まとめ
アポロ11号の月面サンプルでは,隕石と珍しいガスの類似性を明らかにした. 閉じ込められたガスやスパラーションガスの同位体組成は,月の物質と隕石の物質の共通の起源や進化過程を示唆しています.
科学分野:
- 宇宙化学 (コスモケミストリー)
- 惑星科学は惑星科学である.
- 地質化学 地質化学
背景:
- 月面のサンプルに含まれる希少なガスは,太陽系の進化についての洞察を与えてくれます.
- 隕石は,初期の太陽系材料の組成を理解するために重要である.
研究 の 目的:
- アポロ11号の月のサンプルの希少ガスの同位体組成を調べるために.
- 月面の希少ガスデータと,ガス豊富な隕石のデータを比較するために.
主な方法:
- アポロ11号の月面サンプルを,全溶融と段階的な加熱実験を用いて分析した.
- ネオン,クリプトン,クセノンの同位体比を測定する.
- 月面ガスの同位体データと,公表された隕石データとの比較.
主要な成果:
- 月面のサンプルに閉じ込められたネオン20/ネオン22の比率は11.5から15の範囲で,ガス豊富な隕石と似ています.
- クリプトンとクセノンの同位体組成は,月面の微細物質と炭酸性コンドライトに類似性があり,月面のガスには重量同位体の過少量がある.
- 月面のサンプルのスパラションガスの同位体組成は,隕石で見つかったものと非常に似ています.
結論:
- 月の稀有ガスと隕石の稀有ガスは,共通の起源またはプロセスを示唆し,密接な親和性を表しています.
- 月面のクセノンとクリプトンの重イソトープの枯渇は,炭酸性コンドライトと比較して分裂成分が減少していることを示している.
- スパラーションガスの同位体相似性は,月と隕石の物質の関連性をさらに支持しています.
関連する概念動画
01:13Mass Spectrometry: Isotope Effect
Most elements exist in nature as a mixture of isotopes. The isotopes differ in weight due to their respective number of neutrons. The molecular weight of a molecule is different depending on the specific isotope of its elements involved. As a result, the mass spectrum of the molecule exhibits peaks from the same fragment at multiple positions. The positions of these mass signals depend on the mass differences between isotopes. Furthermore, the intensity of these signals is dependent on the...
02:54Noble Gases
The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name “noble” because they were assumed to be nonreactive since they have filled valence shells. In 1962, Dr. Neil Bartlett at the University of British Columbia proved this assumption to be false.
01:28Isotopes and Radioisotopes
In the early 1900s, English chemist Frederick Soddy realized that an element could have atoms with different masses that were chemically indistinguishable. These different types are called isotopes — atoms of the same element that differ in mass. Isotopes differ in mass because they have different numbers of neutrons but are chemically identical because they have the same number of protons. Soddy was awarded the Nobel Prize in Chemistry in 1921 for this discovery.
An isotope containing more...
An isotope containing more...
01:12Isotopes
Elements have a set number of protons that determines their atomic number (Z). For example, all atoms with eight protons are oxygen; however, the number of neutrons can vary for atoms of the same element. The sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have multiple isotopes, for example, carbon-12, carbon-13, and carbon-14.An element's atomic mass, or weight, is a...
02:48Radioactive Decay and Radiometric Dating
Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. The number of disintegrations per unit time is called the activity (A), which is directly proportional to the number of nuclei in the sample. The decay constant (λ) is an average probability of decay per nucleus in unit time.
01:15High-Resolution Mass Spectrometry (HRMS)
The resolution of a mass spectrometer depends on the efficiency of separating ions with different ion masses. The mass of an atom is approximated to the sum of the masses of protons and neutrons inside, considering the masses of protons and neutrons as equal. However, the masses of the proton (1.6726 × 10−24 g) and neutron (1.6749 × 10−24 g) are not truly equal. There is a minor error in the expression of atomic masses relative to the simplest atom of hydrogen. For example, the mass of helium...