In a spiral galaxy, the stars move in a circular motion around the galactic center, and the relation between velocity and the orbital radius is referred to as the rotation curve. Previous astronomical observation data indicate that the rotation curve is flat at the periphery of the galaxy, which completely dissatisfies Keplerian decline. Assuming…

Gravitational lensing is an interesting phenomenon in astronomy and is most typically given rise to by galaxies. The majority of the matter in a galaxy is thought to be dark matter, and the galactic gravitational lensing effect is mainly caused by dark matter halos. In gravitational lensing-related demonstrations in physics education, the feet of…

For this article, we use a 3D printer to print a surface similar to universal gravitation for demonstrating and investigating Kepler's laws of planetary motion describing the motion of a small ball on the surface. This novel experimental method allows Kepler's laws of planetary motion to be visualized and will contribute to improving the…