David McComas investigates heliosphere surrounding our solar system

Scientists have discovered something new about what they call the heliosphere, described as a ‘bubble’ that surrounds our solar system.

David McComas: The heliosphere is nothing more than the region of space dominated by the sun. The heliosphere is the region of space where our sun and the material that comes from our sun basically makes this bubble in our part of the galaxy.

David McComas is principal investigator of NASA’s Interstellar Boundary Explorer, or IBEX. It’s a satellite in orbit around Earth which studies our local heliosphere. McComas said that what’s outside our heliosphere bubble is interstellar material, stuff in the space between our star and others.

David McComas: Outside is basically winds from other stars, and the materials from other stars, novae, and supernovae, charged particles and neutral particles in magnetic fields. And the galaxy is just full of this material.

Our heliosphere travels through this interstellar medium at about 26 kilometers – about 16 miles – per second, said McComas. In 2009, IBEX discovered a bright ribbon of emissions made by our heliosphere as it pushes through the interstellar medium.

David McComas:The pictures actually are shocking. We discovered this narrow, very bright ribbon, two to three times more particles coming from this narrow ribbon than any other part of the sky, not predicted by any models or theories, not expected from any of the previous observations.

Those previous observations are from the Voyagers 1 and 2 spacecraft, which are now approaching the outer edge of our solar system just outside the heliosphere known as the heliopause.

Potentially lethal galactic cosmic rays are screened out by the heliosphere, said McComas.

David McComas: This bubble that the solar wind blows up provides a protective shield around the solar system, and that shield actually stops some of the most dangerous parts of the galactic material from coming in.

McComas spoke about why it’s important to study the heliosphere.

David McComas: If it weren’t for the heliosphere, ten times more galactic cosmic rays would be coming in and would make, for example, the thought of traveling to Mars with manned spaceflight almost impossible to conceive of. Fortunately, we’ve got the heliosphere, and we’ve got this interaction. So we get a large protection from that shielding. But in order to really know how that works, in order to be able to predict it into the future, and know how the shielding might change over time, we have to have an understanding of what the interaction is at the edge of the solar system.

And that’s where NASA’s IBEX satellite mission comes in, says McComas.

David McComas: IBEX is a mission that’s really, for the first time, studying the global interaction at the edge of the solar system. The IBEX satellite, looking out all directions around us and measuring these particles coming in from the boundary region at the end of the solar system, we’re able to take a global picture from the inside looking out, and for the first time, measure the global interaction a this boundary all around us.

January 4, 2010

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