Climate change – debating the rattlesnake’s rattle

My aim with this Basic Questions blog is to encourage people to think “scientifically” and to ask the “right” questions. If you don’t ask the “right questions” then you can’t hope to come up with meaningful, dependable answers.

This applies to all walks of life. There are some issues such as the debate on AGW (anthropogenic global warming) where confusion and misinformation abounds, as highlighted for example by a recent post of mine A little bit of Carbon Dioxide? (the claim that only 3.4% of carbon dioxide, which is only 3.62% of greenhouse gases,  is caused by human activity).

Let’s look at another claim by Burt Rutan (referring again to his PDF and this PowerPoint presentations). At slide 16 of the latter, he talks about dishonest presentation of information, such as the now famous (or perhaps infamous) “hockey stick” claims about global warming:

And at slide 16 he decries what he says is “data manipulation” – the apparent sleight-of-hand in doing away with the medieval warm period -- by the United Nation’s intergovernmental panel on climate change (IPCC):

And so on. There are so very many presentations available that you are likely to lose your way in the overabundance of pretty charts and different data “interpretations” or whatever you want to call them.

Apart from Rutan’s, and as just one other example, try battling your way through some of the presentations by The Global Carbon Project (GCP) such as The Carbon Budget 2007+ presented at CLIMATE CHANGE - Global Risks, Challenges & Decisions (Copenhagen, 10-12 March 2009).

UPDATE: Bill McKibben of 350.org says in Dissecting the sceptics (2) that "Very few people really want to change in any meaningful way, and given half a chance to think they don’t need to, they’ll take it" and “at bottom, that’s a battle as much about courage and hope as about data.”

Who’s “right” and who’s “wrong” about all this complicated stuff, if it can be put so simplistically? There’s dissension among even the climate science specialists, so how can non-specialists make sense of it all and come to logical conclusions about what can be done (if anything) to modify the climate changes?

There’s little doubt that there has been some warming during the last several decades, but my question this time is:

How significant is the present global warming trend in the very-long-term picture of global climate change?

What I’m getting at here is, if we try to estimate what has happened to the climate going back not just a few hundred years (such as the medieval period), but many thousands and even many millions of years, then what picture emerges (and how reliable is it)? It has been a lot hotter at times long ago (such as when there were green forests in what we now call Antarctica), as well as much colder during various ices ages.

Are the current temperature fluctuations, in comparison with with the totality of changes over the eons, like just the rattle on the rattlesnake’s tail?

Imagine that the snake represents climate changes
going way back in time, and we’re positioned
at the very tip of the rattle

Are we focussing too much on the rattle, warning sign though it is, rather than on the picture that emerges if we stand right back and look over the entire rattlesnake?

Is the tiny part of the historical global temperature graph just a “pimple on a pumpkin” and nothing more than a tiny squiggle at the very end of a curve that has had many ups and downs, some of them perhaps much larger than current variations?

I’m not sure, are you? What can and should we do, if anything, to avoid the rattlesnake’s bite?

Technorati Tags: Global Climate,AGW,Misinformation,Data Interpretation,Misrepresentation

The universe is 20 million years older than previously thought

Thanks to my friend William Atkins for pointing out at iTWire that astrophysicists from Princeton and Johns Hopkins universities have determined the age of the universe more precisely, and it turns out to be a “little” older than previously thought.

The scientists have analyzed data from WMAP, NASA’s Wilkinson Microwave Anisotropy Probe, and have come up with an additional 20 million years.

WMAP definitively determined the age of the universe to be 13.73 billion years old to within 1% (0.12 billion years) -as recognized in the Guinness Book of World Records! So a mere 20 million years can be considered just a tiny amendment of the universe’s age!

This Basic Questions blog has a number of earlier posts about such cosmological matters. If you’re at all interested in cosmology, the WMAP site should definitely be on your must-see list. Since 2000, they say, the three most highly cited papers in all of physics and astronomy are WMAP scientific papers.

Timeline of the Universe

Technorati Tags: Cosmology,Age of Universe,NASA,WMAP

Noxious chemical alert – global environmental threat!

It may not be widely realized, but this chemical substance is in heavy use and can be measured in very significant concentrations in our rivers and lakes.

It is also present in all sorts of commercial products including pesticides, is found inside most nuclear reactors, and is used in many other situations which would give any right-minded environmentalist reason to worry.

Please, please, please watch this video and become aware of the global threat to our rivers, oceans and atmosphere.

Show your understanding and support by commenting below. Even Albert Einstein (pictured below?) might sign a petition to ban it. Would you?

Do you see what I mean? Don’t be fooled, stand back and consider it carefully.

As a one-time chemistry teacher -- and putting aside any false modesty due to the serious nature of the environmental threat -– trust me, I’m an expert having considerable knowledge about this pervasive substance.

Technorati Tags: Contamination,Pollution,Global threat,Environment,Dihydrogen Monoxide,Gullibility

A little bit of Carbon Dioxide?

I;ve been following a lot of blogs, web sites, popular press stories and other sources of information concerning climate change, global warming and cooling, supposed causes and effects, and am appalled by the enormous proportion of them that involve non-scientific thought.

Here’s today’s basic question.

Is engineer Burt Rutan exhibiting correct (realistic, logical) thinking and analysis when he applies his analytical skills outside his field of aeronautics and plunges into the battlefield of debate about anthropogenic global warming (AGW)?

Take a look at his reasons for studying AGW, and some of the conclusions he has reached, in this PDF and this PowerPoint presentation.

Here’s a tiny taste of his writings on this topic. With slide 8 of the PowerPoint set he casts serious doubt about the effectiveness of any attempt to curb human-caused CO2 emissions on global warming:

His notes for slide 8 say:

Introducing the AGW scare requires only a look at Greenhouse Gasses. The big block of 100 squares represents all the greenhouse gasses which are dominated by water vapor. The Yellow is CO2 that comes from natural sources (other than Man). The little Red block is CO2 from Human emissions. Stare at this chart while you ask yourself; Why would the economies of the US and the world be threatened by this much of the greenhouse gas, even if the greenhouse were the only driver of planet warming?? It is not, and we will later see what actually controls the planet temperature. There is an enormous push now to reduce the red block by a few % by 2020 - a difficult, expensive goal that will have a nil effect on planet temperature.

The fact that this is so clear reveals that those pushing the hardest and those controlling the funds for research worry little and care little about warming or flooding. If they did, they would not grossly emit carbon and buy homes at Sea Level in West Palm Beach, Florida.

There’s a lot else to ponder in this presentation. For example, in slides 24 and 25 he looks into atmospheric temperature variations over the last 410,000 years (as indicated by Vostok ice cores), and says:

“Is hot or cold bad?? The Alarmist warns that a third of Florida could again be flooded like it was many years ago. However, most of North America and Europe have had a mile-thick ice sheet, most of the time.

Therefore, if you have a of crisis, is it the rescue of those in Disney World or the need for everyone move to Panama/Sahara to keep from freezing?

… The planet preference is the ice age, where the fossil record shows extinction preference”

So my question is, what would you prefer? Examine Rutan’s entire presentation and let me know what you think!

Technorati Tags: Climate Change,Global Warming,AGW

Proof of global warming ... Means exactly what?

This blog is all about aking basic questions and attempting to answer them "scientifically" which is to say that it stands for logical, clear thinking, of which there is a dearth.

I wrote a post several years ago about the science of climate forcing, and since then the topic of climate change has come to the boil. I'd say that my position in the great climate debate is that of an agnostic, a fence-sitter if you like.

Here's a basic question for you to comment on here, but please note that it  must be answered in a cool and scientific fashion -- or else I might exercise my prerogative (as owner of this blog) and delete your posts, since I intensely dislike abusiveness, sloppy thinking, misquoting, and all such negativism.

THE BASIC QUESTION IS ...
Regarding GCC (global climate change) or if you like AGW (anthropogenic global warming), and NOT being concerned with localized weather changes -- and apart from any disagreements about whether the climate actually is warming or cooling, but supposing that it IS warming:

Does proof of global warming amount to proof of man made warming? Is it being unscientific and illogical to claim that it does?

There are some subsidiary basic questions, too, such as: Is it all too big for us to stop, anyway? Doubtless your answers will bring up matters like this!

Cogitating carbon cycle conundrums

I haven’t posted much in this blog for a while, but that’s not to say that I haven’t been pondering lots of different things: cosmology, basic physics, chemistry (my career before getting into information technology forty years ago), evolution, and more.

There has been a lot of controversy for the last decade about climate change, and I’ve written a few posts on this topic. The just-concluded massive United Nations Climate Change Conference in Copenhagen (COP15) may, or may not, lead to significant outcomes, depending on how various countries act (especially those with large populations).

Opinions differ widely about what is happening to the climate – from the doomsayers to the sceptics – and my own position is somewhat ambivalent.

Down here in Australia, with its relatively small population (not too much over 20 million), whatever we do won’t have much effect on the world’s climate. We produce  heavy carbon dioxide outputs per capita, but this amounts only to a tiny fraction of the overall global CO₂ output.

Some of us fear that federal climate change legislation in the offing will lead to savage increases in the cost of electrical power and an uncompetitive economy. What’s a balanced position for us to adopt: go easy on the legislation and suffer the climate consequences (causing only a small part of the global effect), or aim for high CO₂ reductions that will cost us the proverbial arm and leg?

In this blog about “basic questions” one of the key discussion points should be about the science of climate change, rather than the politics and the economics.

So I’m still reading as much as I can find time for about anything and everything related to climate change. One very pertinent article that I’ve stumbled upon just recently is Carbon cycle conundrums in which David Schimel asks “What will control future rates of climate change?”

The carbon cycle is the largest contributor to anthropogenic climate change, yet despite decades of research significant mysteries about its behavior remain. Global analyses show that the Earth system absorbs approximately half of anthropogenic fossil fuel emissions. This uptake is partitioned between absorption by the oceans and storage in terrestrial ecosystems. Uptake by the Earth system reduces the climate effects of emitted CO2 to approximately half of what would occur without sinks. …

The reduction over time of the efficiency of the sinks is of great concern because it implies a weakening in the ability of the Earth system to mitigate the effects of fossil fuel emissions and a potential positive feedback that may strengthen in the future.

And later, under Key Questions:

Although we have learned a great deal about the carbon cycle, the scientific community is still limited in its ability to make confident predictions about the likely response of the carbon cycle to global environmental change. … Getting global phenomena right, like the observed change in the airborne fraction, is critical for testing models. Purely local or process-level validation is not enough because of the great variety of local responses.

And there’s more, please read it yourself. But as one with some science training, I appreciate the honesty and transparency – far from universally acknowledged in the climate debate -- that there are unknowns and that further research is needed!

NASA Swift satellite sees furthest ever cosmic explosion

NASA reported on 23 April 2009 that their Swift satellite and a international team of astronomers detected a ten-second gamma-ray burst from a star that died when the universe was only 630 million years old, or less than five percent of its present age.

The event, dubbed GRB 090423, is the most distant cosmic explosion ever seen. 

In line with other posts in this blog about basic questions, this event sheds further light (no pun intended) on the age and size of the universe.

To quote: "Swift was designed to catch these very distant bursts," said Swift lead scientist Neil Gehrels at NASA's Goddard Space Flight Center in Greenbelt, Md. "The incredible distance to this burst exceeded our greatest expectations -- it was a true blast from the past."

"The burst most likely arose from the explosion of a massive star," said Derek Fox at Pennsylvania State University. "We're seeing the demise of a star -- and probably the birth of a black hole -- in one of the universe's earliest stellar generations."

Read the NASA article to view a short animation of a gamma-ray burst and find out more.

Technorati Tags: NASA,Cosmology,Astronomy,Age of the Universe,gamma-ray burst,black hole

How wide is the universe? (again)

I’ve just been checking out a YouTube flash video downloader, a free Windows desktop one from FLVsoft (Moyea Software) 

I tested it out on a couple of cosmology videos, and it worked very well, with a number of useful configuration options and a nice built-in Flash player. … Recommended!

I’ve tested a number of YouTube downloaders over the last year or two, and some of them are quirky or unreliable. Another recommended one is browser-based KickYouTube. This one couldn’t be simpler to use. There’s no installation required, you merely insert the word “kick” into the URL of the YouTube page immediately in front of the “youtube.com” part) and press the Enter key, select your desired output file format (such as FLV or MP4) and click the green Go button to initiate the download.

Anyway, in the spirit of this blog, here are the two videos that I used for testing the YouTube downloader:

YouTube - The Universe is 156 Billion Light Years Wide

 

Flying Through the Big Wide Universe

Technorati Tags: Universe,YouTube,FLVsoft,Flash video downloader,KickYouTube

Blogger Labels: Universe,YouTube,FLVsoft,Flash video downloader,KickYouTube

When does human life begin?

One of the most difficult and troubling basic questions of all for us is "When does life begin?"

This is an especially awkward question when it applies to human life. Rightly or wrongly, we consider our species more important than and dominant over others. See, for example, Aquinas, Animal Rights, And Christianity or Genesis 1 (verse 26) or Canadian Seal Hunt web site.

When it comes to human life, the question gets even tougher for us. It leads to intricate and sometimes fierce and vociferous debate, sometimes extended to physical attack or even murder. Imagine that: taking human life (by an anti-abortionist) when you're supposedly opposed to the very taking of human life. How irrational and contradictory we can be, how flawed!

I don't mull over such matters very often, preferring to spend my time on more pleasant matters. Strangely enough, I was led to this stream of painful thought when I took an unexpected detour while dallying in my comfort zone of technology and computing.

Perusing Wired Magazine's blog, I just came across McCain Equates Embryos and Fetuses in Stem Cell Statement (19 September 2008).

I encourage you to read the entire short article. A few brief extracts follow:

John McCain's recent statement on embryonic stem cell research was ambiguous in some ways, but clearly misleading in another: He equated human embryos with fetuses, and used language implying that farming fetuses for their tissues is a realistic possibility. ... Though the bill was unanimously approved in the House and Senate, its sponsors were criticized for failing to make clear that "fetal farming" doesn't exist.

Embryos used to produce embryonic stem cells are harvested after five days, when the embryo is still an undifferentiated blob of about 70 cells. While there is no sharp line for when an embryo becomes a fetus, nine weeks is a good rule of thumb; the industry standard for halting development on research embryos is two weeks. No reputable scientist has supported fetus experimentation. For McCain to revive the language of "fetal farming," say bioethicists, was misleading.

This was the first time that I've seen a specific number of cells specified, and a specific number of days or weeks of gestation. Why choose 70 cells rather than 80 or 100, and why is nine weeks a good rule of thumb?

Humanism aside, this is a complex minefield for bioethicists and legislators -- not to mention thise directly involved (medical practitioners, nurses, researchers, mothers, and so on). This is all very alien and uncomfortable for me, but I felt compelled to add such basic questions to this blog.

GORE LIED: Global average temperatures still down significantly since An Inconvenient Truth released

In an earlier post back in October 2008, About Asking the Right Questions, I pointed out work that had been published on the Greenhouse Effect (the issue of climate forcings, etc).

Asking the wrong questions, or avoiding asking the right questions, is famously with us in the form of Al Gore's moneymaking odyssey to spout his ideas about "inconvenient truths" -- or at least, his perception of what are truths.

Doubtless, some of Gore's perceptions are accurate, or at least reasonably so. But is he manipulating things to suit his preconceived notions of what is "the truth"?

Some people seem to think so, so it's not just me ... GORE LIED: Global average temperatures still down significantly since An Inconvenient Truth released

(Click to view a larger image)

The descending "Gore extrapolation line" on this chart indeed makes an interesting comparison with the methodologies discussed in the climate forcings charts (referenced in that earlier posting of mine).

A baker's dozen of unanswered questions

This blog is about asking questions. ... We don't even know all the correct questions to ask, much less the answers.

New Scientist has put together an intriguing list of 13 things that do not make sense that bring home this point:

• The placebo effect
• The horizon problem
• Ultra-energetic cosmic rays
• Belfast homeopathy results
• Dark matter
• Viking's methane
• Tetraneutrons
• The Pioneer anomaly
• Dark energy
• The Kuiper cliff
• The Wow signal
• Not-so-constant constants
• Cold fusion

I'm confident that when (or if) we ever find the answers to these questions, there will be another 13 questions to take their place! Life's interesting, isn't it.

Questions without end -- Science, Religion, God

Fellow iTWire blogger William Atkins has just posted an article Science, Religion, God: Discussions by thinkers that's kicked my grey matter (what's left of it) into overdrive again.

Amongst other things, William mentions the John Templeton Foundation website, which was new to me, and refers to A Templeton Conversation which is the most recent (the third) in a series of conversations among leading scientists and scholars about the "Big Questions" ... Does science make belief in God obsolete?

The foundation's website has a Big Questions Archive which surely is very apposite to the "Basic Questions" theme of this blog!

The other two series so far are Will money solve Africa's development problems? and Does the universe have a purpose?

The contributors' responses are downloadable as PDF files, if you want to browse the responses offline.

Universe is 13.73 Billion Years Old

The latest on the "age of the universe" thread of this blog is news from NASA that it's been estimated to be 13.73 billion years old, see WMAP Reveals Neutrinos, End of Dark Ages, First Second of Universe

"NASA released this week five years of data collected by the Wilkinson Microwave Anisotropy Probe (WMAP) that refines our understanding of the universe and its development. ... WMAP measures a remnant of the early universe - its oldest light. The conditions of the early times are imprinted on this light. It is the result of what happened earlier, and a backlight for the later development of the universe. This light lost energy as the universe expanded over 13.7 billion years, so WMAP now sees the light as microwaves. By making accurate measurements of microwave patterns, WMAP has answered many longstanding questions about the universe's age, composition and development.

Microwave light seen by WMAP from when the universe was only 380,000 years old, shows that, at the time, neutrinos made up 10% of the universe, atoms 12%, dark matter 63%, photons 15%, and dark energy was negligible. In contrast, estimates from WMAP data show the current universe consists of 4.6% percent atoms, 23% dark matter, 72% dark energy and less than 1 percent neutrinos.

WMAP cosmic microwave fluctuations over the full sky with 5-years of data. Colors [in the image] represent the tiny temperature fluctuations of the remnant glow from the infant universe: red regions are warmer and blue are cooler."

Scientific American tells all?

I've been reading articles from Scientific American for fifty years or more, and still enjoy it tremendously. While there are many other extremely worthwhile scientific journals, I'm a creature of habit and this one is good enough for me!

Relative to the "Basic Questions" theme of this blog, I would heartily recommend that you read various online Scientific American articles. The following two articles in particular are very cogent summaries of several aspects of cosmology that I've mentioned in earlier posts, and they're well worth a read:

• Misconceptions about the Big Bang - Baffled by the expansion of the universe? You're not alone. Even astronomers frequently get it wrong. ... Expansion is a beguilingly simple idea, but what exactly does it mean to say the universe is expanding? What does it expand into? Is Earth expanding, too? To add to the befuddlement, the expansion of the universe now seems to be accelerating, a process with truly mind-stretching consequences. ... The universe does not seem to have an edge or a center or an outside, so how can it expand?
• The Universe's Invisible Hand - Dark energy does more than hurry along the expansion of the universe. It also has a stranglehold on the shape and spacing of galaxies. ... Scientists are just starting the long process of figuring out what dark energy is and what its implications are. One realization has already sunk in: although dark energy betrayed its existence through its effect on the universe as a whole, it may also shape the evolution of the universe's inhabitants--stars, galaxies, galaxy clusters. Astronomers may have been staring at its handiwork for decades without realizing it.

By the way, a subscription to the digital edition of Scientific American is only US $3.33 per month ($39.95 per year): they say "the latest Scientific American issue delivered online before it hits newsstands, access over 180 issues of scientific progress from 1993 to the present, and quickly locate, preview and download your selections ... Download to your computer for convenient offline reading ... in high-quality PDF format."

Big -- Mandelbrot Universe

Watch this fractal unfolding, and listen to it too. (It reminds me a bit of scenes near the end of 2001 A Space Odyssey.)

A Mandelbrot the size of the known universe

"An extremely deep dive into the Mandelbrot zoom. If the final frame were the size of your screen, the full set would be larger than the known universe."

There are more Mandelbrot/fractal animations on the same YouTube page. If you want to get a rigid mathematical explanation of Mandelbrot's accomplishments , be sure to listen to the following one as it unfolds:

Mandelbrot Set Zoom

Is the Universe Finite, or Not?

I've just come across a few interesting items in my quest to understand "life and the universe" and would like to share them with you:

• On A Finite Universe With No Beginning Or End (a PDF document) - by Peter Lynds of New Zealand, with the following abstract:
  
  

  "Based on the conjecture that rather than the second law of thermodynamics inevitably be breached as matter approaches a big crunch or a black hole singularity, the order of events should reverse, a model of the universe that resolves a number of longstanding problems and paradoxes in cosmology is presented. A universe that has no beginning (and no need for one), no ending, but yet is finite, is without singularities, precludes time travel, in which events are neither determined by initial or final conditions, and problems such as why the universe has a low entropy past, or conditions at the big bang appear to be so "special," require no causal explanation, is the result. This model also has some profound philosophical implications."

  If the above paper is too much for you, then from Science a Go Go there's a pair of articles that might make it more digestible: The Universe As Magic Roundabout: Part I plus The Universe As Magic Roundabout: Part II
  
  Here's an earlier paper by Peter Lynds (also a PDF document):
  Time and Classical and Quantum Mechanics: Indeterminacy vs. Discontinuity
  
  
• For another view, this time about multiple universes, there's Towards observable signatures of other bubble universes (another PDF document) with the following abstract:
  
  

  "We evaluate the possibility of observable effects arising from collisions between vacuum bubbles in a universe undergoing false-vacuum eternal inflation. Contrary to conventional wisdom, “typical” observers inside a bubble should have access to a large number of collision events. We calculate the expected number and angular size distribution of such collisions on an observer’s “sky”, finding that for typical observers the distribution is anisotropic and includes many bubbles, each of which will affect the majority of the observer’s sky. After a qualitative discussion of the physics involved in collisions between arbitrary bubbles, we evaluate the implications of our results, and outline possible observable effects. In an optimistic sense, then, the present paper constitutes a first step in an assessment of the effects of other bubble universes on the cosmic microwave background and other observables."

Light Speed (and Other Puzzling Data)

Doing a bit of Web searching discover more views and answers to some of my basic questions, I came across the following interesting presentations by by Barry Setterfield (over at YouTube):

• Light Speed and Other Puzzling Data - Part 1 of 6
• Light Speed and Other Puzzling Data - Part 2 of 6
• Light Speed and Other Puzzling Data - Part 3 of 6
• Light Speed and Other Puzzling Data - Part 4 of 6
• Light Speed and Other Puzzling Data - Part 5 of 6
• Light Speed and Other Puzzling Data - Part 6 of 6

How big is BIG?

This morning I was looking at the Web site of the Sloan Digital Sky Survey

Fascinating stuff! SDSS is systematically mapping the entire sky, determining the positions, brightnesses and distances of celestial objects, to give a three-dimensional picture of the universe through a volume one hundred times larger than that explored to date.

They are obviously asking some basic questions. And getting answers, too. one question that really tickles my fancy is described in the article How big is big? Probing the conditions of the universe on the largest scales

Back in May 2006 researchers at SDSS announced the first measurements of galactic structures more than a billion light years across. Now that's getting to be sizable, isn't it!

Dark energy - the pressure exerted by empty space!

I would never have thought it, and even after reading it cannot begin to properly understand or appreciate this:

... dark energy is the pressure exerted by empty space. From a quantum mechanical perspective, empty space is unstable. According to statistics, photons and subatomic particles pop into the vacuum of space in a way that shows that "empty" is only an approximation: Space actually comprises a statistical soup of particles and antiparticles that are in a constant state of creation. Today scientists can demonstrate this by pumping the gases out of any empty chamber. After every atom has been pumped out, particles begin to percolate into existence in a process called vacuum fluctuation. ...

... unless the vacuum itself exerts the negative pressure observed, then the universe must otherwise be composed of as much as 70 percent dark energy.

Read more in the following Dr Dobb's article: Quantum Mechanical Theory Behind 'Dark Energy'?

How Wide is the Universe? - revisited

Way back in November 2005 I asked How Wide is the Universe? and have been pondering it every now and again since then.

Reading Bill Bryson's tour de force "A Short History of Nearly Everything" gave me some additional insights (see the early chapters).

And a few days ago I came across this link at Yahoo! Canada and the following article at www.space.com which I found especially informative on this matter:

Universe Measured: We're 156 Billion Light-years Wide!
If you've ever wondered how big the universe is, you're not alone. Astronomers have long pondered this, too, and they've had a hard time figuring it out. Now an estimate has been made, and its a whopper. The universe is at least 156 billion light-years wide.

In particular, it neatly outlines one aspect that beforehand I simply couldn't get me head around: why, if the universe is some 13 or 14 billion years old, its diameter in light years can be numerically greater than this. And it turns out that the above figure -- converted, of course, into distance in Light Year units -- cannot simplistically be regarded as the radius which, by being doubled, would lead to a diameter of 27 or 28 billion light years. And the key to this is explained thus:

... the universe has been expanding ever since the beginning of time, when theorists believe it all sprang forth from an infinitely dense point in a Big Bang.

"All the distance covered by the light in the early universe gets increased by the expansion of the universe," explains Neil Cornish, an astrophysicist at Montana State University. "Think of it like compound interest."