Understanding cosmic bow shocks Today’s Video of the Day from NASA Science News explains how bow shocks can occur anywhere, even in space.
When planets, stars, and the plasma clouds ejected from supernovae fly at a high speed through a medium, cosmic bow shocks form within that medium.
Scientists study these events to better understand the velocity and structure of astrophysical objects. Cosmic Bow Shocks. Imagine an object moving at super-sonic speed. This object, as it moves through a medium, causes the material in the medium to pile up, compress, and heat up. The result is a type of shock wave, known as a bow shock. When planets, stars, and the plasma clouds ejected from supernovae fly at a high speed through this surrounding medium, cosmic bow shocks are generated in that medium. The solar wind forms a bow shock in front of Earth’s magnetosphere.
The high-speed collisions of stars with the interstellar medium create impressive bow shocks. Hot supergiant star Kappa Cassiopeia creates a shock that can be seen by the infrared detectors on NASA’s Spitzer Space Telescope. In this Spitzer image, the pile-up of heated material around Kappa Cassiopeia is indicated in red. The solar wind forms a bow shock in front of Earth’s magnetosphere. “The fast-moving plasma of the solar wind blows past Earth, but it cannot penetrate our magnetosphere,” explains Maxim Markevitch of NASA’s Goddard Space Flight Center.
Video Credit: NASA Science News