L4 Speaking Task # 1

Opened: Thursday, 7 April 2016, 1:00 AM
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L4 Speaking Task # 1

Directions: (read first)

  1. Begin by reading the passage in the box below. Do not exceed 45 seconds. You can use the clock on the right to time yourself.

  2. Next listen to a lecture about the topic in the passage by clicking the start button in the recording section below. You may take notes as you listen.

  3. Then record your response by clicking the "Add Submission" button at the bottom of the page.

  4. If you get a Flash permission message, check "Allow" and "Close".

  5. Next, click the "Record" button and begin speaking. You will have 60 seconds for your response. You may need to click "Stop" when you have finished.

  6. Finally, click the "Save Changes" button at the bottom to upload your recording for grading and teacher comments.

When you are ready, put on your headset and click the start button on the audio player here to begin this speaking task.

Classification of Planets

The International Astronomical Union (IAU) has been responsible for the naming and nomenclature of planetary bodies and their satellites since the early 1900s. The IAU decided to create a committee to gather opinions from a broad range of scientific interests, with input from professional astronomers, planetary scientists, historians, science publishers, writers and educators.

The Planet Definition Committee of the IAU Executive Committee was formed to prepare a first draft. This first draft proposal focusing on the definition of a planet was debated vigorously by astronomers at the 2006 IAU General Assembly in Prague. Following much discusson, a new version was put to the members of the IAU for a vote at the Closing Ceremony on the 24 August 2006.

By the end of the Prague General Assembly, its members voted that the definition of a planet in the Solar System would be as follows: A celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.

The Solar System officially consists of eight planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A new distinct class of objects called dwarf planets was also decided on. Planets and dwarf planets are two distinct classes of objects. The first members of the dwarf planet category are Ceres, Pluto and Eris. The dwarf planet Pluto is recognized as an important prototype of a new class of Trans-Neptunian Objects. The IAU has given a new denomination for these objects: plutoids.