Thoughts on the inner earth?

Question

Do you believe that what science has explained is inside the earth is true or do you think that there is any truth behind all of the different underworld myths? What would it mean to the world if our understanding about the composition of the earth changed?

This is really a question regarding how we know what we know about the inside of the earth as no one has broken through the earths crust. Are we really so sure about the composition of our earths interior?

Answer 1

Science advances Theories obtained from examination of Data. Myths are changed when someone repeats them incorrectly-which does not mean that Myths start out as wrong, or that there is no Truth behind them.

Our "understanding" changes all the time, and there is no "big secret" coming up, and, there is no "hole in the north pole" that flying saucers or demons use to get to the middle of the Earth.




Earth's Layered Structure and Plate Tectonics
Lithosphere (crust and uppermost mantle, 0-100 km deep), cool, rigid, brittle

Asthenosphere (upper mantle, 100-700 km deep), hot, weak, solid that flows

The Earth's lithosphere is divided into a dozen or so rigid plates that move relative to one another. These plates "float" or ride along on the underlying asthenosphere, which flows and undergoes convection, causing the plates to move.
Plate tectonics is driven by the convection in the asthenosphere (part of the Earth's mantle).

Below a depth of about 700 km, the descending slab begins to soften and flow, losing its form.

How do we know what the Earth's Interior is like?

Drilling

Wells drilled into Earth are mostly in the upper 7 km of the crust

Deepest well = Soviet (Russian) well in northern Kola Peninsula
20 year effort to drill a 12 km hole. Stopped in 1989.
History: 5 years to drill 7 km; 9 years to drill the next 5 km; got stuck at 12 km.
Target depth is 15 km.
Costs are more than $100 million.
Bottom hole temperature is 190 º degrees C
Current status??

Deepest US well is next to San Andreas Fault (Cajon Pass)
Had reached 3.5 km in 1988
Cost was $5 million ($1400 per meter)
Cost overruns and budget cuts suspended drilling in 1988
Other deep holes are planned.

Costs of a German 10 km hole are estimated at $110 million (or $11,000 per meter)
Germans drilled 3.5 km pilot hole and found bottom temperature was 118 º C (instead of the expected 80 º C)


Volcanic activity

Materials are brought up from below.
Xenoliths = foreign rock (pieces of the mantle in lava)
example: coarse-grained olivine (peridotite) xenoliths in basaltic lava
Only useful to depth of about 200 km (the depth from which lava comes)

High pressure laboratory experiments to determine which minerals can exist at high pressures like that of the great depths of the mantle.

Samples of the solar system (meteorites)

Study of seismic waves generated by earthquakes and nuclear explosions -
This is the most important method of determining the internal structure of the Earth.

Probing the Earth's Interior with Seismic Waves
P-waves and S-wave velocities (or travel times) depend on the properties of the rocks through which they travel.

Differences in velocities (or travel times) correspond to differences in rock properties. Wave velocity depends on the density and elasticity of the rock. Seismic waves travel faster in denser rock. The velocity of seismic waves increases with depth. (This is because pressure and density increase with depth in the Earth).
P-waves can travel through all of the layers of the Earth because they can travel through both solids and liquids.

On the other hand, S-waves can travel through the Earth's crust and mantle, but they STOP when they reach the Earth's core. This causes a shadow zone (or area in which no S-waves are detected by seismographs) on the side of the Earth away from the earthquake epicenter.

The presence of the S-wave shadow zone tells us that there is an area in the center of the Earth that is molten (liquid).

The size of the shadow zone gives us a good idea of the size and depth of the Earth's outer liquid core.

The size and depth of the solid inner core was determined from P-waves that reflected (or bounced) off the inner core following nuclear detonations.

Answer 2

Scientists ahve weighed the Earth, and it cannot be hollow with mythical underworlds. Truth beats fantasy. Scientists change their opinions to match the latest evidence, so if something new is learned about the eart's interior, it will become part of science.

Answer 3

Physically, the Earth is what is it but the myths can be explained because these places can actually be accessed by other dimensional portals. This is where the stories came from.

Answer 4

Allah knows all. even our inner thoughts we will be judged on.. however there will be less of a punishment for bad thoughts then there will be actions.

Answer 5

its just a bunch of rocks.