“Extracting reliable records from rocks this old is extremely challenging, and it was really exciting to see primary magnetic signals begin to emerge when we analyzed these samples in the lab.” said Dr. Claire Nichols.

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How long has the Earth’s magnetic field existed? This is what a recent study published in the Journal of Geophysical Research Solid Earth hopes to address as a team of international researchers discovered evidence indicating that the Earth’s magnetic field existed as far back as 3.7 billion years ago and was approximately half as strong as it is today, which puts this as the oldest evidence of Earth’s magnetic field to date. This study holds the potential to help scientists better understand the processes responsible for producing the Earth’s magnetic field, which is responsible for shielding the planet’s atmosphere and surface from harmful space weather.

For the study, the researchers analyzed iron-bearing rock formations among the Isua Supracrustal Belt in Southern West Greenland whose iron particles record the direction and strength of the magnetic field and are locked in time due to crystallization. In the end, the researchers determined that the iron particles exhibit evidence of the Earth’s magnetic field from 3.7 billion years ago along with its strength being half of what it is today.

In a new study published inNature Physics, scientists at the MAJORANA Collaboration have tested the stringency of charge conservation and Pauli’s exclusion principles using underground detectors. Alessio Porcelli has published a News & Views piece on the research in the same journal.

Today, the Standard Model of particle physics is one of two pillars on which modern physics rests. It successfully explains three out of the four fundamental forces and how subatomic particles behave.

Pauli’s exclusion principle and the conservation of charge are two of the principles arising from the symmetries in the Standard Model. They have withstood many theoretical challenges and have repeatedly proven to the point where they are considered axiomatic.

Unlike electrons, particles of light are uncharged, so they do not respond to magnetic fields. Despite this, researchers have now experimentally made light effectively “feel” a magnetic field within a complicated structure called a photonic crystal, which is made of silicon and glass.

Within the crystal, the light spins in circles and the researchers observed, for the first time, that it forms discrete energy bands called Landau levels, which parallels a well-known phenomenon seen in electrons.

This finding could point to new ways to increase the interaction of light with matter, an advance that has the potential to improve photonic technologies, like very small lasers.

The discovery and ongoing research into neutrinos have significantly altered the foundational concepts of particle physics, highlighting the particles’ mass and challenging the accuracy of the standard model.

In the 1930s, it turned out that neither the energy nor the momentum balance is correct in the radioactive beta decay of an atomic nucleus. This led to the postulate of “ghost particles” that “secretly” carry away energy and momentum. In 1956, experimental proof of such neutrinos was finally obtained.

The challenge: neutrinos only interact with other particles of matter via the weak interaction that is also underlying the beta decay of an atomic nucleus. For this reason, hundreds of trillions of neutrinos from the cosmos, especially the sun, can pass through our bodies every second without causing any damage. Extremely rare neutrino collisions with other particles of matter can only be detected with huge detectors.

Researchers at the IceCube Neutrino Observatory in Antarctica have found seven signals that could potentially indicate tau neutrinos—which are famously hard to detect—from astrophysical objects.