Detection of a New Large Free Core Nutation Phase Jump
Zinovy Malkin1, Santiago Belda2,3, Sadegh Modiri4
1Pulkovo Observatory, St. Petersburg 196140, Russia.
Sensors (Basel, Switzerland)
|August 26, 2022
Summary
Scientists detected a significant new jump in the free core nutation (FCN) phase, the second observed in over 30 years. This event, larger than the previous one, may link to recent geomagnetic changes.
Area of Science:
- Geophysics
- Astronomy
- Earth Science
Background:
- The free core nutation (FCN) is a fundamental mode of Earth's rotation.
- Monitoring FCN phase variations provides insights into the Earth's fluid core dynamics and the core-mantle boundary.
- Large, abrupt changes in FCN phase are rare and significant events.
Purpose of the Study:
- To report the detection and characterization of a new large jump in the FCN phase.
- To compare this new event with previously observed FCN phase jumps.
- To investigate potential correlations between the FCN phase jump and other geophysical phenomena.
Main Methods:
- Analysis of a long time series of Very Long Baseline Interferometry (VLBI) observations.
- Development and comparison of two distinct FCN models.
- Quantitative assessment of the FCN phase jump amplitude and duration.
Main Results:
- Detection of a second large FCN phase jump, occurring from 2021 to late 2022.
- The new jump's amplitude is approximately 3 radians, 1.5 times larger than the 1999-2000 event.
- The new FCN phase jump is temporally associated with a geomagnetic jerk beginning in 2020.
Conclusions:
- The observed FCN phase jump is a significant geophysical event.
- The magnitude of the new jump suggests substantial changes in core-mantle interactions.
- A potential link between the FCN phase jump and recent geomagnetic activity warrants further investigation.
Related Concept Videos
01:10Detection of Black Holes
2.3K
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...
2.3K
01:19Phase Changes
4.5K
Phase transitions play an important theoretical and practical role in the study of heat flow. In melting or fusion, a solid turns into a liquid; the opposite process is freezing. In evaporation, a liquid turns into a gas; the opposite process is condensation.
A substance melts or freezes at a temperature called its melting point and boils or condenses at its boiling point. These temperatures depend on pressure. High pressure favors the denser form of the substance, so typically, high pressure...
A substance melts or freezes at a temperature called its melting point and boils or condenses at its boiling point. These temperatures depend on pressure. High pressure favors the denser form of the substance, so typically, high pressure...
4.5K
01:11Atomic Nuclei: Larmor Precession Frequency
1.6K
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,...
1.6K
02:31Phase Transitions
19.7K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
19.7K
01:24Gyroscope: Precession
4.6K
Precession can be demonstrated effectively through a spinning top. If a spinning top is placed on a flat surface near the surface of the Earth at a vertical angle and is not spinning, it will fall over due to the force of gravity producing a torque acting on its center of mass. However, if the top is spinning on its axis, it precesses about the vertical direction, rather than topple over due to this torque. Precessional motion is a combination of a steady circular motion of the axis and the...
4.6K
01:06Forced Oscillations
6.7K
When an oscillator is forced with a periodic driving force, the motion may seem chaotic. The motions of such oscillators are known as transients. After the transients die out, the oscillator reaches a steady state, where the motion is periodic, and the displacement is determined.
6.7K