Search results
Results from the WOW.Com Content Network
The earliest ideas on the nature of magnetism are attributed to Thales (c. 624 BC – c. 546 BC). [1] [2] In classical antiquity, little was known about the nature of magnetism. No sources mention the two poles of a magnet or its tendency to point northward. There were two main theories about the origins of magnetism.
The remaining terms predict that the potential of a dipole source (ℓ=1) drops off as 1/r 2. The magnetic field, being a derivative of the potential, drops off as 1/r 3. Quadrupole terms drop off as 1/r 4, and higher order terms drop off increasingly rapidly with the radius. The radius of the outer core is about half of the radius of the Earth.
A telluric current (from Latin tellūs 'earth'), or Earth current, [1] is an electric current that flows underground or through the sea, resulting from natural and human-induced causes. These currents have extremely low frequency and traverse large areas near or at Earth 's surface.
Pivoting compass needle in a 14th-century handcopy of Peter's Epistola de magnete (1269). Petrus Peregrinus de Maricourt (Latin), Pierre Pelerin de Maricourt (French), or Peter Peregrinus of Maricourt [1] (fl. 1269), was a French mathematician, physicist, and writer who conducted experiments on magnetism and wrote the first extant treatise describing the properties of magnets.
This page was last edited on 13 July 2016, at 01:13 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may ...
Jefimenko says, "...neither Maxwell's equations nor their solutions indicate an existence of causal links between electric and magnetic fields. Therefore, we must conclude that an electromagnetic field is a dual entity always having an electric and a magnetic component simultaneously created by their common sources: time-variable electric ...
Canadian hockey player Matthew Petgrave has begun crowdfunding to help cover his legal fees in connection with the death of fellow hockey player Adam Johnson.
The official planetary K p-index is derived by calculating a weighted average of K-indices from a network of 13 geomagnetic observatories at mid-latitude locations.Since these observatories do not report their data in real-time, various operations centers around the globe estimate the index based on data available from their local network of observatories.