Scientists from NASA have uncovered a strange magnetic field surrounding our solar system, shedding new light on the mysterious boundary between our solar system and interstellar space just beyond the heliosphere.
Combining observations of cosmic ray particles streaming in from other parts of the Milky Way with measurements from NASA’s Interstellar Boundary Explorer, or IBEX, scientists are getting a better idea of the forces at work at our cosmic borders.
IBEX was launched in 2008 and is making its way around the perimeter of the solar system to map the edge. The spacecraft first sent shockwaves through the scientific community in 2009 when it detected a magnetic emission in that region of space. Scientists described it as a “very narrow ribbon that is two to three times brighter than anything else in the sky."
Our sun creates a constant “solar wind” of charged particles that radiate in all directions, forming the heliosphere in which all the planets are contained. This heliosphere is constantly bombarded by galactic cosmic rays coming from outer space, but scientists still aren’t sure exactly why measurements show cosmic rays coming in more from one side of the solar system than the other.
According to the new study, published in the journal Science Express, the answers could lie in the magnetic ribbon and its irregular shape.
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“Observations with the [IBEX] have shown enhanced energetic neutral atom emission from a narrow, circular ribbon likely centered on the direction of the local interstellar medium magnetic field,” the authors wrote. “Here, we show that recent determinations of the local interstellar velocity, based on interstellar atom measurements with IBEX, are consistent with the interstellar modulation of high-energy cosmic rays.”
Studying this magnetic field could allow researchers to gain insight into how the sun’s environment shields the solar system from high-energy cosmic rays.
"It's a fascinating time," Nathan Schwadron, of the University of New Hampshire in Durham and the study’s lead author, said in a statement. "Fifty years ago, we were making the first measurements of the solar wind and understanding the nature of what was just beyond near-Earth space. Now, a whole new realm of science is opening up as we try to understand the physics all the way outside the heliosphere."
How our galaxy’s magnetic fields affect cosmic rays is a critical part of understanding the environment our solar system exists in. It even plays a role in comprehending how life evolved right here on Earth.
“The cosmic ray data we used represent some of the highest-energy radiation we can observe and are at the opposite end of the energy range compared to IBEX’s measurements,” Schwadron said. “That it’s revealing a consistent picture of our neighborhood in the galaxy with what IBEX has revealed gives us vastly more confidence that what we’re learning is correct.”