Deimos

Definition

Deimos is one of the two moons of the planet Mars. It is the smaller and outermost of the two Martian moons, orbiting the planet at a distance of about 23,460 km from the Martian surface. Deimos is a small, irregularly shaped celestial body that has a diameter of just 12.4 km, making it one of the smallest moons in the Solar System.

5 Must Know Facts For Your Next Test

1. Deimos has a very slow rotation, taking 30.3 hours to complete one full rotation on its axis.
2. The low gravity on Deimos, just 0.0003 times that of Earth's, makes it difficult for the moon to retain an atmosphere.
3. Deimos is believed to be composed primarily of rock and ice, with a dark, reddish-grey surface that is heavily cratered.
4. The origin of Deimos and Phobos is still a topic of debate, with some scientists suggesting they may be captured asteroids.
5. Deimos is the smaller of the two Martian moons, with a diameter of just 12.4 km, compared to Phobos' 22.2 km diameter.

Review Questions

• Describe the key characteristics of Deimos, the smaller of the two Martian moons.
  • Deimos is the smaller and outermost of the two moons of Mars, orbiting the planet at a distance of about 23,460 km from the Martian surface. It is a small, irregularly shaped celestial body with a diameter of just 12.4 km, making it one of the smallest moons in the Solar System. Deimos has a very slow rotation, taking 30.3 hours to complete one full rotation on its axis, and its low gravity of just 0.0003 times that of Earth's makes it difficult for the moon to retain an atmosphere. Deimos is believed to be composed primarily of rock and ice, with a dark, reddish-grey surface that is heavily cratered.
• Explain the relationship between the Martian moons, Phobos and Deimos, and their potential impact on the planet's geology and atmosphere.
  • Phobos and Deimos, the two natural satellites of Mars, are believed to be captured asteroids that orbit the planet at relatively close distances. The gravitational forces exerted by these moons on the Martian surface can lead to tidal effects, which can have an impact on the planet's geology and atmosphere. For example, the tidal forces from Phobos, the larger and closer moon, are strong enough to cause slight bulges in the Martian surface, and may even be slowly causing the moon to spiral inward towards the planet. The interactions between the Martian moons and the planet's environment are an area of ongoing research and study.
• Discuss the current theories regarding the origin of the Martian moons, Phobos and Deimos, and how this relates to our understanding of the formation and evolution of the Solar System.
  • The origin of Phobos and Deimos, the two moons of Mars, is still a topic of debate among scientists. One of the leading theories suggests that they may be captured asteroids, which would mean they were not formed along with the planet itself but rather were attracted and pulled into orbit around Mars at some point in the past. This theory is supported by the small size, irregular shape, and composition of the moons, which are similar to that of many asteroids found in the asteroid belt between Mars and Jupiter. The presence of these captured moons around Mars provides valuable insights into the processes that shaped the formation and evolution of the Solar System, as it suggests that the capture of small celestial bodies by larger planets may have been a relatively common occurrence. Understanding the origins of the Martian moons can therefore contribute to our broader knowledge of the complex dynamics that have influenced the development of the Solar System over billions of years.

Related terms

Phobos: Phobos is the larger and innermost of the two Martian moons, orbiting Mars at a distance of just 9,377 km from the planet's surface.

Martian Moons: Mars has two natural satellites, Phobos and Deimos, which are small, irregularly shaped celestial bodies believed to be captured asteroids.

Tidal Forces: The gravitational forces exerted by Phobos and Deimos on the Martian surface can lead to tidal effects, which can have an impact on the planet's geology and atmosphere.