From: Roger Greenway, ENN
Published October 19, 2009 08:32 PM

Our Own Solar System Still Holds Surprises!

NASA scientists have discovered a mysterious ribbon around our solar system, a stripe made of hydrogen. This was entirely unexpected, and inconsistent with what scientists thought the edge of the solar system might look like.

Since it launched a year ago, the Interstellar Boundary Explorer (IBEX) has been monitoring heliosphere and how our Sun interacts with and the local interstellar medium — the gas and dust trapped in the vacuum of space. The first results from the mission, combined with data from the Cassini mission, are showing the heliosphere to be different from what researchers have previously thought. Data show an unexpected bright band or ribbon of surprisingly high-energy emissions. 

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"We knew there would be energetic neutral atoms coming in from the very edge of the heliosphere, and our theories said there would be small variations in their emissions," said David McComas, IBEX Principal Investigator at a press conference on Thursday. "But instead we are seeing two-to-three hundred percent variations, and this is not entirely understood. Whatever we thought about this before is definitely not right."Our solar system is encased in a sort of protective layer called the heliosphere, which shields us from harmful cosmic radiation. The heliosphere is made up of particles blown through space by solar winds —- if you can imagine the sun blowing a giant bubble around the planets, you'll have a pretty good idea of what it's like. Last year, NASA launched the Interstellar Boundary Explorer Mission, or IBEX, which was designed to take a picture of the heliosphere. And according to Fisher, that picture did not conform to expectations.

"It captures an image that looks like what it would be if you were inside of a bubble," Fisher says. "And what it shows is that there is a stripe across the inside of this bubble."

Scientists know the mystery stripe is made of hydrogen, but they don't know why it's there or what it does. "And we also don't understand why it has brighter spots in it," Fisher adds. "It's not just a uniform kind of stripe. It's got intensity and density in it, and what in the world makes that? It's going to be fascinating to see."

NASA released the sky map image Oct. 15 in conjunction with publication of the findings in the journal Science. The IBEX data were complemented and extended by information collected using an imaging instrument sensor on NASA's Cassini spacecraft. Cassini has been observing Saturn, its moons and rings since the spacecraft entered the planet's orbit in 2004.

The IBEX sky maps also put observations from NASA's Voyager spacecraft into context. The twin Voyager spacecraft, launched in 1977, traveled to the outer solar system to explore Jupiter, Saturn, Uranus and Neptune. In 2007, Voyager 2 followed Voyager 1 into the interstellar boundary. Both spacecraft are now in the midst of this region where the energetic neutral atoms originate. However, the IBEX results show a ribbon of bright emissions undetected by the two Voyagers.

"The Voyagers are providing ground truth, but they're missing the most exciting region," said Eric Christian, the IBEX deputy mission scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "It's like having two weather stations that miss the big storm that runs between them."

Image shows orange gas in the representing the interstellar medium. The bow shock is created because the heliosphere is moving through like a boat through the water, crashing through the interstellar gases. Image is from animation created by Walt Feimer (HTSI) (Lead),Dave McComas (SwRI), and Eric Christian Ph.D. (NASA/HQ).

For the animation and more information: http://www.nasa.gov/mission_pages/ibex/allsky_map.html

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