During a recent visit to the Mokena Hotel, in the historic Waikato mining and spa town of Te Aroha, I was trying to record and communicate with an entity that reportedly lingers in room 113. The Maori lady is said to sometimes be seen sitting on or near the bed and gazing out the window, and there is a slight depression on the bed that resembles an imprint of a sitter, an imprint that it is said cannot be permanently smoothed away. The friendly hotel owner and staff informed me about other 'residents', and events in the hotel's past. I wasn't able to perceive or record any of them on my first visit but I hope to try again in future.

So, what is a 'residual haunting'? The word residual obviously comes from residue - a small amount of something that remains after the main part has gone. In regard to haunting, this means that something of a person remains in a place after they're gone. It can also apply to multiple people, animals and objects.

Residual hauntings have been downplayed in books on paranormal investigation and ghost hunting as something rather insignificant that we shouldn't be too concerned with; mere distractions from the quest for a full body apparition or real-time communication with an intelligent entity. OK, I exaggerate, but there is nothing trivial about the concept of residual haunting. If I had strong documentary proof of such a thing - hard, science-grade evidence to back a theory - I wouldn't be writing about it here. I'd be submitting a paper to Nature or some other major science journal and quietly hoping for a Nobel Prize!

There are many published reports of residual hauntings, worldwide and in New Zealand. Their believability comes down to how reliable, and independent, the witnesses are, and things like the quality of interviewing, the credibility of the writer and publisher, or if they have some agenda. What is lacking, overall, is hard evidence that will withstand scientific scrutiny. So far we are reliant on testimony.

A thing I hear or read often is that the ghost in a residual haunting is locked into a loop, endlessly repeating the same pattern or chain of events. Well, that may be so in some reported cases; but is not our daily life fairly routine? We usually eat, sleep, watch TV or sit at a computer at about the same time and place on any given day, work at the same place, etc. If someone from another time was somehow observing our activity they might easily think they're seeing some poor soul doomed to repeating a chain of events for eternity. We living humans are creatures of habit as much as any ghost.

On the other hand, I have interviewed people who have experienced time slips - where they've walked into a room or to an outdoor location and seen events and people as they were in that place decades earlier, and without the people from the past apparently being aware of them. I understand that our senses really aren't that reliable, our memory that accurate, and various other psychological missteps might interfere with our subjective reality and our memory of experiences; but I have, with careful assessment, believed these people. Although I'm not certain that I've experienced such myself, I think for now that residual hauntings and time slips are a thing.

Edwin A.Abbott's 1884 book Flatland was intended as social satire but became more valued for its original and imaginative way of explaining dimensions of space. (In 2007 Flatland was made into a film. It looks fascinating. Must track it down.)

Flatland describes geometrical beings - circles, squares, triangles - living in a two-dimensional world. They perceive each other, viewing edge-on, as lines with various shadings. (Let's not worry about actual thickness, or how the light gets in there - it's just an intellectual model.) A.Square, an inhabitant of this 2D world, is unable to imagine that he might, as a three-dimensional being, visualise his world from above, as he is conceptually trapped in two dimensions.

Where this gets interesting and perhaps pertinent in relation to our paranormal question is when A.Sphere - a three-dimensional being from a higher plane of existence - visits Flatland. A.Square perceives A.Sphere passing through Flatland as at first a point, then a shaded line that gets longer, (reaching maximum length when the circumference of A.Sphere is in Flatland), and then diminishing in length, then a point, then nothing. A.Square's experience of seeing something appear, rapidly grow, shrink and disappear, defies his concept of reality, as experiencing ghosts and time slips do for most of us.

But what we understand, and can easily visualise, is a sphere passing through a plane - a solid object moving in three-dimensional space. Where the plane of Flatland intersects A.Sphere, a circle is formed. A.Square perceives the moving three-dimensional object as a two-dimensional object changing over time.

Edwin A.Abbott encourages us to make this extrapolation: what if, like A.Square, we were to encounter a being from a universe with one more spatial dimension than our own - a four-dimensional alien - moving through our 3D world? How would we describe this event?

Could we possibly see this creature passing through as something changing in time? A thing appears from nothing, changes in some way (maybe it grows, or spreads out, or does something), then it disappears (without necessarily moving off or being bound by time). Or another possibility (albeit a stretch); if it were, say, a cosmos-exploring cat, we might see the sudden appearance of a newly born kitten and watch it grow rapidly into an adult cat before our eyes, then grow old, die, shrivel and vanish. In other words, we see the visitor's entire life development as it moves through our space; we see it in every state of its own existence within the amount of time it takes to transcend our plane of existence. We see its movement as change over time.

Meanwhile, in 4D world, Kosmo Kat is able to move around in four dimensions quite freely, back and forward in time as we would understand it; but, in its perception, the 5th dimension might be called Time, and it might be as much at the mercy of progress in that dimension as we are in our 4th dimension of time.

Stepping back to the end of the 19th century, it was widely thought (mainly thanks to Sir Isaac Newton's brilliant work) that physics was near complete, with just a few details to fill in. Then along cometh Albert Einstein with his damned Relativity theories (Special and General) to turn our concept of reality on its head.

Quantum mechanics gives us the Many Worlds Interpretation. By this, or some other concept of multiple or parallel universes, it might be that dimensions can somehow rub up against one another, momentarily intersecting to allow some perceptive (or lucky) individuals to perceive events in parallel but time-shifted dimensions. (Tying knots in my hanky now, as I type - which is indeed quite tricky.)

Fast forward to now. Only a very smug, ignorant person would say that physics is basically complete except for the the last minor details, or that it will from now on merely progress in small increments. Just because they can't imagine how our understanding of nature might again undergo forced, radical change doesn't mean it can't happen. We've been here before, remember. The next way of re-understanding the cosmos might turn up next week, year, decade, or tomorrow. And, if we're lucky, with it might come an understanding of time that allows for and explains ghosts of the past or the future, for time slips, maybe even for Roman soldiers to march through our living rooms. 

By James Gilberd, co-author of Spooked - Exploring the Paranormal in New Zealand.

I just spent some time writing this reply to a genuinely concerned person who took the trouble to email Strange Occurrences for advice. (This is a slightly modified and expanded version.) I hope it doesn't come across as scornful or grumpy; that's not the intention. It's just that, more than anything, I'm feeling exasperated. Why are paranormal investigators, in 2015, still hung up on orbs?

Propagating the belief that dust orbs are spiritual in nature makes the paranormal community look like idiots in the eyes of skeptics and denies us any degree of credibility.

I'm not going to print the received email, but here's my reply:

"J___, please don't worry about the orbs in photos. They're not paranormal, they're totally harmless photographic anomalies.

"Frankly, it amazes me that people who should know better (i.e. those running 'ghost tours', or people in paranormal investigation groups) still treat orbs as paranormal phenomena. Often, they're just winding people up - giving the impression that something paranormal is happening when really there's nothing except dust. This is mostly to make their commercial activities seem more exciting, when, in reality, most of the time nothing remotely paranormal occurs during paid-for paranormal investigations or ghost tours.

"These orb thingies began cropping up in large numbers early this century, about the time people lots of people started using compact digital cameras. Here's an explanation of how orbs occur. (Admittedly, this article was written a good few years ago, before there were cellphone cameras with LED flashes, which produce orbs that look a little different, but the physics is the same.)

"With each different camera model and type you use, the orbs will appear different in colour, size, texture, etc. More professional-type DSLR cameras don't show orbs at all, which is why professional photographers are often puzzled by them.

"Orbs can look amazing, especially when you zoom up on them. They don't look like anything from the natural world (except maybe microscopic organisms, which they are not). They can have strange looking surfaces, corona, patterns within them that sometimes look like something recognisable, and they can come in all sorts of colours (due in part to lens coatings) and shapes (due to the shape of the lens aperture blades - see photos below). They can even look like they're partially behind things that are far back in the photo. But it's all to do with optics, lens coatings, lens imperfections, camera design, and digital sharpening, compression and interpolation. And of course psychological factors in the interpretation of the images - see pareidolia.

"If you are lucky enough to see - with your own eyes, not the camera's - a little light source floating around in the middle of a room, then it may well be something paranormal! Take a photo of it; take heaps of photos; shoot a video. But the orbs that you can't see with your eyes but which keep appearing in your digital photos are easily explained, and they are extremely unlikely to be paranormal in any respect."

ADDENDA:
This part of my reply has less to do with the photographic orbs, but here it is anyway:

"The behaviour of your cat and dog will be totally unconnected to the orb photos. Rememeber that they have much sharper hearing than we do, and can probably hear tiny, faint sounds like maybe a beetle chewing through wood deep in the walls somewhere, or they can smell something we can't. Dogs and cats are especially sensitive to human emotions, so if you're getting a bit freaked out by something, the dog or cat will probably also react, even if it is unaware of the source of your fear. Also, these animals are intelligent and have the capacity to imagine things, just as we do.

"Once we get thinking about a paranormal reason for odd things occurring (for example; a poltergeist as a reason for something falling or turning up in an unusual place), our minds naturally make the jump to attributing other, unconnected events to the same cause. But in all likelihood these things are totally  unrelated. Looking at things more objectively requires stepping back from them, which is where paranormal investigators (sensible, experienced ones) can be of assistance.

"However, in the meantime, I would advise you to take a note of anything strange that happens - the time, place, weather conditions, who was present - a detailed description, with photos. Keep a diary, in other words. Then if you decide to get paranormal investigators in, they will have specific things to take a close look at. We love it when we can go to someone's house and find they've kept an accurate record of a bunch of stuff that's unexplained. Then we can examine it piece by piece and see if we can find natural causes, and any rational connections between events. Also see 'What to do if you see a ghost'.

"Please let me know if anything else interesting happens, or you get any more intriguing photos."