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Asteroids_and_Comets_Notes Powered By Docstoc
					              Name: _________________________________________ Period: __________
                      Solar System Debris: Keys to Our Origin?
   • ______________________ - any of the small rocky celestial bodies found especially
      between the orbits of Mars and Jupiter

   •   ______________________ - small particles of solar system matter that are observable
       on entry into the atmosphere

   •   ______________________ - meteor that reaches the surface of the earth

   •   ______________________ - sand to boulder-sized particle of debris in the Solar

Inner Solar System

About ______________________ have been identified so far.
Three largest:

                           940 km

                           580 km

                           540 km

Ceres and Vesta

_______________________ shows evidence of volcanism; the reason is not understood.

Solar System Debris                                                        Page 1 of 4
               Name: _________________________________________ Period: __________
                       Solar System Debris: Keys to Our Origin?
Asteroids are classified in types:
    _______________________: carbonaceous, dark

      _______________________: silicate (rocky)

     _______________________: metallic; iron and nickel
C-type asteroid Mathilde
     The NEAR spacecraft visited the C-type asteroid Mathilde, on its way to its main target,
       Eros. Mathilde, like many other asteroids, has a very _______________________, and
       is probably not _______________________.
S-type Asteroids
     Two small S-type asteroids, Gaspra and Ida, were visited by the Galileo probe. Gaspra
       (left) is in false color; it is really gray. Note that Ida (right) has a small moon, Dactyl:
Apollo Asteroids
     Some asteroids have orbits so _______________________ that they cross Earth’s orbit.
       They are called _______________________ asteroids, and raise the concern of a
       possible collision.
     2600 such asteroids have been discovered so far, of which about
       _______________________ have been designated as potentially hazardous, due to
       their size.
Trojan Asteroids
     Some asteroids, called _______________________, orbit at the L4 and L5 Lagrangian
       points of Jupiter’s orbit:
     Lagrangian points – places where the gravity of the Sun and a planet ______________
K-T Boundary

   •   ______________million years old

   •   Found around the ______________

   •   ____________ rich

   • No ____________________________above this level
Impact Site
   • ____________________________Crater in the Yucatan
   • Now filled in with mud and debris
   • Crater found using ground penetrating ____________________________
   • associated with a given comet intersects Earth's orbit at specific locations,
   • giving rise to meteor showers at certain fixed times of the year
Meteor Showers
   • associated with a given comet intersects _______________________at specific
   • giving rise to meteor showers at certain fixed ____________________________

Solar System Debris                                                              Page 2 of 4
                  Name: _________________________________________ Period: __________
                          Solar System Debris: Keys to Our Origin?
Meteor Showers 2011
Name                 Date of Peak                  Moon
                           night of January 3                    New

                               night of April 21         Rises after midnight
  Eta Aquarids
                               night of May 5            Sets in early evening

                           night of August 13                    Full
                           night of October 8           Sets around midnight
                          night of October 21            Rises after midnight

                         night of November 17           Rises around midnight
                         night of December 13                Just past full
Comet Structure
   Comets have a very small _______________________,
   a _______________________of gas and dust that is the most visible part and can be
      very large,
   a _______________________envelope,
   a _______________________tail, and an _______________________tail.
   The comet’s _______________________always points away from the sun, due to the
        The ion tail is _______________________than the dust tail.
        Comets have very _______________________orbits.
        _______________________comets have periods of hundreds of thousands, or even
         millions, of years.
        _______________________comets are less common, and have periods of less than 200
        _______________________is one of the most famous; it has a period of _____years
         and has been observed since antiquity. Its most recent visit, in 1986, was not

Solar System Debris                                                              Page 3 of 4
              Name: _________________________________________ Period: __________
                      Solar System Debris: Keys to Our Origin?
      _______________________has a shorter period than most comets, but its
       _______________________is not in the plane of the solar system, probably due to an
       encounter with a larger object.
     Typical cometary mass: ________________ kg
     Each trip close to the Sun removes some material;
     Halley’s comet, for example, is expected to last about another ________________
   Sometimes a comet’s ________________ can ________________ violently
Comet Resevoirs

      No objects have been observed in the ____________________ – it is simply too far
      However, some _________________________objects (KBOs) have been observed –
       over 1000 so far.

Solar System Debris                                                       Page 4 of 4