Related Experiment Video
Updated: Jul 10, 2025
11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
10.4K
Cosmic-void observations reconciled with primordial magnetogenesis
David N Hosking1,2,3,4, Alexander A Schekochihin5,6
1Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH, UK. dhosking@princeton.edu.
Nature Communications
|November 19, 2023
Summary
Early Universe magnetic fields from the electroweak phase transition (EWPT) are too weak. A new theory involving magnetic reconnection strengthens these relic fields, aligning them with observations and potentially resolving the Hubble tension.
Area of Science:
- Cosmology
- Astrophysics
- Particle Physics
Background:
- The intergalactic medium's weak magnetic field may originate from the early Universe.
- Standard models predict relic magnetic fields from the electroweak phase transition (EWPT) are too weak to explain observed phenomena like gamma-ray scattering from blazars.
Purpose of the Study:
- To propose a new mechanism for the decay of early Universe magnetic fields.
- To reconcile the EWPT-relic hypothesis with observational constraints.
- To investigate the potential of these relic fields to address cosmological puzzles like the Hubble tension.
Main Methods:
- Investigating turbulent magnetohydrodynamic decay.
- Proposing magnetic reconnection as the mediating process for field decay.
- Conserving the mean square fluctuation level of magnetic helicity during decay.
Main Results:
- The proposed theory predicts relic magnetic fields several orders of magnitude stronger than previously thought.
- This significant strengthening restores consistency between the EWPT-relic hypothesis and observational data.
- Efficient EWPT magnetogenesis can generate fields strong enough to impact recombination and seed galaxy-cluster fields.
Conclusions:
- Magnetic reconnection offers a viable pathway for preserving early Universe magnetic fields.
- The EWPT-relic hypothesis is strengthened by this new understanding of magnetic field decay.
- These stronger relic fields have implications for resolving the Hubble tension and understanding cosmic magnetic field origins.
Related Concept Videos
01:28Magnetostatic Boundary Conditions
964
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
964
01:26Divergence and Curl of Magnetic Field
3.0K
The magnetic field due to a volume current distribution given by the Biot–Savart Law can be expressed as follows:
3.0K
01:17The Principle of Superposition and the Gravitational Field
1.3K
The principle of superposition applies to gravitational forces of objects that are sufficiently far apart. It states that the net gravitational force on a point object is the vector sum of the gravitational forces on it due to various objects. The principle helps calculate the force by listing the individual forces and then vectorially summing them up. However, it should be noted that the principle of superposition is not always apparent. In the presence of a second force, the first force could...
1.3K
01:10Detection of Black Holes
2.2K
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...
2.2K
01:19Magnetic Field Lines
4.1K
The representation of magnetic fields by magnetic field lines is very useful in visualizing the strength and direction of the magnetic field. Each of the magnetic field lines forms a closed loop. The field lines emerge from the north pole (N), loop around to the south pole (S), and continue through the bar magnet back to the north pole.
Magnetic field lines follow several hard-and-fast rules:
Magnetic field lines follow several hard-and-fast rules:
4.1K
01:24Potential Due to a Magnetized Object
296
Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
The vector...
296