From NASA: “Cosmic Bow Shocks”

NASA image
NASA

No writer credit


No video credit

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.

A bow shock gets it’s name from bow waves, the curved ridge of water in front of a fast-moving boat created by the force of the bow pushing forward through the water. Bow waves and bow shocks can look similar, however bow waves only occur on the surface of water while bow shocks occur in 3 dimensions.

There are bow shocks everywhere, even in space–and these cosmic bow shocks can tell scientists cosmic secrets.

Even the emptiest regions of space contain protons, electrons, atoms, molecules and other matter. 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.

Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase

“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.

NASA Goddard Campus


“The solar wind has a magnetic field, and the Earth’s magnetosphere is almost like a solid body for that wind. So the solar wind forms a bow shock in front of the outer edge of the magnetosphere.”

Studying Earth’s bow shock can unlock the secrets of the solar wind, allowing us to better understand its complicated effects on our planet.

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.

NASA/Spitzer Infrared Telescope

In this Spitzer image, the pile-up of heated material around Kappa Cassiopeia is indicated in red.

2
http://www.spitzer.caltech.edu/images/5730-sig14-003-The-Shocking-Behavior-of-a-Speedy-Star
Kappa Cassiopeiae, or HD 2905 to astronomers, is a runaway star—a massive, hot supergiant gone rogue. What really makes the star stand out in this image is the surrounding, streaky red glow of material in its path. Such structures are called bow shocks, and they can often be seen in front of the fastest, most massive stars in the galaxy.

Bow shocks form where the magnetic fields and wind of particles flowing off a star collide with the diffuse, and usually invisible, gas and dust that fill the space between stars. How these shocks light up tells astronomers about the conditions around the star and in space. Slow-moving stars like our sun have bow shocks that are nearly invisible at all wavelengths of light, but fast stars like Kappa Cassiopeiae create shocks that can be seen by Spitzer’s infrared detectors.
Incredibly, this shock is created about 4 light-years ahead of Kappa Cassiopeiae, showing what a sizable impact this star has on its surroundings.

Studying stellar bow shocks can reveal the secret motions of the underlying stars, telling us how fast they’re moving, which way, and what they’re moving through.

An example of a bow shock on an even grander scale is seen in this cluster of galaxies located in the Carina constellation, called 1E 0657-558.

3
Anne’s Astronomy News
The Bullet cluster (1E 0657-558) consists of two colliding galaxy clusters in Carina.

This X-ray image from the Chandra observatory captures the moment of a gigantic collision of two smaller clusters, the two white regions in the image.

NASA/Chandra Telescope

Markevitch says, “The clusters are filled with hot plasma, and one of them — the cluster on the right — is smaller and denser. As it flies through the less-dense cloud of plasma that is the bigger cluster it forms a bow shock.”

Scientists study such cluster shocks to deduce their velocity in the plane of the sky. And the fine structure of the shocks reveals a lot about the interesting, complicated physical processes in the plasmas present in clusters as well as in many other astrophysical objects across the universe.

For more on shocking phenomena found beyond our solar system, stay tuned to science.nasa.gov.

See the full article here .

Please help promote STEM in your local schools.

STEM Icon

Stem Education Coalition

The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.