Tag: Hydrogen

Sciency Words: Hydrogen

~ J.S. Pailly ~ 4 Comments

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we talk about the definitions and etymologies of scientific names and terms.  In today’s episode of Sciency Words, we’re talking about:

HYDROGEN

I want to start this with a personal story.  Imagine me, twenty years ago, fresh out of college with a degree in television and film production.  One of my first jobs was working for a company that made educational cartoons for children.  At one point, I ended up being assigned to a two minute animated music video about water.  The name of the video: “Water Can Never Be New.”

Now I’m no scientist.  I cannot call myself an expert (I’m just very enthusiastic about this subject).  And twenty years ago, I was even less of an expert than I am today.  Still, even way back then, I had a nagging suspicion that this “Water Can Never Be New” video was a lie.  Which brings me to the subject of today’s post: hydrogen.

Definition of hydrogen: Hydrogen is the very first element on the periodic table of elements.  Typically, hydrogen atoms consist of one proton orbited by one electron.  Molecular hydrogen consists of two hydrogen atoms bonded to each other.  Under Earth-like temperatures and Earth-like atmospheric pressure, hydrogen is a gas.  It’s also rather rare here on Earth; elsewhere in the universe, it’s extremely common.  In fact, hydrogen is by far the most common, most abundant chemical element in the universe.

Etymology of hydrogen: Hydrogen was first discovered in 1671 by British natural philosopher Robert Boyle.  Boyle referred to this new kind of air he discovered as “inflammable air,” because of how easily he could light it on fire.  Over a century later, French chemist Antoine Lavoisier found that burning “inflammable air” somehow produced water vapor as a byproduct.  Thus, Lavoisier changed the name of “inflammable air” to hydrogen, from two Greek words meaning “water” and “creation.”

It’s hard to imagine today just how much the discovery of hydrogen must have rocked the world of science (a.k.a. natural philosophy) back in the 17th and 18th Centuries.  Up until that point, the Aristotelian view of world had prevailed.  According to Aristotle, four elements—fire, earth, air, and water—were the fundamental building blocks of nature.  Then Robert Boyle comes along with a new kind of air (can we really call air a fundamental element if there are different kinds of it?), and Lavoisier subsequently demonstrates that you can use this new kind of air to make water (is water really a fundamental element if you can make it out of other stuff?).

Today, we know more about what happens when you light hydrogen gas on fire.  The heat energy from the flame causes hydrogen to react with oxygen, producing H2O molecules.  Water, in other words.  New water.  And, in fact, many chemical reactions involving hydrogen and oxygen-containing compounds will produce water molecules as a byproduct.  Due to the energy involved in these reactions, this new water may be too hot to form a liquid, but water vapor is still water (and it will condense into a liquid eventually, once it has time to cool off).

Of course, hydrogen does much more than help make new water molecules.  Hydrogen is the fuel that keeps the Sun shining.  It’s a necessary component in the organic compounds that make life as we know it possible, and hydrogen ions play an important role in acid-base chemistry (not counting Lewis acids and bases).  Given the wide variety of jobs that hydrogen does, you may wonder why we stick to using a name that means, simply, “water generator.”

But the discovery of hydrogen and its water generating ability helped upend some deeply entrenched and woefully inaccurate scientific ideas.  The name seems appropriate to me as a way to honor that moment in the history of science when the old Aristotelian view of nature really started to crumble.  It’s a shame more people don’t know about this story.  Maybe somebody should make an educational cartoon for children about it.

A Breath of Fresh Hydrogen

~ J.S. Pailly ~ 10 Comments

Hello, friends!

So let’s imagine that extraterrestrials don’t breathe oxygen.  Oxygen is a pretty dangerous chemical, after all, so there’s good reason why alien organisms might want to avoid it.  But what would these aliens breathe instead?

A few years back, I came across an interesting “fact” on a conspiracy theory website.  The government doesn’t want you to know this, but apparently a lot of alien species breathe hydrogen.  That conspiracy theory website said a lot of weird and wacky things, but this hydrogen-breathing alien idea… based on what I know about chemistry, that idea kind of made sense to me.

You see we Earthlings use oxygen to oxidize our food.  This oxidation reaction generates the energy we need to stay alive.  But oxidation reactions are sort of equal-and-opposite to reduction reactions.  Oxygen is a powerful oxidizing agent, obviously, but hydrogen?  Hydrogen is a pretty effective reducing agent.

A paper published earlier this year examined the possibility of Earth-like planets with hydrogen-rich atmospheres.  Such planets could, in theory, exist, but they’d have to meet one or more of the following criteria:

  • The planet would have to be much colder than Earth (think Titan or Pluto-like temperatures).
  • The planet would have to have much higher surface gravity than Earth.
  • The planet would have to continuously outgas hydrogen from some underground source (subsurface reservoirs of water ice mixed with methane ice might do the trick).

If one or more of these conditions are not met, then a hydrogen-rich atmosphere would quickly fizzle out into space through a process called Jeans escape.

Now, could life exist in that sort of hydrogen-rich environment?  The answer is yes.  Absolutely yes.  Even here on Earth, there are organisms that “breathe” hydrogen and use it to generate energy through reduction reactions.  These organisms can be found deep underground, or clustered around deep-sea hydrothermal vents, or in other exotic niche environments where hydrogen is plentiful and oxygen is rare.

The real question is: could hydrogen-breathers evolve into complex, multicellular life forms?  Earth’s hydrogen-breathers are mere microorganisms.  Their version of respiration is nowhere near as efficient as the oxygen-based system we humans and our animal friends use.  The inefficiency of hydrogen-based respiration has stunted the evolutionary development of Earthly hydrogen-breathers.

But maybe on another planet—a planet with a hydrogen-rich atmosphere unlike anything Earth has ever seen—maybe complex multicellular life could evolve on a planet like that.  Maybe.

It’s plausible enough for science fiction, at least.