Magnets, hangovers, dogs eating grass, and the mysterious origins of common English words: here are 7 more everyday things that can’t be explained.
(See also my first post on this topic: ‘8 Everyday Things That Can’t Be Explained’)
It helps power your electronic devices, protects the Earth from the sun, and keeps things stuck to your fridge door; the effects of magnetism are all around us. And yet there is much about this invisible force that we don’t understand.
Magnetism can be traced to the atomic structure of matter.
Atoms have three buildings blocks: protons and neutrons, found in the nucleus, and electrons, which surround them. The electrons carry a negative electrical charge, as they move this creates a magnetic field.
The magnetic field automatically has two poles, which are called north and south.
The magnetic poles of most electrons point in different directions, and so cancel each other out; these substances are magnetically neutral. But if the poles align in the same direction, that generates a net magnetic field: this is what is happening on your fridge door.
This alignment of magnetic poles occurs naturally in some elements, and it can sometimes be forced into existence through an artificial means, like introducing an electric current.
Magnetism was first observed thousands of years ago, and has been studied in detail ever since. Its effects are well understood. What is mysterious, is why is any of this happening.
‘We just observe that when you make a charged particle move, it creates a magnetic field and two poles. We don’t really know why. It’s just a feature of the universe.’
– Jearl Walker, physicist, Cleveland State University
Scientists do not know why moving electrons create magnetic fields, nor why they have two poles. They also do not really understand why the required alignment occurs in some materials, and not others.
There are a large number of theories, but no consensus.
A further mystery: take a bar magnet, and cut it in half. Rather than one magnet cut in two, you have now instantly created two new magnets, each with their own north and south poles.
In theory, a magnet with one pole should be possible, although one has never been observed or created.
Further Reading: Popular Mechanics – How Do Magnets Work?
Dogs Eating Grass
If you have ever owned a dog, or just seen one at the park, you have likely seen them eating a mouthful of grass. When I was a kid, mum used to tell me that it was because the dog was unwell, and trying to make itself sick to settle its stomach.
It turns out, the reason for this behaviour is unclear.
One explanation is that the dog eats grass for dietary reasons. Grass provides fibre, eating it may help regulate the dog’s digestion. Some experts even think the dog may be seeking certain vitamins and minerals from the grass, it is otherwise lacking.
Another possibility is that dogs eat grass for psychological reasons. Dogs are complex animals with sophisticated needs, eating grass could help them cope with stress, or even just be a way to fill in time when they are bored.
All of these theories have supporters, but conclusive proof for them is lacking.
What is more certain is that the widely held belief, shared by my mum, that dogs eat grass to make themselves sick is not true. Studies have been conducted into this aspect of the behaviour, and no correlation has been shown between grass eating and subsequent vomiting.
‘The bottom line is that the majority of grass-eating dogs are not sick beforehand and do not vomit afterwards.’
– Dr Malcom Weir, VCA Animal Hospital
There is, of course, an even simpler explanation available: dogs may just like the taste.
Further reading: Why Do Dogs Eat Grass?
Why Are Moths Attracted to Lights?
Another mystery from nature relates to moths, and their well-known attraction to bright lights. Scientists are not sure why this occurs, either.
It is actually many types of flying insect that are attracted to lights, not just moths; some of the potential explanations link this to how the creatures navigate.
It is thought, although not proven, that some insects navigate by using the moon or the stars as a reference point. A large, bright, artificial light could then scramble this navigational system.
While this idea has a lot of support, and is often claimed as the explanation for the behaviour, critics point out a flaw: insects do not fly directly at the moon, as they do with artificial lights.
But a variant on the theory could explain this aspect; the much more intense strength of an artificial light could overwhelm the insects vision receptors. They may have been effectively blinded by the light, and are flying towards it as the only thing they can then see.
A third theory suggests that it is not the light that actually attracts the insects.
Very bright lights create the illusion of dark areas at their border, a visual phenomenon known as ‘Mach Bands.’ The insects may then be attracted to these perceived darker areas, thinking they are a good place to hide.
Some final mysterious elements: not all flying insects are attracted to lights. The ones that are exhibit different behaviours; some fly straight into the lights directly, while others circle them at a distance.
Further reading: The Conversation – Why Are Moths Attracted to Light?
Hangovers seem to exist in a simple transaction of cause and effect: have too much to drink, and you will feel seedy the next day. Only, scientists cannot figure out exactly how this works.
‘We know a lot about the long-term effects of alcohol on the body. What’s happening in the body while you’re drinking and when you’re hungover—that’s more of a mystery.’
– Dr Vijay Sundaram, Cedars-Sinai Hospital
For a long time it was thought that dehydration was the mechanism that caused hangovers. But this was dispelled through clinical study; people who consumed alcohol at the required level – about 3 to 5 standard drinks – were shown to be no less hydrated than people who had not drunk anything.
Further studies then turned up a host of other possibilities.
Once ingested, the liver processes alcohol, and produces a toxic by-product called acetaldehyde. This builds up while we are drinking, and then quite quickly dissipates when we stop. Acetaldehyde makes people feel unwell, and so provides a potential hangover explanation.
But then: why do we feel worse the day after a drinking session, when our acetaldehyde levels are lower?
Alcohol also causes inflammation of the immune system, which releases ‘cytokines’ to combat the effect. Elevated levels of cytokines have also been shown to make people feel hangover like symptoms.
But an inflamed immune system should mean that anti-inflammatories, like ibuprofen, will be an effective treatment. And while many people find them helpful, proper studies on their effectiveness have shown varied results.
Yet another idea is that hangovers can be traced to the brain, and how alcohol alters its complex neurological functioning.
Hangovers are surprisingly complex, and could also be produced by a combination of the above factors.
Further reading: The science of hangovers
Unlike hangovers, the physical mechanism behind blushing is well understood: the capillaries near your skin dilate, allowing more blood to flow through them, giving you a rosy hue. What is not understood, is why our bodies evolved this function.
Natural selection shows that different organisms will have different traits; the ones that have traits most favourable will be more likely to survive, and pass on their genes.
People blush for a variety of reasons, but they are usually emotional: we feel embarrassed, or ashamed, or awkward. In a way, it is revealing our thoughts and feelings.
Why would this trait be favourable?
‘As blood rushes to your face, there is a noticeable effect on your appearance. Many psychologists believe that this suggests that blushing is a defense mechanism, a response we developed to help avoid a potential fight-or-flight confrontation.’
– Professor Phil Kesten, Santa Clara University
So blushing could have evolved as an appeasement action, to mitigate confrontations. This link to our fight-or-flight response is a common explanation, but has not been conclusively proven.
Another idea is that blushing is a sign of certain personality traits.
Studies have shown that people who blush are perceived by others to be kinder, more honest, or even more generous. These traits that may have made them more desirable as partners, and then parents of future prone-to-blush children.
Further reading: New Scientist – 10 Mysteries of You
Where Did Earth’s Water Come From?
Earth is famously a blue planet: see an image of our home from space, and that’s the dominant colour. And most people have heard the statistic: about 70% of the earth’s surface is covered in water.
What we don’t know, for certain, is where it all came from.
Like the rest of the solar system, the Earth formed out of a vast, dusty disk of matter. Gravity brought this material together, in larger and larger clumps, over many billions of years this eventually formed our sun and its orbiting planets.
Water would have been present in these primordial building blocks.
But the earth is relatively close to the sun, and water would have been scarce in the warm zone where our planet formed; our sun would have vaporised most of it, and scattered it further out into the solar system.
So how did such a large amount of water find its way here?
One theory is that it was brought by comets or meteorites. These exist in great numbers in the outer solar system, where it is cold enough for water to accumulate and form ice.
Comets and meteorites sometimes venture into the inner solar system, where they can collide with larger bodies. A high enough number of these impacts could have brought sufficient ice water to the Earth.
Other experts think this is unlikely:
‘This idea that Earth’s water came from the outer solar system would have required something unusual, like Jupiter having a little trip through the inner solar system to send water-rich asteroids our way.’
– Nell Greenfieldboyce, NPR
Another idea is that the rocks the Earth formed from could have provided the water more directly.
Rocks similar to the original material of the solar system, called ‘enstatite chondrites’, have hit the Earth as meteorites, and been studied.
These show high concentrations of hydrogen; if enough of these were present when the Earth formed, they could have mixed with the oxygen that was here and created a large quantity of water.
This theory was first published only in 2020, and is still being investigated. For now, we remain uncertain if Earth’s water was here originally, or if it arrived from space.
Further reading: Where did earth’s water come from?
Girls and Boys
The English language is full of mysterious words without a known point of origin, including some of the most commonly used. Among these: ‘girl’ and ‘boy’, which both appeared, seemingly from nowhere.
The first uses of girl – originally spelt ‘gyrl’ or ‘gerl’ – date from the 13th century. There is no known equivalent word in either Old English or Old German, to where most new English words from this period can be traced; girl simply started to appear in texts from this time.
Girl was originally used to denote a young child of either gender. Sometimes a qualifier was added: a ‘knave girl’ was a female, and a ‘gay girl’ male.
Linguists have guessed that its likely origin was another term in common use, that was then colloquialized to reference children; suggestions include ‘gierela’ (garment), or ‘garrulus’ (talkative).
Another idea links it to the European words ‘gorre’ (Norwegian) or ‘gurre’ (Swedish), which both denote children. But how these words may have transferred to English in this era, and then became rapidly popularised, has not been shown.
By the 14th century, ‘girl’ was attached specifically to female children. An equally mysterious new term then appeared for male kids.
Regular use of ‘boy’ may have started as something of a joke.
Theories as to its origin include the Dutch word ‘boef’, meaning knave, and the French ‘embuie’ or Latin ‘boia’, which both mean chained, or in fetters. Another possibility is the Middle English word ‘boi’, which meant devil.
Our forbears may have had a dim view of the behaviour of young male children.
‘A noticeable number of the modern words for ‘boy’, ‘girl’, and ‘child’ were originally colloquial nicknames, derogatory or whimsical, in part endearing, and finally commonplace.’
– Carl Darling Buck, Philologist
Which, if any, of these terms is the actual root of ‘boy’ is still not known.
Further reading: Huff Post – History of the word ‘girl’