Kuiper Belt:

The Kuiper (pronounced Ki-Per) Belt is often called our Solar System's 'final frontier.' This disk-shaped region of icy debris is about 4.5 to 7.5 billion km (2.8 billion to 4.6 billion miles), 30 to 50 Astronomical Units (AU). from our Sun. Its existence confirmed only a decade ago, the Kuiper Belt and its collection of icy objects - KBOs - are an emerging area of research in planetary science.

No spacecraft has ever traveled to the Kuiper Belt, but NASA's New Horizons mission, planned to arrive at Pluto in 2015, might be able to penetrate farther into the Kuiper Belt to study one of these mysterious objects.

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