The volatile nucleus of the comet Tempel 1 blows off a stream of dust that was captured in these transition sequence images by the Hubble Space Telescope, scientists said June 27, 2005. The dust jet could be a preview of what astronomers see on July 4, when NASA's Deep Impact space probe is set to collide with the comet, giving the first glimpse inside the heart of a comet, the scientists said in a statement. (Photo: Yahoo)

    BEIJING, June 28 -- NASA scientists have planned a spectacular celestial show for July 4th. That's the date on which a probe from the Deep Impact spacecraft is scheduled to slam into Comet Tempel 1 in an attempt to learn more about the comet's billion-year-old interior.

    New images snapped by the Hubble Space Telescope are giving researchers a sneak peak at what type of conditions they might find.

    The two images snapped by Hubble were taken seven hours apart on June 14, showing a plume of dust spewing from the comet toward the sun. One shows a view of the comet before the outburst; the other shows the jet, which extends about 1,400 miles (2,200 km). The dust jet could be a preview of what astronomers see on July 4.

    The NASA team hopes the close encounter next week will provide new insight into Tempel 1's core, as well as "lead to a better understanding of both the solar system's formation and the implications of comets colliding with Earth", as the smashup will release more primordial material trapped inside the comet, which formed billions of years ago.

    The crash landing on Tempel 1 will not change the comet's orbital path, but it should leave a crater that is between two and 14 stories deep and at least as wide as a house. The collision is scheduled for 1:52 a.m. EST on July 4.

    (Agencies)