Universe Today

In 1912, astronomer Victor Hess discovered strange, high-energy particles called "cosmic rays." Since then, researchers have hunted for their birthplaces. Today, we know about some of the cosmic ray "launch pads", ranging from the Sun and supernova explosions to black holes and distant active galactic nuclei. What astronomers are now searching are sources of cosmic rays within the Milky Way Galaxy. One such source is a pulsar wind nebula sending high-energy particles out to space.

Shortly after astronomers detected asteroid 2024 YR4 on December 27th, 2024, they realized it posed no threat to Earth. But it still might impact the Moon in 2032. The impact debris could threaten satellites and trigger an extraordinarily stunning meteor shower.

Very massive stars (VMSs), which typically has masses about 100 times that of our own Sun, are critical components in our understanding of the formation of important astronomical structures like black holes and supernovae. However, there are some observed characteristics of VMSs that don’t fit the expected behavior based on the best models we have of them. In particular, they hover around a relatively limited band of temperatures, which are hard to replicate with typical stellar evolution models. A new paper from Kendall Shepherd and their co-authors at the Institute for Advanced Study (SISSA) in Italy describes a series of new models based on updated solar winds that better fit the observations of VMSs in their natural environment, and might aid in our understanding of the development of some of the most fascinating objects in the Universe.

LUNAA Journeys (St. LUcia National Astronomy Association) is looking to address an all too common problem in the global astronomical community. Too often, participation in astronomy is seen as cost prohibitive, the sole pursuit of large universities or organizations that can afford to build a large modern observatory, or launch the Hubble Space Telescope. This is unfortunate, as there’s never been an era of more readily accessible information, out there in terms of astronomy and skywatching.

During its commissioning phase, NASA's [*Polarimeter to Unify the Corona and Heliosphere*](https://science.nasa.gov/blogs/punch/) (PUNCH) mission captured high-resolution images of a [Coronal Mass Ejection](https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections) (CME) in greater detail than was previously possible.

Solar sails are space's ultimate free ride, they get their propulsion from the Sun, so they don't need to carry propellant, but they come with their own challenges. A sail has a large surface area but a low mass, which creates a huge moment of inertia and makes it difficult to control, especially with reaction wheels. A team of engineers have cracked it though with "smart mirrors" that can instantly switch their reflectivity on command, transforming sunlight from an unruly force into a precision steering tool.