Question 1: Define a planet and explain the criteria used to classify an object as a planet in the Solar System.

Answer: A 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 hydrostatic equilibrium (nearly round) shape, and has cleared its orbit of other debris.

Question 2: List three key differences between terrestrial planets and gas giants.

Answer: Terrestrial planets are composed mainly of rock and metal, have solid surfaces, and are closer to the Sun. Gas giants are composed mainly of gases like hydrogen and helium, lack a solid surface, and are larger and further from the Sun.

Question 1: The average orbital radius of Earth is approximately 149.6 million km, and its orbital period is 365.25 days. Calculate Earth's orbital speed in km/s. (Use the formula: speed = distance / time).

Answer: Approximately 29.78 km/s

Question 2: Based on the data, which planet has the highest average surface temperature? Provide the approximate temperature and explain how its distance from the Sun influences this.

Answer: Venus, with an average surface temperature of about 464°C. Its proximity to the Sun and thick cloud cover with greenhouse gases trap heat, leading to higher temperatures.

Question 3: Identify which planet has the greatest mass and describe one method scientists use to determine planetary mass.

Answer: Jupiter has the greatest mass. Scientists determine planetary mass by observing the gravitational effects on other bodies, such as moons or spacecraft.

Question 4: The planet Mars has an average radius of approximately 3,390 km. Calculate its surface area using the formula: 4πr². Use π ≈ 3.14.

Answer: Approximately 143,700,000 km²

Question 1: Describe a basic experimental setup that could be used to measure the thermal radiation emitted by a planet's surface. Include variables that should be controlled.

Answer: A possible setup involves using a spectrometer or infrared sensor placed at a known distance from the planet. Variables such as distance, atmospheric conditions, and sensor calibration should be controlled to ensure accurate measurements of thermal radiation.

Question 2: Explain why understanding planetary atmospheres is crucial for future space missions and the potential for human colonisation.

Answer: Understanding planetary atmospheres helps assess the habitability, identify hazards, and develop life support systems. It informs decisions about landing sites, resource utilisation, and safety measures necessary for successful human colonisation.

Question 1: Discuss how data from planetary missions has contributed to advancements in satellite technology and telecommunications.

Answer: Data from planetary missions has improved satellite design, enabling better communication systems, navigation, and Earth observation. Technologies such as high-gain antennas, durable materials, and propulsion systems have been developed or refined through space exploration research.

Question 2: Explain how understanding planetary orbits and distances assists in planning interplanetary travel and satellite deployment.

Answer: Knowledge of planetary orbits and distances allows precise calculation of travel times, fuel requirements, and optimal launch windows. It helps in synchronising satellite orbits for communication networks and planning missions with minimal energy expenditure.