Related Experiment Video
Updated: Jun 5, 2026
06:14
Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
Published on: July 30, 2020
Seismic detection of the lunar core
Renee C Weber1, Pei-Ying Lin, Edward J Garnero
1NASA Marshall Space Flight Center, 320 Sparkman Drive, Huntsville, AL 35805, USA. renee.c.weber@nasa.gov
Science (New York, N.Y.)
|January 8, 2011
Summary
New seismic analysis reveals the Moon has a solid inner core and a fluid outer core, suggesting a partially molten boundary layer and a volatile-depleted interior. This deep lunar insight enhances our understanding of the Moon's internal structure.
Area of Science:
- * Planetary Science
- * Seismology
- * Lunar Geology
Background:
- * Limited understanding of the Moon's deep interior persists despite satellite data and Apollo-era seismic analysis.
- * Previous seismic data from the Apollo missions provided foundational but incomplete insights into lunar structure.
Purpose of the Study:
- * To reanalyze Apollo lunar seismograms using advanced array-processing techniques.
- * To identify seismic reflections and conversions indicative of the lunar core.
- * To refine models of the Moon's internal composition and structure.
Main Methods:
- * Application of array-processing methods to existing Apollo lunar seismograms.
- * Analysis of seismic wave behavior, including reflections and conversions, originating from the lunar core.
- * Interpretation of seismic data in conjunction with iron alloy phase diagrams.
Main Results:
- * Detection of seismic energy reflected and converted from the lunar core.
- * Evidence supporting a layered core structure: a solid inner core and a fluid outer core.
- * Identification of a partially molten boundary layer above the core.
- * Estimation that the lunar core is approximately 60% liquid by volume.
- * Determination that the core likely contains less than 6% lighter alloying elements.
Conclusions:
- * The Moon possesses a differentiated core comprising solid and fluid layers.
- * The core's composition is consistent with a volatile-depleted interior, containing minimal lighter elements.
- * This study significantly advances the understanding of deep lunar interior structure and composition.
Related Concept Videos
01:10Detection of Black Holes
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
01:11Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
01:05Gravimetry: Overview
Gravimetric analysis is a quantitative method where the analyte is isolated and weighed directly or after conversion into a substance of known composition. Gravimetric analysis can be classified as precipitation, electrogravimetry, volatilization, and particulate gravimetry, based on the method used to isolate the analyte.
In precipitation gravimetry, the analyte is converted into a precipitate and weighed. For example, the silver content in a sample can be estimated by precipitating and...
In precipitation gravimetry, the analyte is converted into a precipitate and weighed. For example, the silver content in a sample can be estimated by precipitating and...
01:24X-ray Imaging
German physicist Wilhelm Röntgen (1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible "ray" would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound. In 1895, Röntgen made the first durable record of the internal parts of a living human: an "X-ray" image (as it came to be called) of his wife’s hand. Scientists worldwide quickly began their own experiments with X-rays, and by 1900, X-ray was widely...
01:03Precipitation Gravimetry
Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
01:05Atomic Nuclei: Magnetic Resonance
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...