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[Bell tone]

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Launched on October 19th 2008, the Interstellar Boundary

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Explorer, or IBEX, spacecraft, is unique in NASA's heliophysics fleet.

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IBEX looks at the very edge of the sun's reach, starting at about 8 billion miles away.

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This region begins with the termination shock, and ends with the heliopause. Between those two is the heliosheath,

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a teardrop-shaped region sculpted by the pressure of the interstellar medium. IBEX is

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also different because it makes its images from particles instead of light. Over the course of 6 months,

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and many orbits, IBEX can paint a picture of the entire sky in energetic neutral atoms,

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or ENAs for short. During its first 5 years, IBEX has made some astounding

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discoveries. New narrator: The IBEX mission science

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team has used data from the spacecraft to construct the first-ever all-sky map

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of the interactions occurring at the edge of the solar system, where the sun's influence

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diminishes and interacts with the interstellar medium. The most

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startling finding as a result of this map is a bright ribbon of energetic neutral

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atoms, emanating toward the sun from the edge of the solar system.

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New narrator: New data from NASA's Interstellar

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Boundary Explorer, reveal that conditions at the edge our solar system

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may be much more dynamic than previously thought. This second

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set of all-sky maps show the evolution of the interstellar boundary region.

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The mysterious ribbon feature at the nose of the heliosphere

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has changed shape, and a knot-like feature has formed.

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This variation over time is forcing scientists to try to

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understand how the heliosphere can be changing so rapidly.

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New narrator: Because IBEX is orbiting Earth, it also can observe

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the creation of energetic neutral atoms along the nose of

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Earth's magnetosphere. ENAs are created there as solar wind protons

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take electrons from hydrogen atoms in the outermost vestiges of our

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atmosphere, known as the exosphere. IBEX has also

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scanned another nearby world, with surprising results. The moon

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has no atmosphere or magnetosphere, so the solar wind slams unimpeded into

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its surface. About 10 percent of the impinging solar wind protons

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bounce off the lunar surface, becoming ENAs as they do.

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New narrator: IBEX has now made the first direct measurements of

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hydrogen, oxygen and neon from outside the solar system.

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The measurement of these atoms has enabled scientists to get a better grasp on

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the environment around our solar system. The speed of the

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galactic wind registered around 52,000 miles per hour.

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Heavy interstellar atoms show a difference from the solar system and galaxy

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as a whole. This puzzle may mean that the sun has moved out of the region

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where it formed, or that some of the oxygen has been captured by dust

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in interstellar space.

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New narrator: New measurements by IBEX have suggested that there is no bow shock to the

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heliosphere. The previous understanding of the boundary of the heliosphere was that

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outside the influence of the sun, a shockwave was formed by the entire

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heliosphere pushing through the interstellar material around it.

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New narrator: IBEX recently mapped the boundaries of the solar

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system's tail, called the heliotail. If we could look straight down the tail

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we would see a shape a little like a four-leaf clover.

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The two side leaves are filled with slow-moving particles, and the upper and

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lower leaves with fast ones. The entire shape is rotated slightly.

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This indicates that as it moves farther away from the sun's magnetic

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influence, the charged particles have begun to be pulled into a new

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orientation, aligning with the magnetic field of the local galaxy.

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New narrator: Recent measurements of the interstellar wind

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by IBEX have shown that its direction has changed by about 7 degrees

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in only the last 40 years. While the cause of this shift

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is unknown, it may be telling us something about the changing conditions as we move

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through the Milky Way. New narrator: As IBEX

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continues to scan the edge of the sun's influence, who knows what other discoveries it will

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make? [Music]

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Beeping

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Beeping