関連する実験動画
Updated: May 28, 2026
06:04
Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
メッセンジャーからの水星表面の放射性元素:惑星の形成と進化への意味
Patrick N Peplowski1, Larry G Evans, Steven A Hauck
1The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA. patrick.peplowski@jhuapl.edu
Science (New York, N.Y.)
|October 1, 2011
まとめ
メッセンジャー メッセンジャー
科学分野:
- 惑星科学は惑星科学である.
- 地質化学 地質化学
- 核天体物理学 核天体物理学とは
背景:
- 水星の表面の組成は,その形成と進化のヒントを提供します.
- カリウム (K),トリウム (Th),ウラン (U) のような放射性元素は,惑星の過程の重要な指標である.
研究 の 目的:
- 水星の北半球におけるK,Th,Uの表面濃度を測定する.
- これらの豊富さを利用して,水星の形成と熱の歴史のモデルを制約する.
主な方法:
- メッセンジャー・ガンマ線スペクトロメーターのデータを活用した.
- 水星の北半球におけるK,Th,Uの表面平均濃度を測定した.
主要な成果:
- 平均表面濃度:K (1150±220ppm),Th (220±60ppb),U (90±20ppb) となっている.
- K/ThとK/U比は,極度の加熱ではなく,揮発性物質に富んだ物質から形成されたことを示唆しています.
- 豊富さは,形成以来の内部熱生成の有意な減少を示しています.
結論:
- 水銀は,コンドリート隕石に似た揮発性物質から形成された可能性が高い.
- 広範囲にわたる火山活動は,水星の歴史の初期に発生し,その後活動が減少しました.
- これらの発見は,形成中に極端な惑星の加熱を必要とするモデルに挑戦しています.
関連する概念動画
01:27The Periodic Table and Organismal Elements
Elements are the smallest units of matter that cannot be broken down further by chemical processes. There are 118 known elements, but not all of these are naturally occurring, and only a few of them are essential for life. Living matter is composed primarily of carbon, nitrogen, hydrogen, and oxygen, with smaller amounts of other elements like calcium, phosphorus, potassium, and sulfur. Other elements are also necessary for life but only in trace amounts.
Periodic Table Provides Information...
Periodic Table Provides Information...
00:57The Periodic Table and Organismal Elements
OverviewElements are the smallest units of matter that cannot be broken down further by chemical processes. There are 118 known elements, but not all of these are naturally-occurring, and fewer still are essential for life. Living matter is composed primarily of carbon, nitrogen, hydrogen, and oxygen, with smaller amounts of other elements like calcium, phosphorus, potassium, and sulfur. Other elements are also necessary for life but only in trace amounts.The Periodic Table Provides Information...
03:20Nuclear Transmutation
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed protons being...
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...