Jitro wrote:
Fnord wrote:
How would you know? According to some old books, Hell is hot, dry, sulfurous, and filled with the souls of the damned. According to real-world seismic and geomagnetic data, the Earth's core is composed of iron, nickel, and radioactive metals in a compressed liquid state.
Well the core has never been directly observed. No probe has every been sent down there to take pictures.
Well, Hell has never been directly observed; no probe has every been sent there to take pictures, either. It's all a figment of some iron-age religious leader's imagination.
Seismic and geomagnetic data can be analyzed to determine the materials that make up the Earth's core. If it was a hot, open space with a sulfurous atmosphere, the data would skew one way. If it's composed of compressed molten metals, then the data would skew another way.
The data skews in the exact way necessary to prove the existence of a compressed liquid metal core.
This "Hollow Earth" myth you love so much was debunked long before you were born, kid.
The Hollow Earth hypothesis proposes that the planet Earth is either entirely hollow or otherwise contains a substantial interior space. The hypothesis has been shown to be wrong by observational evidence, as well as by the modern understanding of planet formation; the scientific community has dismissed the notion since at least the late 18th century. Religious nutters still hold on to the idea, anyway.
The concept of a hollow Earth still recurs in folklore and as the premise for subterranean fiction, a subgenre of adventure fiction. It is also featured in some present-day pseudo-scientific and conspiracy theories.
The picture of the structure of the earth that has been arrived at through the study of seismic waves is quite different from the hollow earth theory. The Earth's interior is made up of layers of molten rock and various elements, in a mantle and core.
Another set of scientific arguments against a hollow Earth or any hollow planet comes from gravity. Massive objects tend to clump together gravitationally, creating non-hollow spherical objects we call stars and planets. The solid sphere is the best way in which to minimize the gravitational potential energy of a physical object; having hollowness is unfavorable in the energetic sense. In addition, ordinary matter is not strong enough to support a hollow shape of planetary size against the force of gravity; a planet-sized hollow shell with the known, observed thickness of the Earth's crust, would not be able to achieve hydrostatic equilibrium with its own mass and would collapse.
Someone on the inside of a hollow Earth would not experience a significant outward pull and could not easily stand on the inner surface; rather, the theory of gravity implies that a person on the inside would be nearly weightless. This was first shown by Newton, whose shell theorem mathematically predicts a gravitational force (from the shell) of zero everywhere inside a spherically symmetric hollow shell of matter, regardless of the shell's thickness. A tiny gravitational force would arise from the fact that the Earth does not have a perfectly symmetrical spherical shape, as well as forces from other bodies such as the Moon. The centrifugal force from the Earth's rotation would pull a person (on the inner surface) outwards if the person was traveling at the same velocity as the Earth's interior and was in contact with the ground on the interior, but even the maximum centrifugal force at the equator is only 1/300 of ordinary Earth gravity.
The mass of the planet also indicates that the hollow Earth hypothesis is unfeasible. Should the Earth be largely hollow, its mass would be much lower and thus its gravity on the outer surface would be much lower than it is.
The deepest hole drilled to date is the SG-3 borehole which is 12.3 km (7.6 mi) deep, part of the Soviet Kola Superdeep Borehole project; thus, visual knowledge of the Earth's structure extends that far.
References:
- Press, Frank; Siever, Raymond; Grotzinger, John; Jordan, Tom (2003). Understanding Earth (4 ed.). New York, New York: W. H. Freeman. pp. 484–487. ISBN 0-7167-9617-1.
- USGS - Earth's interior
- Eagleson, Mary (1994). Concise Encyclopedia Chemistry. Walter de Gruyter, p799. ISBN 3-11-011451-8
Where do you get your weird, outdated ideas from, anyway?
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No love for Hamas, Hezbollah, Iranian Leadership, Islamic Jihad, other Islamic terrorist groups, OR their supporters and sympathizers.
09 Nov 2012, 3:08 pm
