2000 SPACE SCIENCE VIDEOTAPES |
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Tape Title | Record ID | Date Produced | TRT: |
Synopsis |
| AGE OF COMETS | G00-065 | 07/19/00 | 00:03:15 | If you've seen one comet, you've seen them all, right? According to recent research, comets could have formed at different times during the evolution of the solar nebula, and may reveal their age by the structure of their dust grains. If true, NASA may be able to "time travel" though different epochs of the solar system's formation by visiting comets that formed during different periods.
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TAPE CONTENTS: |
| ITEM (1): Comet Hale-Bopp - Comets are frozen relics, or 'dirty snowballs' comprised of gas and dust that are among the oldest in the solar system. As they formed, dust from the evolving solar nebula was incorporated into the ice that comprises the comet. They reside in the Kuiper Belt and Oort Cloud (beyond Neptune and cloud surrounding the solar system, respectively) and are occasionally sent tumbling into space by a nearby object or star. Once there, solar heat and light vaporize the gas and liberates dust from the comet's surface, giving it its tail. As seen here, comets often have two tails: the pale yellow is the dust tail and the blue is the gas tail.
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| ITEM (2): Comet Animation - NASA scientists have found two kinds of dust grains: amorphous (grains with haphazardly placed molecules) and crystalline (orderly structure). They believe the comets with amorphous grains are older, because in order to become crystalline, the grain would have to be heated by the Sun. Those with amorphous dust were formed before the Sun had time to heat and distribute much crystalline dust.
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| ITEM (3): STARDUST Animation - Stardust is a NASA mission that will collect comet dust and interstellar dust particles when it meets up with Comet Wild 2 in 2004. Launched in 1999, it began collecting interstellar dust in February and will return to Earth with its data in 2006.
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