The Disturbing Fate of a Planet Made of Blueberries | Hacker News Reader

The Disturbing Fate of a Planet Made of Blueberries

atlasobscura.com

At the risk of being the you-must-be-fun-at-parties guy - why would a planet "made of blueberries" be comprised of any air at all to begin with? :)

"Releasing the air that had separated each berry from its neighbors" - the question, at least the way it's phrased here, doesn't say anything about any air. Made of blueberries means made of blueberries, period.

> the question, at least the way it's phrased here, doesn't say anything about any air

Nor does it mention water, but blueberries contain water. Likewise, the paper finds "the air content of the berries" to be "211 times the mass of Earth’s atmosphere" [1].

[1] https://arxiv.org/pdf/1807.10553.pdf page 3

I'm okay with the water that blueberries actually CONTAIN, and the same with any air INSIDE them.

I just don't think that "air that had separated each berry from its neighbors" should count.

> Supposing that the entire Earth was instantaneously replaced with an equal volume of closely packed, but uncompressed blueberries, what would happen from the perspective of a person on the surface?

Closely packed but uncompressed means you're going to have air between some bits of them.

Or sonething else, like Methane. If we put vacuum sealed blueberries on the moon, they wouldn’t be separated by air.

More importantly, that description means Earth's atmosphere is left behind.

No, it doesnt mean that.

The original question asked about "closely packed, but uncompressed" blueberries. I think it's more reasonable to assume this means berries with a small amount of air between them (the state of blueberries as the writer was probably thinking of them), rather than a void-free blueberry mass, or blueberries with pockets of vacuum between them.

Seems the original question on Stackexchange has been removed :(

I really hope I live long enough to see scaled-up spectroscopy of exoplanets [1]. (I don't have enough optimism for hope for actual imaging.) It'll be fascinating to get a sense of the true range of world-types out there and see how often planets end up developing life.

(Picking up oxygen would be a high-confidence indicator of the presence of life, since oxygen reacts with everything and so can maintain a stable fraction of a planet's atmosphere only by continual replenishment, the only known mechanism for which is biological.)

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4156723/

Would all of the air at the core of the sphere necessarily escape into the atmosphere, or could it stay trapped and solidify?

That was my first thought as well. I can see how air relatively close to the surface could geyser out, but I'd guess that deeper air would likely be trapped. Given the high pressure and density farther down, compressed blueberries would probably behave like the rock that traps water and methane in the Earth's crust. Because of the trapped air, maybe the planet would shrink a little less than the author predicts. (Of course it will shrink a lot, because the air compresses, but maybe just a little less than predicted.)

Aw, I thought the thought experiment would be the ecological damage to Earth if all crops were replaced by blueberries.

Well, I'd say, what's keeping you/us? Go!

I'm not an expert on agriculture effects on ecosystems. Baseless speculation isn't nearly as interesting.

This sounds like a lost level from Jazz Jackrabbit or Zool.

Blueberry Planet would not be a nice place to live, but it would be the most delicious planet ever. Until somebody accumulated an earth's mass worth of chocolate, that is.

if it does not have enough mass, it will lose its atmosphere quickly. I wonder what the minimum mass and surface gravity to have a viable atmosphere is

To first order you can just use the ideal gas law to calculate the average velocity (v_rms = sqrt(3Tk_b/m)) of pick-a-molecule and compare it to the escape velocity (v_e = sqrt(2GM/r)

And then you need to consider the magnetic fields of your blueberry planet. Without them, the solar wind will slowly blast away the atmosphere.

well I mean, it's very unlikely to have a magnetic core.

That said Wikipedia tells me Mars looses ~.1Kg per second to the solar wind. Bump that up to a Kg/s because the Earth is closer and that still leaves 100 Billion Years before the atmosphere is completely stripped from Earth, so not an immediate concern.

Related: My understanding (from the book Oxygen) is that our oxygen-rich atmosphere keeps our hydrogen (and hence, water) safe. Free hydrogen can’t make it to the upper atmosphere without getting snagged by an oxygen molecule, so we lose relatively little atmosphere, mostly helium - everything else is too heavy.

Sandberg says he would visit the jammy planet he imagined—“With protective gear. And probably a supply of ice cream.”

Urp. Given "a roaring ocean of boiling jam", the surface doesn't sound likely to be very appetizing!

Reminds me of xkcd's "What If?" series.

What if you had a mole of moles?

https://what-if.xkcd.com/4/

A bunch of publications stole the idea from a popular tweet, apparently: https://twitter.com/sannewman/status/1025176560951808001.

It doesn't seem like the publications stole it from the tweet. It's just that someone presumably saw the tweet, asked the question on StackExchange (question is gone now so not sure whether the asker mentioned the tweet), and then StackExchange was where the answer was, so the people writing articles probably had no reason to assume there was a deeper source.

That tweet came this week. What-If is atleast 3 years old. There is a book published by Randall too.

I, for one, worry about spoiledge. Awful waste of food! Jk

Excellent Saturday morning read.

If the blueberry mass were interspersed with some additional sugar, it would cook into preserves.

Everything was replaced with blueberries, so there'd be no organisms to break things down. The sun would mostly dry things out probably, but eventually would start to change things.

Presumably life would eventually evolve.

There's nothing reproducing on blueberry planet so there's no evolution.

It is a boiling mass of organic compounds so maybe life would spontaneously form again. But the planet is mostly sugar so as soon as something evolved to metabolize that, it'd completely take over then starve to death. Possibly at a pre cellular stage - just a chemical reaction that turns sugar into whatever catalyst causes this reaction.

Without specifying sterilized blueberries, I would assume that the surface of the blueberries contain the same flora and fauna that you find in nature.

But the heat would boil them, returning the planet to sterility.

Or alcohol would be made

Reminds me of Randall Munroe's Mole of Moles thought experiment:

https://what-if.xkcd.com/4/

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