New theory on the earth's interior

New theory on the earth's interior

Play all audios:

Loading...

ABSTRACT _Sky and Telescope_ of February contains a brief account ofthe theory of R. B. Borcherds which he advocated m his address as retiring chairman of the Cape Centre of the Astronomical Society of South Africa. This theory suggests that the characteristics of tne earth's interior can be described on the basis of variations in condition rather than composition. Assuming a temperature-gradient of one degree for every 90 ft. of depth, he finds that the observed discontinuities in the transmission of earthquake waves at depths of 7½ , 23 and 38 miles can be attributed to changes of state due to high temperature and pressure. He describes a transitional region between 750 and 1,800 miles within which depths the temperature and pressure are estimated to increase respectively from 44,000° to 105,000° C., and from 5,150,000 Ib. to 12,300,000 Ib. per square inch. The pressure at the centre of the earth is calculated at 50 million pounds per square inch, and in such circumstances anounce of hydrogen would be compressed into 0-001 to 0-003 of a cubic foot. If 100,000° is above the critical temperature for any of the known elements, no pressure applied to these substances at this temperature would cause them to liquefy or solidify; hence he considers that the earth's centre is gaseous, although highly compressed. The gas would be ionized and compounds would produce much higher densities than the known average of 5-52 for the earth. He thinks that iron would lose its magnetic properties under the intense heat at the earth's centre, so the old iron-nickel theory of the earth's core, developed to explain the earth's magnetic properties, cannot be sustained, and in any event is unnecessary if rotating bodies develop magnetism, as has been recently found for stars. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS OPTIONS Access through your institution Subscribe to this journal Receive 51 print issues and online access $199.00 per year only $3.90 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE New Theory on the Earth's Interior. _Nature_ 164, 344 (1949). https://doi.org/10.1038/164344a0 Download citation * Issue Date: 27 August 1949 * DOI: https://doi.org/10.1038/164344a0 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative

ABSTRACT _Sky and Telescope_ of February contains a brief account ofthe theory of R. B. Borcherds which he advocated m his address as retiring chairman of the Cape Centre of the Astronomical


Society of South Africa. This theory suggests that the characteristics of tne earth's interior can be described on the basis of variations in condition rather than composition.


Assuming a temperature-gradient of one degree for every 90 ft. of depth, he finds that the observed discontinuities in the transmission of earthquake waves at depths of 7½ , 23 and 38 miles


can be attributed to changes of state due to high temperature and pressure. He describes a transitional region between 750 and 1,800 miles within which depths the temperature and pressure


are estimated to increase respectively from 44,000° to 105,000° C., and from 5,150,000 Ib. to 12,300,000 Ib. per square inch. The pressure at the centre of the earth is calculated at 50


million pounds per square inch, and in such circumstances anounce of hydrogen would be compressed into 0-001 to 0-003 of a cubic foot. If 100,000° is above the critical temperature for any


of the known elements, no pressure applied to these substances at this temperature would cause them to liquefy or solidify; hence he considers that the earth's centre is gaseous,


although highly compressed. The gas would be ionized and compounds would produce much higher densities than the known average of 5-52 for the earth. He thinks that iron would lose its


magnetic properties under the intense heat at the earth's centre, so the old iron-nickel theory of the earth's core, developed to explain the earth's magnetic properties,


cannot be sustained, and in any event is unnecessary if rotating bodies develop magnetism, as has been recently found for stars. Access through your institution Buy or subscribe This is a


preview of subscription content, access via your institution ACCESS OPTIONS Access through your institution Subscribe to this journal Receive 51 print issues and online access $199.00 per


year only $3.90 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during


checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS


ARTICLE CITE THIS ARTICLE New Theory on the Earth's Interior. _Nature_ 164, 344 (1949). https://doi.org/10.1038/164344a0 Download citation * Issue Date: 27 August 1949 * DOI:


https://doi.org/10.1038/164344a0 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently


available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative