Comments of the Week #153: from the expanding Universe to the CMB’s location [Starts With A Bang]


“Science and religion are both the same thing. They’re there; they’re life. If it’s not science, it’s not a fact.” -Chuck Berry

We always take pride in what we put out into the world here at Starts With A Bang, and I like to think that all of you take that same pride in everything you do. Before we get into anything else, I have some sad news to share with you: one of our long-time commenters, known here as MandoZink, has died of cancer. (He also commented elsewhere as BeyondApsis, if you knew or encountered him elsewhere.) His real name was Ron. He was so curious about everything; he loved knowledge and learning. He was overjoyed every time he learned how something worked. And he also spent time in jail at the Muhlenberg County Detention Center for growing his own medical chemo-relief medicine while he battled his cancer. He loved the mandolin; he loved John Prine; and he loved learning about the Universe. He wasn’t ready for his time to end, and I’d like to thank his sister, Donna, for reaching out to me to share the news of his passing. A bright candle has gone out amidst the great expanse of the Universe.

Image credit: ESA/Hubble & NASA; Acknowledgement: Judy Schmidt.

Image credit: ESA/Hubble & NASA; Acknowledgement: Judy Schmidt.

It makes me think about what we put out into the world and about how we treat each other. Recently, I have seen a few of you who disagree get engaged in name-calling wars, baiting each other and generally engaging in “poking the bear.” I can think of nothing better to do than to try and make peace. We all have different ways of interacting with the world, different perspectives and different opinions. Some of them are downright incorrect, but I would encourage and implore you to be good to each other, always, even when you observe bad behavior. It’s only through our goodness to each other that existence becomes bearable. Thanks for being willing to consider my suggestion, even if you choose not to take it.

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration.

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration.

With that introduction out of the way, we’ve had a busy, information-filled week here, and I’m happy to share everything new we’ve published:

I’ve decided to only highlight the comments that I’ve chosen as the best (and it’s subjective, as always), so let’s continue onto our comments of the week!

Moving close to the speed of light results in times and distances transforming, with lengths -- including the length of your starship -- becoming shorter in the direction of motion. Image credit: David Taylor of Northwestern, via http://ift.tt/2m8aTPM.

Moving close to the speed of light results in times and distances transforming, with lengths — including the length of your starship — becoming shorter in the direction of motion. Image credit: David Taylor of Northwestern, via http://ift.tt/2m8aTPM.

From Michael Mooney on special relativity and length contraction: “So the distance between stars depends on the speed of the traveler (no objective cosmos independent of frame of reference), but spherical bodies in space don’t flatten out (contract in diameter) depending on speed of the observing point of view. (“We don’t think so” anyway.) So what is the difference here? Please explain.”

There is a big difference between what different observers see; that’s the key point of special relativity, and one of the biggest sources of confusion for those trying to learn it and wrap their minds around it. From the point of view of someone on the spaceship, traveling close to the speed of light, the distances of external (but not internal) objects along their direction of motion are contracted, as are the distances between objects. To someone watching the spaceship, the fast-moving ship itself is contracted. If there were an electric (or gravitational) field coming from the fast-moving object, it would have the effect of being contracted as well.

The difficulty comes in trying to interact. For example, you might try and put a relativistic train that’s 200 feet long into a 100 foot long barn that’s at rest. Could you, if the train were moving fast enough? The answer is “no,” and that’s one of the tough parts of how special relativity works. Both observers need to agree on what result you’d get, and they don’t. This is sometimes referred to as the ladder paradox. It is well-understood in physics, even if it’s not well-understood by most people in general.

Image credit: Duncan K Bliths, via Reddit at http://ift.tt/2n4LBWa.

Image credit: Duncan K Bliths, via Reddit at http://ift.tt/2n4LBWa.

From eric on out-of-control comments: “As an aside, does anyone know if there is a way you can not-see posts from specific posters? I think that can be done on some boards, just not sure whether it can be done here or how.”

I think everyone who’s actively posting here should continue to retain the rights and privileges to post, but the repeat comments have got to go. It is just spam to me, and to everyone else. If you can’t help yourselves, I will enact a temporary 1-week ban on anyone (and it’s going to take two of you, I imagine, in which case I’ll knock you both off for a week) who’s just filling up the comment threads here — particularly new, active ones — with garbage.

This was designed as a place for people to come and talk about science, the article, or their thoughts related to it. It’s not a place to just be terrible to one another, even if (perhaps, especially if) you think the other person is legitimately terrible.

Image credit: © 2005–2009 by Rainer Sparenberg, image editing by Stefan Binnewies, via http://ift.tt/1q9mSX6.

Image credit: © 2005–2009 by Rainer Sparenberg, image editing by Stefan Binnewies, via http://ift.tt/1q9mSX6.

From John on why we aren’t expanding if the Universe is: “This ties back neatly to the “Cosmic superclusters, the Universe’s largest structures, don’t actually exist” thread.”

What’s pretty interesting about this is that if you take a bound object — like say, a planet or star — and have it exist stably within a gravitationally bound structure, the expansion of the Universe will have no effect on it, ever. It will remain bound. But if it gets ejected, perhaps gravitationally, from the structure it’s in, suddenly the expansion of the Universe will begin to increase its velocity away from the object it was formerly bound to. The Universe doesn’t stop expanding just because an object is bound; it’s only that it’s ineffective so long as there’s sufficient binding. Remove that binding by whatever means necessary, and the expansion occurs again.

Image credit: White Dwarf, Earth, and Black Dwarf, via BBC / GCSE (L) and SunflowerCosmos (R).

Image credit: White Dwarf, Earth, and Black Dwarf, via BBC / GCSE (L) and SunflowerCosmos (R).

From Ragtag Media on the far future of the Universe: “The Universe mathematically and factually (and Biblically) only has enough informational “energy” to sustain itself until it does not.. and then…. Poof. Nothing…LOL”

Well, that’s not quite mathematically and factually true. (And my bible doesn’t have anything to say about this at all, but perhaps you read a different version than I do.) Information is not energy, and energy cannot accurately be described as informational. In fact, the word you’re looking for, entropy (which is related to information), always increases. As energy drops and the Universe expands, and gravity unbinds or causes the merger of objects, as the stars burn out and die, as space becomes emptier and emptier, the Universe comes no closer to ending. As far as we can tell, it should sustain itself for an infinite amount of time into the future… although we cannot say this for certainty, just to a certain (the limits of our measured) precision.

Hubble Space Telescope optical image (green), mass map (Limousin et al 2012; contours), and CSO/Bolocam 140 GHz (red) and 268 GHz (blue) maps of the galaxy cluster MACS J0717+3745. The lack of 268 GHz signal at subcluster B (second large concentration from upper right) is due to the kinetic Sunyaev-Zeldovich effect. Image credit: P. Korngut.

Hubble Space Telescope optical image (green), mass map (Limousin et al 2012; contours), and CSO/Bolocam 140 GHz (red) and 268 GHz (blue) maps of the galaxy cluster MACS J0717+3745. The lack of 268 GHz signal at subcluster B (second large concentration from upper right) is due to the kinetic Sunyaev-Zeldovich effect. Image credit: P. Korngut.

From Anonymous Coward on what to call the individual merging clusters in MACS J0717: “I know it’s just some silly pareidolia on the last image in the synopsis, but might they be called, from left to right: the fried egg cluster, the slug cluster, the chick cluster, and the fish cluster?”

These contour maps that show cluster masses all look like frogs to me. I would call them, from left to right: bug-eyed frog, surprised frog, delirious frog and pollywog frog.

Which is to say, I think we’re in agreement here.

Left: An infrared view of the sky in Ursa Major. Right: an enhanced view with known sources masked, showing fluctuations of the infrared background. Credits: NASA/JPL-Caltech/A. Kashlinsky (Goddard).

Left: An infrared view of the sky in Ursa Major. Right: an enhanced view with known sources masked, showing fluctuations of the infrared background. Credits: NASA/JPL-Caltech/A. Kashlinsky (Goddard).

From B.A. on dark matter: “There are those of us that believe dark matter is nothing more than particle sized and up, primordial black holes formed at the time of the Big Bang.”

And perhaps those of you who believe that will someday publish and present your good evidence for believing that. Primordial black holes are disfavored by:

  • a huge slew of observational constraints that have almost entirely closed their mass window for being the dark matter,
  • the lack of a mechanism for producing them that doesn’t violate quantum rules during inflation or the observed Harrison-Zel’dovich spectrum,
  • X-ray and gamma-ray observations that show no evidence for PBH dark matter under any circumstances.

There are a few true believers out there, but even Barrow, Carr and the other founders of the PBH idea have all but abandoned it in the face of damning evidence against it. There are non-physicists on the internet who are still believers, but until there’s evidence for it in some fashion, your “belief” is unfounded in physics.

Image credit: NASA / GISS global average temperature data from 2011.

Image credit: NASA / GISS global average temperature data from 2011.

From Denier on something respectable: “My driving motivation is in trying to give my 4-year old son the best world I can. I have learned that people can be far more threatening than can a tenth of a degree or a few millimeters of ocean rise. Given what I do know about economics, governments, history, human nature, and the threat of a warmer climate, I’m satisfied with my position currently but it’s always adaptable as I learn more.”

Well if you’re more concerned with economics and politics than climate change, and the future of your four-year-old son, perhaps you would care to share what you believe the quantified economic and political costs of ignoring climate change are? There are people who study those things professionally, including the United States military (who views climate change as a national security threat), and they have their own quantifications. It sounds like yours is far, far lower than what they attest.

I’m curious as to what your reasoning is, and as to why you think you’re more qualified to make those assessments than the professionals in the field?

Image credit: © Средняя оценка, via http://ift.tt/2mK8Nq6.

Image credit: © Средняя оценка, via http://ift.tt/2n501FP.

From John on infinities in physics: “It is noteworthy that in certain instances infinity is considered a problem in Physics, one example being the singularity of a black hole, while in others, it is presented as a solution to problems in Physics, as in some versions of the multiverse.”

I would encourage you to think a little deeper about this. Infinity is a mathematical construct that gets applied in a variety of physical contexts, but this is usually in the context of limits. In the case of a singularity at a black hole, it’s not that “infinity” itself is the problem, but rather than distances below a certain scale (or times below a certain scale, thanks to their interconversion by the speed of light) run into inherent quantum limits. Infinities in the context of the multiverse aren’t, as they’re often touted, solutions to anything, but rather as features of the theory.

There are many people who point to things like the “coincidence problem” — why are two seemingly unrelated things so close together — or the “hierarchy problem” — why are two seemingly related things so far apart — and say that these are examples of how physicists will never be satisfied. In reality, these are both examples of fine-tuning problems: why are things the way they are and not slightly different, especially given that slight differences would have substantial consequences?

I’d encourage you to think about the particulars of the problem, rather than to try and lump “infinity” in as the thing they have in common.

A quantum optics setup. Image credit: Matthew Broome, winner of the Australian Research Council’s photo & data competition from the Centre for quantum computation and communication technology. Via http://ift.tt/1RM3hKZ.

A quantum optics setup. Image credit: Matthew Broome, winner of the Australian Research Council’s photo & data competition from the Centre for quantum computation and communication technology. Via http://ift.tt/1RM3hKZ.

From Carl on a summary of what the comment thread has degenerated into: “This arguing and name calling is very immature. John taunts, Wow spews a venom and profanity-laden tantrum.
There are no winners here, boys.”

And we are all losers when we can’t talk to each other like we have the common interest of advancing our understanding. We may disagree about how to go about that, but I mean it; knock it off — and Carl has nailed it: it’s boyish, taunting, venomous and tantrum-like behavior — starting now.

Detection and Attribution as Forensics (source: NOAA NCDC), in: Walsh, J., et al. (11 January 2013), “Appendix II: The Science of Climate Change”, in FEDERAL ADVISORY COMMITTEE DRAFT CLIMATE ASSESSMENT. A report by the National Climate Assessment Development Advisory Committee.

Detection and Attribution as Forensics (source: NOAA NCDC), in: Walsh, J., et al. (11 January 2013), “Appendix II: The Science of Climate Change”, in FEDERAL ADVISORY COMMITTEE DRAFT CLIMATE ASSESSMENT. A report by the National Climate Assessment Development Advisory Committee.

From dean on the way climate change has been unfairly and dishonestly politicized: “Part of the reason these models are so effectively ridiculed by the deniers (dishonestly, of course, since they grossly misrepresent the models and what they say) comes is in no small part due to this:

Models have been very effective in predicting climate change, but have not been as effective in predicting its impact on ecosystem[s] and human society. The distinction between the two has not been stated clearly.

The liars are very smooth at saying this means the models fail in any number of ways (just as they are smooth in lying when they say that climate science is not a real science and its practitioners support restricting the rights of people). Once the false narrative has been released the only way to counter it is with a technical discussion, and in today’s world too many people “don’t have time for that.””

I think this is exactly right. This is the same line of attack that creationists/ID proponents use when attacking evolution (how does evolution explain the origin of life?), or that gish-gallopers (the debate tactic is known as “spreading”) use when trying to undermine any legitimate point. Say something that takes a long time to refute clearly, say it many times and in many different ways, say a lot of those arguments, all with the same goal: delay, confuse, and sow uncertainty. But that in no way changes the scientific facts or the success of the scientific models.

Heat-trapping emissions (greenhouse gases) far outweigh the effects of other drivers acting on Earth’s climate. Source: Hansen et al. 2005, Figure adapted by Union of Concerned Scientists.

Heat-trapping emissions (greenhouse gases) far outweigh the effects of other drivers acting on Earth’s climate. Source: Hansen et al. 2005, Figure adapted by Union of Concerned Scientists.

From Denier in two different spots: “I’m not going to pull my punches here. Ethan has flat out lied to everyone. In the article he wrote the following bit in a way that made it appear to be not only a conclusion of the paper but a direct quote of the paper. […] First of all that quote is not anywhere in the paper although there is similar language with regards to a 5-fold increase of stratospheric water vapor. Secondly, the number provided is wrong. Lastly, and worst of all it implies a conclusion which the authors roundly rejected.

[…]

I’m wrong. I did find the quote Ethan pulled. It was in the abstract. While Ethan’s assertion of “Predicted Global Warming Almost Perfectly” is still ridiculous, the line that drew my wrath was indeed from the authors and my attacks directed at Ethan with regards to that line were unwarranted. Ethan did not lie. I was wrong.”

Good for you for admitting your wrongness when you convinced yourself of it. Yes, if you had read the fourth sentence of the abstract, you would have found your error immediately. But your “secondly” and “lastly” points are also wrong, and the authors have been quite public about standing behind their work and its conclusions for… you know, fifty years. That paper I referred to has been named as the single most influential climate change paper in all of climate science in a 2015 poll.

In other words, the full suite of your attacks were and are unwarranted, at least as respects the climate science.

Global land and global ocean surface temperature anomalies. Light lines are 12-month running means and heavy lines are 132-month (11-year) running means. Image credit: "Global Temperature in 2016", J. Hansen et al. (2017), via http://ift.tt/2iBAUtD.

Global land and global ocean surface temperature anomalies. Light lines are 12-month running means and heavy lines are 132-month (11-year) running means. Image credit: “Global Temperature in 2016”, J. Hansen et al. (2017), via http://ift.tt/2iBAUtD.

Commenter Craig Thomas on another feature of climate models: “Every one of two dozen or more research projects by a variety of people using a variety of data have all produced confirmation that the original hockey stick paper was accurate.”

I remember when I first became aware of the hockey stick when I was in middle school, and how lots of people claimed it was absurd. Scientists who helped come up with the model have since said that the hockey stick was the icon that they thought the anti-warmist camp could smash, and if they could smash that, the results of climate science would be smashed, too. But the hockey stick has held up to scrutiny in every study done so far. The Earth is warming, CO2 is the cause, and this effect will run away causing warming, ocean acidification and sea level rise. The only question is by how much, and that is directly dependent on how much additional CO2 we continue to emit.

If the answer to the latter question is “all of it,” as in all of the sequestered carbon in fossil fuels, then the answer to “how much” is also all of it, as in all of the polar icecaps will melt, the temperature will rise by 6 degrees C or more, and the ocean’s pH will acidify by approximately 0.3 on the pH scale (last I heard), which is a catastrophic amount to much of marine life.

A famous photo circulated across news media of a certain wing. Is it photoshopped? You decide.

A famous photo circulated across news media of a certain wing. Is it photoshopped? You decide.

From SteveP on what the Earth and our nations’ leaders will do about it: “Well, I see that topic of infrared absorption and re-emission by carbon dioxide molecules in the Earth’s atmosphere has once again been livened up by the interjection of financially motivated mindlessness! Who is going to win this contest of wits, ladies and gentlemen? The Wall Street Journal Op Ed readers? The Limbaugh and Hannity listeners? The scientists who actually study this topic and understand it? Or the fearless live pigeon shooter and fossil fuel spokesmen from hell, Jim Inhofe? Stay tuned….”

Why don’t we just take a look at how the various models — historical and modern — work when compared to the data?

As you can see, the predictions by prominent climate contrarians Lindzen, Easterbrook and Atasofu fail to match the observations spectacularly. Mainstream work has been getting it right since Wallack Broecker’s work in the 1970s, or — if you go back to the paper I wrote the article about — 1967.
The Harvard Diamond, created by a team led by Mikhail Lukin, has so many nitrogen impurities that it turned black. This is one of two independent physical systems used to create a time crystal. Image credit: Georg Kucsko.

The Harvard Diamond, created by a team led by Mikhail Lukin, has so many nitrogen impurities that it turned black. This is one of two independent physical systems used to create a time crystal. Image credit: Georg Kucsko.

From Wow on time crystals: “Yeah, never really accepted that time crystals were a thing. Just a result of a way of modelling time in a theory. A bit like when they talk about slowing down the speed of light. Doesn’t really, it just impedes the time taken for the energy to reach the destination.”

Well, they are a thing, but they’re a thing like a perpetual motion machine is a thing. In other words, if you drive something externally, you can achieve perpetual motion. There are cool ways you can “barely” drive it, and there may even be, in principle, ways you can drive it that don’t add any external energy, but simply rearrange the internal energy, that achieve it. But what we call a “time crystal” is in no way a crystallized version of time, nor is it, as Wilczek envisioned, possible in a system in thermal equilibrium.

For my money, I think that if Wilczek’s name weren’t on this, nobody would’ve cared much about it.

Image credit: Screenshot from Attack of the Clones, via http://ift.tt/UIbUQt.

Image credit: Screenshot from Attack of the Clones, via http://ift.tt/UIbUQt.

From Sinisa Lazarek on where the CMB is: “It’s all around you, it penetrates you and binds the galaxy together 😀 .. well… not so much the last part, maybe that’s why we don’t have Jedis”

411 CMB photons per cubic centimeter. At an age of 13.8 billion years, this is true everywhere in the Universe that isn’t shielded from CMB photons. (I.e., anywhere that isn’t in a location opaque to microwave/radio radiation.)

Image credit: Ned Wright's cosmology tutorial.

Image credit: Ned Wright’s cosmology tutorial.

And finally, from Paul Dekous on how we know the CMB is primordial: “If you photograph a pot of boiling water with a regular camera you get a clear image of that pot, just like we can take a sharp image of the stars. Now if you photograph that same pot with a heat-camera you get a very different image with flows. The question now is how do you know that the light is old and from one specific point in time, and not some heat/light flowing around from more recent times even now. How are the two distinguishable from each other?”

The above data is how, taken by COBE in the 1990s. (In black.) If there were a late-time emission that was shifted to lower energies, it wouldn’t have the same blackbody spectrum that the CMB is seen to exhibit. This detail — as I go into in depth in chapter 6 of my first book, Beyond The Galaxy — is something that no cosmological alternative can reproduce.

I am looking forward to better behavior from all of you, but particularly from Wow and John. There’s no reason for it (and that is not an invitation to tell me your reason), and I know you can choose to behave if you choose it. Choose it. And I’ll see you all back here tomorrow!



from ScienceBlogs http://ift.tt/2mKnuJu

“Science and religion are both the same thing. They’re there; they’re life. If it’s not science, it’s not a fact.” -Chuck Berry

We always take pride in what we put out into the world here at Starts With A Bang, and I like to think that all of you take that same pride in everything you do. Before we get into anything else, I have some sad news to share with you: one of our long-time commenters, known here as MandoZink, has died of cancer. (He also commented elsewhere as BeyondApsis, if you knew or encountered him elsewhere.) His real name was Ron. He was so curious about everything; he loved knowledge and learning. He was overjoyed every time he learned how something worked. And he also spent time in jail at the Muhlenberg County Detention Center for growing his own medical chemo-relief medicine while he battled his cancer. He loved the mandolin; he loved John Prine; and he loved learning about the Universe. He wasn’t ready for his time to end, and I’d like to thank his sister, Donna, for reaching out to me to share the news of his passing. A bright candle has gone out amidst the great expanse of the Universe.

Image credit: ESA/Hubble & NASA; Acknowledgement: Judy Schmidt.

Image credit: ESA/Hubble & NASA; Acknowledgement: Judy Schmidt.

It makes me think about what we put out into the world and about how we treat each other. Recently, I have seen a few of you who disagree get engaged in name-calling wars, baiting each other and generally engaging in “poking the bear.” I can think of nothing better to do than to try and make peace. We all have different ways of interacting with the world, different perspectives and different opinions. Some of them are downright incorrect, but I would encourage and implore you to be good to each other, always, even when you observe bad behavior. It’s only through our goodness to each other that existence becomes bearable. Thanks for being willing to consider my suggestion, even if you choose not to take it.

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration.

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration.

With that introduction out of the way, we’ve had a busy, information-filled week here, and I’m happy to share everything new we’ve published:

I’ve decided to only highlight the comments that I’ve chosen as the best (and it’s subjective, as always), so let’s continue onto our comments of the week!

Moving close to the speed of light results in times and distances transforming, with lengths -- including the length of your starship -- becoming shorter in the direction of motion. Image credit: David Taylor of Northwestern, via http://ift.tt/2m8aTPM.

Moving close to the speed of light results in times and distances transforming, with lengths — including the length of your starship — becoming shorter in the direction of motion. Image credit: David Taylor of Northwestern, via http://ift.tt/2m8aTPM.

From Michael Mooney on special relativity and length contraction: “So the distance between stars depends on the speed of the traveler (no objective cosmos independent of frame of reference), but spherical bodies in space don’t flatten out (contract in diameter) depending on speed of the observing point of view. (“We don’t think so” anyway.) So what is the difference here? Please explain.”

There is a big difference between what different observers see; that’s the key point of special relativity, and one of the biggest sources of confusion for those trying to learn it and wrap their minds around it. From the point of view of someone on the spaceship, traveling close to the speed of light, the distances of external (but not internal) objects along their direction of motion are contracted, as are the distances between objects. To someone watching the spaceship, the fast-moving ship itself is contracted. If there were an electric (or gravitational) field coming from the fast-moving object, it would have the effect of being contracted as well.

The difficulty comes in trying to interact. For example, you might try and put a relativistic train that’s 200 feet long into a 100 foot long barn that’s at rest. Could you, if the train were moving fast enough? The answer is “no,” and that’s one of the tough parts of how special relativity works. Both observers need to agree on what result you’d get, and they don’t. This is sometimes referred to as the ladder paradox. It is well-understood in physics, even if it’s not well-understood by most people in general.

Image credit: Duncan K Bliths, via Reddit at http://ift.tt/2n4LBWa.

Image credit: Duncan K Bliths, via Reddit at http://ift.tt/2n4LBWa.

From eric on out-of-control comments: “As an aside, does anyone know if there is a way you can not-see posts from specific posters? I think that can be done on some boards, just not sure whether it can be done here or how.”

I think everyone who’s actively posting here should continue to retain the rights and privileges to post, but the repeat comments have got to go. It is just spam to me, and to everyone else. If you can’t help yourselves, I will enact a temporary 1-week ban on anyone (and it’s going to take two of you, I imagine, in which case I’ll knock you both off for a week) who’s just filling up the comment threads here — particularly new, active ones — with garbage.

This was designed as a place for people to come and talk about science, the article, or their thoughts related to it. It’s not a place to just be terrible to one another, even if (perhaps, especially if) you think the other person is legitimately terrible.

Image credit: © 2005–2009 by Rainer Sparenberg, image editing by Stefan Binnewies, via http://ift.tt/1q9mSX6.

Image credit: © 2005–2009 by Rainer Sparenberg, image editing by Stefan Binnewies, via http://ift.tt/1q9mSX6.

From John on why we aren’t expanding if the Universe is: “This ties back neatly to the “Cosmic superclusters, the Universe’s largest structures, don’t actually exist” thread.”

What’s pretty interesting about this is that if you take a bound object — like say, a planet or star — and have it exist stably within a gravitationally bound structure, the expansion of the Universe will have no effect on it, ever. It will remain bound. But if it gets ejected, perhaps gravitationally, from the structure it’s in, suddenly the expansion of the Universe will begin to increase its velocity away from the object it was formerly bound to. The Universe doesn’t stop expanding just because an object is bound; it’s only that it’s ineffective so long as there’s sufficient binding. Remove that binding by whatever means necessary, and the expansion occurs again.

Image credit: White Dwarf, Earth, and Black Dwarf, via BBC / GCSE (L) and SunflowerCosmos (R).

Image credit: White Dwarf, Earth, and Black Dwarf, via BBC / GCSE (L) and SunflowerCosmos (R).

From Ragtag Media on the far future of the Universe: “The Universe mathematically and factually (and Biblically) only has enough informational “energy” to sustain itself until it does not.. and then…. Poof. Nothing…LOL”

Well, that’s not quite mathematically and factually true. (And my bible doesn’t have anything to say about this at all, but perhaps you read a different version than I do.) Information is not energy, and energy cannot accurately be described as informational. In fact, the word you’re looking for, entropy (which is related to information), always increases. As energy drops and the Universe expands, and gravity unbinds or causes the merger of objects, as the stars burn out and die, as space becomes emptier and emptier, the Universe comes no closer to ending. As far as we can tell, it should sustain itself for an infinite amount of time into the future… although we cannot say this for certainty, just to a certain (the limits of our measured) precision.

Hubble Space Telescope optical image (green), mass map (Limousin et al 2012; contours), and CSO/Bolocam 140 GHz (red) and 268 GHz (blue) maps of the galaxy cluster MACS J0717+3745. The lack of 268 GHz signal at subcluster B (second large concentration from upper right) is due to the kinetic Sunyaev-Zeldovich effect. Image credit: P. Korngut.

Hubble Space Telescope optical image (green), mass map (Limousin et al 2012; contours), and CSO/Bolocam 140 GHz (red) and 268 GHz (blue) maps of the galaxy cluster MACS J0717+3745. The lack of 268 GHz signal at subcluster B (second large concentration from upper right) is due to the kinetic Sunyaev-Zeldovich effect. Image credit: P. Korngut.

From Anonymous Coward on what to call the individual merging clusters in MACS J0717: “I know it’s just some silly pareidolia on the last image in the synopsis, but might they be called, from left to right: the fried egg cluster, the slug cluster, the chick cluster, and the fish cluster?”

These contour maps that show cluster masses all look like frogs to me. I would call them, from left to right: bug-eyed frog, surprised frog, delirious frog and pollywog frog.

Which is to say, I think we’re in agreement here.

Left: An infrared view of the sky in Ursa Major. Right: an enhanced view with known sources masked, showing fluctuations of the infrared background. Credits: NASA/JPL-Caltech/A. Kashlinsky (Goddard).

Left: An infrared view of the sky in Ursa Major. Right: an enhanced view with known sources masked, showing fluctuations of the infrared background. Credits: NASA/JPL-Caltech/A. Kashlinsky (Goddard).

From B.A. on dark matter: “There are those of us that believe dark matter is nothing more than particle sized and up, primordial black holes formed at the time of the Big Bang.”

And perhaps those of you who believe that will someday publish and present your good evidence for believing that. Primordial black holes are disfavored by:

  • a huge slew of observational constraints that have almost entirely closed their mass window for being the dark matter,
  • the lack of a mechanism for producing them that doesn’t violate quantum rules during inflation or the observed Harrison-Zel’dovich spectrum,
  • X-ray and gamma-ray observations that show no evidence for PBH dark matter under any circumstances.

There are a few true believers out there, but even Barrow, Carr and the other founders of the PBH idea have all but abandoned it in the face of damning evidence against it. There are non-physicists on the internet who are still believers, but until there’s evidence for it in some fashion, your “belief” is unfounded in physics.

Image credit: NASA / GISS global average temperature data from 2011.

Image credit: NASA / GISS global average temperature data from 2011.

From Denier on something respectable: “My driving motivation is in trying to give my 4-year old son the best world I can. I have learned that people can be far more threatening than can a tenth of a degree or a few millimeters of ocean rise. Given what I do know about economics, governments, history, human nature, and the threat of a warmer climate, I’m satisfied with my position currently but it’s always adaptable as I learn more.”

Well if you’re more concerned with economics and politics than climate change, and the future of your four-year-old son, perhaps you would care to share what you believe the quantified economic and political costs of ignoring climate change are? There are people who study those things professionally, including the United States military (who views climate change as a national security threat), and they have their own quantifications. It sounds like yours is far, far lower than what they attest.

I’m curious as to what your reasoning is, and as to why you think you’re more qualified to make those assessments than the professionals in the field?

Image credit: © Средняя оценка, via http://ift.tt/2mK8Nq6.

Image credit: © Средняя оценка, via http://ift.tt/2n501FP.

From John on infinities in physics: “It is noteworthy that in certain instances infinity is considered a problem in Physics, one example being the singularity of a black hole, while in others, it is presented as a solution to problems in Physics, as in some versions of the multiverse.”

I would encourage you to think a little deeper about this. Infinity is a mathematical construct that gets applied in a variety of physical contexts, but this is usually in the context of limits. In the case of a singularity at a black hole, it’s not that “infinity” itself is the problem, but rather than distances below a certain scale (or times below a certain scale, thanks to their interconversion by the speed of light) run into inherent quantum limits. Infinities in the context of the multiverse aren’t, as they’re often touted, solutions to anything, but rather as features of the theory.

There are many people who point to things like the “coincidence problem” — why are two seemingly unrelated things so close together — or the “hierarchy problem” — why are two seemingly related things so far apart — and say that these are examples of how physicists will never be satisfied. In reality, these are both examples of fine-tuning problems: why are things the way they are and not slightly different, especially given that slight differences would have substantial consequences?

I’d encourage you to think about the particulars of the problem, rather than to try and lump “infinity” in as the thing they have in common.

A quantum optics setup. Image credit: Matthew Broome, winner of the Australian Research Council’s photo & data competition from the Centre for quantum computation and communication technology. Via http://ift.tt/1RM3hKZ.

A quantum optics setup. Image credit: Matthew Broome, winner of the Australian Research Council’s photo & data competition from the Centre for quantum computation and communication technology. Via http://ift.tt/1RM3hKZ.

From Carl on a summary of what the comment thread has degenerated into: “This arguing and name calling is very immature. John taunts, Wow spews a venom and profanity-laden tantrum.
There are no winners here, boys.”

And we are all losers when we can’t talk to each other like we have the common interest of advancing our understanding. We may disagree about how to go about that, but I mean it; knock it off — and Carl has nailed it: it’s boyish, taunting, venomous and tantrum-like behavior — starting now.

Detection and Attribution as Forensics (source: NOAA NCDC), in: Walsh, J., et al. (11 January 2013), “Appendix II: The Science of Climate Change”, in FEDERAL ADVISORY COMMITTEE DRAFT CLIMATE ASSESSMENT. A report by the National Climate Assessment Development Advisory Committee.

Detection and Attribution as Forensics (source: NOAA NCDC), in: Walsh, J., et al. (11 January 2013), “Appendix II: The Science of Climate Change”, in FEDERAL ADVISORY COMMITTEE DRAFT CLIMATE ASSESSMENT. A report by the National Climate Assessment Development Advisory Committee.

From dean on the way climate change has been unfairly and dishonestly politicized: “Part of the reason these models are so effectively ridiculed by the deniers (dishonestly, of course, since they grossly misrepresent the models and what they say) comes is in no small part due to this:

Models have been very effective in predicting climate change, but have not been as effective in predicting its impact on ecosystem[s] and human society. The distinction between the two has not been stated clearly.

The liars are very smooth at saying this means the models fail in any number of ways (just as they are smooth in lying when they say that climate science is not a real science and its practitioners support restricting the rights of people). Once the false narrative has been released the only way to counter it is with a technical discussion, and in today’s world too many people “don’t have time for that.””

I think this is exactly right. This is the same line of attack that creationists/ID proponents use when attacking evolution (how does evolution explain the origin of life?), or that gish-gallopers (the debate tactic is known as “spreading”) use when trying to undermine any legitimate point. Say something that takes a long time to refute clearly, say it many times and in many different ways, say a lot of those arguments, all with the same goal: delay, confuse, and sow uncertainty. But that in no way changes the scientific facts or the success of the scientific models.

Heat-trapping emissions (greenhouse gases) far outweigh the effects of other drivers acting on Earth’s climate. Source: Hansen et al. 2005, Figure adapted by Union of Concerned Scientists.

Heat-trapping emissions (greenhouse gases) far outweigh the effects of other drivers acting on Earth’s climate. Source: Hansen et al. 2005, Figure adapted by Union of Concerned Scientists.

From Denier in two different spots: “I’m not going to pull my punches here. Ethan has flat out lied to everyone. In the article he wrote the following bit in a way that made it appear to be not only a conclusion of the paper but a direct quote of the paper. […] First of all that quote is not anywhere in the paper although there is similar language with regards to a 5-fold increase of stratospheric water vapor. Secondly, the number provided is wrong. Lastly, and worst of all it implies a conclusion which the authors roundly rejected.

[…]

I’m wrong. I did find the quote Ethan pulled. It was in the abstract. While Ethan’s assertion of “Predicted Global Warming Almost Perfectly” is still ridiculous, the line that drew my wrath was indeed from the authors and my attacks directed at Ethan with regards to that line were unwarranted. Ethan did not lie. I was wrong.”

Good for you for admitting your wrongness when you convinced yourself of it. Yes, if you had read the fourth sentence of the abstract, you would have found your error immediately. But your “secondly” and “lastly” points are also wrong, and the authors have been quite public about standing behind their work and its conclusions for… you know, fifty years. That paper I referred to has been named as the single most influential climate change paper in all of climate science in a 2015 poll.

In other words, the full suite of your attacks were and are unwarranted, at least as respects the climate science.

Global land and global ocean surface temperature anomalies. Light lines are 12-month running means and heavy lines are 132-month (11-year) running means. Image credit: "Global Temperature in 2016", J. Hansen et al. (2017), via http://ift.tt/2iBAUtD.

Global land and global ocean surface temperature anomalies. Light lines are 12-month running means and heavy lines are 132-month (11-year) running means. Image credit: “Global Temperature in 2016”, J. Hansen et al. (2017), via http://ift.tt/2iBAUtD.

Commenter Craig Thomas on another feature of climate models: “Every one of two dozen or more research projects by a variety of people using a variety of data have all produced confirmation that the original hockey stick paper was accurate.”

I remember when I first became aware of the hockey stick when I was in middle school, and how lots of people claimed it was absurd. Scientists who helped come up with the model have since said that the hockey stick was the icon that they thought the anti-warmist camp could smash, and if they could smash that, the results of climate science would be smashed, too. But the hockey stick has held up to scrutiny in every study done so far. The Earth is warming, CO2 is the cause, and this effect will run away causing warming, ocean acidification and sea level rise. The only question is by how much, and that is directly dependent on how much additional CO2 we continue to emit.

If the answer to the latter question is “all of it,” as in all of the sequestered carbon in fossil fuels, then the answer to “how much” is also all of it, as in all of the polar icecaps will melt, the temperature will rise by 6 degrees C or more, and the ocean’s pH will acidify by approximately 0.3 on the pH scale (last I heard), which is a catastrophic amount to much of marine life.

A famous photo circulated across news media of a certain wing. Is it photoshopped? You decide.

A famous photo circulated across news media of a certain wing. Is it photoshopped? You decide.

From SteveP on what the Earth and our nations’ leaders will do about it: “Well, I see that topic of infrared absorption and re-emission by carbon dioxide molecules in the Earth’s atmosphere has once again been livened up by the interjection of financially motivated mindlessness! Who is going to win this contest of wits, ladies and gentlemen? The Wall Street Journal Op Ed readers? The Limbaugh and Hannity listeners? The scientists who actually study this topic and understand it? Or the fearless live pigeon shooter and fossil fuel spokesmen from hell, Jim Inhofe? Stay tuned….”

Why don’t we just take a look at how the various models — historical and modern — work when compared to the data?

As you can see, the predictions by prominent climate contrarians Lindzen, Easterbrook and Atasofu fail to match the observations spectacularly. Mainstream work has been getting it right since Wallack Broecker’s work in the 1970s, or — if you go back to the paper I wrote the article about — 1967.
The Harvard Diamond, created by a team led by Mikhail Lukin, has so many nitrogen impurities that it turned black. This is one of two independent physical systems used to create a time crystal. Image credit: Georg Kucsko.

The Harvard Diamond, created by a team led by Mikhail Lukin, has so many nitrogen impurities that it turned black. This is one of two independent physical systems used to create a time crystal. Image credit: Georg Kucsko.

From Wow on time crystals: “Yeah, never really accepted that time crystals were a thing. Just a result of a way of modelling time in a theory. A bit like when they talk about slowing down the speed of light. Doesn’t really, it just impedes the time taken for the energy to reach the destination.”

Well, they are a thing, but they’re a thing like a perpetual motion machine is a thing. In other words, if you drive something externally, you can achieve perpetual motion. There are cool ways you can “barely” drive it, and there may even be, in principle, ways you can drive it that don’t add any external energy, but simply rearrange the internal energy, that achieve it. But what we call a “time crystal” is in no way a crystallized version of time, nor is it, as Wilczek envisioned, possible in a system in thermal equilibrium.

For my money, I think that if Wilczek’s name weren’t on this, nobody would’ve cared much about it.

Image credit: Screenshot from Attack of the Clones, via http://ift.tt/UIbUQt.

Image credit: Screenshot from Attack of the Clones, via http://ift.tt/UIbUQt.

From Sinisa Lazarek on where the CMB is: “It’s all around you, it penetrates you and binds the galaxy together 😀 .. well… not so much the last part, maybe that’s why we don’t have Jedis”

411 CMB photons per cubic centimeter. At an age of 13.8 billion years, this is true everywhere in the Universe that isn’t shielded from CMB photons. (I.e., anywhere that isn’t in a location opaque to microwave/radio radiation.)

Image credit: Ned Wright's cosmology tutorial.

Image credit: Ned Wright’s cosmology tutorial.

And finally, from Paul Dekous on how we know the CMB is primordial: “If you photograph a pot of boiling water with a regular camera you get a clear image of that pot, just like we can take a sharp image of the stars. Now if you photograph that same pot with a heat-camera you get a very different image with flows. The question now is how do you know that the light is old and from one specific point in time, and not some heat/light flowing around from more recent times even now. How are the two distinguishable from each other?”

The above data is how, taken by COBE in the 1990s. (In black.) If there were a late-time emission that was shifted to lower energies, it wouldn’t have the same blackbody spectrum that the CMB is seen to exhibit. This detail — as I go into in depth in chapter 6 of my first book, Beyond The Galaxy — is something that no cosmological alternative can reproduce.

I am looking forward to better behavior from all of you, but particularly from Wow and John. There’s no reason for it (and that is not an invitation to tell me your reason), and I know you can choose to behave if you choose it. Choose it. And I’ll see you all back here tomorrow!



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