https://history.siggraph.org/animation-video-pod/towers-in-the-tempest-by-shirah/

(PDF) Space Weather Impact on GNSS Performance

https://www.msn.com/en-us/video/animals/scientists-tried-to-talk-to-whales-and-something-answered-back/vi-AA21sAZC?ocid=BingHp01&cvid=562ad79dbef44541ac51f17b23013550&ei=16

Here's an interesting idea, just published Physical Review Letters, that on its face may solve all the problems of quantum gravity. The basic idea as that once upon a time space was four dimensional without time, and that a quantum fluctuation converted one of the spacial dimensions into time. At that moment, the universe began to change in time, rapidly inflated, and became the one we see around us. Before then (how can one talk about "before" something happened inside a universe without time? But I digress) the energy density was so great that the equations that described gravity included a quadratic term, and this term is what kept the solutions of the Einstein Field Equations finite. Theorists seem to think this model actually solves all the main problems with quantum gravity. But... as Sabine asks--is it right? Enjoy

Julian Schwinger was one of my professors when I was a grad student at UCLA. I leaned Electricity and Magnetism from him, as well as Quantum Kinematics. He won the Nobel Prize with Richard Feynman and Sin'ichiro Tomonaga in 1965 for developing Quantum Electrodynamics or (QED) which is widely regarded as the best theory ever developed in terms of its ability to calculate observable quantities in the quantum world. Here he explains relativity theory as Einstein intended--"as simple as possible, but no simpler." He even provides the most intuitive justification for Einstein's famous E=mc^2 that I've ever seen. If you'd like to develop an intuitive feel for the counter intuitive aspects of Special Relativity, I strongly recommend this video. (And it has no commercials!) Since I knew the guy, at least as a professor in my department, I thought I'd share this bit of history... In 1982 I was a graduate student in Physics at UCLA. He taught a graduate class in electromagnetism, and instead of assigning a book written by another physicist, he provided notes of his lectures that he and some co-authors later published as his own textbook entitled "Classical Electrodynamics." His lectures were fluent and brilliant, but they were very difficult to master because he moved effortlessly through the material at a rate that mere mortals could not follow. He was like an experienced trail guide who kept flicking branches in the faces of the people who were trying to keep up with him. His lectures ran for two hours--no break--twice a week on Tuesday and Thursday afternoon. I took 400 mg of caffein tablets to be able to stay focused through the entire lecture. In every lecture he would start at the upper-left corner of the double blackboard at the front of the room, fill the space completely in one hour, then erase the entire board and start again. Then just as the second hour was coming to a close he would be writing the list bit of his lecture in the lower right corner--look at the time, and then be the first person out the door. He never stayed to answer questions, and strongly discouraged students from asking questions, one time brutally dressing down a student who dared interrupt him by yelling "DO YOU MEAN TO TELL ME THAT I HAVE TO EXPLAIN THE CONCEPT OF AN INFINITESSIMAL TO A GRADUATE LEVEL CLASS?" The class fell silent, and no one dared interrupt him again.