posted on Mar, 20 2006 @ 08:04 AM
Actually, you don't have to worry about the earth exploding. In the same way you don't have to worry about the sun (at least our sun) exploding.
What happens in a star is that as the pressure rises and the energy/area increases, nuclear fussion progresses more rapidly, resulting in a greater
"outward" force. Thus, once the "inward" force of gravity meets the outward force of fussion they cancel out and put the sun at equilibrium.
As fusionable material runs out, the Sun starts to collapse, getting smaller. However, energy remains the same and so energy/area increases (it gets
hotter). Eventually you reach the Helium Flash where the Sun begins Helium Fusion - it's the same as Hydrogen Fusion, except, due to the higher
temperatures, occurs faster. Thus, the Sun has a shorter lifespan when in the Hydrogen fusion.
This keeps going on until there is not enough fusionable material left in general, and the Sun will continue to collapse until it reaches electron
support (or some word like that) where the further collapse is prevented by the electro-magnetic force of the electrons.
Now, in very large stars fusionable material goes all the way into producing Iron - although the star is likely only producing iron for 1 day before
it then goes Supernova. You see, anything below Iron is fusionable for energy, and anything above Iron is fissionable for energy, however Iron itself
is the asymtop - you can't get energy out of it either way. Thus, when that runs out, the collapse of the star is unpreventable.
When it does hit that electron point, the force of gravity (due to the star's massive size) isn't strong enough, and the electrons are pushed into
the atomic nucleus - creating neutrons. At this point a supernova occurs, releasing off tons and tons of energy. What's left is either a Neutron Star
or a Black hole (where even Neutron pressure is unable to hold the star in one piece - imagine a Neutron star as a giant atom, because that's
essentially what it is). A Neutron star, however, doesn't actually create any energy. In fact, it's just slowly releasing stored up energy. Also,
since the spin increases as a star shrinks (watch figure-skaters that bring their arms and legs in close), the surface of a Neutron star can be moving
extremely fast (fastest recorded is 1/3rd the speed of light).
Anyways, the Earth is under a similar equilibrium. As the pressure increases, the "push" from pressure begins to form into a natural equilibrium of
the "pull" of gravity. This is what prevents the Earth from both exploding and from collapsing into a black hole. Since it's a natural equlibrium,
its actually very difficult to disrupt - and so one should never worry about it.
Also, since no additional mass is entering the system, it's just mass moving around within the system, it's not like have more mass on the surface
will change things. The overall mass remains constant. Whether it's lava inside or outside the Earth is irrelevant.
Finally, for those wondering why I didn't include how the Sun expands to massive proportions nearing the end of it's life, I didn't think it was
important to go through that process. Another interesting fact is, though, that if a Star isn't massive enough to undergo Carbon fusion, then if one
found a dead star's core of Carbon it would essentially be the biggest diamond in the universe... or at least in your part of the universe.