Does Mercury Have a big Iron Core Because it’s so Close to the Sun’s Magnetic Field?

Magnetic fields are great for lots of things – directing explorers, levitating trains, and containing nuclear fusion reactions are just an example of what these invisible forces can do.  Now we can ascribe another feature to magnetic fields – they can give planets a rocky core.

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Scientists in Japan Have Found a Detailed Record of the Earth’s Last Magnetic Reversal, 773,000 Years Ago

Every 200,000 to 300,000 years Earth’s magnetic poles reverse. What was once the north pole becomes the south, and vice versa. It’s a time of invisible upheaval.

The last reversal was unusual because it was so long ago. For some reason, the poles have remained oriented the way they are now for about three-quarters of a million years. A new study has revealed some of the detail of that reversal.

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Astronomers Measure a 1-billion Tesla Magnetic Field on the Surface of a Neutron Star

We recently observed the strongest magnetic field ever recorded in the Universe. The record-breaking field was discovered at the surface of a neutron star called GRO J1008-57 with a magnetic field strength of approximately 1 BILLION Tesla. For comparison, the Earth’s magnetic field clocks in at about 1/20,000 of a Tesla – tens of trillions of times weaker than you’d experience on this neutron star…and that is a good thing for your general health and wellbeing.

Neutron stars are the “dead cores” of once massive stars which have ended their lives as supernova. These stars exhausted their supply of hydrogen fuel in their core and a power balance between the internal energy of the star surging outward, and the star’s own massive gravity crushing inward, is cataclysmically unbalanced – gravity wins. The star collapses in on itself. The outer layers fall onto the core crushing it into the densest object we know of in the Universe – a neutron star. Even atoms are crushed. Negatively charged electrons are forced into the atomic nuclei meeting their positive proton counterparts creating more neutrons. When the core can be crushed no further, the outer remaining material of the star rebounds back into space in a massive explosion – a supernova. The resulting neutron star, made of the crushed stellar core, is so dense that a single sugar-cube-sized sampling would weigh billions of tons – as much as a mountain (though if you’re “worthy” you MIGHT able to lift it since Thor’s Hammer is made of the stuff). Neutron stars are typically about 20km in diameter and can still be a million degrees Kelvin at the surface.

But if they’re “dead,” how can neutron stars be some of the most magnetic and powerful objects in the Universe?

Composite image of the maelstrom at the heart of the Crab Nebula powered by a neutron star – Chandra X-Ray Observatory
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Earth’s Magnetic Field is Changing Surprisingly Quickly

If you’ve ever used a compass, you know that the magnetic needle always points North. Well, almost North. If you just happen to be out camping for the weekend, the difference doesn’t matter. For scientists studying the Earth’s interior, the difference is important. How Earth’s magnetic field changes over time give us clues about how our planet generates a magnetic field in the first place.

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Magnetic north is migrating towards Siberia. Here’s why

The North Pole ain’t what it used to be. Well, the geographic North Pole stays fixed over time (mostly because we define it to stay fixed over time) but the magnetic north pole constantly moves. And over the past decade it’s been moving out of Canada towards Siberia four times faster than it has in the past couple centuries. Armed with data from the ESA’s Swarm satellite, scientists might finally know why: the shifting of our magnetic field north pole is caused by a titanic struggle between two competing massive magnetic plumes.

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Magnetic Fields Around Mars InSight are 10x Stronger than Scientists Expected

When NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (Insight) lander set down on Mars in November of 2018, it began its two-year primary mission of studying Mars’ seismology and interior environment. And now, just over a year and a half later, the results of the lander’s first twelve months on the Martian surface have been released in a series of studies.

One of these studies, which was recently published in the journal Nature Geosciences, shared some rather interesting finds about magnetic fields on Mars. According to the research team behind it, the magnetic field within the crater where InSight’s landed is ten times stronger than expected. These findings could help scientists resolve key mysteries about Mars’ formation and subsequent evolution.

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The Moon’s Magnetosphere Used to be Twice as Strong as the Earth’s

For decades, scientists have held that the Earth-Moon system formed as a result of a collision between Earth and a Mars-sized object roughly 4.5 billion years ago. Known as the Giant Impact Hypothesis, this theory explains why Earth and the Moon are similar in structure and composition. Interestingly enough, scientists have also determined that during its early history, the Moon had a magnetosphere – much like Earth does today.

However, a new study led by researchers at MIT (with support provided by NASA) indicates that at one time, the Moon’s magnetic field may have actually been stronger than Earth’s. They were also able to place tighter constraints on when this field petered out, claiming it would have happened about 1 billion years ago. These findings have helped resolve the mystery of what mechanism powered the Moon’s magnetic field over time.

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