I Tweeted the following inscrutable remark. Probably best left unexplained, but upon reflection I can’t resist.

My consciousness freely travels up and down my world line, but sadly it only carries the memories appropriate to the moment it inhabits.

The point is that (some) people don’t think about the flow of time in the right way, and this leads to a couple of unfortunate consequences: a difficulty in understanding the psychology of time, and a scattering of entertaining but illogical science-fiction scenarios.

Modern physics suggests that we can look at the entire history of the universe as a single four-dimensional thing. That includes our own personal path through it, which defines our world line. This seemingly conflicts with our intuitive idea that we exist at a moment, and move through time. Of course there is no real conflict — just two different ways of looking at the same thing. There is a four-dimensional universe that includes all of our world line, from birth to death, once and for all; and each moment along that world line defines an instantaneous person with the perception that they are growing older, advancing through time.

Given special relativity, by which events taking place at near-light speeds over nonzero spans of space can be described in multiple, contradictory, but equally correct sequences by various observers in different frames of reference, it might be a meaningless question to ask whether Han shot first.

Most of the set on Huron was obscured by a white screen for moderating light, and platform for equipment I’m not going to guess the function of. It’s the sausage making-machinery of movie magic.

A security officer told us gawkers that the real action was happening at the other side of the street, on Prospect. A small contingent of us then set down a freakishly and nonthreatening clean alleyway (way to be on your best behavior, Cleveland!), and past some catering trucks. I was afraid crew would look at me weird if I took pictures of their food trailers, so I didn’t.

But when we got around to Prospect, there was no one close enough to give us weird looks; onlookers were sequestered a couple hundred feet from the staged wreckage of a Times Square battle involving Captain America (Chris Evans) and a foe yet to be confirmed, but which everyone who knows The Avengers comics* assumes are the Skrulls.

Here is my Sasquatch hunter-caliber photo of two men in contemporary Army fatigues walking away from the wreckage site. I saw several more on the Huron side of the set earlier.

Here are a few vehicles on site with New York-y markings. Thoroughness!

Nothing was happening, and my meter was running out, so I headed back down the nonthreatening alley. It was occupied by some extras in FDNY firefighter and EMT costumes. Some hipsters were engaging them in conversation; my social anxiety and the specter of a Meter Valkyrie kept me from doing the same.

I hope to make it down to the set again before Whedon wraps the Cleveland leg of filming at the end of the month, and file another report. With good fortune, the next one will have a more exciting takeaway than the fact I WAS WITHIN ONE CITY BLOCK OF JOSS WHEDON. We probably breathed the same air at some point, and if I were a superstitious man, that would mean something. But I’m not (my own views on heroic object veneration are close to this essay), and it doesn’t.

*I am not such a person. The only title I ever read as a kid was The Amazing Spider Man. Granted, it took place in the Marvel universe continuity–the same occupied by the Avengers–but there was never a crossover in the few years (months?) I followed it.

A thin band of antimatter particles called antiprotons enveloping the Earth has been spotted for the first time.

The find, described in Astrophysical Journal Letters, confirms theoretical work that predicted the Earth’s magnetic field could trap antimatter. The team says a small number of antiprotons lie between the Van Allen belts of trapped “normal” matter. The researchers say there may be enough to implement a scheme using antimatter to fuel future spacecraft.

The antiprotons were spotted by the Pamela satellite (an acronym for Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) – launched in 2006 to study the nature of high-energy particles from the Sun and from beyond our Solar System – so-called cosmic rays.

These cosmic ray particles can slam into molecules that make up the Earth’s atmosphere, creating showers of particles. Many of the cosmic ray particles or these “daughter” particles they create are caught in the Van Allen belts, doughnut-shaped regions where the Earth’s magnetic field traps them. Among Pamela’s goals was to specifically look for small numbers of antimatter particles among the far more abundant normal matter particles such as protons and the nuclei of helium atoms.

The new analysis, described in an online preprint, shows that when Pamela passes through a region called the South Atlantic Anomaly, it sees thousands of times more antiprotons than are expected to come from normal particle decays, or from elsewhere in the cosmos. The team says that this is evidence that bands of antiprotons, analogous to the Van Allen belts, hold the antiprotons in place – at least until they encounter the normal matter of the atmosphere, when they “annihilate” in a flash of light.

 

Andre masson, "Antille 2," 1943

The strangest version of all parallel universe proposals is one that emerged gradually over 30 years of theoretical studies on the quantum properties of black holes. The work culminated in the last decade, and it suggests, remarkably, that all we experience is nothing but a holographic projection of processes taking place on some distant surface that surrounds us. You can pinch yourself, and what you feel will be real, but it mirrors a parallel process taking place in a different, distant reality.

Plato likened our view of the world to that of an ancient forebear watching shadows meander across a dimly lit cave wall. He imagined our perceptions to be but a faint inkling of a far richer reality that flickers beyond reach. Two millennia later, Plato’s cave may be more than a metaphor. To turn his suggestion on its head, reality—not its mere shadow—may take place on a distant boundary surface, while everything we witness in the three common spatial dimensions is a projection of that faraway unfolding. Reality, that is, may be akin to a hologram. Or, really, a holographic movie.

The journey to this peculiar possibility combines developments deep and far-flung—insights from general relativity; from research on black holes; from thermodynamics, quantum mechanics, and, most recently, string theory. The thread linking these diverse areas is the nature of information in a quantum universe.

Physicists Jacob Bekenstein and Stephen Hawking established that, for a black hole, the information storage capacity is determined not by the volume of its interior but by the area of its surface. But when the math says that a black hole’s store of information is measured by its surface area, does that merely reflect a numerical accounting, or does it mean that the black hole’s surface is where the information is actually stored? It’s a deep issue and has been pursued for decades by some of the most renowned physicists. The answer depends on whether you view the black hole from the outside or from the inside—and from the outside, there’s good reason to believe that information is indeed stored at the event horizon. This doesn’t merely highlight a peculiar feature of black holes. Black holes don’t just tell us about how black holes store information. 
Black holes inform us about information storage 
in any context.

Think of any region of space, such as the room in which you’re reading. Imagine that whatever happens in the region amounts to information processing—information regarding how things are right now is transformed by the laws of physics into information regarding how they will be in a second or a minute or an hour. Since the physical processes we witness, as well as those by which we’re governed, seemingly take place within the region, it’s natural to expect that the information those processes carry is also found within the region. But for black holes, we’ve found that the link between information and surface area goes beyond mere numerical accounting; there’s a concrete sense in which information is stored on their surfaces. Physicists Leonard Susskind and Gerard ’t Hooft stressed that the lesson should be general: Since the information required to describe physical phenomena within any given region of space can be fully encoded by data on a surface that surrounds the region, then there’s reason to think that the surface is where the fundamental physical processes actually happen. Our familiar three-dimensional reality, these bold thinkers suggest, would then be likened to a holographic projection of those distant two-dimensional 
physical processes.

If this line of reasoning is correct, then there are physical processes taking place on some distant surface that, much as a puppeteer pulls strings, are fully linked to the processes taking place in my fingers, arms, and brain as I type these words at my desk. Our experiences here and that distant reality there would form the most interlocked of parallel worlds. Phenomena in the two—I’ll call them Holographic Parallel Universes—would be so fully joined that their respective evolutions would be as connected as me and 
my shadow.

I can’t help but wonder what repercussions this theory would have on our discussions of causality, agency, and “free will” if it were proven plausible, let alone true.

It would be a victory for determinists, no doubt, but I can’t imagine what we would do with it. Most contemporary literature by determinists I’ve read has been less concerned with actually proving the reality of physical necessity (for example their failure to really sieze the Rietdijik-Putnam argument is especially striking) with demonstrating we do not have to abandon commonsense moral intuitions with the specious doctrines of libertarianism. But holographic cosmology would surely inspire some interesting papers. I don’t have a clear enough head right now to imagine what they would contain; but it could be a fun thought exercise for Sunday.

The most surprising aspect of the results is how basic the expressed needs were, and yet how profoundly unmet many of these needs went. Asked what would have helped them with their grief, the survey-takers talked again and again about acknowledgement of their grief. They wanted recognition of their loss and its uniqueness; they wanted help with practical matters; they wanted active emotional support. What they didn’t want was to be offered false comfort in the form of empty platitudes. Acknowledgement, love, a receptive ear, help with the cooking, company—these were the basic supports that mourning rituals once provided; even if we’ve never experienced a loss ourselves, we know from literature and history that people require them. Yet as American culture has become divorced from death and dying, we no longer know how to address the most rudimentary aspects of another’s loss—what to say, when to say it, how to say it. Disconcerted by discomfort, friends or colleagues are all too likely to disappear or turn the conversation to small talk in the aftermath of a loss, not knowing what to say. Our survey-takers reported wanting to grieve communally and yearning to find ways to relate to those around them.

They are not the only ones yearning. “What should I say to my friend?” more than one person has asked each of us, about talking to grievers. Everyone fears putting a foot in his mouth, because in a world without scripted rituals to guide us, there is no “right answer”: What comforts one person sometimes pains another. But what the survey reflected was that mourners want their loss to be recognized and reflected back at them.

And so mourners were sensitive to anything that seemed to minimize their grief. Platitudes offering false comfort were seen as unsupportive, and even hurtful. Saying the loved one was “in heaven” or that it was “a blessing” that they were “out of pain” was not helpful; nor was saying, “I know how you feel” or “It’s all for the best” or “Time heals all wounds” or “It was God’s Plan.” No one wanted to hear these things, especially right after someone they loved and cared about had died. Instead, one wrote, “It helped me when people acknowledged—even nonverbally/tacitly—that I was grieving. Their acknowledgment meant (to me) that they knew I wasn’t ‘normal’ and they weren’t going to hold me to my usual standard. It felt unhelpful/unsupportive when people expected me to act like everything was normal (or seemed to expect that), since I did not feel like myself and didn’t have the energy for the activities and conversations that were the norm before my mom died.”

Quantum physicists following Hugh Everett argued the jittery indeterminism and anti-realism of quantum mechanics was an illusion, and every possible wave function realized itself in some parallel plane. String theory posited our universe was a four-dimensional membrane or “brane” in an unfathomable stack of cosmic tissue. The inflationary cosmologies of  Guth, Vilenkin, and Linde predict the universe created in our Big Bang is merely one bubble in an inexhaustible foaming spacetime sea.

Now, none of the theories of a multiverse are interchangeable. All posit the existences of universes causally isolated from, but equally real from our own. But each theory posits their own universes exist in a different way from those predicted by other theories. Proving one right would not be a “proof” for another–but it would also not be a refutation of the other two. The theories attempt to describe different phenomena, so aren’t in competition. As they are not mutually exclusive, it is possible to believe in all three without contradicting oneself–though I would not recommend making this leap yet, because it is still something of a leap of faith. The mathematical descriptions of quantum mechanics, string theory, and inflation are all incomplete, and the latter two are still controversial in-of-themselves in their respective fields, regardless of their content on parallel worlds.

And, more importantly, there has been no unambiguous empirical evidence for the existence of any parallel universe, let alone an infinite quantity of them. Quantum physics and inflation have both made mathematical predictions which have been confirmed in observations. This has led some of their defenders to claim that because these theories maths have proved consistent with experiment, they should also vouch for their content which is beyond our current capacity to test. In short, they say because the theories apply to accessible parts of reality have proven true, they are likely true when they speak of the inaccessible parts, too. But this is not solid science. As the English biologist Thomas Henry Huxley said, “Many a beautiful theory was killed by an ugly fact.” Whether the facts compliment the beauty of our best and brightests’ equations has yet to be determined.

However, we may finally have the first solid fact (ugly or otherwise, depending on your commitment to human exceptionalism) to put one multiversal hypothesis to the test. A recent paper in Physical Reviews letter claims to have observed the “shadow” of four other universes created by inflation:

The idea that other universes – as well as our own – lie within “bubbles” of space and time has received a boost. Studies of the low-temperature glow left from the Big Bang suggest that several of these “bubble universes” may have left marks on our own. 

… The preliminary work, to be published in Physical Review D, will be firmed up using data from the Planck telescope. For now, the team has worked with seven years’ worth of data from the Wilkinson Microwave Anisotropy Probe, which measures in minute detail the cosmic microwave background (CMB) – the faint glow left from our Universe’s formation.

The theory that invokes these bubble universes – a theory formally called “eternal inflation” – holds that such universes are popping into and out of existence and colliding all the time, with the space between them rapidly expanding – meaning that they are forever out of reach of one another.

But Hiranya Peiris, a cosmologist at University College London, and her colleagues have now worked out that when these universes are created adjacent to our own, they may leave a characteristic pattern in the CMB.

Dr Peiris’ team first proposed these disc-shaped signatures in the CMB in a paper published in Physical Review Letters, and the new work fleshes out the idea, putting numbers to how many bubble universes we may be able to see now.

Crucially, they used a computer program that looked for these discs automatically – reducing the chance that one of the collaborators would see the expected shape in the data when it was not in fact there.

The program found four particular areas that look likely to be signatures of the bubble universes – where the bubbles were 10 times more likely than the standard theory to explain the variations that the team saw in the CMB.

However, Dr Peiris stressed that the four regions were “not at a high statistical significance” – that more data would be needed to be assured of the existence of the “multiverse”.

“Finding just four patches is not necessarily going to give you a good probability on the full sky,” she explained to BBC News. “That’s not statistically strong enough to either rule it out or to say that there is a collision.”

Dr Peiris said that data from the Planck telescope – a next-generation space telescope designed to study the CMB with far greater sensitivity – would put the idea on a firmer footing, or refute it. However, the data from Planck cannot be discussed publicly before January 2013.

So, things to stay alive through 2013 for: Cabin in the Woods, The Avengers,  and evidence for or against a multiverse.

Further reading suggestion:  Many Worlds in One, by Alex Vilenkin, father of eternal infation. A popular, accessible, and funny, but by no means breezy, exposition of the theory Peiris and her team are trying to prove.