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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

#131

Post by snakeyjake »

itronitron wrote: post #3

Seems like a low risk approach for taking over a planet would be to just park a large shade between the planet and it's star then let it enter a deep freeze. Then you could just remove the shade and let the planet warm back up before settling down.

Any sentient species that can generate, store, and then convert the amount of energy to either move a sunshade or move the infrastructure needed to construct and then deploy a sunshade at the distances needed to reach inhabitable worlds no longer cares about planets.

They can use that same technology to create, on a whim, inhabitable structures of arbitrary size and composition around any star- converting gas giants (or gas clouds or the solar winds) into perfectly positioned and constructed habitats in ideal locations.

Competition over planets would probably be as foreign and incomprehensible to them as what occurred in the universe prior to the Planck epoch is currently to us.

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

#132

Post by eber »

apothegm wrote: post #117
twojacobtwo wrote: post #39

> Co-author Professor Dietmar Müller from the University of Sydney said: Geology ruled climate at this time. We think the Sturtian ice age kicked in due to a double whammy: a plate tectonic reorganisation brought volcanic degassing to a minimum, while simultaneously a continental volcanic province in Canada started eroding away, consuming atmospheric CO2. Research: > Duration of Sturtian “Snowball Earth” glaciation l…

How would erosion consume CO2?

I believe the cycle they are referring to is:

2 CO2 + H2O + CaSiO3 -> Ca^2+ + 2HCO3- + SiO2

and

Ca^2+ + 2HCO3- -> CaCO3 + CO2 + H2O

https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cyc...

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

#133

Post by thaumasiotes »

WalterBright wrote: post #123
justinator wrote: post #113

Earlier quoted context omitted.

There's a chance - however small - that WE live in that simulation.

The simulation theory is indistinguishable from any religious explanation.

Things are weirder than that. It's also indistinguishable from the "brain in a vat" theory, which everyone has heard of and which nobody finds interesting. It escapes me why anyone finds "simulation theory" more interesting than that.

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

#134

Post by iszomer »

WalterBright wrote: post #123
justinator wrote: post #113

Earlier quoted context omitted.

There's a chance - however small - that WE live in that simulation.

The simulation theory is indistinguishable from any religious explanation.

It can be from a secularization point of view.

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

#135

Post by richardjam73 »

apothegm wrote: post #117
twojacobtwo wrote: post #39

> Co-author Professor Dietmar Müller from the University of Sydney said: Geology ruled climate at this time. We think the Sturtian ice age kicked in due to a double whammy: a plate tectonic reorganisation brought volcanic degassing to a minimum, while simultaneously a continental volcanic province in Canada started eroding away, consuming atmospheric CO2. Research: > Duration of Sturtian “Snowball Earth” glaciation l…

How would erosion consume CO2?

Chemical processes in rock can store or release gases. Erosion can expose rocks leading to this occurring.

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

#136

Post by smdyc1 »

justinator wrote: post #113
huytersd wrote: post #101

Earlier quoted context omitted.

I wonder if we’ll get to a computational space where we can completely simulate every atom in a small closed system. Are we there yet? Can you simulate at the atomic scale and get a perfect representation of reality or do we have to try and simulate something smaller?

There's a chance - however small - that WE live in that simulation.

Then can I ask the owner of whatever device we're running on, to add one or two zeros to my bank balance?

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

#137

Post by adastra22 »

huytersd wrote: post #111
adastra22 wrote: post #109

Earlier quoted context omitted.

We can get up to 100 or so lightweight atoms (the real limiter is the number of electrons, not the number of atoms. Larger atoms cost more). Maybe a thousand or so on supercomputers. Quantum computing will change this though.

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

No, for multiple reasons. To your first question, there's still simplifying assumptions. These things usually treat the nucleus as fixed and static, for example, and often other approximating assumptions are used. Outside of the interior of a star, radioactive elements, or when relativistic energies are involved, these are good approximations though.

More fundamentally, quantum systems are inherently random. You literally can't know the exact future of hundreds of atoms in perpetuity--that's not how quantum physics works.

But you can get an idea of minimum energy states, the energy barriers holding those states in place, and therefore what the stable outcomes might be.

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

#138

Post by globalise83 »

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 was referring to a way of categorizing uncertainties in a mutually exclusive and collectively exhaustive way. There are many scenarios that are genuinely unknowable - it has nothing to do with competence. He probably saw the matrix on a McKinsey consultants slide earlier that day while they were using their 6 months of strategy consulting experience out of college to help him run the war.

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

#139

Post by mjfisher »

huytersd wrote: post #111
adastra22 wrote: post #109

Earlier quoted context omitted.

We can get up to 100 or so lightweight atoms (the real limiter is the number of electrons, not the number of atoms. Larger atoms cost more). Maybe a thousand or so on supercomputers. Quantum computing will change this though.

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 ground up now!

[1] https://en.m.wikipedia.org/wiki/Ab_initio_methods_(nuclear_p...

[1]

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

#140

Post by slashdev »

digging wrote: post #126
slashdev wrote: post #26

Earlier quoted context omitted.

Or you could just smack it with a really big rock. That nicely sterlizes the planet too, so you can reseed it with life from your planet after to make it more comfortable. Honestly it's all kind of silly because distances are so vast. It makes little sense to travel to a distant star - much better to build space habitats in your own star system. And even if you were going to do that for some crazy reason, there's no…

> a really big rock ... nicely sterlizes the planet Have you seen Earth? We've been hit with a big rock, we've turned out atmosphere into poison, and had several other mass extinctions, none of which sterilized the Earth. Unless you mean a Theia-level rock to turn the entire surface into lava, but you risk changing the mass, composition, and satellite system of the planet. At that point it's a different planet entire…

It came pretty close, remember life slowly bounced back afterward. Something a little larger would almost do the trick. You just clean up what survives.
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