(April 24, 2024)
The age of the Earth’s magnetic field remains under question in part because we don’t fully understand what causes it today. We know it is a product of movements in the molten outer core, whose high iron content turns convection currents into a dynamo, and these currents in turn are produced by the solidification of the inner core.
(April 2018)
Using constraints from experiments, simulations, and theory, we show that spontaneous crystallization in a homogeneous liquid iron alloy at Earth‘s core pressures requires a critical supercooling of order 1000 K, which is too large to be a plausible mechanism for the origin of Earth‘s inner core. We consider mechanisms that can lower the nucleation barrier substantially. Each has caveats, yet the inner core exists: this is the nucleation paradox.
(February 9, 2018)
„Everyone, ourselves included, seemed to be missing this big problem,“ study author Steven Hauck, a professor of Earth, Environmental and Planetary Sciences at Case Western Reserve University in Ohio, said in a statement. Namely, they were missing „that metals don‘t start crystallizing instantly unless something is there that lowers the energy barrier a lot.“
In chemistry, this extra energy is known as the nucleation barrier: the point at which a compound visibly changes its thermodynamic phase.
(…)
In their paper, the researchers proposed one possibility: Perhaps a massive nugget of solid metal alloy dropped from the mantle and plunged into the liquid core.
(June 11, 2026)
The observation provides new insights into the behaviour of the liquid outer core, which plays a key role in generating Earth’s magnetic field. Without this magnetic shield, the planet would be dangerously exposed to solar radiation.
Researchers at the University of Edinburgh checked ground observations and satellite data between 1997 and 2025. They report in The Journal of Studies of Earth’s Deep Interior, that in 2010, a broad region of iron-rich fluid beneath the equatorial Pacific switched from moving weakly westwards to strongly eastwards.
(May 28, 2026)
We use Sun-as-a-star helioseismology data, collected by the Birmingham Solar-Oscillations Network, to examine the relationship between the solar-cycle-induced frequency shifts of whole-Sun, low-angular degree solar p modes and well-known proxies of global solar activity. Changes in behaviour between the low-frequency modes and proxies, which in a previous study we found had occurred on the declining phase of Cycle 23, appear to have persisted into Cycle 25. More striking is a significant change in the relationship for higher-frequency modes, which the new Cycle 25 data now reveal. The observed mean frequency shifts in Cycle 25 are much stronger than one would expect for these modes based on the relationship between the frequencies and proxies seen in previous cycles, in particular Cycle 22. In sum, Cycle 25 is as strong as Cycles 22 and 23 when observed in this higher-frequency seismic band, in marked contrast to the relative sizes of the cycles seen in the global activity proxies, where Cycle 25 is noticeably weaker. (…)
The last few solar cycles have seen significant changes in overall levels of activity and differences in the evolution of magnetic fields at different solar latitudes (e.g. see D. H. Hathaway 2015; A. Norton et al. 2023). Cycle 24 was significantly weaker in well-known proxies of global solar activity than previous cycles, and marked a departure from the preceding so-called modern maximum epoch (I. G. Usoskin 2017). While the current Cycle 25 has peaked at higher activity, it did not return to pre-Cycle-24 levels.
(May 28, 2026)
Professor Sarbani Basu, from Yale University, said, “We discovered that the relationship between internal solar oscillations and surface activity has evolved over the past few cycles. This trend cannot be explained simply by weaker magnetic fields. Instead, it indicates a structural reorganisation of how the Sun’s magnetic activity is stored beneath the surface.”
Ongoing collection and analysis of BiSON solar data over what remains of Cycle 25 and into the upcoming Cycle 26 will be crucial in determining whether the changes discovered in the Sun’s activity point to a sustained, systematic change in solar magnetic behaviour.
(May 29, 2026)
Here‘s where it gets strange. Traditional measurements of solar activity such as sunspot counts and magnetic field strengths at the surface suggest that cycle 25 is relatively modest. But the helioseismic data tells a different story. Look at the high-frequency oscillations, which probe the shallowest layers, and cycle 25 appears just as powerful as its predecessors. The Sun looks different depending on where you look. The surface is playing it down but the interior is not.
What does this mean? The honest answer is that nobody is entirely sure yet.
The northern lights are caused by the solar wind, a stream of charged particles from the sun that interacts with Earth’s magnetic field. As charged particles strike Earth’s magnetic field, they accelerate down its magnetic field lines at the north and south poles, exciting particles in the atmosphere to create ovals of green and red.
(July 19, 2024)
The current solar cycle, named Cycle 25 because it is the 25th since 1755 when extensive recording of solar sunspot activity began, started in 2019.
It is not expected to end for another six years but the first signs that the next solar cycle is beginning have been spotted by researchers from the University of Birmingham and presented at the Royal Astronomical Society‘s National Astronomy Meeting in Hull.
(February 12, 2026)
Scientists call the current cycle Solar Cycle 25, the 25th numbered cycle since recordkeeping began in the 1700s. Even though it may feel like the northern lights have been more common in recent years, Solar Cycle 25 ranks among the lowest of the past 126 years.
(…)
Earth’s magnetic field has been slowly weakening for more than a century, which means our natural shield isn’t quite as strong as it used to be. That doesn’t create solar storms, but it can change how much of that energy actually makes it through when a strong one hits.
(March 9, 2022)
This complex environment surrounds the planets and ultimately has a crucial effect on the formation, evolution, and destiny of planetary systems. For one thing, our heliosphere acts as a giant shield, protecting the planets from galactic cosmic radiation. Earth is additionally shielded by its own magnetic field, the magnetosphere, which protects us not only from solar and cosmic particle radiation but also from erosion of the atmosphere by the solar wind. Planets without a shielding magnetic field, such as Mars and Venus, are exposed to such processes and have evolved differently.
NASA‘s studies of the heliosphere include research into: how the solar wind behaves near Earth; what causes and sustains magnetic and electric fields around other planets; how does the heliosphere interact with the interstellar medium; what do the boundaries of the heliosphere look like; what is the origin and evolution of the solar wind and the interstellar cosmic rays; and what contributes to the habitability of exoplanets.
(June 1981)
This paper describes in detail how we are led to the first approximation expression for the solar wind-magnetosphere energy coupling function ɛ, which correlates well with the total energy consumption rate U T of the magnetosphere. It is shown that ɛ is the primary factor which controls the time development of magnetospheric substorms and storms. The finding of this particular expression ɛ indicates how the solar wind couples its energy to the magnetosphere; the solar wind and the magnetosphere constitute a dynamo. In fact, the power P generated by the dynamo can be identified as ɛ by using a dimensional analysis. Furthermore, the finding of ɛ indicates that the magnetosphere is closer to a directly driven system than to an unloading system which stores the generated energy before converting it to substorm and storm energies.
(January 13, 2026)
Coining the term “near-Earth astrophysics,” Fasel has devoted much of his career to investigating solar-terrestrial interactions between the Sun and Earth, using the aurora borealis to obtain clues regarding the coupling mechanisms between the solar wind and the Earth’s terrestrial magnetic field.
“Stars have winds,” says Fasel. “And this includes our Sun. While solar wind is a relatively continuous stream of particles that interact with the Earth’s magnetic field, the Sun can also produce powerful solar storms. These storms expel billions of charged particles [plasma] coupled to magnetic fields, called coronal mass ejections, which bang up into the Earth’s magnetic field.”
The Earth’s magnetic field lines, Fasel explains, “act like wires” on which these particles travel down into the Earth’s upper atmosphere, specifically the ionosphere. The aurora is an end result of this interaction, where high-energy electrons collide with oxygen to produce green light, while those of lower energy produce a raspberry-red color.
(May 20, 2020)
Over the last 200 years, the magnetic field has lost around 9% of its strength on a global average. A large region of reduced magnetic intensity has developed between Africa and South America and is known as the South Atlantic Anomaly.
(May 22, 2020)
According to the European Space Agency (ESA), the magnetic field has lost around 9 percent of its strength over the preceding two centuries. One section of the magnetic field has been found to have weakened considerably since 1970.
This patch, called the South Atlantic Anomaly, sits between Africa and South America. Over the last 50 years, it has grown and moved farther west at a rate of roughly 12 miles per year. However, in the last five years, part of the anomaly appears to have split off into a cell which the ESA calls a „second center of minimum intensity“ located southwest of Africa.
(29.3.2018)
The strength of Earth’s main magnetic field is currently about 29.5 microteslas, down 5 microteslas, or 14 percent from its strength three centuries ago.
We know this. There is no question of this.
(August 2008)
Correlations between geomagnetic-field and climate parameters have been suggested repeatedly, but possible links are controversially discussed. Here we test if weak (Earth-strength) magnetic fields can affect climatically relevant properties of seawater. We found the solubility of air in seawater to be by 15% lower under reduced magneticfield (20 mT) compared to normal field conditions (50 mT). The magnetic-field effect on CO2 solubility is twice as large, from which we surmise that geomagnetic field variations modulate the carbon exchange between atmosphere and ocean. A 1% reduction in magnetic dipole moment may release up to ten times more CO2 from the surface ocean than is emitted by subaerial volcanism.
(December 30, 2016)
Earth’s magnetic field is built up from many contributing sources ranging from the planet’s core to the magnetosphere in space. Untangling and identifying the different sources allows geomagnetic scientists to gather information about the individual processes that combine to create the full field.
One contributor is the ocean. But how do the tides affect Earth’s magnetic field? Seawater is an electrical conductor, and therefore interacts with the magnetic field. As the tides cycle around the ocean basins, the ocean water essentially tries to pull the geomagnetic field lines along. Because the salty water is a good, but not great, conductor, the interaction is relatively weak. The strongest component is from the regular lunar tide that happens about twice per day (actually 12.42 hours).
November 13, 2025
People across the United States weren’t the only ones treated to a spectacular celestial show. This week’s intense geomagnetic storm illuminated the night sky around the world. Check out some of the most stunning displays from Europe to Mongolia to Australia.
(July 19, 2024)
The current solar cycle, named Cycle 25 because it is the 25th since 1755 when extensive recording of solar sunspot activity began, started in 2019.
It is not expected to end for another six years but the first signs that the next solar cycle is beginning have been spotted by researchers from the University of Birmingham and presented at the Royal Astronomical Society‘s National Astronomy Meeting in Hull.
(July 23, 2024)
Solar max affects activity on the sun’s surface. Sunspots, flares and coronal mass ejections are all more rampant at solar maximum. This leads to a surge in electromagnetic energy hurtling toward Earth, making auroras visible more often and at lower altitudes.
The current solar cycle – Cycle 25 – started in 2019. It has the name Cycle 25 because it’s the 25th since 1755, when extensive recording of solar sunspot activity began.
It is not expected to end for another six years, but researchers have spotted the first signs that the next solar cycle is beginning. Researchers from the University of Birmingham presented their findings at the Royal Astronomical Society’s National Astronomy Meeting in Hull on July 18, 2024.
Jun 11, 2020
Far, far beyond the orbits of the planets lie the hazy outlines of the magnetic bubble in space that we call home.
This is the heliosphere, the vast bubble that is generated by the Sun’s magnetic field and envelops all the planets. The borders of this cosmic bubble are not fixed. In response to the Sun’s gasps and sighs, they shrink and stretch over the years.
Now, for the first time, scientists have used an entire solar cycle of data from NASA’s IBEX spacecraft to study how the heliosphere changes over time. Solar cycles last roughly 11 years, as the Sun swings from seasons of high to low activity, and back to high again. With IBEX’s long record, scientists were eager to examine how the Sun’s mood swings play out at the edge of the heliosphere. The results show the shifting outer heliosphere in great detail, deftly sketch the heliosphere’s shape — a matter of debate in recent years, and hint at processes behind one of its most puzzling features. These findings, along with a newly fine-tuned data set, are published in The Astrophysical Journal Supplements on June 10, 2020.
(August 2008)
Correlations between geomagnetic-field and climate parameters have been suggested repeatedly, but possible links are controversially discussed. Here we test if weak (Earth-strength) magnetic fields can affect climatically relevant properties of seawater. We found the solubility of air in seawater to be by 15% lower under reduced magneticfield (20 mT) compared to normal field conditions (50 mT). The magnetic-field effect on CO2 solubility is twice as large, from which we surmise that geomagnetic field variations modulate the carbon exchange between atmosphere and ocean. A 1% reduction in magnetic dipole moment may release up to ten times more CO2 from the surface ocean than is emitted by subaerial volcanism.
(…)
The fact that the MF effect is similar among the molecular gases suggests that effects seen with air are not due to the paramagnetic susceptibility of O 2, which is too small to explain the observed magnetic-field effects in terms of magnetization effects.
(June 13, 2025)
The strength of Earth’s magnetic field seems to rise and fall in line with the abundance of oxygen in the planet’s atmosphere, a study of geological records spanning the past half a billion years has found.