Yellowstone
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23-12-2013, 02:06 PM
RE: Yellowstone
(23-12-2013 12:11 PM)WeAreTheCosmos Wrote:  
(23-12-2013 11:57 AM)Momsurroundedbyboys Wrote:  This is why I like ostriches.

They're full of pressurized magma? Consider

Sorry I dont know much about ostriches, ive basically got my head in the sand when it comes to them.

They stick their heads in the sand when frightened. I've been known to do the same thing, or so I'm told. Angel


God is a concept by which we measure our pain -- John Lennon

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23-12-2013, 02:08 PM
RE: Yellowstone
(22-12-2013 10:21 AM)Chas Wrote:  it's not fluffy bunnies and sparkly unicorns.

Sad Sadcryface Weeping


God is a concept by which we measure our pain -- John Lennon

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23-12-2013, 03:00 PM
RE: Yellowstone
Shy
(23-12-2013 01:24 PM)Chas Wrote:  
(23-12-2013 01:00 PM)kim Wrote:  When our core finally does cool off completely, we will lose our atmosphere, like our planetary neighbor, Mercury. No worries there: our sun will have already enveloped us by that time and we'll already be dead.

And likely Mars.

We will lose our atmosphere because we will have no magnetic field to deflect the solar wind, which will then shred our atmosphere and carry it all away. Weeping

Ha, yea. Tongue


There there, 'lil Chas... Hug at least then, you won't have to hire someone to shovel your snow.


Oh, if I don't see you before the end: Cheers, Chas. Drinking Beverage

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23-12-2013, 04:49 PM (This post was last modified: 23-12-2013 04:53 PM by Chas.)
RE: Yellowstone
(23-12-2013 03:00 PM)kim Wrote:  Shy
(23-12-2013 01:24 PM)Chas Wrote:  And likely Mars.

We will lose our atmosphere because we will have no magnetic field to deflect the solar wind, which will then shred our atmosphere and carry it all away. Weeping

Ha, yea. Tongue


There there, 'lil Chas... Hug at least then, you won't have to hire someone to shovel your snow.


Oh, if I don't see you before the end: Cheers, Chas. Drinking Beverage

Yeah, thanks, you too. It's been a slice. Smile

Skepticism is not a position; it is an approach to claims.
Science is not a subject, but a method.
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26-12-2013, 09:58 AM
RE: Yellowstone
(23-12-2013 01:00 PM)kim Wrote:  Just to be clear: we actually want our planet's core to be solid, followed by a liquid middle layer, and then another rigid layer just under the upper mantle and then the crust. We want the liquid core to stay molten for as long as possible.
[Image: Layers-of-Earth.jpeg]
As the Earth continues to age and cool, more and more of the core becomes solid, and when it does, the Earth shrinks a little bit. That's why we have earthquakes.

When our core finally does cool off completely, we will lose our atmosphere, like our planetary neighbor, Mercury. No worries there: our sun will have already enveloped us by that time and we'll already be dead.

Merry Christmas! Shy

Errr... No.

(1) We have Earthquakes because of plate tectonics. The North American plate is drifting northwest at about the rate your fingernails grow, the Pacific plate is drifting east at 4-5 times that rate. Where the two go bump in the night stresses build up and are released catastrophically. There is no evidence that the planet s shrinking due to thermal contraction or any other mechanism.

(2) The overwhelming majority of our atmosphere is held in by gravity. Gas molecules need to exceed our planet's escape velocity of 11.8 km/s in order to be lost and this is very rare. Mercury, the Moon, Mars, the Gallilean Moons of Jupiter all have lower escape velocities and have lost much or all of their atmosphere over time, despite volanic activity on Io, ice volcanoes on Europa and possible recent volcanic activity on Mars. On the other hand, Venus, which has an escape velocity similar to Earth's but is tectonically inert has the thickest atmosphere of any rocky planet. Our atmosphere will be here long after the last volcano goes extinct.

(3) Vulcanism is not driven by the Earth's molten outer core. Certain types of vulcanism, hot spot vulcanism, originate at the core-mantle boundary. These are the minority and even they only derive their heat from the core. Most vulcanism is driven by plate tectonics, either sea-floor spreading or subduction.

As mentioned, solidification of the outer molten core will take an obscenely long time, but when/if it ever happens our planet will keep on keeping on. There will be some interesting changes but nothing that would end life as we know it if it happened today.
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26-12-2013, 11:09 AM
RE: Yellowstone
A few notes on the Yellowstone Caldera:

- It isn't going to blow any time soon. The magma reservoir beneath Yellowstone is filling but it's been doing that since before we've known about it. There's frequent increases and decreases in activity in the park, shifts of geothermal activity from one place to another, etc. This is typical activity for this type of geothermal system. The activity is dynamic but minor changes do not herald the next great eruption. A major eruption would be preceded by large-scale uplift and doming, hugely increased gas-venting, increased hydrothermal activity and large increases in seismic activity. We ought to have a few decades warning.

- Yellowstone doesn't always blow big. The "supervolcano" aspect of it gets so overdramatized that the frequent small eruptions and flows get largely ignored. Lava flows, "small" ash eruptions and phreatomagmatic explosions (what you get when you pump cold water into a hot magma chamber) are all common to the park.

- A full-scale eruption would be very ugly but wouldn't be the end of the US. The ash fall maps that you see are the maximum extend of detectable ash fall preserved in the geological record. The ash layer in the immediate vicinity of Yellowstone would be several hundred meters thick and would bury large portions of the adjacent states. Further out you're looking at much more tolerable levels of deposition, from a few feet to an inch or two. Anywhere from a real nuisance to some light entertainment. All in all it'd end up being ploughed into the soil and likely enriching a lot of cropland. Rivers and lakes would take the biggest hit but most would recover. Precautions would need to be taken to avoid pulmonary problems from ash inhalation. Evacuation of the western US would be unnecessary. Wyoming, Montana and Idaho would likely need large-scale evacuation but all are sparsely populated and the decades of warning should make this easier to handle. The worst problem we'll face is global cooling courtesy of craploads of sulfate aerosol being blown into the stratosphere. Mean Global Temperature would fall significantly for the following decade or so, but right now that could be a good thing.

- When it blows Yellowstone won't go the way of normal stratovolcanoes. Yellowstone's a massive caldera, consisting of a solid rock lid overlying a magma chamber 30 to 50 km across. The rock lid is denser than the magma below it and only stays up because of its immense strength (it's tens of km thick) and pressure in the magma chamber. Things will start relatively small, an eruption similar to Mt. St. Helens at a single vent. This will release the pressure that's helping to hold the lid up. As the pressure drops the lid will begin to rupture along multiple locations along pre-existing faults and other lines of weakness. More vents will form and begin erupting. This releases yet more pressure, further weakening the lid that's holding everything in and leading to a positive-feedback runaway. Eventually the lid of the caldera subsides into the magma chamber, acting like a piston driving the magma upward around the rim and anywhere else it can escape.

- There's nothing we can do. It's a force of nature like a hurricane or tsunami only much, much more powerful. Yellowstone is being powered by heat rising from the core-mantle boundary and has been building up for ~600,000 years. Bad ideas that have been proposed include:
--- Pumping water in. Aside from the engineering nightmare this would be, water is what makes volcanoes erupt. They're steam-powered. It'd be like fighting a forest fire with gasoline assuming you could manage to get any significant amount down there.
---Nuking it. This has actually been proposed. If you were lucky you'd use a low-yield nuke and just get no effect. If you were unlucky and used a high-yield H-bomb you'd crack the lid holding the whole thing in check and precipitate the disaster you're trying to avoid but with no time to prepare or evacuate. If you were truly imbecilic you could build a nuke big enough to completely destroy the caldera but causing worse devastation than a mere supervolcano could ever manage. Radioactive fallout + volcanic ash = bad.
---Chilling it. An extremely aggressive hydrothermal energy extraction system could, in theory, cool the Yellowstone caldera. It'd be an engineering nightmare and would need you to tap off more thermal energy that North America could ever burn through but assuming it could be done you don't want to. The first effect would be to cool the lid of the caldera making it denser and more brittle. As cooling extended into the magma chamber itself you'd set up a vigorous convection effect as cool, dense lava near the roof descended and hot, bouyant lava rose to take its place. This is a good way to make things go boom sooner than expected.

All in all though, don't worry about it. It makes for a great natural spectacle and even if it started showing signs of erupting today probably wouldn't reach the point of actually blowing within your lifetime. In fact, that sort of implacable natural threat might actually provide some good incentives for working on some really handy new technologies and possibly getting our arses off this dirtball.
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26-12-2013, 11:36 AM
RE: Yellowstone
(26-12-2013 11:09 AM)Paleophyte Wrote:  All in all though, don't worry about it.

Thank you for a healthy and overdue perspective.

Sheesh you guys, calm down!

He's not the Messiah. He's a very naughty boy! -Brian's mum
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26-12-2013, 01:39 PM
RE: Yellowstone
(26-12-2013 09:58 AM)Paleophyte Wrote:  
(23-12-2013 01:00 PM)kim Wrote:  Just to be clear: we actually want our planet's core to be solid, followed by a liquid middle layer, and then another rigid layer just under the upper mantle and then the crust. We want the liquid core to stay molten for as long as possible.
[Image: Layers-of-Earth.jpeg]
As the Earth continues to age and cool, more and more of the core becomes solid, and when it does, the Earth shrinks a little bit. That's why we have earthquakes.

When our core finally does cool off completely, we will lose our atmosphere, like our planetary neighbor, Mercury. No worries there: our sun will have already enveloped us by that time and we'll already be dead.

Merry Christmas! Shy

Errr... No.

(1) We have Earthquakes because of plate tectonics. The North American plate is drifting northwest at about the rate your fingernails grow, the Pacific plate is drifting east at 4-5 times that rate. Where the two go bump in the night stresses build up and are released catastrophically. There is no evidence that the planet s shrinking due to thermal contraction or any other mechanism.

(2) The overwhelming majority of our atmosphere is held in by gravity. Gas molecules need to exceed our planet's escape velocity of 11.8 km/s in order to be lost and this is very rare. Mercury, the Moon, Mars, the Gallilean Moons of Jupiter all have lower escape velocities and have lost much or all of their atmosphere over time, despite volanic activity on Io, ice volcanoes on Europa and possible recent volcanic activity on Mars. On the other hand, Venus, which has an escape velocity similar to Earth's but is tectonically inert has the thickest atmosphere of any rocky planet. Our atmosphere will be here long after the last volcano goes extinct.

(3) Vulcanism is not driven by the Earth's molten outer core. Certain types of vulcanism, hot spot vulcanism, originate at the core-mantle boundary. These are the minority and even they only derive their heat from the core. Most vulcanism is driven by plate tectonics, either sea-floor spreading or subduction.

As mentioned, solidification of the outer molten core will take an obscenely long time, but when/if it ever happens our planet will keep on keeping on. There will be some interesting changes but nothing that would end life as we know it if it happened today.

When the Earth no longer has a molten core, it will no longer have much, if any, magnetic field.

Without the geomagnetic field, the solar wind will shred our atmosphere, blowing it off into space, and then the oceans would eventually go.

Skepticism is not a position; it is an approach to claims.
Science is not a subject, but a method.
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27-12-2013, 11:53 AM
RE: Yellowstone
(17-12-2013 05:08 PM)kingschosen Wrote:  That's actually pretty disconcerting. Can we do anything about it?

Let's put baking soda on it.
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02-01-2014, 06:27 AM (This post was last modified: 02-01-2014 06:38 AM by DeepThought.)
RE: Yellowstone
Interesting observations thankyou for your post.

(26-12-2013 11:09 AM)Paleophyte Wrote:  - A full-scale eruption
The worst problem we'll face is global cooling courtesy of craploads of sulfate aerosol being blown into the stratosphere. Mean Global Temperature would fall significantly for the following decade or so, but right now that could be a good thing.

I think the worst problem we could face here is this attitude: "Oh Cool! We don't have to deal with our pollution... Lets keep pumping CO2 into the atmosphere... The planet will take care of itself!"

20 Years Later: "Damn now we are screwed! Lets set off another volcano with a H-Bomb to help offset our greenhouse gasses."

(26-12-2013 11:09 AM)Paleophyte Wrote:  ---Nuking it. This has actually been proposed. If you were lucky you'd use a low-yield nuke and just get no effect. If you were unlucky and used a high-yield H-bomb you'd crack the lid holding the whole thing in check and precipitate the disaster you're trying to avoid but with no time to prepare or evacuate. If you were truly imbecilic you could build a nuke big enough to completely destroy the caldera but causing worse devastation than a mere supervolcano could ever manage. Radioactive fallout + volcanic ash = bad.

It has actually be proven, the more powerful the bomb the greater the efficiency with less radioactive fallout. Hydrogen bombs use fission as the primary to set off the secondary tritium-deuterium fusion reaction. That's extra pressure and extra neutron flux. This means that more fissile material is burnt up or converted into shorter half-life isotopes. The amount of energy you would need to set off that volcano would definitely require a hydrogen bomb. To make the bomb cleaner you can add a third fusion stage. Since this isn't a weapon that needs to be delivered via an ICBM there aren't concerns about weight, more can be done to make it clean and efficient where most of its energy comes from fusion.

“Forget Jesus, the stars died so you could be born.” - Lawrence M. Krauss
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