Question 1: Define a dwarf planet and list two key features that distinguish it from a full-sized planet.

Answer: A dwarf planet is a celestial body that orbits the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a nearly round shape, but has not cleared its neighbouring region of other objects. Key features include: it is rounded in shape due to its gravity, and it shares its orbital zone with other objects.

Question 2: Explain why Pluto was reclassified from a planet to a dwarf planet in 2006.

Answer: Pluto was reclassified because it has not cleared its orbit of other debris and objects, which is a requirement for full planetary status according to the International Astronomical Union. It shares its orbital zone with other objects in the Kuiper Belt.

Question 3: Identify two dwarf planets in our Solar System other than Pluto.

Answer: Haumea and Makemake.

Question 4: Multiple Choice: Which of the following is NOT a characteristic of a dwarf planet?

Answer: It has cleared its orbital neighbourhood.

Question 5: Fill in the blank: The primary reason Pluto was classified as a dwarf planet rather than a full-sized planet is because it has not ____________ its orbital zone.

Answer: cleared

Question 6: Calculate the gravitational force between Pluto and its largest moon, Charon, given that Pluto's mass is approximately 1.31 x 10^22 kg, Charon's mass is about 1.52 x 10^21 kg, and the average distance between them is 1.96 x 10^7 meters. Use Newton's law of gravitation: F = G * (m1 * m2) / r^2, where G = 6.674 x 10^-11 N m^2/kg^2.

Answer: F = (6.674 x 10^-11) * (1.31 x 10^22) * (1.52 x 10^21) / (1.96 x 10^7)^2; F ≈ 2.41 Newtons

Question 7: Describe a scientific method that could be used to determine whether a celestial body is a dwarf planet or a full-sized planet. Include the key variables that need to be measured.

Answer: A scientific method involves measuring the body's mass and size to determine its shape and gravitational influence. Key variables include mass (via orbital dynamics or gravitational interactions), radius (via telescopic observations or radar), and the body's orbit (to assess if it has cleared its orbital zone). By comparing these measurements to the criteria for planets and dwarf planets, scientists can classify the celestial body accurately.

Question 8: Analyse how the presence of dwarf planets impacts our understanding of the formation and evolution of the Solar System.

Answer: The discovery and study of dwarf planets like Pluto, Haumea, and Makemake suggest that the Solar System's formation involved numerous small bodies that did not clear their orbits. This challenges the earlier view that only a few large planets shaped the Solar System. Dwarf planets provide evidence of the diversity and complexity of planetary formation processes, indicating that many small objects can share the same space, influencing theories about accretion, collision, and orbital dynamics.

Question 9: Considering current space exploration technologies, discuss one method by which scientists could collect data on a dwarf planet's surface and composition.

Answer: One method involves sending a robotic spacecraft equipped with spectrometers and imaging instruments to orbit or land on the dwarf planet. The spacecraft can analyse surface composition through spectroscopic readings, which identify minerals and ices. It can also capture high-resolution images for surface mapping. Data transmitted back to Earth helps scientists understand the dwarf planet's geology and history.