re:"that the standard cosmological model can expla

[devent]

If we can't observe anything new. And by "new" I mean something that was not predicted by a scientific theory. Of course, there is always the possibility to observe something new, but it's like an asymptote. New scientists will be less and less excited, because they will just confirm established theories.

Re:"that the standard cosmological model can expla

[devent]

In science, it's irrelevant if you admit it or not. Either your model works or not, and if it's not working somebody will come up with a better model and replace yours. People will use the better model because it works better. Or maybe I misunderstand you. Newton's laws of gravity works "almost right", Einstein's theory is better. But in cosmonautics and mechanics we use Newton's laws, because they are good enough.

Re:"that the standard cosmological model can expla

[thegarbz]

I was hoping that everyone was wrong and we get some new physics.

It's a Medium article. I think if you read it in detail you'll probably find they made up some new physics anyway.

Re:"that the standard cosmological model can expla

[Anonymous Coward]

No one is going to like to be shown wrong in that way, in fact most will never admit it

Most physicists have had to deal with being off by a factor of pi, 2, or a negative sign somewhere in grad school. The easy at which it happens can make it a constant minor fear to most, but something most have also had to deal with. But if things work as is, then occasionally there is two factors that are off that fix each other (or a paper has a typo, far most common answer to such missing factors, with the math working out right without typo). Otherwise, when things are off by such a factor, there are usually some hints that help you catch it before publishing.

I reject your reality and substitute my own.

[donkwich]

I still choose to believe that the CMB cold spot is a parallel universe entangled with ours, and I want my belief treated with respect. #teachthecontroversy