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you

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here from astrophysics to geophysics

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I'll be talking about basically whether

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or not you expect planets to look like

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earth with some amount of continents and

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some amount of ocean or what I define

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here is a water world that is a planet

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that has the surface completely covered

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in water and so there's no exposed

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continent and so this kind of ties into

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the talks earlier today about volatile

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delivered-to planets where here I'm

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basically just going to take a wide

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variety of initial water contents or

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planets and then calculate whether or

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not they should be water worlds that is

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water covered and so before I talk about

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the water cycle this advances I'll talk

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about the carbon cycle because it's kind

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of an analogue to the water cycle when

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it motivates why this is an important

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problem to understand

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so just to briefly review right the main

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sources of carbon from the interior of

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Earth or any terrestrial planet with

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plate tectonics to the atmosphere ocean

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system is basically through volcanism

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either at arc arc focus on like the

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Cascade Range in Northwest USA or at

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mid-ocean ridges and the main return

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mechanisms are seafloor weathering

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basically hydrothermal alteration at the

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seafloor which then gets abducted and

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returns carbon in the mantle and then

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most importantly silicate weathering and

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so the silicate weathering occurs when

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you have basically right rain falling it

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mixes with co2 to make carbonic acid

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which then dissolves silicates on the

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continents and then this creates like

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bicarbonate which then flow into the

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ocean and then eventually lissa phi on

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the seafloor and then our subducting in

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return to the mantle and so importantly

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the silicate weathering

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process occurs as a negative feedback

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which stabilizes the climate of

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terrestrial planets this is because

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chemical reactions on the surface of a

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planet will run faster if the climate of

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the planet is hotter right and so the

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silicate weathering feedback will

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stabilize your Cartman if you put more

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co2 in the atmosphere so look at weather

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weather and will run faster remove co2

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from the atmosphere into the interior of

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the planet and reduce the surface

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temperature of the planet and notably

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it's not known whether or not seafloor

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weathering depends on the climate of the

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planet and so if it does not and then

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you have a water world where you no

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longer has silicate weathering it would

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expect then the climate of the planet to

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not be stable you would easily runaway

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greenhouse unless you very finely tuned

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the climate of the planet and so just

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look at a little schematic here you can

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envision this just by looking at the

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habitable zone for water world versus

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planets with silicate weathering here

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the red area of these of these of these

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of these cartoons is where oceans boil

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where you enter a runaway greenhouse the

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blue the blue region is where greenhouse

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gases freeze this is the co2

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condensation limit for the habitable

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zone and then the green area that is the

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habitable zone basically the habitable

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zone for Waterworld should be much much

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smaller than for planets with silicate

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weathering with and with plate tectonics

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and so if we want to understand then

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whether water world's our Comment we

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need to understand how water is

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partitioned between the service and the

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interior of the planet that is the deep

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water cycle and we can look at the deep

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water cycle basically it's almost the

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same as the carbon cycle but the intake

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process into the mantle is slightly

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different and so here's just using the

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same stacks Kemetic but replacing the

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subduction process for water right water

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is produced from the interior to the

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atmosphere through volcanism just like

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carbonates but it's returned in a

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different way basically water hydrates

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basalt through serpentinization and then

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the tighter your basalt is then

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subducted in the mantle but it's an open

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question so far in literature exactly

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what regulates water cycling on fresh

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locks of planets and earth itself there

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are basically two leading ideas one

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leading idea is that mantle convection

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regulates water cycling that is if you

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have a hundred mantle you'll more fuel

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more volcanism and if you have a hotter

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mantle you'll have reduced return of

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water into the mantle because the amount

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of water you can store in the crust is

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lessened and then the other idea is the

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surface water budget and so the second

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idea is relatively new and I'll walk you

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through it quickly and also just to just

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to run everybody I'm assuming plate

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tectonics here and it's not necessarily

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expected that all terrestrial exoplanets

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have plate tectonics there may be other

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tectonic modes like say stagnant laid

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tectonics or vertical heat pipe like

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tectonics and water cycling would work

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completely different on planets with

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with these other tectonic regimes so

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just keep that caveat in mind and so to

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envision how the amount of surface water

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affects water cycling let's just look at

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go back to the schematic and say we have

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some amount of outgassing written by W

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up here and some amount of in gassing

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written by W down here and if and we

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have some ocean depth if we increase the

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ocean depth we would expect that the in

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gassing increases just because we have

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more around the surface available too

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and gas and also the outgassing will

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decrease because you have a greater load

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pressure on mid-ocean ridges and so this

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reduces the amount of volcanism at

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mid-ocean ridges and so recently Nick

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Cowen and Doreen Abbott have looked at

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this using a simple steady-state model

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so they assume that water second one was

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in steady state and wrote down very

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simple power laws this is much simpler

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physics and the last talk

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saying that the the degassing are--

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gassing rates are just power laws and

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the seafloor pressure that is basically

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just the ocean depth and so if you have

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more water on the surface that is a

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greater seafloor pressure you'll have

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less outgassing and if you have more

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water on the surface you'll have more in

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gassing and so using this you can

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basically just predict how much water

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you need for the surface of the water to

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be serviced with the plan to be covered

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to be covered in water as a function of

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planetary parameters if I can get it to

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move okay so here on the y axis this is

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how much water you have on the planet as

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a function of its total mass that is the

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water mass fraction the planet here

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normalized earth where as was mentioned

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earlier Earth's water mass fraction is

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about 0.1% and then only on the x axis

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of the planet mass normalized to earth

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and each of these lines shows different

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combinations of these parameter values

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and if you're above each individual line

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your water world that is the plane of

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the surface of the planet is totally

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covered in water and if you're below the

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line there's partial line coverage and

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you have the silica weathering feedback

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and the climate should be stable and so

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you can see that whether or not the plan

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is the Waterworld depending on planet

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mass and water mass fraction is

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extremely dependent on the assumed

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seafloor pressure feedbacks in the model

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and so this is a natural problem we

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don't we don't know whether or not

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seafloor seafloor pressure alone

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regulates water cycling but also we

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don't understand in detail how

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what what these power law dependencies

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should be for seafloor pressure and then

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this is just one paradigm for water

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cycling what about the other paradigm

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temperature dependent water cycling and

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so in this case I mentioned earlier the

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degassing right rate is set by the

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mental temperature through the melt

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fraction if you have more melt field

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more volcanism and therefore you'll have

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more out casting and the Riu gassing

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rate is set by the depth at which rocks

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becomes hydrated because subsidization

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can only occur below a critical

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temperature and so this was looked at

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recently in detail for exoplanets by

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Schafer and SAS love and they found here

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the results from them further from their

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numerical model for two different

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assumptions for the viscosity ones the

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high viscosity of the mantle which is

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relevant for the deeper mantle of Earth

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and one for the low viscosity mantle and

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here are the results for the fraction of

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the surface covered by water where one

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would be a water world and zero will be

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a planet without any surface water as a

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function of time and you can see that

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for the high viscosity case none of

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their models these lines adjust for

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different planet masses reaches the

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steady-state over ten billion years but

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if one assumes the low viscosity

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relevant for the shallow mantle you can

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see this phase of initial outgassing and

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then really fast recasting and then you

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end with essentially no service water

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available which is in

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itself a problem for habitability right

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and so we have these two different

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paradigms which predict extremely

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different rates at which planet should

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become water worlds and so I looked at

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this with Doreen Abbott in a simple

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non-dimensional framework so we

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considered three different possibilities

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for water cycling we considered this

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pressure dependent framework that I

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talked about from Cowen Abbott a

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temperature dependent model and then we

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also looked at a hybrid model basically

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combining the two where the recasting

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rate is depends on temperature the

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reason why is because it has not been

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shown experimentally that recasting

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should be dependent on how much water is

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available on the surface and so we

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basically just ignored that possibility

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and then the the degassing rate is

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dependent on pressure and the reason why

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is because at late times pressure Japan

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you guessing should have a greater

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influence on the you guessing rate than

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the mantle temperature because the

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mantle is so cold and so we use a simple

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non-dimensional framework because then

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we can understand the effects of various

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unknowns because as you can see there

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are lots of unknowns in this problem

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that affect the solution on water

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cycling and nicely we actually found

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that there's only one unknown that

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really matters and that is how much how

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much water you can stuff from the mantle

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all the other unknowns are only about a

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factor of two make about a factor of two

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difference and how and how common water

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worlds are and given that we won't be

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able to observe too many water worlds

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for about twenty years it's not such a

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big deal

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so okay so what happens if we just

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evolve our model looking at these three

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different paradigms for water cycling so

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here I'm just showing the ocean depths

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that are predicted from the model as a

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function of time here in billions of

276
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years and so the earth-like ocean depth

277
00:08:56,780 --> 00:08:55,560
is shown by the dashed line and each of

278
00:08:58,490 --> 00:08:56,790
these different lines is for the

279
00:08:59,540 --> 00:08:58,500
different models so you can see that for

280
00:09:02,269 --> 00:08:59,550
the pressure dependent model there's

281
00:09:04,790 --> 00:09:02,279
essentially just a simple

282
00:09:06,500 --> 00:09:04,800
a relaxation to a given ocean depth and

283
00:09:07,790 --> 00:09:06,510
then for the temperature pennant in the

284
00:09:09,650 --> 00:09:07,800
hybrid model because the mantle

285
00:09:11,000 --> 00:09:09,660
temperature is hot as hot at the start

286
00:09:12,949 --> 00:09:11,010
and cools off with time you have initial

287
00:09:14,930 --> 00:09:12,959
really fast outgassing and then really

288
00:09:16,819 --> 00:09:14,940
fast in gassing and the hybrid model you

289
00:09:17,870 --> 00:09:16,829
you end up with something similar to the

290
00:09:19,759 --> 00:09:17,880
pressure dependent model in terms of how

291
00:09:21,019 --> 00:09:19,769
much service water is on the surface but

292
00:09:22,449 --> 00:09:21,029
for the temperature credit model you end

293
00:09:25,310 --> 00:09:22,459
up with very little water on the surface

294
00:09:27,530 --> 00:09:25,320
and so you can see that at the ends of

295
00:09:31,069 --> 00:09:27,540
these integrations I'm running these out

296
00:09:32,569 --> 00:09:31,079
to well past the edge of the universe

297
00:09:34,340 --> 00:09:32,579
each of these lines seems a flattened

298
00:09:36,379 --> 00:09:34,350
out so it looks like a steady-state but

299
00:09:37,819 --> 00:09:36,389
if one looks at this in more detail one

300
00:09:39,500 --> 00:09:37,829
can see that actually the temperature

301
00:09:41,000 --> 00:09:39,510
dependent model is not in a steady state

302
00:09:43,100 --> 00:09:41,010
so here I'm plotting the recasting idea

303
00:09:44,870 --> 00:09:43,110
in via gassing fluxes from the model so

304
00:09:46,400 --> 00:09:44,880
the solid line is the reacting flux and

305
00:09:47,900 --> 00:09:46,410
the dashed lines of the degassing fluxes

306
00:09:49,670 --> 00:09:47,910
from the models of the same colors and

307
00:09:50,750 --> 00:09:49,680
you can see that the hybrid model in the

308
00:09:52,639 --> 00:09:50,760
pressure dependent model do reach a

309
00:09:53,780 --> 00:09:52,649
steady state where the lines balance out

310
00:09:55,970 --> 00:09:53,790
for the two and the temperature

311
00:09:57,740 --> 00:09:55,980
dependent muddle the rege assing at late

312
00:09:59,720 --> 00:09:57,750
times dominates over the degassing and

313
00:10:01,579 --> 00:09:59,730
notably this is actually currently what

314
00:10:02,960 --> 00:10:01,589
what we think is happening on earth and

315
00:10:05,180 --> 00:10:02,970
so this temperature credit model is the

316
00:10:06,800 --> 00:10:05,190
most relevant for Earth but it's

317
00:10:10,519 --> 00:10:06,810
possible at these other paradigms maybe

318
00:10:12,470 --> 00:10:10,529
maybe relevant as well and so now using

319
00:10:13,790 --> 00:10:12,480
these end results these steady States we

320
00:10:16,340 --> 00:10:13,800
can make predictions because their model

321
00:10:17,660 --> 00:10:16,350
is essentially analytic for how much

322
00:10:19,069 --> 00:10:17,670
water you need to become a water roll

323
00:10:21,079 --> 00:10:19,079
just like the count and Abbott and

324
00:10:22,430 --> 00:10:21,089
Abbott model did but now for all these

325
00:10:25,160 --> 00:10:22,440
different paradigms for water cycling

326
00:10:26,449 --> 00:10:25,170
and so doing so here I'm showing this is

327
00:10:27,769 --> 00:10:26,459
the same plot as I showed before if

328
00:10:30,230 --> 00:10:27,779
you're above the line near water world

329
00:10:31,280 --> 00:10:30,240
for a given water mass fraction and if

330
00:10:33,079 --> 00:10:31,290
you're below the line you have partial

331
00:10:34,670 --> 00:10:33,089
Lange coverage and this is again the

332
00:10:36,259 --> 00:10:34,680
x-axis planet master normalized Earth

333
00:10:37,819 --> 00:10:36,269
and I'm showing the earth value of the

334
00:10:40,550 --> 00:10:37,829
water mass fraction which is about 0.05

335
00:10:41,990 --> 00:10:40,560
percent in the dashed line and so I'm

336
00:10:43,069 --> 00:10:42,000
showing these different models so black

337
00:10:44,269 --> 00:10:43,079
line is the temperature dependent model

338
00:10:46,100 --> 00:10:44,279
and you can see that you need quite a

339
00:10:47,540 --> 00:10:46,110
bit of water you need to be about one

340
00:10:49,370 --> 00:10:47,550
percent of water by mass even if you're

341
00:10:50,540 --> 00:10:49,380
a super earth to become a Waterworld at

342
00:10:52,069 --> 00:10:50,550
the temperature dependent paradigm and

343
00:10:54,110 --> 00:10:52,079
the pressure dependent paradigm are

344
00:10:55,730 --> 00:10:54,120
correct I notably this line is

345
00:10:57,860 --> 00:10:55,740
essentially just regulated by how much

346
00:10:59,750 --> 00:10:57,870
water one can fit into the mantle and so

347
00:11:01,519 --> 00:10:59,760
this basically Maxima mental water mass

348
00:11:03,530 --> 00:11:01,529
fraction so slowly determines where this

349
00:11:04,879 --> 00:11:03,540
line is and so if one can stuff more

350
00:11:06,500 --> 00:11:04,889
water into the mantle of the super earth

351
00:11:09,259 --> 00:11:06,510
with a different mineralogy say it has a

352
00:11:10,790 --> 00:11:09,269
post products cat mantle then this line

353
00:11:12,980 --> 00:11:10,800
would move upwards it would be even less

354
00:11:15,199 --> 00:11:12,990
likely that super Earths will be water

355
00:11:15,980 --> 00:11:15,209
world's but you can see that this hybrid

356
00:11:18,080 --> 00:11:15,990
line

357
00:11:19,430 --> 00:11:18,090
is actually very close to a limit where

358
00:11:21,020 --> 00:11:19,440
there's no water cycling at all which is

359
00:11:22,640 --> 00:11:21,030
shown by the dashed out of line this

360
00:11:23,990 --> 00:11:22,650
would basically just be if all the water

361
00:11:25,550 --> 00:11:24,000
available was on the surface and there

362
00:11:27,590 --> 00:11:25,560
were there was no water in the interior

363
00:11:29,240 --> 00:11:27,600
and so if this hybrid model is relevant

364
00:11:30,560 --> 00:11:29,250
one would expect it's about an order of

365
00:11:32,780 --> 00:11:30,570
magnitude easier in terms of how much

366
00:11:34,250 --> 00:11:32,790
water you need as a fraction of the

367
00:11:36,050 --> 00:11:34,260
total planet mass for a plan to become a

368
00:11:38,690 --> 00:11:36,060
water world and so this is a relatively

369
00:11:39,860 --> 00:11:38,700
a large difference and one what one

370
00:11:40,970 --> 00:11:39,870
would expected in the future we might

371
00:11:42,740 --> 00:11:40,980
actually be able to observational e

372
00:11:44,690 --> 00:11:42,750
distinguish this difference with

373
00:11:48,530 --> 00:11:44,700
telescopes issues Lavar making maps of

374
00:11:49,730 --> 00:11:48,540
terrestrial exoplanets and so just hit

375
00:11:51,470 --> 00:11:49,740
the point home that the maximum and

376
00:11:53,450 --> 00:11:51,480
we'll wash water mass fraction is the

377
00:11:55,280 --> 00:11:53,460
key unknown here I'm showing how the

378
00:11:57,230 --> 00:11:55,290
maximum amount of water mass fraction

379
00:11:58,460 --> 00:11:57,240
shown on the x-axis changes the water

380
00:11:59,870 --> 00:11:58,470
mass fraction at which the planet

381
00:12:01,340 --> 00:11:59,880
becomes a water world and we're going to

382
00:12:02,720 --> 00:12:01,350
see that it's essentially just a power

383
00:12:04,940 --> 00:12:02,730
law relationship between the two and so

384
00:12:07,220 --> 00:12:04,950
this is a really key unknown for future

385
00:12:08,420 --> 00:12:07,230
experiments to determine how much water

386
00:12:10,730 --> 00:12:08,430
can you stuff into high pressure

387
00:12:14,870 --> 00:12:10,740
minerals that are not like earth

388
00:12:16,190 --> 00:12:14,880
minerals and so just a parameters only

389
00:12:19,400 --> 00:12:16,200
change the water or boundary by about a

390
00:12:21,680 --> 00:12:19,410
factor of two and so just to summarize

391
00:12:23,180 --> 00:12:21,690
how water cycling depends on properties

392
00:12:24,650 --> 00:12:23,190
of the planet makes a pretty significant

393
00:12:25,910 --> 00:12:24,660
but an order of magnitude difference as

394
00:12:28,130 --> 00:12:25,920
to whether or not water worlds are

395
00:12:29,450 --> 00:12:28,140
common in the universe and potentially

396
00:12:31,400 --> 00:12:29,460
this could be resolved of course just by

397
00:12:32,900 --> 00:12:31,410
understanding better how water cycling

398
00:12:34,190 --> 00:12:32,910
happens on earth right and so we could

399
00:12:36,260 --> 00:12:34,200
have more detailed modeling of Rou

400
00:12:37,579 --> 00:12:36,270
gassing and degassing processes and also

401
00:12:38,900 --> 00:12:37,589
experiments would be nice to show if the

402
00:12:40,430 --> 00:12:38,910
salt hydration does depend on the

403
00:12:41,750 --> 00:12:40,440
overburden pressure and whether or not

404
00:12:44,360 --> 00:12:41,760
this Coward Navarrete prescription is

405
00:12:45,440 --> 00:12:44,370
actually relevant for exoplanets but the

406
00:12:47,690 --> 00:12:45,450
coolest way is because this is an

407
00:12:49,070 --> 00:12:47,700
astrobiology conference is to map

408
00:12:51,110 --> 00:12:49,080
services with pressure electric planets

409
00:12:52,850 --> 00:12:51,120
to reflected light with perhaps leVoir

410
00:12:54,530 --> 00:12:52,860
maybe in twenty years or so and then

411
00:12:56,450 --> 00:12:54,540
actually count how many planets or water

412
00:12:58,730 --> 00:12:56,460
worlds and how many are not and given

413
00:13:00,740 --> 00:12:58,740
some model for the the water delivered

414
00:13:02,810 --> 00:13:00,750
exoplanets like heist I was talking

415
00:13:04,340 --> 00:13:02,820
about earlier then you can basically

416
00:13:05,960 --> 00:13:04,350
figure out which of these models is

417
00:13:08,150 --> 00:13:05,970
correct and so we might be able to and

418
00:13:09,290 --> 00:13:08,160
the very far future use exoplanets to

419
00:13:10,880 --> 00:13:09,300
teach us something about Earth and so I

420
00:13:17,150 --> 00:13:10,890
think that's really neat and thank you

421
00:13:22,170 --> 00:13:20,730
thanks tad we have about a minute or so

422
00:13:23,389 --> 00:13:22,180
for questions and then we'll move into a

423
00:13:25,499 --> 00:13:23,399
discussion

424
00:13:27,389 --> 00:13:25,509
so there's other one of the property

425
00:13:29,519 --> 00:13:27,399
abortions that you didn't speak about

426
00:13:32,160 --> 00:13:29,529
and I'm curious is the salinity of the

427
00:13:34,259 --> 00:13:32,170
water there's adding salt affect the

428
00:13:35,720 --> 00:13:34,269
femini properties enough to change any

429
00:13:38,869 --> 00:13:35,730
of your conclusions

430
00:13:42,350 --> 00:13:38,879
hi I have no idea

431
00:13:44,699 --> 00:13:42,360
yeah I mean I would

432
00:13:46,559 --> 00:13:44,709
it definitely doesn't affect the

433
00:13:48,660 --> 00:13:46,569
outgassing but it may affect in gassing

434
00:13:51,090 --> 00:13:48,670
of water yeah I don't understand some

435
00:13:52,740 --> 00:13:51,100
prepend ization enough but yeah there's

436
00:13:54,569 --> 00:13:52,750
there's that there's been sessions on

437
00:13:56,660 --> 00:13:54,579
that earlier yeah I don't either but

438
00:14:00,090 --> 00:13:56,670
that's great

439
00:14:02,910 --> 00:14:00,100
so my question is about the deep earth

440
00:14:04,650 --> 00:14:02,920
the deep planet minerals which is it's

441
00:14:06,660 --> 00:14:04,660
been shown that bridge night cannot hold

442
00:14:07,769 --> 00:14:06,670
on to water very well at all and even in

443
00:14:10,769 --> 00:14:07,779
a super-earth you would still go through

444
00:14:12,840 --> 00:14:10,779
Bridgman night phase it may be shallow

445
00:14:14,970 --> 00:14:12,850
but you would still have it so if in

446
00:14:17,610 --> 00:14:14,980
this in gassing model if you go through

447
00:14:19,639 --> 00:14:17,620
if your plate or whatever is in gassing

448
00:14:22,490 --> 00:14:19,649
has to go through a region that

449
00:14:25,740 --> 00:14:22,500
nominally can't hold on to water

450
00:14:27,240 --> 00:14:25,750
how does that change the story well that

451
00:14:28,650 --> 00:14:27,250
seems it actually being I mean earth

452
00:14:29,970 --> 00:14:28,660
goes through this the same sort of

453
00:14:31,499 --> 00:14:29,980
transition I didn't talk about this but

454
00:14:32,879 --> 00:14:31,509
most most of Earth's water is stuck at a

455
00:14:34,769 --> 00:14:32,889
region the mental call that transitions

456
00:14:37,050 --> 00:14:34,779
them and so it essentially be the same

457
00:14:38,400 --> 00:14:37,060
story as Earth in terms of these models

458
00:14:40,110 --> 00:14:38,410
all you need to do is just get the water

459
00:14:42,090 --> 00:14:40,120
into the mantle and then how it deep it

460
00:14:43,079 --> 00:14:42,100
goes is not really relevant because it

461
00:14:44,759 --> 00:14:43,089
should just be mixed on the mantle

462
00:14:46,340 --> 00:14:44,769
convection or overturn timescale which

463
00:14:48,269 --> 00:14:46,350
is relatively short

464
00:14:50,850 --> 00:14:48,279
depends on the on the plant on the

465
00:14:52,379 --> 00:14:50,860
planet properties of course but yeah I

466
00:14:54,540 --> 00:14:52,389
would expect not to change the story

467
00:14:56,490 --> 00:14:54,550
that much well I wonder because your the

468
00:14:59,280 --> 00:14:56,500
depth of your transition zone and the

469
00:15:00,870 --> 00:14:59,290
sort of width of your transition zone

470
00:15:02,790 --> 00:15:00,880
should be smaller on super-earths as

471
00:15:06,590 --> 00:15:02,800
well so I'd be I'd be curious to talk to

472
00:15:11,069 --> 00:15:08,790
okay thanks Ted we'll move on to

473
00:15:13,309 --> 00:15:11,079
discussion I certainly have a few

474
00:15:16,650 --> 00:15:13,319
questions but

475
00:15:19,470 --> 00:15:16,660
so we've talked about planet composition

476
00:15:21,139 --> 00:15:19,480
and observe observations and the origins

477
00:15:23,429 --> 00:15:21,149
of water and so

478
00:15:24,710 --> 00:15:23,439
you don't really have a discussion topic

479
00:15:26,610 --> 00:15:24,720
per se but

480
00:15:28,320 --> 00:15:26,620
do we have more questions for the

481
00:15:29,570 --> 00:15:28,330
speaker or do we see a theme popping up

482
00:15:32,130 --> 00:15:29,580
in terms of

483
00:15:38,270 --> 00:15:32,140
the formation of habitable planets and

484
00:15:38,280 --> 00:15:42,530
yeah Elizabeth

485
00:15:46,410 --> 00:15:44,400
questions for last week I may have

486
00:15:49,070 --> 00:15:46,420
missed it but did we talk about topology

487
00:15:50,810 --> 00:15:49,080
and gravity

488
00:15:53,670 --> 00:15:50,820
[Music]

489
00:15:55,500 --> 00:15:53,680
good question so to calculate whether or

490
00:15:58,260 --> 00:15:55,510
not a plant should be a Waterworld we

491
00:16:00,690 --> 00:15:58,270
basically just assume that the maximum

492
00:16:02,370 --> 00:16:00,700
topography of a planet is exactly what

493
00:16:03,960 --> 00:16:02,380
it would be for Earth and so we just say

494
00:16:05,370 --> 00:16:03,970
that the maximum topography is the

495
00:16:06,660 --> 00:16:05,380
Himalayas for an earth-like planet and

496
00:16:08,940 --> 00:16:06,670
then if you increase the mass of the

497
00:16:10,560 --> 00:16:08,950
planet because it has a greater volume

498
00:16:12,600 --> 00:16:10,570
to surface area ratio it should have a

499
00:16:14,760 --> 00:16:12,610
reduced topography and so basically just

500
00:16:16,620 --> 00:16:14,770
have a scaling that says that the

501
00:16:18,690 --> 00:16:16,630
maximum topography is the Himalayas

502
00:16:20,310 --> 00:16:18,700
times gravity to the minus one which

503
00:16:21,570 --> 00:16:20,320
accounts for that and so then we were

504
00:16:22,680 --> 00:16:21,580
when we're tracking whether or not a

505
00:16:25,050 --> 00:16:22,690
planet is the Waterworld you're just

506
00:16:26,370 --> 00:16:25,060
saying if the ocean depth is greater

507
00:16:35,370 --> 00:16:26,380
than what the Himalayas would be on a

508
00:16:39,180 --> 00:16:37,800
can you repeat the question so he asked

509
00:16:40,920 --> 00:16:39,190
about erosion I think I think the

510
00:16:42,690 --> 00:16:40,930
relevant thing is whether or not the

511
00:16:44,670 --> 00:16:42,700
continent would start flowing under its

512
00:16:46,140 --> 00:16:44,680
own weight so it's not a rosin it's it's

513
00:16:48,110 --> 00:16:46,150
a much more serious constraint it's

514
00:16:51,090 --> 00:16:48,120
isostasy yeah I

515
00:16:53,460 --> 00:16:51,100
had a question for Owen which was about

516
00:16:56,510 --> 00:16:53,470
the in regards to what Stephen asked in

517
00:16:59,580 --> 00:16:56,520
terms of magnetic fields is

518
00:17:01,080 --> 00:16:59,590
we know we may not think the earth may

519
00:17:03,120 --> 00:17:01,090
not have had a magnetic field at the

520
00:17:06,030 --> 00:17:03,130
moment it you know had this proto

521
00:17:08,550 --> 00:17:06,040
atmosphere so how quickly would a planet

522
00:17:11,040 --> 00:17:08,560
need to have a magnetic field in order

523
00:17:13,740 --> 00:17:11,050
for that effect even need to be taken to

524
00:17:15,330 --> 00:17:13,750
into account for for an earth-mass

525
00:17:18,000 --> 00:17:15,340
planet you would have to be very quick

526
00:17:20,790 --> 00:17:18,010
it loses its entire proto atmosphere and

527
00:17:21,870 --> 00:17:20,800
maybe ten million years so if you if it

528
00:17:23,970 --> 00:17:21,880
took more than that for a magnetic

529
00:17:25,860 --> 00:17:23,980
fields to form then then I wouldn't even

530
00:17:27,660 --> 00:17:25,870
expect that okay and how about says you

531
00:17:29,970 --> 00:17:27,670
go out to five or six or eight masses

532
00:17:31,860 --> 00:17:29,980
out of that range then you're going past

533
00:17:34,050 --> 00:17:31,870
you know tens of millions of years into

534
00:17:36,390 --> 00:17:34,060
that range so maybe 50 60 million years

535
00:17:38,550 --> 00:17:36,400
for some of the model parameters but is

536
00:17:40,440 --> 00:17:38,560
it ever a billion years or anything like

537
00:17:42,090 --> 00:17:40,450
that by the time you hit seven or eight

538
00:17:43,950 --> 00:17:42,100
earth masses then you're looking at sort

539
00:17:45,600 --> 00:17:43,960
of the billion year time scales but at

540
00:17:47,430 --> 00:17:45,610
that point the XUV flux is dropping off

541
00:17:49,410 --> 00:17:47,440
so you know then the solar wind would

542
00:17:51,870 --> 00:17:49,420
probably be the dominant loss process at

543
00:17:53,070 --> 00:17:51,880
that point instead and then another

544
00:17:56,220 --> 00:17:53,080
question I had was how does that change

545
00:17:57,330 --> 00:17:56,230
with spectral type is like just a

546
00:17:58,950 --> 00:17:57,340
different year for forming planets

547
00:18:00,840 --> 00:17:58,960
around a different star that's not like

548
00:18:02,340 --> 00:18:00,850
so that's actually a great question and

549
00:18:04,470 --> 00:18:02,350
so we were only looking at the sun-like

550
00:18:06,420 --> 00:18:04,480
stars to compare our model to the Rogers

551
00:18:08,640 --> 00:18:06,430
paper which is looking at planets around

552
00:18:10,950 --> 00:18:08,650
sun-like stars since it's difficult to

553
00:18:12,420 --> 00:18:10,960
measure the properties of those those M

554
00:18:15,060 --> 00:18:12,430
dwarf planets because they're so faint

555
00:18:16,830 --> 00:18:15,070
but if you have the that's XE V

556
00:18:19,410 --> 00:18:16,840
saturation time around m dwarf planets

557
00:18:20,670 --> 00:18:19,420
can be much longer than 100 100 million

558
00:18:23,160 --> 00:18:20,680
years that you see for some like stars

559
00:18:25,650 --> 00:18:23,170
in which case I would expect to be able

560
00:18:27,750 --> 00:18:25,660
to erode larger mass planets so you

561
00:18:29,970 --> 00:18:27,760
could maybe get that limiting radii

562
00:18:32,040 --> 00:18:29,980
pushed up a little bit if indeed that

563
00:18:33,510 --> 00:18:32,050
XUV saturation time is lasting for

564
00:18:34,920 --> 00:18:33,520
billions of years in terms closing

565
00:18:36,420 --> 00:18:34,930
planets so that's not something that

566
00:18:38,100 --> 00:18:36,430
I've modeled so I'm not sure if that's

567
00:18:39,560 --> 00:18:38,110
actually how it would turn out

568
00:18:42,210 --> 00:18:39,570
Thanks

569
00:18:46,500 --> 00:18:42,220
any more questions for our speakers sir

570
00:18:48,269 --> 00:18:46,510
yeah excellent yeah Jake go ahead oh and

571
00:18:51,200 --> 00:18:48,279
I have a quick question for you I was

572
00:18:54,000 --> 00:18:51,210
wondering if you know how high up the

573
00:18:56,190 --> 00:18:54,010
the x-ray flux is penetrating so

574
00:18:59,419 --> 00:18:56,200
relative to the surface where the peak

575
00:19:02,039 --> 00:18:59,429
and x-ray absorption is

576
00:19:05,100 --> 00:19:02,049
so the x-ray absorption is typically

577
00:19:06,690 --> 00:19:05,110
within SOTA and a pressure coordinate

578
00:19:09,659 --> 00:19:06,700
would be at about 0.1 so maybe 10

579
00:19:12,840 --> 00:19:09,669
Pascal's from the top of the atmosphere

580
00:19:14,399 --> 00:19:12,850
something to depends how much you how

581
00:19:16,799 --> 00:19:14,409
much atmosphere you have accreted so for

582
00:19:18,320 --> 00:19:16,809
a few weight percent I'm not sure what

583
00:19:21,419 --> 00:19:18,330
the actual

584
00:19:23,340 --> 00:19:21,429
distance and say kilometers would be but

585
00:19:24,720 --> 00:19:23,350
it's so we assumed in our model is that

586
00:19:26,879 --> 00:19:24,730
below that point the atmosphere is in

587
00:19:27,930 --> 00:19:26,889
hydrostatic equilibrium and so you can

588
00:19:30,570 --> 00:19:27,940
just calculate it from the hydrostatic

589
00:19:34,549 --> 00:19:30,580
equation with that that upper pressure

590
00:19:40,610 --> 00:19:38,840
have a question for this

591
00:19:45,779 --> 00:19:40,620
scientist

592
00:19:47,190 --> 00:19:45,789
have you thought about and discussed

593
00:19:49,440 --> 00:19:47,200
with the relevant people the

594
00:19:53,250 --> 00:19:49,450
implications of your discovery that the

595
00:19:56,430 --> 00:19:53,260
Earth's primeval water was a factor of

596
00:20:01,919 --> 00:19:56,440
two or more lower in deuterium than the

597
00:20:05,700 --> 00:20:01,929
ocean because if if the primeval water

598
00:20:07,169 --> 00:20:05,710
is much poorer in in deuterium than for

599
00:20:09,389 --> 00:20:07,179
instance that means that for instance

600
00:20:11,789 --> 00:20:09,399
you got Mars okay it's got six times the

601
00:20:14,250 --> 00:20:11,799
deuterium to hydrogen ratio that Earth

602
00:20:16,919 --> 00:20:14,260
does okay so people been saying well

603
00:20:20,240 --> 00:20:16,929
that means that it once had six times as

604
00:20:24,149 --> 00:20:20,250
much water or more than it does now and

605
00:20:29,100 --> 00:20:24,159
hydrogen went away and the deuterium has

606
00:20:32,940 --> 00:20:29,110
been enriched accordingly but if Mars is

607
00:20:34,549 --> 00:20:32,950
primeval water was only half as rich in

608
00:20:38,129 --> 00:20:34,559
DT reham as

609
00:20:40,169 --> 00:20:38,139
the Earth's ocean and not equal to the

610
00:20:44,240 --> 00:20:40,179
Earth's ocean then it means that Mars

611
00:20:46,649 --> 00:20:44,250
has lost twice as much water than

612
00:20:49,080 --> 00:20:46,659
they think and that means there was a

613
00:20:52,400 --> 00:20:49,090
lot more water on the surface of ancient

614
00:20:55,310 --> 00:20:52,410
Mars than and people currently suppose

615
00:20:57,860 --> 00:20:55,320
and also a lot more water on the ancient

616
00:21:01,430 --> 00:20:57,870
earth for that matter in others that

617
00:21:03,530 --> 00:21:01,440
there's implications this for lots of

618
00:21:14,110 --> 00:21:03,540
things I have you had discussions with

619
00:21:21,980 --> 00:21:18,680
no I haven't I do know that Lydia Callis

620
00:21:24,650 --> 00:21:21,990
has looked at the DTH in some of the

621
00:21:26,750 --> 00:21:24,660
Mars meteorites and has found have found

622
00:21:30,980 --> 00:21:26,760
some that are equivalent to Earth's

623
00:21:34,780 --> 00:21:30,990
oceans so Yoshi I'm not sure that the

624
00:21:37,220 --> 00:21:34,790
data H of Mars has been established yet

625
00:21:39,380 --> 00:21:37,230
certainly this has implications on the

626
00:21:42,020 --> 00:21:39,390
sources of water because if it turns out

627
00:21:44,510 --> 00:21:42,030
we get down as low as the solar nebula

628
00:21:46,670 --> 00:21:44,520
gas then that means we don't need an

629
00:21:48,710 --> 00:21:46,680
exogenous delivery at all it could be

630
00:21:50,930 --> 00:21:48,720
some of the models that just say earth

631
00:21:53,270 --> 00:21:50,940
got its water from the gases out of

632
00:21:55,160 --> 00:21:53,280
which we formed I think this is very

633
00:21:57,500 --> 00:21:55,170
much like a question of what is the

634
00:21:59,960 --> 00:21:57,510
origin of life the farther you dig the

635
00:22:01,820 --> 00:21:59,970
more questions you come up with and I

636
00:22:02,470 --> 00:22:01,830
think we're also seeing that there may

637
00:22:05,090 --> 00:22:02,480
be

638
00:22:06,680 --> 00:22:05,100
processes within the earth that we have

639
00:22:08,170 --> 00:22:06,690
to take account of in terms of

640
00:22:12,290 --> 00:22:08,180
fractionation

641
00:22:16,010 --> 00:22:12,300
mantle and I think that's why Steve is

642
00:22:18,170 --> 00:22:16,020
standing behind me also so I think it's

643
00:22:20,750 --> 00:22:18,180
an interesting story that's now opening

644
00:22:22,490 --> 00:22:20,760
up some new avenues before you come up

645
00:22:24,410 --> 00:22:22,500
to the mic Steve someone was in front of

646
00:22:31,570 --> 00:22:24,420
you in terms of those mic I know we well

647
00:22:35,810 --> 00:22:34,040
hi amber Britt Goddard Space Flight

648
00:22:38,090 --> 00:22:35,820
Center I just had a quick question about

649
00:22:40,250 --> 00:22:38,100
the water worlds talk and being outside

650
00:22:42,350 --> 00:22:40,260
of that particular subject was really

651
00:22:44,990 --> 00:22:42,360
interesting and I wanted to know why

652
00:22:46,400 --> 00:22:45,000
plate tectonics were being assumed for

653
00:22:50,090 --> 00:22:46,410
all these water worlds that a safe

654
00:22:51,680 --> 00:22:50,100
assumption for every water world's

655
00:22:56,270 --> 00:22:51,690
that's terrestrial are we just looking

656
00:22:59,600 --> 00:22:57,920
the inserts because we don't know how

657
00:23:01,300 --> 00:22:59,610
volatile is like we work if it wasn't

658
00:23:04,070 --> 00:23:01,310
plate tectonics

659
00:23:05,540 --> 00:23:04,080
there's work by bread Foley that'll be

660
00:23:06,910 --> 00:23:05,550
coming up soon talking about the

661
00:23:10,850 --> 00:23:06,920
stagnant lid

662
00:23:12,290 --> 00:23:10,860
the dynamics and volatile cycling on

663
00:23:13,720 --> 00:23:12,300
stagnant lead planets so keep an eye out

664
00:23:16,970 --> 00:23:13,730
for that

665
00:23:19,940 --> 00:23:16,980
so I wanted to address Bob's comment

666
00:23:22,250 --> 00:23:19,950
about the Hallett's at all result it is

667
00:23:23,870 --> 00:23:22,260
very hard to lower D to H ratios of

668
00:23:25,250 --> 00:23:23,880
course you can raise d-date ratios by

669
00:23:27,980 --> 00:23:25,260
hydrogen loss but it's hard to lower

670
00:23:30,530 --> 00:23:27,990
them so a low D to H ratio I would argue

671
00:23:33,020 --> 00:23:30,540
does demand and a component of in

672
00:23:36,110 --> 00:23:33,030
gassing of hydrogen gas into the magma

673
00:23:38,690 --> 00:23:36,120
ocean and I present it work we were

674
00:23:42,410 --> 00:23:38,700
doing at ASU at LPS C I presented this a

675
00:23:44,450 --> 00:23:42,420
model that we're soon to publish showing

676
00:23:47,000 --> 00:23:44,460
that we think that earth accreted may be

677
00:23:49,700 --> 00:23:47,010
over ten oceans worth of water and then

678
00:23:51,830 --> 00:23:49,710
immediately stored much of it much of

679
00:23:53,450 --> 00:23:51,840
the hydrogen in the core with an

680
00:23:55,490 --> 00:23:53,460
isotopic fractionation that went along

681
00:23:57,830 --> 00:23:55,500
with that and so I think that might

682
00:24:00,170 --> 00:23:57,840
demand a radically different view of how

683
00:24:01,700 --> 00:24:00,180
water is stored and then that would have

684
00:24:03,140 --> 00:24:01,710
implications for Mars as well although I

685
00:24:06,070 --> 00:24:03,150
don't know what they'd be maybe you want

686
00:24:11,300 --> 00:24:09,410
so on the question of Mars data age we

687
00:24:14,870 --> 00:24:11,310
published a paper paper in science in

688
00:24:17,470 --> 00:24:14,880
2015 in which we had mapped both HDO and

689
00:24:19,370 --> 00:24:17,480
h2o on the planet over several seasons

690
00:24:22,490 --> 00:24:19,380
using high-resolution infrared

691
00:24:24,200 --> 00:24:22,500
spectroscopy and we were able to show

692
00:24:27,130 --> 00:24:24,210
that the data weight ratio in the

693
00:24:31,100 --> 00:24:27,140
atmosphere is in fact a very misleading

694
00:24:33,980 --> 00:24:31,110
number in terms of the average if you do

695
00:24:37,370 --> 00:24:33,990
the analysis properly what you find out

696
00:24:39,710 --> 00:24:37,380
is that the near the polar cap you see

697
00:24:43,190 --> 00:24:39,720
d2h enriched by a factor of eight

698
00:24:45,770 --> 00:24:43,200
relative to be small and this means that

699
00:24:48,050 --> 00:24:45,780
the north polar cap is in fact even more

700
00:24:50,630 --> 00:24:48,060
highly enriched in deuterium than the

701
00:24:52,880 --> 00:24:50,640
atmospheric water that you see and so

702
00:24:54,770 --> 00:24:52,890
based on that we compared that with the

703
00:24:58,160 --> 00:24:54,780
measurement of dido H in a very early

704
00:25:01,490 --> 00:24:58,170
meteorite from Mars which was dated some

705
00:25:04,270 --> 00:25:01,500
years ago just recently and it had to be

706
00:25:07,720 --> 00:25:04,280
small without 1.3

707
00:25:12,190 --> 00:25:07,730
Dida wage was 1.3 be small at four point

708
00:25:12,960 --> 00:25:12,200
three years of age very early but in

709
00:25:16,330 --> 00:25:12,970
addition

710
00:25:19,539 --> 00:25:16,340
curiosity showed that in a Hesperian age

711
00:25:21,310 --> 00:25:19,549
Tito aged near Gale Crater in the soil

712
00:25:24,370 --> 00:25:21,320
was actually enriched by a factor of

713
00:25:26,409 --> 00:25:24,380
three so if you look at this over time

714
00:25:28,720 --> 00:25:26,419
you can estimate the amount of water

715
00:25:33,190 --> 00:25:28,730
that Mars actually had to lose in order

716
00:25:35,289 --> 00:25:33,200
to go from 1.3 be smoked to a little

717
00:25:37,539 --> 00:25:35,299
more than eight in the current reservoir

718
00:25:42,600 --> 00:25:37,549
and that turns out to have been an ocean

719
00:25:44,770 --> 00:25:42,610
the size of the Arctic on Mars or if

720
00:25:46,870 --> 00:25:44,780
scaled to the earth would have been the

721
00:25:49,419 --> 00:25:46,880
North and South Atlantic together it's

722
00:25:52,330 --> 00:25:49,429
about 20% of the cover 20% of the

723
00:25:54,730 --> 00:25:52,340
Earth's surface so anyway it was a lot

724
00:25:57,630 --> 00:25:54,740
of water and the number we came up with

725
00:26:00,340 --> 00:25:57,640
was actually consistent with the

726
00:26:03,279 --> 00:26:00,350
amount that was required to form the

727
00:26:06,430 --> 00:26:03,289
valley channels but I think it was Nick

728
00:26:07,600 --> 00:26:06,440
Baker some 20 years ago who or 25 years

729
00:26:09,669 --> 00:26:07,610
ago we've actually worked on that

730
00:26:11,799 --> 00:26:09,679
problem so there is there are two lines

731
00:26:14,080 --> 00:26:11,809
of evidence that suggest that this was

732
00:26:20,730 --> 00:26:14,090
in fact a correct amount for the amount

733
00:26:26,159 --> 00:26:24,390
which companies Mike

734
00:26:30,669 --> 00:26:26,169
what

735
00:26:34,419 --> 00:26:30,679
the Earth's original if you know it's

736
00:26:38,409 --> 00:26:34,429
people comparing Mars is d2h to what we

737
00:26:42,340 --> 00:26:38,419
commonly see on earth and if there if

738
00:26:45,490 --> 00:26:42,350
the original earth had a d2h ratio much

739
00:26:47,620 --> 00:26:45,500
lower than what we commonly see on earth

740
00:26:51,070 --> 00:26:47,630
that moves the baseline on these

741
00:26:52,840 --> 00:26:51,080
calculations so that it could be twice

742
00:26:56,680 --> 00:26:52,850
as much water in other words if you're

743
00:27:00,460 --> 00:26:56,690
comparing Mars is elevated d2h to you

744
00:27:02,169 --> 00:27:00,470
know the water in the ocean here but

745
00:27:04,480 --> 00:27:02,179
really should be comparing it to the

746
00:27:07,659 --> 00:27:04,490
primeval water here then the then the

747
00:27:09,640 --> 00:27:07,669
elevation is twice as much that's true

748
00:27:13,320 --> 00:27:09,650
but we really compare it with the value

749
00:27:17,130 --> 00:27:13,330
at 4.30 years that is

750
00:27:19,260 --> 00:27:17,140
the young moto meteorite and so that is

751
00:27:20,940 --> 00:27:19,270
irrelevant to what earth had it's really

752
00:27:23,420 --> 00:27:20,950
a quantitative measure what was lost

753
00:27:27,000 --> 00:27:23,430
from Mars over the last four point three

754
00:27:28,500 --> 00:27:27,010
billion years and so one can argue about

755
00:27:31,530 --> 00:27:28,510
whether the Earth's number should be

756
00:27:33,780 --> 00:27:31,540
smaller originally or not in be small

757
00:27:35,820 --> 00:27:33,790
that's a very valid argument but what we

758
00:27:39,420 --> 00:27:35,830
can say is that the u.s. ratio in this

759
00:27:42,390 --> 00:27:39,430
early marta meteorite was in fact forget

760
00:27:44,880 --> 00:27:42,400
about v snow it was essentially nine

761
00:27:47,490 --> 00:27:44,890
times the terrestrial excuse me the

762
00:27:49,380 --> 00:27:47,500
nebular value of d2h okay that's a

763
00:27:51,450 --> 00:27:49,390
better metric in my view because we know

764
00:27:53,730 --> 00:27:51,460
earth isn't be snow is enriched by a

765
00:27:57,120 --> 00:27:53,740
factor of seven but with a Buehler

766
00:27:59,280 --> 00:27:57,130
hydrogen so I think you want to take the

767
00:28:02,640 --> 00:27:59,290
earth out of the picture Mars still lost

768
00:28:04,640 --> 00:28:02,650
an ocean in the last 4.3 billion years

769
00:28:07,560 --> 00:28:04,650
it was on the size of the Arctic Ocean

770
00:28:09,270 --> 00:28:07,570
so something that comes up bringing it

771
00:28:12,620 --> 00:28:09,280
back to the more broad topic of water

772
00:28:15,330 --> 00:28:12,630
worlds is

773
00:28:16,800 --> 00:28:15,340
if that amount of water was delivered to

774
00:28:20,010 --> 00:28:16,810
Mars and this amount of water was

775
00:28:21,600 --> 00:28:20,020
delivered to earth are those small

776
00:28:22,860 --> 00:28:21,610
numbers compared to what we expect on

777
00:28:25,410 --> 00:28:22,870
water worlds or is that a large amount

778
00:28:27,560 --> 00:28:25,420
sort of in the in the broader scope of

779
00:28:30,150 --> 00:28:27,570
planetary diversity

780
00:28:31,160 --> 00:28:30,160
do we have a definition for water worlds

781
00:28:34,320 --> 00:28:31,170
and

782
00:28:36,020 --> 00:28:34,330
I think that's a good play a good

783
00:28:38,100 --> 00:28:36,030
question to start with

784
00:28:40,640 --> 00:28:38,110
okay is there any way to keep track of

785
00:28:43,820 --> 00:28:40,650
where it even came from

786
00:28:47,220 --> 00:28:43,830
so I think

787
00:28:48,750 --> 00:28:47,230
we've got about five minutes note one

788
00:28:52,670 --> 00:28:48,760
minute so you can have that conversation

789
00:28:57,480 --> 00:28:55,110
water world something that has no

790
00:29:00,720 --> 00:28:57,490
continent or is it something that has

791
00:29:04,020 --> 00:29:00,730
one or ten percent water by mass I think

792
00:29:05,340 --> 00:29:04,030
we should decide that well I think you

793
00:29:07,290 --> 00:29:05,350
would be hard-pressed to have continents

794
00:29:10,500 --> 00:29:07,300
if you had ten weight percent water well

795
00:29:12,900 --> 00:29:10,510
right right but but but if it's only

796
00:29:16,200 --> 00:29:12,910
like five oceans and you just submerge

797
00:29:18,960 --> 00:29:16,210
the Himalayas is that now what right

798
00:29:22,470 --> 00:29:18,970
yeah so defining a water world in terms

799
00:29:26,400 --> 00:29:22,480
of its behavior not necessarily

800
00:29:28,770 --> 00:29:26,410
yeah so GCMs that use like full surface

801
00:29:30,720 --> 00:29:28,780
oceans often call them aqua planets so

802
00:29:32,760 --> 00:29:30,730
maybe we could call water world's the

803
00:29:34,200 --> 00:29:32,770
things that are mostly water by mass and

804
00:29:37,620 --> 00:29:34,210
call the things that are covered in

805
00:29:40,490 --> 00:29:37,630
water aqua planets that could work done

806
00:29:43,350 --> 00:29:40,500
thanks Ted I'll stop using the term

807
00:29:46,330 --> 00:29:43,360
alright thank you everyone thank all the