GED Science TestEarth and Space ScienceMedium

A space agency is planning a mission to explore a newly discovered exoplanet. The exoplanet is described as having a thick atmosphere composed primarily of hydrogen and helium, with no solid surface, and a very strong magnetic field. Based on this description, which type of planet is it most likely to be?

  1. ATerrestrial planet (e.g., Earth, Mars)
  2. BDwarf planet (e.g., Pluto, Eris)
  3. CIce giant (e.g., Uranus, Neptune)
  4. DGas giant (e.g., Jupiter, Saturn)
Show answer & explanation

Correct answer: D. Gas giant (e.g., Jupiter, Saturn)

The description of a thick atmosphere of hydrogen and helium, no solid surface, and a strong magnetic field are all characteristic features of gas giant planets like Jupiter and Saturn in our own solar system.

Why the other options are wrong

  • A. Terrestrial planets have solid surfaces, thinner atmospheres (if any), and are primarily rocky.
  • B. Dwarf planets are smaller, have solid surfaces, and are typically icy/rocky, not gas-dominated.
  • C. While ice giants also lack a solid surface and have thick atmospheres, their primary composition includes heavier elements like water, methane, and ammonia ices.

Gas Giant Planets

Large planets primarily composed of hydrogen and helium, lacking a solid surface, and characterized by thick atmospheres and strong magnetic fields.

  • Examples: Jupiter and Saturn in our solar system.
  • Formed further from the sun where lighter elements were abundant.
  • Have many moons and ring systems.

Memory trick: Gas Giants: Gassy, Grand, and Gravitational.

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