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Palomar

Member

From: USA

Registered: 2002-05-30

Posts: 9,734

Re: Loki's Lava - ...and other vulcanism in Solar System

http://www.spaceref.com/news/viewpr.html?pid=13891]In going back to *this* article, you can see that Loki "churns out about 1,000 square meters of lava -- about the size of a soccer field -- per **second**" during the most intensive periods in its eruption cycle.
 
http://www.earthsky.com/shows/showsmore … 20031007]I did some Googling.  This article says Loki's eruption cycle throughout the 1990s averaged once every 540 days.  Doesn't say how long the peak activity lasts, though.

Anyway, it does churn out a heckuva lot of lava during the peaks of its eruption cycle (equivalent of a soccer field per second?!).  Where does all this lava come from?    I don't know much about vulcanism, etc. 

Check out speculation on vulcanism on Europa, etc. and geysers on Triton.   

Anyway, I'm curious to know if lava is somehow reproduced in a planetary's system like blood is in the human body.  Probably a goofy question, but I'll ask anyway. 

--Cindy

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We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

clark

Member

Registered: 2001-09-20

Posts: 6,362

Re: Loki's Lava - ...and other vulcanism in Solar System

It would be similar to how the human blood is created if our skin was sucked into our body, and then converted into blood.

The mantle is constantly moving, and in subduction zones it gets sucked back into the Earth, where the pressure and heat cause the rock to liquify.

The heat within the core of the Earth results from the high pressure of compressed matter, which slowly dissipates out and explodes on the surface, ala volcano lava.

Just watch "Journey to the Center of the Earth."  :laugh:

SBird

Banned

Registered: 2004-03-10

Posts: 490

Re: Loki's Lava - ...and other vulcanism in Solar System

Correct on the subduction, et al.  What happens is that the Earth's mantle is convecting like water on the stove and the crust gets carried along.  At points where the mantle dives back down, some of the crust is carried down with it.  Since the crust material is much lighter, when it melts, it bubbles back up and burns through the crust in the form of volcanos.  The Pacific rim activity is a result of this.

As for pressure causing heating, that's a no go.  The pressure at the center of the Earth caused a lot of heating originally but that heat would have dissapated quickly.  Someone (lord Kelvin, IIRC) used that as proof that the Earth was less than 10,000 years old.

Instead, the decay of radionucleotides such as uranium and its decay products keep the furnace burning as it were.  Being dense, most of the uranium is in the mantle and core and releases tremendous amounts of energy as it decays, constantly heating the core of the Earth.

clark

Member

Registered: 2001-09-20

Posts: 6,362

Re: Loki's Lava - ...and other vulcanism in Solar System

How do we know what is in the center of the Earth

My understanding was that heat is maintained through energy exchanges resulting from the orbital influences of the moon on the Earth, which causes the basic tectonic movement, which creates a feedback loop in terms of energy and heat disipation.

SBird

Banned

Registered: 2004-03-10

Posts: 490

Re: Loki's Lava - ...and other vulcanism in Solar System

The exact composition of the Earth's core is speculative but we can make educated guesses.  Seismic mapping has given us very detailed maps of the density of the core from which we can infer something about the composition.  Furthermore, we can also infer a lot about the mantle and upper core composition from magma in eruptions.  Ratios of helium isotopes tell a lot about the overall readioactivity of the lower layers of the Earth and we know that there is a lot of radioactivity going on. 

The tidal infleunce of the Moon also probably contribues although I don't know the relative ratios of the two in contributing to the heating.  Since most of the references refer primarily to the radioactive heating, I assume that the rads do the majority of the heating.