Category Astronomy/Space

This is an X-ray image of the Perseus galaxy cluster, approximately 240 million light-years away from Earth. The x-ray radiation emitted by galaxies and galaxy clusters still poses numerous puzzles to astrophysicists. In particular, it may provide clues to the nature of the mysterious dark matter. Credit: NASA

Physicists propose a new theory of dark matter based on the detection of unusual x-ray radiation from galaxies. It implies that dark matter particles may be very different from what is normally assumed. In particular, their theory involves dark matter particles which are extremely light – almost 100X lighter than electrons, in stark contrast to many conventional models that involve very heavy dark matter particles instead.

According to common theory, dark matter must exist because ot...

The result shows the presence of a reinforced multilayer magnetic cage (orange and pink) in which the magnetic rope (blue) develops during the last hours before the eruption. Credit: © Tahar Amari et al. / Centre de physique théorique (CNRS/École Polytechnique).

Just one phenomenon may underlie all solar eruptions, according to researchers from the CNRS, École Polytechnique, CEA and INRIA. They have identified the presence of a confining ‘cage’ in which a magnetic rope forms, causing solar eruptions. It is the resistance of this cage to the attack of the rope that determines the power and type of the upcoming flare...

Visualization of molecular dynamics simulations showing the fast diffusion of hydrogen ions (pink trajectories) within the solid lattice of oxygen in superionic ice. Credit: S. Hamel/M. Millot/J.Wickboldt/LLNL/NIF

Scientists have provided the first experimental evidence for superionic conduction in water ice at planetary interior conditions, verifying a 30-year-old prediction. Among the many discoveries on matter at high pressure that garnered him the Nobel Prize in 1946, scientist Percy Bridgman discovered 5 different crystalline forms of water ice, ushering in more than 100 years of research into how ice behaves under extreme conditions.

One of the most intriguing properties of water is that it may become superionic when heated to several thousand degrees at high pressure, similar to the...

Magnetic loops gyrate above the sun, March 23-24, 2017. Credit: NASA/GSFC/Solar Dynamics Observatory

The Sun might emit less radiation by mid-century, giving planet Earth a chance to warm a bit more slowly but not halt the trend of human-induced climate change. The cooldown would be the result of what scientists call a grand minimum, a periodic event during which the Sun’s magnetism diminishes, sunspots form infrequently, and less ultraviolet radiation makes it to the surface of the planet. Scientists believe that the event is triggered at irregular intervals by random fluctuations related to the Sun’s magnetic field.

Scientists have used reconstructions based on geological and historical data to attribute a cold period in Europe in the mid-17th Century to such an event, named the “Maunder...