UNIVERSE
SURVEY OF THE PLANETS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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could be seen in the opposite direction of the Sun (at night)
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could be seen in the same direction as the Sun (during the day)
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are bigger than the Earth
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are made of gas, which makes them easier to see.
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Detailed explanation-1: -Thus, in the Copernican model the Sun was at the center, but the planets still executed uniform circular motion about it. As we shall see later, the orbits of the planets are not circles, they are actually ellipses.
Detailed explanation-2: -This retrograde motion was a great puzzle to ancient astronomers. Copernicus gave the correct explanation: all planets, including the Earth, move around the Sun in the same direction; retrograde motion is an illusion created when we observe other planets from the moving planet Earth.
Detailed explanation-3: -It’s an illusion, caused by the ways that Earth and Mars orbit the sun.
Detailed explanation-4: -When an inferior planet is on the opposing side of the Sun with respect to the Earth, the planet is in superior conjunction. Inferior and superior conjunctions occur only for inferior planets.
Detailed explanation-5: -Copernicus’s Theory Can Be Summarized Like This: 01-The center of the Earth is not the center of the Universe, only of Earth’s gravity and of the lunar sphere. 02-The Sun is fixed and all other spheres revolve around the Sun. (Copernicus retained the idea of spheres and of perfectly circular orbits.