Galactic magnetic fields may control boundaries of our solar system

October 17th, 2009 - 2:53 pm ICT by ANI  

Washington, October 17 (ANI): The first all-sky maps developed by NASA’s Interstellar Boundary Explorer (IBEX) spacecraft suggests that galactic magnetic fields may control the boundaries of our solar system.

A “solar wind” of charged particles continuously travels at supersonic speeds away from the Sun in all directions.

This solar wind inflates a giant bubble in interstellar space called the heliosphere - the region of space dominated by the Sun’s influence in which the Earth and other planets reside.

As the solar wind travels outward, it sweeps up newly formed “pickup ions,” which arise from the ionization of neutral particles drifting in from interstellar space.

IBEX measures energetic neutral atoms (ENAs) traveling at speeds of roughly half a million to two and a half million miles per hour.

These ENAs are produced from the solar wind and pick-up ions in the boundary region between the heliosphere and the local interstellar medium.

The IBEX mission just completed the first global maps of these protective layers called the heliosphere through a new technique that uses neutral atoms like light to image the interactions between electrically charged and neutral atoms at the distant reaches of our Sun’s influence, far beyond the most distant planets.

It is here that the solar wind, which continually emanates from the Sun at millions of miles per hour, slams into the magnetized medium of charged particles, atoms and dust that pervades the galaxy and is diverted around the system.

The interaction between the solar wind and the medium of our galaxy creates a complex host of interactions, which is thought to shield the majority of harmful galactic radiation that reaches Earth and fills the solar system.

“The magnetic fields of our galaxy may change the protective layers of our solar system that regulate the entry of galactic radiation, which affects Earth and poses hazards to astronauts,” said Nathan Schwadron of Boston University’s Center for Space Physics and the lead for the IBEX Science Operations Center at BU.

The first IBEX maps are strikingly different than any of the predictions, which are now forcing scientists to reconsider their basic assumptions of how the heliosphere is created.

“The most striking feature is the ribbon that appears to be controlled by the magnetic field of our galaxy,” said Schwadron.

Although scientists knew that their models would be tested by the IBEX measurements, the existence of the ribbon is “remarkable”, according to Geoffrey Crew, a Research Scientist at MIT and the Software Design Lead for IBEX.

“It suggests that the galactic magnetic fields are much stronger and exert far greater stresses on the heliosphere than we previously believed,” he added. (ANI)

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