What is kerr-newman-black-hole-visualizer?

Kerr-Newman-black-hole-visualizer is an interactive tool for exploring the physics of a Kerr-Newman black hole, which is the mathematical description of a black hole that is both spinning and electrically charged. It renders this in both two and three dimensions using a coordinate system called Boyer-Lindquist coordinates, and it does not include the path a falling object would trace, known as a geodesic. The tool calculates the actual physical quantities of the black hole's spacetime exactly, using real world units for gravity and the speed of light rather than the simplified units physicists often use where those constants are just set to one. In the interactive 3D plot you can see grid lines marking out the coordinate system, the black hole's inner and outer horizons, the ergosphere, which is the region around a spinning black hole where nothing can stay still, arrows showing how spacetime itself gets dragged around by the rotation, and the ring shaped singularity at the center. You can adjust the black hole's mass, spin, and electric charge, along with how large an area is shown and how thick or transparent the plotted lines appear. The author notes that while the underlying physics values are computed exactly, the visual lines on the grid are exaggerated somewhat to make the shapes easier to see and more visually clear, so the picture is not meant to be a perfectly accurate geometric embedding. The project states plainly that it is meant for educational purposes, to help people build an intuitive sense of what a rotating, charged black hole looks like, rather than to serve as a precise research tool. Beyond the core Kerr-Newman visualizer, the README mentions two additional updates: a two dimensional simulation of a simpler black hole and white hole pair, called a Schwarzschild black hole, and a three dimensional version of that same simulation. To run any of this, you need Python along with the NumPy and Matplotlib libraries installed. The README does not mention a license for this project.