How is it even POSSIBLE?

Question

that there is still 'lava' (magma) in the earth's core? the planet has been here for approximately 4.6 billion years.. wouldn't the magma have burned out by now? what fuels it?

thanks

Answer 1

Just like it takes a pie longer to cool down the bigger it is or the further it is from the still-warm oven the earth hasn't finished cooling. The moon and Mars are cooled down more hence no plate tectonics or volcanic activity. Some day our crust will have thickened enough to eliminate both as well.

Answer 2

Lava isn't a chemical fire burning, it's more like a hot piece of metal that's just holding lots of heat. The Earth's interior is heated by several things - pressure from the weight of the material above it, tidal forces from the Moon and Sun, and also by the heat resulting from radioactive decay of things like Uranium and such.

Like others have said - the Earth's surface is like an insulating blanket, holding the heat in and preventing it from radiating out into space.

Oh and yes, if the Earth were to cool down, there would be no more volcanic eruptions. (Mars is like this - there are some enormous volcanoes there, but they've been dead for millions of years). However, this would be a very bad thing, since it's the convection currents inside the Earth's molten core which produce the magnetic field that protects us from the bulk of the Sun's harmful radiation.

If the core cooled off, the field would go away along with those pesky volcanoes, and we'd be naked to the Sun's full fury. The solar winds would begin to blow the atmosphere off of the Earth, and the increased radiation would fry the surface, killing most species on Earth's surface. This would be a mass extinction event to be sure - and once the atmosphere thinned out, the water would evaporate, and the Earth would become a barren desert eventually - just like Mars, only not as cold.

Answer 3

you gotta start with thermodynamics.  UGH.  No, I am not kidding.

The Earth is a planet (no surprises so far, but you get what you pay for).  If you assume the Earth is a closed system (not a good assumption, but shut yer pie hole, I am expostulatin' here), then all the heat from the formation of the planet would have to radiate off into space in order for the liquid MAGMA (god, I love that word... Me and Dr Evil), to cool off.  Heat just doesn't "Go Away", it has to go SOMEPLACE else.

Problem 1)  The Earth was formed out of "mostly iron" and a LOT of other things, MANY of which were radioactive.  Note:  I said "WERE", because much of this material has decayed. The process of decay GIVES OFF HEAT.  d**n, just as we were getting someplace!

Problem 2)  The Earth is NOT a closed system.  We receive quite a bit of heat from the Sun onto the surface, reducing the core's ability to efficiently radiate off its heat.  Also, the tides from the Sun and Moon cause heat, sort of the way a metal rod gets warm when you flex it back and forth.

Problem 3) (yeah, I AM rather long-winded, thanks for noticing) About a billion years into the formation of the Solar System, when all the other planets were slowly ticking down little by little in temperature, the Earth got SMACKED by a very large planetoid.  This was the origin of the Moon, but more importantly for our discussion, like Brewster's Millions, it just added more heat to the stack, making it nearly impossible to get rid of.

Expect the Earth to finally cool off (well, become more equilibriated) in several billion years.

Answer 4

Gravity pulls matter toward its center.  Tectonics and pressure release magma.  The void is quickly refilled due to the nature of gravity.  As long as the earth is geologically active, and the earth has mass, there will never be a depleted supply of magma.  

Answer 5

Your question is a good one.  The heat in the Earth was calculated to limit the Earth to an age ot 25 million years old - or less.  That was with the sources of heat known then ( late 1800s).

Radioactivity was discovered and that explained how the Earth could still be hot after 4.5 billion years,  The core of the Earth contains radioactive elements that give the Earth its internal heat.

Answer 6

If the Earth cools, it contracts, right?  But that releases gravitational energy, which then heats it up.

Besides, dirt is a good insulator.

And, lots of heavy radioactive materials are down in the core.

And, the Sun and the Moon produce tides.  It's not just the oceans, it's also the ground.  And that heats things up.

Answer 7

Extreme pressure  

Answer 8

well theres really no way for it to cool.

transfers of heat (ie. cooling) happen by convection and conduction. that requires matter to actually touch. in the earth is surrounded by vacuum, what matter is going to carry away heat? none. the earth has to cool by radiation, which is much much slower than other forms of heat transfer.

also, it is fueled by the radioactive decay of heavy elements in its core.

Answer 9

The reason the center of the earth is hot is because of the decay of radioactive material.  .