I don’t understand the expression, “God’s green Earth”. Nothing bothers me about the "God" part. No, I’m more concerned with the “green” part of it. Why is Earth described as green? Don’t people know that about 70.8% of Earth is covered in water? So, shouldn’t the saying really go, “God’s Blue Earth”? The trick is that water isn't blue. Water is clear (at least pure water, right?). Water only appears to be blue because it is reflecting the color from the sky. So, maybe it should be "God's Clear Earth"?

But when you think about it, why are we limiting the color description to what the human eye can see? To do so is unimaginative. The statement,“God’s green Earth” fails to account for the nearly immeasurable types of waves bouncing around in the atmosphere. There is everything from radio waves to gamma rays in our atmosphere and we are limiting ourselves to the color spectrum.

Technically, it depends upon your altitude. Most of the electromagnetic spectrum doesn’t get through to Earth’s surface. This means that we have even one more metric to delineate in this once vague phrase. Let’s just say, for the sake of argument, that we are talking about the Earth’s surface because that's what people mainly look at.

The question then becomes, "which waves actually make it to the surface?" Well, an article from Windows To The Universe notes that mainly the color spectrum (~400 - 800 nm) and radio waves (1 cm - 11 m) make it all the way to the surface (Russell). This means that the originators of this phrase actually weren’t too far off - minus limiting the color to green. Although, I bet you that there a lot more radio waves bouncing about than there are waves from the color spectrum because of all of our technology.

To be fair and practical, that’s all really just a side note. I mean, how many people are going to be looking at radio waves? I suppose I’ll concede that we stick to the color spectrum when describing the Earth. If I may, though, I would like to jump back to the color green again.

What do these folks mean by green? Do they mean Apple Green? Mantis Green? How about Yellow-Green? What shade of green are they talking about? There are so many shades of green! Further, and I hate to be the guy to point this out, but isn’t green really just blue and yellow? But wait, there it is again - Blue! This only goes to prove my point further! There is more blue on this planet’s surface than green!

Let’s humor them, though, and say that we are only counting the land when considering the color of this planet. I, once again, have to ask why they chose green. I would think, and I doubt you’ll disagree, that there is far more brown than there is green. If you haven't noticed, dirt and sand are everywhere! Further, guess what else is brown. Tree trunks (With the exception of Birch trees, of course)!

And what about the winter time or ice in general? About 10% of the Earth’s surface is covered in ice. So there is a good chunk of the surface area that is white and not green. Again, though, snow isn't really white. Snow is just beautifully constructed ice crystals which are clear. The reason that snow appears white is due to the fact that snow reflects all colors indiscriminately. So really, the snow covered portions of earth are really just covered in clear ice - like the oceans. Which means we now realize that up to about 80% of the earth is always covered in water (or ice) which is clear.

~~~ Really Nerdy Bit ~~~

Remember from that science class you slept through that things have color because they absorb all wavelengths with the exception of the color, or set of colors, which are reflected. That is why a strawberry, for example, appears to be red. All the incoming light to the strawberry is absorbed by the strawberry with the exception of red. Red is reflected, and so the strawberry seems red. So, going back to snow, all of the colors from the incoming light are reflected with little to none being absorbed (See the "P.S." if you are a real nerd and want to understand the truth about what light is absorbed by snow).

If all the incoming light is being reflected then the light being reflected appears as it came in. Since the whole color spectrum reaches earth, the color is white. Recall that all the colors of light combined make white (while the exact opposite is true if you combine all the colors from your 120 Crayola crayon box set on a piece of paper making the color black - or the color that absorbs all incoming light and reflects none). However, if you are "fortunate" enough to live in a place with snow and you go outside at night, you can do your own testing on the color of snow. If you shine a red light on the snow it appears red. If you shine a blue light on snow it appears blue. So on and so forth. Try it yourself!

~~~ Okay, Nerdy Bit Over ~~~

All I’m saying is that precision of language is key to communication, and I don’t want to look like a fool in front of the next alien I run into when I try to describe the place I’m from. Then again, maybe the alien I meet won't be able to discern the color green from the color blue like some cultures on earth. The Himba tribe is one example, as is reported by The New York Times:

"The Himba tribe from northern Namibia, for instance, does not classify green and blue separately, the way Westerners do, but it does differentiate among various shades of what we call green. ... While the English language has 11 separate color categories — red, green, blue, yellow, black, white, grey, pink, orange, purple and brown — the Himba have only five." (Newton)

So in the end it may not matter! Anyway, thanks for listening to my rant. My main hope is that next time someone says "What on God's green earth...?!" You'll get the urge to say, "Well, actually...."

Stay skeptical my friends.

~~~

P.S.

The phrase "God's Green Earth" may have originated from a poem published in The Scottish Christian Herald.

Okay, here is the really really nerdy bit: Water - and therefore ice and snow - does actually absorb some light. The frequencies of light that are absorbed are dependent on the state of the water. If the water is liquid, then it absorbs different frequencies than if the water is solid (ice) or a vapor (gas). If you want to know more, then start with the Wikipedia page on Electromagnetic Absorption by Water. Basically, water absorbs very little light in the color spectrum. However, it is really important when absorbing other frequencies. For instance, being underwater could help protect you against UVA and UVB rays, but only if you go really deep. But water is also used in nuclear reactors to absorb the neutrons being released from the nuclear decay and for storing nuclear waste.

~~~

Bibliography:

Newton, Maud. "It's Not Easy Seeing Green." The 6th Floor Its Not Easy Seeing Green Comments. The New York Times, 4 Sept. 2012. Web. 11 July 2016.

Russell, Randy. "Solar Energy in Earth's Atmosphere." - Windows to the Universe. N.p., 1 Sept. 2012. Web. 11 July 2016.