What Causes the Apparent Retrograde Motion of the Planets

question 114

Multiple Choice

What causes the apparent retrograde motion of the planets?

• A)As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change.
• B)Apparent retrograde motion is an illusion created by turbulence in Earth's atmosphere.
• C)As Earth passes another planet, its gravitational pull slows down the other planet so that it appears to be traveling backward.
• D)The other planets never really appear to move backward; the background stars shift due to Earth's revolution around the Sun.
• E)When planets are farther from the Sun, they move slower than when they are nearer the Sun; it is during this slower period that they appear to move backwards.

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Definitions:

Phylogenetic Systematics

A method of classifying organisms based on their evolutionary history and relationships, using phylogenetic trees.

Cladograms

A diagram used in cladistics which shows relations among organisms.

Molecular Clocks

Methods used to estimate the time of evolutionary events based on the hypothesis that genetic mutations accumulate at a predictable rate over time.

Fishlike Vertebrates

Aquatic animals featuring a backbone, including both true fish and fish-shaped species with similar living habitats and structures.