 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
 by Staff Writers Sendai, Japan (SPX) Jul 07, 2021
Scientists from Tohoku University and the University of Maryland have pinpointed the strong magnetic field of the early sun as the reason behind the radial variation of rock and metal in rocky planets' cores. This magnetic field, which pulled small iron grains inward, explains Mercury's big iron core and why Mars has so little iron in its core. The details of their research were published in the journal Progress in Earth and Planetary Science on July 5, 2021. Planets have iron cores surrounded by a rocky shell, mostly made up of mantle and a thin skin of crust. The four inner planets of our Solar System, Mercury, Venus, Earth, and Mars have their own distinctive size and density. These differences have long since puzzled scientists. Mercury has a metallic core making up about 3/4 of its mass, with the remaining 1/4 being a rocky silicate shell. The cores of Earth and Venus possess a metallic core of only 1/3 of their mass, with the rest being rock. Mars has a measly core comprising only 1/4 of its mass. These radical changes in metal content offer clues about what controlled the distribution of raw materials in the early formation of the solar system. During this period, swirling gas and dust cloud drew matter into the Solar System's center, thus forming the Sun. The rapid delivery to the center caused many collisions and heated the inner region of the Solar System. When the Sun was big enough to have its own internal gravity, it caused its proton-rich core to ignite its nuclear fuel, brightly turning on the Sun. Following this, the Sun's core began convecting, creating a dynamo generating a strong magnetic field. The high temperatures of the inner Solar System turned elements into a vapor state. As the element cloud cooled down it rained out mineral compounds. Evidence from primitive meteorites reveals the compounds precipitated were either silicates or metals. The sun's magnetic field pulled the metal particles inwards. The composition of inner rocky planets is remarkably similar to primitive meteorites. Also known as chondrites, these meteorites are jumbled mixtures of rock and metal in different proportions. Unlike rocky planets, they do not have cores. The raw materials making up the rocky planets are just four unevenly distributed elements: oxygen, iron, magnesium, and silicon. This represents about 93% of a rocky planet's mass. Around 70% of that is equal measure oxygen and iron, whilst the rest consists of equal measure magnesium and silicon. "Planetary cores are a big deal," proclaims coauthor of the study Bill McDonough. "They control where elements end up in the planet." McDonough points to the Earth's abundance of the nutrient phosphorus concentrated in its core as an example. "Planetary habitability also depends upon the size and compositions of its core in addition to the lifetime of its dynamo." The core's dynamo generates a magnetic shield that protects us from cancer-causing cosmic rays. Once Mars lost its core dynamo, its surface water disappeared quickly thereafter. Early on in Solar System formation, a cloudy disc of gas and dust surrounded the Sun and planets, serving as a conduit for the Sun's magnetic field. The strength of the magnetic field weakened as it got further away from the Sun. Mercury formed in the prime location - close to where the Sun's magnetic field was strongest, thus explaining its large iron core.
Proximity to Sun's magnetic field influenced Mercury's hefty iron core College Park, MD (SPX) Jul 05, 2021 For decades, many scientists argued that hit-and-run collisions with other bodies during the formation of our solar system blew away much of Mercury's rocky mantle and left the big, dense, metal core inside. But new research reveals that collisions don't explain the planet's composition-the sun's magnetism does. William McDonough, a professor of geology at the University of Maryland, and Takashi Yoshizaki of Tohoku University developed a model showing that the density, mass and iron content of a r ... read more
|
|||||||||||||
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |
del.icio.us
Digg
Reddit
Google
