Periodic Table of Etymologies: Sunstuff


The Sun of all Fears

Australia is a weird place, at least for an outsider. As I have previously written elsewhere, there are a lot of differences that strike a visitor. How easy they are to adapt to is partly a function of how familiar they are in the first place. For instance, some of the linguistic quirks are quite famous in the rest of the world, so they are not so surprising. The same is true of the unique local animals. Someone who takes an interest in such things can even brace themselves for the stars being in the "wrong" places in the night sky. But the strangest, most disconcerting thing about visiting the opposite hemisphere to where one grew up is the Sun. It goes the other way across the sky.

G'day! The sun in Australia. Credit: Alex Brown

We take our local star for granted. It gives us warmth and light (which are actually two sides of the same coin), and its gravity keeps our little planet from floating off into space. Although it should never be directly gazed at, it has gripped humanity's imagination for aeons. Across many human cultures, myths about a Sun god show how important it is to us. The ancient Greeks called it Helios. In 1868, scientists observing the light from the Sun found its yellow-ness had characteristics which could not be explained by known elements, such as sodium. They concluded they had found a new element, and named it after the Sun. Thus, Helios gave his name to helium, the second element in the periodic table. The Elementymology website also lists interesting "variants" of helium, such as coronium, nebulium and archonium. Scientists thought they had discovered these "extra" elements when they analysed the light coming from various other objects in the sky. It would seem that in the 19th century, astronomy and chemistry were one and the same!

The light of helium gas in a tube. Credit: Heinrich Pniok (www.pse-mendelejew.de), Licence: CC-BY-NC-ND

So this is the story of helium: its name, its chemistry, its uses... and what we can learn from it.

This post is the second in my series about the names of the elements of the periodic table. The first was hydrogen, the most common element in the Universe. Now we turn our attention to the second element in the periodic table, helium. As it happens, helium is also the second most common element in the Universe. In fact, as a general rule of thumb, the higher an element's rank in the table, the less common it is in nature. This is down to how elements are formed in the first place.

An example of a nuclear reaction. Credit: Wikipedia user Michalsmid

On the Origin of Elements

In the seconds and minutes after the Universe came into existence (the "Big Bang"), the first subatomic particles of matter (neutrons and protons) joined together to form the nuclei, or cores of atoms. The simplest nucleus, as we have seen before, is just a proton by itself: hydrogen. Slightly larger isotopes or versions of hydrogen are deuterium and tritium, which also have just one proton, but also include one or two neutrons, respectively. If you add a second proton, you are no longer dealing with hydrogen; that is helium.

In theory, two protons stuck together by themselves would be a form of helium. However, protons brought that close together repel each other very strongly, and the atom would not be stable. In nature, we only see helium-3 and (far more commonly) helium-4, which have two protons and one or two neutrons each, respectively. As their name suggests, neutrons have a neutral electric charge (ie no electric charge), so they act as a sort of buffer between the positively charged protons. Helium-5 , -6 can be made in laboratory conditions, but they have even more neutrons, which are quickly ejected because such nuclei are not stable (this is a kind of radioactivity).

"Alpha radiation" is a type of radioactivity where a helium atom or "alpha particle" is emitted from a larger atom. Not to be confused with neutron radiation.

Just after the Big Bang, the protons and neutrons bashed into each other, forming hydrogen and helium. It then took a long time, as the Universe expanded and cooled rapidly, before any heavier elements could be formed. Indeed, it was only when the effects of gravity (the weakest force of all) began to kick in, that hydrogen and helium atoms began to clump together. Eventually, they would form huge masses, which grew into stars. The huge pressures and temperatures which gradually built up in the centres of stars would cause the hydrogen and helium atoms to fuse together, creating larger, heavier elements. When stars then died, they released their newborn atoms into space. So, you can see why bigger elements are generally rarer than small ones. Heavier elements can only be made from lighter ones, which in turn are made from even lighter ones, and so on down to the original stock of hydrogen and helium. Now, don't get me wrong, there is a lot of this stuff in human terms. Just think of all the iron in the Earth. But as Douglas Adams once wrote: "that's peanuts to space".

So much for where the element itself comes from. We've also seen that it gets its name from the Sun. But where else does our friend Helios turn up?

 

Helios at the centre of it all

Unsurprisingly, the root helios is the origin of the word "heliocentrism". This is the idea that the Earth travels around the Sun, instead of the opposite. With the Sun in the middle, the movement of the other planets are a lot simpler than if the Earth is in the middle. In the heliocentric model, their orbits are shaped like ellipses (sort of oval-ish) rather than baffling cycles-within-cycles. Seen from Earth, the paths of the planets hardly make sense. Indeed, the word "planet" itself even comes from the Greek πλανήτης (planetos) meaning "wanderer".

The path of Mars across the sky, as seen from Earth. Credit: Eugene Alvin Villar, 2008.

Although variants of this idea have been around for a long time, it was Polish astronomer Copernicus who first proposed a full model of the Solar System, in the 16th century CE. Other notables proponents of heliocentrism were Kepler and Newton. There was also Galileo, who was famously placed under house arrest by the Catholic Church in the 17th Century. It was perceived by some that the Sun being at the centre of the Universe, rather than the Earth, would be an affront to Man's special place in God's Universe. It would be hundreds of years before the Church revised its position. In the meantime, science has gone further, discovering that the our supposedly mighty Sun is in fact quite average, as stars go. It is one of billions in our galaxy, the Milky Way, which is itself one of billions of galaxies in the Universe.

The Milky Way - nothing special in the grand scheme of things. Credit: NASA

Of course, it may seem perfectly natural to think that the Sun goes around the Earth. For example, even the audience on this episode of the (French version of) Who Wants to be a Millionaire? thinks so, though they might be conspiring against the contestant for fun. On the other hand, as supposedly remarked by the philosopher Wittgenstein, what would have to happen in the sky for it to naturally look like the Earth is going around the Sun? After all, that is what actually happens, and it looks the way it does!

 

Shining bright like a helicopter... or not

One place where Helios seems to appear, but doesn't, is the German word hell. Though you definitely describe our Sun as hell, which means "bright" (and die Helligkeit is "brightness"), I doubt this has anything to do with Helios (nor the supposedly extremely high temperature of Hell in mythology). By the way, Hell is also a village in Norway. Again, nothing to do with Helios, it's just a coincidence. Apparently, Helir in old Norwegian is a kind of rock or cave formation, which the village is named after.

I wouldn't go so far as to call hell a false friend, but I still think it's a nice coincidence.

Meanwhile, you might at first sight think that the word "helicopter" could be related to helium. After all, helium balloons (because the gas is lighter than air) go up in to the sky, just like a helicopter. But the worlds of language and science don't always work like that  (if it did, homeopathy would work). In fact, the heli- part actually comes from the Greek helikos, which means "spiral".

From this angle, the bannister is in a spiral shape. However, the stairs are actually in a helix, unlike the Milky Way above, which really is a spiral, made largely of helium. Credit: Wikipedia user Mcginnly

Incidentally, the -pter root, which means "wing", also turns up in pterodactyls ("wing-fingers": flying dinosaurs), coleoptera ("sheath-winged": beetles) and lepidoptera ("scale-winged": butterflies and moths), to name but a few. As regular readers of this blog will have realised by now, I find these kinds of linguistic connections fascinating. I love letting my mind wander from place to place, hopping from word to word, seeing how all of nature is connected (or in the case of helium and helices, not connected). But enough for now. It's all well and good looking at the origins of the element and its name, but what does it actually do?

 

Helium is He-lla dope, yo

William Ramsay, who won the 1904 Nobel Prize in chemistry for his work on the elements found in air. He was also the first to isolate helium on Earth.

So far, we've looked at the nuclear and particle physics of the element helium. But what about its chemistry? Well, it turns out that chemically, helium is quite boring. Unlike hydrogen, it doesn't react with much at all - it's the smallest of the noble gasses, so called because they behave as if other elements are not worthy of interacting with them.

Helium is probably most famous for its effect on people's voices. If you speak after inhaling a lungful of helium, your voice sounds squeaky. Helium being lighter than air, it affects how sounds are formed in your voicebox. Although the pitch of your voice is not affected, the sounds bounce around your vocal folds in your throat differently, producing the unusual voice. This is a different phenomenon to when whales communicate through water, which also lets sound through faster than air does.

Because it is lighter than air, helium is often used in balloons to keep them off the ground. You may have seen helium in balloons at parties, or in their larger cousins, blimps. As a gas it is also very safe because it is inert, which means reacts with almost no other chemicals (very much unlike hydrogen).

Being such a light gas, it is not present in the air around us - it just floats off into space. And if it doesn't react with other chemicals to form more complicated molecules, where do we get it from in the first place? We certainly haven't got ships trawling around in space, grasping at passing wisps of gas. For one thing, that would be very inefficient, and the technology involved would probably (I'm speculating here) require using up more helium than would be gathered in the first place!

Instead, we get our helium from the ground. Certain radioactive minerals emit helium atoms as part of their natural alpha decay (see picture above). However, helium supplies on Earth are running out. The radioactive process in the ground is very slow. it has taken millions of years for the amounts we see today to be produced by the rocks, and we are using it up far faster than it is being produced. (Sound familiar?)

It's not just balloons which are using up helium. In medicine, magnetic resonance imaging (MRI) machines are used to take detailed pictures of the positions of subatomic particles inside the body. These machines rely on liquid helium to cool down their huge superconducting magnets. These magnets need to be so cold (close to absolute zero, the coldest possible temperature in the world, around -270 degrees celsius) because they are so powerful. Indeed, the electrical currents involved would be very dangerous if they were allowed to heat up!

 

"He-He" - Helium: too cool for chemistry. Credit: Wikipedia user Pslawinski

Several of these ideas I have brought up here are also covered in the Periodic Table of Videos clip below, including a demonstration with a justified use of liquid nitrogen (as opposed to just smashing flowers because it's pretty) to illustrate the idea of a gas' volume:

At the end of the video above, Professor Poliakoff of the University of Nottingham mentions using liquid helium for "cooling". It's not just MRI machines that need to be kept cool. As it happens, this kind of extremely low temperature is the kind of thing they use at CERN. In fact, the incident which happened when CERN turned on the Large Hadron Collider (LHC) in 2008 was a helium leak. Here's the inimitable Poliakoff again, explaining how the LHC's superconducting magnets work and what went wrong:

While we're watching these, this final one from the Periodic Table of Videos team features a very neat experiment all about hydrogen and helium. I include it mostly so you can get a more visual idea of what all these different nuclei, atoms, molecules, protons, neutrons, electrons etc are. There's also a neat digression into how good ideas come about. Check out the periodic table tie, too!

 

In Sunnary

So, despite being the least reactive of all the elements, its other characteristics mean that helium has its uses. As we have seen, however, it is running out. It is somewhat ironic that the second most abundant element in the Universe is so rare on Earth. It's almost as if this place was not made with us in mind. Not only do we rely on the Sun for heat, warmth and gravity, but we also owe the very atoms we are made of to the nuclear furnace in other stars just like it, too. Praise be.

The spectrum of light emitted by helium. Note the yellow band,

So, next time you're in Australia, or travel to the other hemisphere to the one you're used to, think about the Sun going the "wrong way". Think about the story of helium. From being born in the heart of stars, through being put to either frivolous or fascinating use, to being wastefully released back into space, its life reflects our own. Its Greek namesake consistently rose and charted his course across the sky, every day, for all of time.

The element He, however, is not eternal. Eventually, it will all be destroyed when the Universe comes to an end. Well before then, our own life-giving Sun will have died, destroying much of the Solar System in the process. Its helium will escape into interstellar space, destined to float around uselessly, wandering aimlessly, just as the planets appeared to do.

However, this seemingly bleak outlook is not to be taken melodramatically. It is only the natural consequence of our existence in the first place. Here's the wonderful Carl Sagan telling the story of life, the Universe and everything in terms of star stuff:

Knowing that this is where we came from gives all the more weight to Sagan's words in this final clip, below. It is the famous "Pale Blue Dot" speech, which reminds us of the small-yet-huge place we occupy in the world, just like helium.

 

Over to you:

  • Have you experienced the Sun going the "wrong" way when you switch hemispheres? How did it make you feel?
  • How do you say "the Sun" in your language?
  • Do you think we should stop using helium in balloons, and/or for squeaky-voice fun?
  • What are your favourite helico- or -pter- words? (10 points to anyone who says "helicobacter")
  • Does your language have a different word for helium? What is the origin of that word?
  • Word other words or ideas are related to the Greek god Helios?

7 Responses to “Periodic Table of Etymologies: Sunstuff”

  1. elkement Reply | Permalink

    Quite an entertaining tour through the history of science! :-)
    As usual I am not able to contribute something about German terms related to Helium that you won't know. I had always been intrigued by the sun being a female noun and the moon being male in German, in contrast to Romance languages. Do you know the reason for that?
    All kinds of company names come to my mind including helio-..., one being an Austrian manufacturer of heat pumps (sun=heat?) and the other own being a trademark for dewar vessel holding liquid helium - HELIOS. Somebody should have secured the copyright and helium / heli-. This person would be rich today.

    • Alex Brown Reply | Permalink

      Ah, but just because *I* now the German words doesn't mean yo shouldn't also post them here, Elke! There are others reading this too, you know! :-)

      Meanwhile, I hadn't noticed the "switching" of genders for the Sun and Moon. How curious. "Die Sonne"und "Der Mond" as opposed to (eg) "le soleil" and "la lune" - intriguing...

      As for scientific companies naming themselves after elements, I think it's a bit like the number 2000 (or 3000 these days) - good for marketing!

  2. Marianne Reply | Permalink

    As a Latin scholar (well, in the past) I'm disappointed that Sol gets no mention as the generator of the sun adjective (solar) and obviously solar system. All kinds of fun segways into solar power, solar days, solariums (cough, solaria) and stuff there :) http://en.wiktionary.org/wiki/sol#Etymology_2

    I think it's a shame it's not more widely used; "The Sun" seems awfully lazy and also human-centric, given any star with planets around it is technically a sun (right?).

    Also I think that usage leaves room for the fact that the Sun IS a star to completely pass people by. Always a facepalm moment when someone denies it or is surprised, but it happens disturbingly frequently...

    Oh it's also not a brilliant idea to inhale helium (yes I've done it)
    http://www.slate.com/articles/news_and_politics/explainer/2006/06/stay_out_of_that_balloon.html

    • Alex Brown Reply | Permalink

      Ah yes, I could have thought a bit more about Sol. That one might come up a bit more in future posts, though!

      As for breathing helium, there was a discussion about the safety of helium versus other gasses on an email list for people designing science demonstrations; views were mixed, to say the least.

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