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What made Earth a giant snowball 700M years ago? Scientists have an answer

sydney.edu.au

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Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#171

Post by psunavy03 »

js2 wrote: post #96
macintux wrote: post #87

Earlier quoted context omitted.

Rumsfeld’s unknown unknowns.

Rumsfeld is famous for the quip, but it's basically an expression of the first stage of the four stages of competence: 1. You don't know what you don't know. 2. You know what you don't know. 3. You know what you know. 4. You don't know what you know. https://en.wikipedia.org/wiki/Four_stages_of_competence

No, it is much closer to the Cynefin framework's understanding that complex systems are affected by the influence of variables which are too small for us to measure or even know they exist until after they act.

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#172

Post by psunavy03 »

JohnFen wrote: post #86
duxup wrote: post #17

A recent PBS documentary did a great job talking about all the changes the earth has gone through: https://www.pbs.org/wgbh/nova/article/the-history-of-earth-i... They had a series on planets and some of their history too. Growing up I honestly thought that planets evolved into a sort of natural stable state that I guess I assumed would last until the sun or other external force decided otherwise. But it’s interestin…

> Growing up I honestly thought that planets evolved into a sort of natural stable state that I guess I assumed would last This seems to be another expression of the truth that "people tend to mistake the limits of their view for the limits of the world."

"Pardon him, Theodotus. He is a barbarian, and thinks that the customs of his tribe and island are the laws of nature."

- George Bernard Shaw, "Ceasar and Cleopatra"

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#173

Post by mr_toad »

roskelld wrote: post #162
nullhole wrote: post #19

Earlier quoted context omitted.

That'd make for a good story setup: aliens park a shadeship (c) at L1 and wait. They block out most but not all of the sun. After some time (months? years?), conditions on Earth become unbearable, so earthlings have to mount an attack. Kind of like the movie Sunshine, but with more believable physics. Edit: as a bonus, it could take place in ~50-100 years, when global warming has gotten worse. The aliens could disgui…

That sounds like a great idea for a sci-fi novel, but before I steal and write it I thought I'd ask ChatGPT if it already exists, and it seems it does. "The Forge of God" by Greg Bear The Makers deploy a vast, self-replicating robotic spacecraft called the "Doomsday Rock" near Earth's sun. The purpose of this massive construct is to absorb energy from the sun, causing it to dim and ultimately leading to the freezing…

That’s not the plot of The Forge of God. Maybe it’s some other novel, but definitely not the Forge of God.

Spoiler alert: in The Forge of God the Earth gets literally blown to pieces.

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#174

Post by mr_toad »

mistermann wrote: post #61
nullhole wrote: post #19

Earlier quoted context omitted.

That'd make for a good story setup: aliens park a shadeship (c) at L1 and wait. They block out most but not all of the sun. After some time (months? years?), conditions on Earth become unbearable, so earthlings have to mount an attack. Kind of like the movie Sunshine, but with more believable physics. Edit: as a bonus, it could take place in ~50-100 years, when global warming has gotten worse. The aliens could disgui…

Another good story setup involving aliens: aliens pop by, tell us we have 25 years to "get our shit together, and the ambiguity here is deliberate, humans " on this planet, or we will be garbage collected. Then they come back a year later: "I have bad news: the timeline has been accelerated, you now have 10 years". What to do? To whom shall we turn for a plan?

https://en.m.wikipedia.org/wiki/The_Day_the_Earth_Stood_Stil...

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#175

Post by adastra22 »

mjfisher wrote: post #139
huytersd wrote: post #111

Earlier quoted context omitted.

Is it an absolutely perfect simulation? Like would we know the exact future of those hundreds of atoms in perpetuity?

The other reason the answer to this is "no" is that we don't even really understand how an atom even works its entirety yet. We don't know fundamentally know what makes the potential energy of an atomic nuclear be structured in the way it is. EDIT: I thought I'd double check that since it's been a while since I studied physics formally; apparently it is possible to model light nuclei[1] (up to four nucleons) from the…

You are confusing exact solutions with the ability to solve. We know how atoms work and can solve for any property we might want to measure. Ab initio systems aren't very practical for large systems because of computational costs, but they would work if given infinite compute (or a quantum computer). We just solve them numerically instead of closed-form.

It's like polynomials: there's a quadratic formula, and a cubic and even quartic formula for exact solutions (although the quartic is ridiculous and no one would ever use it). Higher order polynomials have NO exact, closed-form solutions using standard arithmetic operations. But we can still solve any polynomial no matter the degree using numerical methods. To say that we don't even know how how degree 5 polynomials work would be flat out wrong.

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#176

Post by adastra22 »

huytersd wrote: post #154
luma wrote: post #149

Earlier quoted context omitted.

I’d recommend reading up on Heisenberg’s Uncertainty Principle to understand why what you suggest is, to our knowledge, physically impossible.

Yeah, I’m aware. I was assuming some sort of aligned starting state with atoms whose configurations were perfectly known but I guess that’s not really possible.

If you're thinking "yeah but what if we really knew the starting configuration" then you're not really understanding the uncertainty principle. There is no hidden state that we just don't have access to.

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#177

Post by fineIllregister »

js2 wrote: post #96
macintux wrote: post #87

Earlier quoted context omitted.

Rumsfeld’s unknown unknowns.

Rumsfeld is famous for the quip, but it's basically an expression of the first stage of the four stages of competence: 1. You don't know what you don't know. 2. You know what you don't know. 3. You know what you know. 4. You don't know what you know. https://en.wikipedia.org/wiki/Four_stages_of_competence

Rumsfeld's embarrassment over that line was well earned. He was trying to sell a war based on Iraq having weapons of mass destruction. He was asked why we should go along when there was no evidence for that. He tried to sound smart saying, "Sometimes you don't know what you don't know", basically admitting that there was no evidence to justify his predetermined course of action.

They weren't "unknown unknowns". We knew. He knew too, but he was trying to muddy the waters. He got his way at the expense of one million dead Iraqi civilians, thousands of dead US soldiers, and 3 trillion dollars of US money.

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#178

Post by huytersd »

adastra22 wrote: post #176
huytersd wrote: post #154

Earlier quoted context omitted.

Yeah, I’m aware. I was assuming some sort of aligned starting state with atoms whose configurations were perfectly known but I guess that’s not really possible.

If you're thinking "yeah but what if we really knew the starting configuration" then you're not really understanding the uncertainty principle. There is no hidden state that we just don't have access to.

Yes, that’s the realization I came to as well.

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#179

Post by adastra22 »

huytersd wrote: post #178
adastra22 wrote: post #176

Earlier quoted context omitted.

If you're thinking "yeah but what if we really knew the starting configuration" then you're not really understanding the uncertainty principle. There is no hidden state that we just don't have access to.

Yes, that’s the realization I came to as well.

You’re one of today’s lucky 10,000. Even Einstein had trouble believing that quantum must be random, but it is. The EPR paradox proves that.

Re: What made Earth a giant snowball 700M years ago? Scientists have an answer

#180

Post by rufus_foreman »

ReptileMan wrote: post #65
nullhole wrote: post #19

Earlier quoted context omitted.

That'd make for a good story setup: aliens park a shadeship (c) at L1 and wait. They block out most but not all of the sun. After some time (months? years?), conditions on Earth become unbearable, so earthlings have to mount an attack. Kind of like the movie Sunshine, but with more believable physics. Edit: as a bonus, it could take place in ~50-100 years, when global warming has gotten worse. The aliens could disgui…

>The aliens could disguise their motives for a while, claiming to be there to help counteract global warming. Warnings from a lone scientist would be ignored. It's a cookbook!

Humans are so suspicious. The title is actually "How to Cook for Humans".
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