Barns Are Painted Red Because of the Physics of Dying Stars | Hacker News Reader

Barns Are Painted Red Because of the Physics of Dying Stars

blogs.smithsonianmag.com

80 pointssaraid21654 comments

The astrophysics here is not quite right. Stars actually do make elements heavier than iron (where else would they come from?), they just don't get any energy out of them.

Also, it's a misconception that the iron on Earth is made in the cores of stars. That iron is almost all trapped in the resulting neutron star or black hole. The iron released to the rest of the universe is formed from the decay of nickel and cobalt in the supernova explosion.

It's not only that they don't get any energy out of them (elements heavier than iron); they actually lose energy. Which means that splitting any elements heavier than iron that happen to be created will actually liberate energy. So yes, stars will temporarily make heavier elements, but surely not in any appreciable amount. Supernova explosions are where they generally come from.

This is true. Although fusion into elements heavier than iron happens both during the last stages of a star's life and during the supernova itself, the last stages of the star's life last only a few hours anyway. At that point it really doesn't make too much sense to talk of a "star" since it's no longer in anything resembling equilibrium. It's more of an "event." Heavy elements fused deep in the star's core are likely to remain there during core collapse, and heavy elements fused in the shells or in the envelope during the explosion are likely to escape.

Here's a cool picture showing the layers of a star before collapse http://upload.wikimedia.org/wikipedia/commons/3/37/Evolved_s...

"The astrophysics here is not quite right," is my new favorite HN quote.

This is definitely a "Just So" scientific story. That is, it is an unverifiable account of why things might have happened. They used to be common in evolutionary thought until it became clear they were often wrong.

Just so stories can be thought provoking, but I'd prefer it if people writing them made it clear what they are, since they can often lead to muddled ideas rather than clarity. The tone of this article bugged me a little.

I've also heard this story before, and if you google you will see there are many alternative explanations, for example that red paint was chosen because it is a fungicide rather than because it was most plentiful. Why add any pigment at all, if cost is the issue?

This didn't seem like an egregious example, because I didn't sense it was meant to be taken all that seriously. "Just So" stories are alive and well in evolutionary psychology. How could you verify that X behavior came about because it helped humans get away from tigers in Africa 20 million years ago? It sounds plausible, I guess, if you take for granted that it must be explicitly coded for somewhere in the genome. But I don't.

Why add pigment. Every stood next to a white wall in bright sunshine? There's also the aesthetic reasons, people don't just optimize for cost, they like things they live with to look a certain way.

The likely reason is a bunch of reasons, including human nature, herd mentality, or what we today call going viral. Possibly it was just a really good paint salesman that had a load of spare red going cheap.

The tone didn't bug me in the slightest, it took it for what it was, a bit of fluff writing that had a pretty photo to look at.

Unpigmented "paint" is not white, it is usually* clear-ish. Titanium dioxide is the usual white pigment.

On the topic of why iron oxide pigments are used rather than keeping paint clear: they protect the surface from UV light.

* There are multitudes of paint bases, all the ones I can recollect are transparent with a yellow/brown tinge. One exception is acrylic emulsion paint base, which looks white but dries clear, unless a pigment is added.

Herd mentality is very likely.

Many barns in USA are red. Most barns in USSR were not painted at all. Most French barns don't appear to be red either: http://www.google.com/search?q=image+barn+france

Your looking at stone barns in France, wooden barns and wooden doors on stone barns are often red.

I was under the impression that it was red because it was best color for keeping the heat absorption even.

Here's another explanation, which I think is much better.

http://www.farmersalmanac.com/blog/2008/09/16/farmers-almana...

Indeed. I feel dumber for having wasted time of this clickbait.

The reactions stop at 56 because Iron has the highest binding energy of any element, which the author doesn't mention. Even under the extreme conditions of stellar nuclear fusion, the binding energy cannot be overcome past this point.

However, this doesn't really explain the abundance of red paint. It explains the abundance of iron and lighter elements. The fact that Iron Oxide has a red color has nothing to do with the "physics of dying stars".

The argument goes: Because iron oxide is abundant, it's cheap. Because it's cheap, it's used to paint barns.

There are a lot of arguments in the comments below but many of them actually support the statement. E.G. farmers used cow's blood or rust because they mixed their own paint. In other words, red was the most common and readily available pigment.

Arguments about modern storebought paint having the same price for all colors are also besides the point. (a) The tradition was well established before the 20th century and all prices being equal gives little incentive to change it. (b) Do they still make red paint from rust? (c) Do you really believe the paints all cost the manufacturer exactly the same?

That said, I don't really know anything about the history of red barns. I'm just saying as presented, it's a stronger case than many are giving it credit for.

But...why aren't most homes painted red, inside and out? Homes have existed for as long as barns. And while many people might want to splurge more for their home, it seems we should still see a relatively high number of red paint schemes in cheaper homes

Because homes are built out of different materials. Stone houses get whitewashed. White wash is a very thin plaster - lime, salt, water, sometimes molasses.

One Indian town - Jaipur - has pink houses. This is because of the local stone, and because they painted everything pink when Prince Albert went to visit. It's pink! (http://www.sherwin-williams.com/homeowners/color/find-and-ex...)

(http://commons.wikimedia.org/wiki/File:Jaipur_city_palace_in...)

> But...why aren't most homes painted red, inside and out? Homes have existed for as long as barns. And while many people might want to splurge more for their home, it seems we should still see a relatively high number of red paint schemes in cheaper homes

There are psychological impacts of color schemes which make heavy use of it undesirable for dwellings (its also why it is frequently used in fast food restaurants, because its gets people out the door faster.)

That seems too pat an explanation; I've sen a lot of very nice red rooms, and in other cultures it has more positive associations than in the Anglosphere. Also, how you react to color depends on the saturation as well as the hue.

In any case, this doesn't answer the question of why more people don't (or historically didn't) paint the outside of their houses red.

Perhaps because houses are often made of materials that are not wood? Stone and brick homes are almost never painted, thus setting a theme for homes that deviates from red. Houses are also rather small in comparison to barns. It could just be a matter of being able to afford other options at the smaller scale.

>its also why it is frequently used in fast food restaurants, because its gets people out the door faster

In design courses I was always taught that red and yellow are psychologically associated with hunger/food and this is why most fast food branding uses them [1]. I haven't seen any actual science behind this, it's always presented as fact.

I have personally encountered the color black being linked to death/unluckiness in Asia, as a new franchise of a major eCommerce company insisted I make their website's background white, instead of black like every other country's.

[1] http://www.colorschemer.com/blog/2007/07/17/why-food-compani...

> I have personally encountered the color black being linked to death/unluckiness in Asia, as a new franchise of a major eCommerce company insisted I make their website's background white, instead of black like every other country's.

Funnily enough, in Asia white is also linked to death or morning. Thus the ban on white t-shirts in some parts of China this month.

In my country, all the barn are the colour of iron - galvanised iron. I don't think I've ever seen a red one. Ye Olde wooden barns aren't red here either - if a barn is painted, it's usually white.

> The reactions stop at 56 because Iron has the highest binding energy of any element ...

Not exactly. Nickel-56 is produced in great abundance by the nuclear fusion of silicon. It then decays rapidly to cobalt-56, which then decays quickly to iron-56. The element with the highest binding energy is nickel-62, but it is not as easily formed during a supernova explosion.

Most likely because Red ochre paint is also easy to make. Around here (Finland) every other paint is bought, but Red ochre is occasionally boiled on site for painting out farm buildings and summer cottages. Partly for economic reasons, but mostly because it continues centuries old Scandinavian tradition. This and log cottages found their way to America with immigrant Forest Finns from northern Sweden. They practised slash and burn agriculture, which became frowned upon because it was thought to threaten the wood supply for building ships. So they had to find another frontier. This shared heritage could explain why some commenters point out never seeing red barns where they grew up, when they are commonplace in others.

Instructions for diy Red ochre paint: http://www.kaupunkiyhdistys.jns.fi/punamulta/english/redtext...

Maybe red paint was cheaper historically, but I'm seeing 1 gallon of red barn paint at the same price as white barn paint:

http://www.homedepot.com/p/BEHR-1-Gal-Red-Exterior-Barn-Fenc...

http://www.homedepot.com/p/BEHR-1-Gal-White-Exterior-Barn-Fe...

Aren't we also all here discussing this because of the Physics of dying stars? In other words, isn't pretty much everything - not just red paint - related to the Physics of dying stars?

Aside from presupposing the fact that life could not possibly have existed in the form it currently does on earth before stars started dying... it kind of misses the direct connection the author is going for (correct or not, and other commentors have already taken the latter angle).

My friends and I had this discussion during a camping trip. We resorted to Google, and the explanations varied from the cheapness of iron to it being a good luck tradition to include the blood of your first-slaughtered livestock in the paint (presumably, the paint was also red...or else you'd need a lot of blood).

The OP doesn't add much to the speculation and the headline makes quite an egregious speculation.

In the comments in the OP's website, I found another theory:

Barns are painted red so they are seen from a distance, not only during snow storms but every day of the year. Livestock need to be able to recognize and return to it daily. Barns have to be visible from country roads and fields by humans as well as beasts. It would not be wise to paint your barn lets say white to blend into the snow, or green to blend into the summer crops. (Comment by Yvonne Wenz)

As you already noted from your searches on Google, there is a lot of speculation out there -- who knows if theory is correct or not. But I thought it was non-obvious and quite interesting.

Cows are red/green colour blind, so a red shed against green fields and trees wouldn't be so visible to them.

(http://academic.research.microsoft.com/Paper/5494786)

(Google - your internet-enabled spell checker grey-underlined "Colour blind" and a right click suggested "colorblind" even though my settings are for a UK dictionary. I wonder if we'll see language drift as more and more people spell check with crowd-sourced dictionaries?)

Off topic, but I've been making that argument for years. I actually was more concerned that language would stop evolving to accommodate spell checking. I'm glad to see that text messaging has proven me wrong, but in many ways I'm more concerned about what the next generation will consider to be "language."

This must at least in parts be a cultural thing - I'm not from the U.S., and I've never seen a red barn in my life.

Not to be snarky, but technically almost everything we know about is a result of the physics of dying stars.

This article, while correct in that red paint is "cheap", misses the real reason why barns are painted red.

Iron oxide is a natural fungicide which protects the crops and animals inside the barn.

EDIT: The article is good for someone like me with very little scientific knowledge.

I thought that ferrous oxide was added because it's a fungicide?

(http://home.howstuffworks.com/question635.htm) Doesn't have any references.

(http://www.grit.com/Community/Why-Are-Barns-Red.aspx#axzz2VI...) seems to at least have read a book or two.

Meh. Iron is very common. But it is also heavy so most of the iron on Earth is locked up in the core where we can't get to it.

You may or may not have noticed, but there are lots of available colorful things on the surface of the planet that aren't red.

> It makes more 56 nucleon containing things than anything else (aside from the super light stuff in the star that is too light to fuse)

What is this "super light stuff" a reference to? Neutrinos?

Since fusion is a nuclear process and Hydrogen (and all heavier elements) can undergo fusion reactions, probably any nucleus with a massnumber of 0.

I have a feeling this is a contributing factor, but the real reason is because historically it is what worked. Red pigment would be cheap, apparently has anti-fungal properties, but it was what their parents and grand parents used; perhaps because it was cheap, or the wood lasted longer without rotting.

Interestingly, this is written by Yonatan Zunger, who is the Chief Architect for Google+: https://plus.google.com/+YonatanZunger/about

After a beat of bafflement on seeing the title, I actually figured this out, and clicked through to discover I was correct. I credit the Zelazny short story "Dismal Light"...

If you think red paint is inexpensive, try painting a car red.

This article is artifice.

I think I can debunk this: red paint for some reason needs more coats than any other color (house painter speaking, step back!) At least with modern paint. Before Behr Ultra a deep red wall would almost always need three or four coats, don't ask me why.

Maybe they went with red paint because it was cheaper and they didn't know they would need three times as much to paint it. But more likely it was because red barns just look better against a green field.

But more likely it was because red barns just look better against a green field.

I feel similarly. This discussion of dying stars and heavy metals is interesting, and it certainly could explain why barns are often painted red, but I tend to believe that color theory has more to do with the tradition of red barns than the physical state of the entire universe.

If you want your barn to stand out against a green field you paint it red because that's the complimentary color of green. If the field were yellow you'd paint it blue. Pretty simple explanation when you think about it, no need for astrophysics.

*violet

Could it also be that the red paint lasts longer since there are so many coats?

Eh, maybe but I doubt it, they could have used multiple coats of whatever color they liked. But farmers might want to draw attention to their barn and the best way to do that is paint it red so it clashes with the green all around it because they're polar opposites on a color wheel. Half mile away you'd see the red barn but if it were yellow or blue, maybe not.

A house painter that is pumping Behr Ultra? Definitely stand back. Yuck. I am a benjamin moore guy.

Benjamin Moore's Aura line will do reds with two coats of paint and one coat of the tinted primer.

Benjamin Moore is great but I get 25% off Behr and Home Depot is open on Sundays! haha

Try painting your bedroom (B Moore) Admiral blue. I'm not sure 4 coats is enough, even with the dark primer.

With any deep color get that paint & primer in one stuff at Home Depot. I'm no pitchman but it's saved me a lot of time & money.

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