Halley's comet

Halley's Comet

Summary
To understand the orbital characteristics of Halley's comet.

Background and Theory
Some of you may have seen Halley's comet when it sped past perihelion in 1986. This encounter was not very good as the comet was on the other side of the Sun at perihelion. Now, as Halley's comet makes its way towards the outer solar system, it is very hard to see, even with the largest telescopes.

Procedure

  1. Define briefly each of the following terms:
    1. perihelion

    2. aphelion

    3. prograde

    4. retrograde

    5. gas tail

    6. dust tail

    7. period (of an orbit)

  2. The diagram below shows the path of Halley's comet through the solar system. The diagram shows the solar system "looking down from North". The dates on the diagram correspond to the position of Halley's comet at different times. Use the information in the diagram to answer the questions.

  3. What is the approximate period of Halley's comet?

  4. Does the comet move at uniform speed at all times?

  5. Why or why not? (Be specific)

     

  6. Indicate on the diagram where the comet is moving at its fastest speed, and where it is moving at its slowest speed.

  7. Is its motion prorade or retrograde?

  8. In approximately what year will it again be at aphelion?

  9. In what year will it be at its next perihelion?

  10. How old will you be then?

  11. For each of the locations shown in the diagram, sketch the positions of the gas and dust tails, if the comet were to have them at that location.

  12. Mark on the diagram where Halley's comet is today.

  13. Do you think Halley's comet has any tails now?

  14. Why or why not? (Again, be specific.)