- Who Killed Schrodinger's Cat?
- Fine-Tuning BICEP Results
- "Ashes From an Exploding Star"
Or click to something else online, go for a walk, take a coffee break, whatever.
Getting a Grip About Truth
Basically, I don't think we have to choose between either believing that God conforms to Ussher's chronology or that religion is stupid. (September 21, 2014; July 15, 2014)
Since I'm a Catholic, I believe that God created, and is creating, everything. Since I also believe that God isn't a liar, and that truth cannot contradict truth: honest research cannot hurt faith. (Catechism of the Catholic Church, 144, 159)
Sometimes what we learn upsets just about everything we thought we knew about how the universe works. That's been happening a lot lately.
We may not live in the only space-time continuum. Some of what we're learning makes more sense if reality includes more than one "universe."
This isn't the sort of 'parallel universe' scenario in "Invasion from an Alternate Dimension!..." or "Prisoners of the Lost Universe." I've enjoyed stories like "In a Mirror, Darkly:" but reality is probably much stranger. (April 2, 2013)
This week's first item is about a branching multiverse, or many-worlds interpretation of quantum mechanics. It's one of the more pedestrian multiple-universe hypotheses, since each new branch is simply a continuation of its 'root.'
One of my favorites is the Mathematical universe hypothesis, or "Ultimate Ensemble," where every possible variation on reality actually exists.
I think scientists and mathematicians who found objections to Max Tegmark's hypothesis make good points. If nothing else, it'd probably be difficult or impossible to confirm that such an Ensemble exists.
On the other hand, I suspect that Tegmark may be right: or at least close to the truth. For example, physical "constants" like the speed of light in a vacuum and the elementary charge seem to be arbitrary. (April 2, 2013)
Theoretical physicists, cosmologists, and mathematicians have worked out internally-consistent continua more-or-less like the familiar three-dimensions-plus-time one we live in — with more or fewer physical dimensions, and different physical constants.
For us, universe-building is a strictly 'paper and pencil' exercise. We can't actually make another universe. God? Well: "...whatever God wills is done." (Psalms 115:3)
26 Centuries in 124 Words
Two dozen centuries back, Anaximander's wheel rims became celestial spheres. Both models agreed pretty well with what we can see of the universe.
The Pythagorean astronomical system was a little closer to how things really work. By the 1st century AD, most natural philosophers had agreed that Earth was a sphere.
The Copernican model wasn't exactly a new idea in the 1500s. I'll get back to Aristotle, God, and getting a grip in a bit.
Johannes Kepler's math provided Isaac Newton with a foundation for his theory of universal gravitation.
By the end of the 19th century, other scientists noticed that light from some "nebulae" resembled starlight.
A little less than a century ago, astronomers identified "nebulae" like the M81 as other "island universes." (September 19, 2014; July 15, 2014)
Unscrewing the Inscrutable
In physics, quantum mechanics describes how things act at an atomic a sub-atomic scale. Unlike the classical mechanics Newton described, quantum mechanics is anything but intuitive.
We're used to seeing and touching things that seem to be either energy or matter, waves or particles. For things big enough for us to see or touch, that's a pretty good model.
Scientists noticed that light acts like waves (1803) and particles (1877). Since then, we've learned that tiny bits of matter, like the parts of an atom, act like particles and waves.
Then there's the joke about the Quantum Motel: after staying there, you either loved or hated it. If you think that's funny — you may find stuff under Background at the end of this post interesting. Or not.
Quantum mechanics involves statements like "φ = h f0," and isn't something most folks need to know about. But if scientists hadn't been trying to unscrew the inscrutable of subatomic physics, we wouldn't have tech like transistors and Magnetic Resonance Imaging (MRI).
1. Who Killed Schrodinger's Cat?
(From Science Photo Library, via BBC News, used w/o permission.)
("Schrodinger's thought experiment was designed to illustrate problems with one interpretation of quantum physics"
"Brian Cox: 'Multiverse' makes sense"By now, a music group may have called themselves the Quantum Mechanics: it sounds appropriate for techno. Or maybe not.
BBC News (September 23, 2014)
"The presenter and physicist Brian Cox says he supports the idea that many universes can exist at the same time.
"The idea may sound far-fetched but the 'many worlds' concept is the subject of serious debate among physicists.
"It is a particular interpretation of quantum mechanics - which describes the often counter-intuitive behaviour of energy and matter at small scales....
"...In a famous thought experiment devised by the Austrian physicist Erwin Schrodinger, a cat sealed inside a box can be both alive and dead at the same time. Or any combination of different probabilities of being both dead and alive.
"This is at odds with most common perceptions of the way the world is. And Schrodinger's experiment was designed to illustrate the problems presented by one version of quantum mechanics known as the Copenhagen interpretation.
"This proposes that when we observe a system, we force it to make a choice. So, for example, when you open the box with Schrodinger's cat inside, it emerges dead or alive, not both...."
Turns out, Quantum Mechanix is "a Los Angeles-based creative studio and developer of screen-accurate replicas, collectibles, apparel, artwork, and digital apps and games inspired by entertainment's most beloved shows and movies."
That's what their website says, anyway. They're working on a Firefly-based online role playing game, that's quite enough name-dropping for one post, and that's another topic. Topics.
An Infinitely Branching Universe?
(From Christian Schirm, via Wikimedia Commons, used w/o permission.)
("The quantum-mechanical 'Schrödinger's cat' paradox according to the many-worlds interpretation. In this interpretation, every event is a branch point; the cat is both alive and dead, even before the box is opened, but the 'alive' and 'dead' cats are in different branches of the universe, both of which are equally real, but which do not interact with each other."
(Bryce Seligman DeWitt, via Wikipedia))
"....'That there's an infinite number of universes sounds more complicated than there being one,' Prof Cox told the programme. [The Life Scientific, BBC Radio 4 (September 23, 2014)]In a way, it doesn't matter if there are an infinite number of universes — with a new one branching each time a subatomic particle anywhere changes its state: or doesn't.
" 'But actually, it's a simpler version of quantum mechanics. It's quantum mechanics without wave function collapse... the idea that by observing something you force a system to make a choice.'
"Accepting the many worlds interpretation of quantum mechanics means also having to accept that things can exist in several states a the same time.
"But this leads to a another question: Why do we perceive only one world, not many?
"A single digital photograph can be made from many different images superimposed on one another. Perhaps the single reality that we perceive is also multi-layered...."
The only one that matters to me is the one I'm in "now," since what happens in other branches can't affect the one I'm in.
That's assuming that the branching, or many-worlds interpretation, of quantum mechanics is accurate.
A century or so from now, scientists may have learned that the many worlds interpretation is an elegant, plausible, and basically correct, model of how reality works. Or they may have learned that it's as accurate as the phogiston theory of combustion.
I'd be more than a little surprised if we had all the answers about quantum mechanics today: particularly since it's been little more than a century since scientists confirmed that atoms and molecules exist. (Brownian motion, Wikipedia)
Predictably, the new ideas in quantum mechanics have upset quite a few folks.
Quantum Gears and Philosophical Implications
Under "Philosophical implications," the Wikipedia page about quantum mechanics says that "...the many counter-intuitive aspects and results of quantum mechanics have provoked strong philosophical debates...."
One of the big problems many folks, including scientists, had with quantum mechanics was probability.
When the basics of quantum mechanics started hitting the fan, Newtonian physics was about two centuries old.
Scientists had gotten used to the idea that the universe operated according to physical laws which, in principle, would allow someone to predict exactly what would happen next. The clockwork universe idea is, in its own way, comforting. But that doesn't mean that it's real. (June 8, 2009)
Oddly enough, quantum gears are real, or could be.
2. Fine-Tuning BICEP Results
(From NSF, via BBC News, used w/o permission.)
("BICEP's South Pole telescope targeted what the team hoped was a relatively clean part of the sky"
"Cosmic inflation: BICEP 'underestimated' dust problem"We're pretty sure that this universe started very abruptly, some 13,798,000,000 years ago, give or take 37,000,000. (September 21, 2014)
Jonathan Amos, BBC News (September 22, 2014)
"One of the biggest scientific claims of the year has received another set-back.
"In March, the US BICEP team said it had found a pattern on the sky left by the rapid expansion of space just fractions of a second after the Big Bang.
"The astonishing assertion was countered quickly by others who thought the group may have underestimated the confounding effects of dust in our own galaxy.
"That explanation has now been boosted by a new analysis from the European Space Agency's (Esa) Planck satellite.
"In a paper published on the arXiv pre-print server, Planck's researchers find that the part of the sky being observed by the BICEP team contained significantly more dust than it had assumed.
"This new information does not mean the original claim is now dead. Not immediately, anyway...."
Cosmic inflation apparently happened early in the first picosecond, after the strong force and electronuclear force separated, and before quarks and anti-quarks formed.
What scientists are learning about the first moments of this universe are similar, in a poetic sense, to God's actions in Genesis 1:3.
Since I'm a Christian, and a Catholic, I think folks who wrote medieval bestiaries had a point. God created, and is creating, everything: and this creation makes sense. (June 9, 2012)
But I don't assume that each creature has one particular symbolic meaning, apart from the sort of qualities we use for metaphors: 'dog-like loyalty,' for example. And that's yet another topic.
Where was I? Cosmic inflation, picoseconds, quarks. Right.
About a hundred years back, an astronomer noticed that some "nebulae" were moving away from us: fast. About a decade later, most astronomers agreed that spiral nebulae were "island universes:" vast groups of stars, like our Milky Way.
We call them "galaxies" now, they come in clusters, and the other clusters are all moving away from Earth.
That would make sense, if Aristotle was right about Earth being in the middle of everything.
But — the Ancient Greek's fan base notwithstanding — Aristotle wasn't right about everything. The Catholic Church told scholars remember that God's God and Aristotle's not in 1277. (February 23, 2014)
Using mathematical tools like the FLRW metric and Friedmann equations, scientists learned that this universe is expanding.
Once they figured out how fast its expanding, they could work back to when it started, more than 13 billion years ago.
Galaxies, Quantum Entanglement, and the White-Juday Warp Field Generator
That raised more questions. Lots more questions. For one thing, places that haven't been near each other for billions of years are all at pretty much the same (average) temperature.
That shouldn't be possible, since information, heat, energy, or anything else can't travel faster than light. Well, almost anything. Maybe.
Quantum field entanglement may be a naturally-occurring example of information traveling faster than light. (May 3, 2013; January 17, 2014)
Artificial faster-than-light effects apparently don't take nearly as much energy as the original Alcubierre equations said.
The last I heard, NASA still had funding for the White-Juday warp field generator. It's strictly a lab test.
Best-case warp field strength with today's tech would be barely measurable. Decades, or maybe centuries from now — that's still another topic. (May 24, 2013; May 17, 2013)
Phlogiston and Picoseconds
Cosmic inflation is a pretty good way of explaining why the universe has the same temperature and other physical properties all over.
But phlogiston was a pretty good way of explaining combustion in 1667.
Around the 1780s, new tech and analysis showed that some metals gain mass when they burn: instead of getting lighter as the "phlogiston" escapes. Scientists who liked the phlogiston theory said that phlogiston must have negative mass, or at least was lighter than air.
By the end of that century, only a few chemists still used the term "phlogiston." Joseph Priestley, the inventor of soda water, was one of the phlogiston diehards. He also tried to combine theism, materialism, and determinism: with — ah — interesting results. Despite the name, by the way, he wasn't Catholic. At all.
The point is that cosmic inflation may be a pretty good description for what happened in the first picosecond of this universe.
Or, like phlogiston, new facts may show that cosmic inflation was a good idea that didn't reflect reality. (January 17, 2014)
Either way, I'm quite sure that there's a great deal more to learn about this universe.
Excitement, Thought, and Pulsars
(From Planck Collaboration, via BBC News, used w/o permission.)
("Planck's Northern (L) and Southern (R) sky projections. Note the parts of the sky that are clearer of dust (dark blue). The black box in the Southern projection is where BICEP looked"
"...The BICEP and Planck groups are currently working on a joint assessment of the implications, and this will probably be released towards the end of the year.I think the key phrase here is "had ... downgraded confidence in its own result...."
"However, if the contention is eventually shown to be unsupportable with the available data, it will prove to be a major disappointment, especially after all the initial excitement and talk of Nobel Prizes.
"What BICEP (also known as BICEP2) claimed to have done was find the long-sought evidence for 'cosmic inflation'....
"...'It's possible, but the error in our measurement is quite high,' Planck scientist Dr Cécile Renault told BBC News.
" 'The conclusion really is that we need to analyse the data together - BICEP and Planck - to get the right cosmological [versus] galactic signal. It's really too early to say.'
"The American group had already downgraded confidence in its own result when it finally published a paper on the inflation claim in Physical Review Letters in June...."
(Jonathan Amos, BBC News)
Scientists are human, and get excited like anyone else. Since they're scientists, though, they generally think before jumping to conclusions. The discovery of pulsars is a pretty good example:
"...When observations with another telescope confirmed the emission, it eliminated any sort of instrumental effects. At this point, Burnell notes of herself and Hewish that 'we did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem—if one thinks one may have detected life elsewhere in the universe, how does one announce the results responsibly?'..."The first pulsar pulsed at 1.33-second intervals: so thinking that it might be an artificial signal made sense. At the time, in 1967, the only naturally-occurring objects to produce that much energy were stars: and all stars were quite simply too big to pulse that fast.
When scientists found another pulsar, in another part of the sky, the odds that pulsars were natural phenomena went up. On the other hand, the second pulsar's period was different. Then more pulsars turned up, all over the part of the galaxy we can see: each pulsing at a different rate.
Eventually, scientists found that pulsars are rapidly-spinning neutron stars. But before they collected enough data to show that the things act like natural phenomena — I think there was a niggling suspicion that we might be looking at navigation beacons set up by a galaxy-spanning civilization.
Spinning Dust Grains
Getting back to the BICEP findings and downgraded results, it looks like the problem is dust.
The BICEP team knew that there's dust in interstellar space: but they hadn't taken what happens when those dust grains spin.
"...The main source of this inconvenient 'noise' is spinning dust grains.That "directional quality" is polarization. Knowing how polarization works gave us polarized sunglasses and liquid-crystal displays (LCDs). Not taking polarization fully into account in their pre-publication analysis means - - - I'll get to that next.
"These countless particles become trapped and aligned in the magnetic fields that thread through our galaxy.
"As a consequence, these grains also emit their light with a directional quality, and this is capable of swamping any primordial background signal...."
(Jonathan Amos, BBC News)
3. "Ashes From an Exploding Star"
(From New Scientist, used w/o permission.)
("This plot shows the patch of the sky that BICEP2 observed (multicolored patch) and the giant loops detected by radio telescopes (blue lines)."
"Star dust casts doubt on recent big bang wave result"This article showed up about a month after the first public announcement of the BICEP data that I saw. The "ashes from an exploding star" is the polarized dust discussed in the BBC article. It's a rather poetic — and accurate — way of telling where the dust comes from.
Maggie McKee, New Scientist (April 15, 2014)
"An imprint left on ancient cosmic light that was attributed to ripples in spacetime – and hailed by some as the discovery of the century – may have been caused by ashes from an exploding star.
"In the most extreme scenario, the finding could suggest that what looked like a groundbreaking result was only a false alarm. Another possibility is that the stellar ashes could help bring the result in line with other cosmic observations. We should know which it is later this year, when researchers report new results from the European Space Agency's Planck satellite.
"On 17 March, researchers led by John Kovac of Harvard University announced that gravitational waves from the early universe had been found by a telescope called BICEP2 at the South Pole.
"The waves were said to be the 'smoking gun' evidence for the theory of inflation, which suggests that space expanded faster than the speed of light in the first moments after the universe's birth. The announcement sent shock waves through the physics world. 'I was so excited,' recalls Philipp Mertsch of Stanford University in California.
Later on in the New Scientist article, Maggie McKee describes what the BICEP 2 team did to minimize effects of interstellar dust. They pointed their telescope well away from the Milky Way's plane: so it was looking part of the sky that's well away from the local galactic 'horizon.'
The BICEP 2 folks also took dust that they knew was there into account. What Stanford's Philipp Mertsch says they didn't do was look for, and avoid, dust shells from supernova remnants.
Magnetic field lines passing through these shells should, he said, get compressed and lined up: which would affect dust particles containing iron.
The University of Copenhagen in Denmark's Hao Liu led a team, including Mertsch, that plotted positions of several nearby supernova remnant shells. One of them goes through the middle of the BICEP 2 field of view.
I'm a bit disappointed that the BICEP 2 data isn't as conclusive as it seemed at first: but not terribly surprised.
For one thing, the BICEP team knew about interstellar dust, but hadn't been focusing their attention on supernova remnants. Hao Liu's team apparently had: and they had to analyze their data to confirm that one of the shells ran though BICEP 2's field of view.
For another — things take time.
Gravitational Waves: 98 Years and Counting
We've known that gravitational waves should exist since 1916. Less than a century later, we've got indirect evidence that they exist: and more theoretical reasons for thinking that they do.
As a Wikipedia page said, "gravitational waves are not easily detectable."
I think that's a masterful understatement. The big problem is massive background noise in the low frequencies scientists predict for the phenomenon.
My guess is that using today's equipment, detecting gravitational waves is a bit like detecting someone's whisper over a jet engine's noise — using an old Hughes carbon microphone. It's not impossible: but will involve analyzing available data with great care — and, most likely, a very powerful computer.
Luminiferous Aether — or — There's More to Learn
I think it's noteworthy that nobody in the last almost-a-century has come up with either evidence that gravitational waves don't exist: or good theoretical reasons for thinking that they shouldn't.
The absence of evidence isn't evidence of absence. Not definitely, anyway.
Besides, this sort of research takes time.
For example, Isaac Newton suggested a particle theory of light in 1704, but suggested that an "Aethereal Medium" accounted for diffraction. Augustin Fresnel's wave theory of light (1818) treated light as a transverse wave traveling in an aether. The Michelson—Morley experiment's failure to detect "ether wind" in 1887, 1902 to 1905, and the 1920s, was the first strong evidence that luminiferous aether doesn't exist.
Then, in the 20th century, scientists learned that at very small scales, matter and energy acts like particles and waves: and started working the bugs out of quantum mechanics.
As I've said before, "my guess is that we have a great deal more to learn about our universe: and maybe others." (March 21, 2014)
- "Scientific Discoveries: an Invitation to 'Even Greater Admiration' "
(September 21, 2014)
- "Science, Faith, and Leaving the 19th Century Behind"
(July 15, 2014)
- "Jadeite from Space; a Moon of Mars; and Kepler's New Mission"
(May 30, 2014)
- "Gravity Waves: Finding Ripples From the Big Bang"
(March 21, 2014)
- "Science, Faith, and Albertus Magnus"
(February 23, 2014)
- Andromeda galaxy
- Chronology of the universe
- Horizon problem
- Inflation (cosmology)
- Introduction to quantum mechanics
- Metric expansion of space
- Observable Universe
- "Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes"
Planck Collaboration: R. Adam, P. A. R. Ade, N. Aghanim, M. Arnaud, J. Aumont, C. Baccigalupi, A. J. Banday, R. B. Barreiro, J. G. Bartlett, N. Bartolo, E. Battaner, K. Benabed, A. Benoit-Lévy, J.-P. Bernard, M. Bersanelli, P. Bielewicz, A. Bonaldi, L. Bonavera, J. R. Bond, J. Borrill, F. R. Bouchet, F. Boulanger, A. Bracco, M. Bucher, C. Burigana, R. C. Butler, E. Calabrese, J.-F. Cardoso, A. Catalano, A. Challinor, A. Chamballu, R.-R. Chary, H. C. Chiang, P. R. Christensen, D. L. Clements, S. Colombi, L. P. L. Colombo, C. Combet, F. Couchot, A. Coulais, A. Curto, F. Cuttaia, L. Danese, R. D. Davies, R. J. Davis, P. de Bernardis, G. de Zotti, J. Delabrouille, J.-M. Delouis, F.-X. Désert, C. Dickinson, J. M. Diego, K. Dolag, H. Dole, S. Donzelli, O. Doré, M. Douspis, A. Ducout, et al. (171 additional authors not shown) (September 22, 2014)
- BICEP2 2014 Release Papers
- "BICEP2 2014 I: Detection of B-mode Polarization at Degree Angular Scales by BICEP2"
The BICEP2 Collaboration, Phys. Rev. Lett. 112, 241101, 2014 (June 20, 2014)
- "BICEP2 2014 II: Experiment and Three-year Data Set"
The BICEP2 Collaboration, 2014 (June 20, 2014)
- "BICEP2 2014 I: Detection of B-mode Polarization at Degree Angular Scales by BICEP2"
- "Fingerprints of Galactic Loop I on the Cosmic Microwave Background"
Hao Liu, Philipp Mertsch, Subir Sarkar; abstract; Cosmology and Nongalactic Astrophysics, Cornell University Library (April 7, 2014; last revision July 29, 2014))
Post a Comment