Which statement is true about the motion of planets in the solar system?
A.
The sun is at one focus of each planet's elliptical orbit.
B.
The sun is at the exact center of each planet's elliptical orbit.
C.
The speed of a planet's elliptical orbit is proportional to its mass.
D.
The planets have circular orbits around the Sun.
A. The sun is at one focus of each planet's elliptical orbit.
A. The sun is at one focus of each planet's elliptical orbit.
To determine which statement is true about the motion of planets in the solar system, we need to have a basic understanding of planetary motion.
The correct statement is A. The sun is at one focus of each planet's elliptical orbit.
This statement refers to Kepler's first law of planetary motion, also known as the law of ellipses. An ellipse is a shape similar to a stretched-out circle with two foci. According to Kepler's first law, the sun is located at one of the foci of each planet's elliptical orbit.
To arrive at this answer, you could have eliminated options B and C. Option B suggests that the sun is at the exact center of each planet's elliptical orbit, but in reality, it is only at one focus. Option C states that the speed of a planet's elliptical orbit is proportional to its mass, which is incorrect. The speed of a planet's orbit is influenced by factors such as its distance from the sun, but not its mass.
Option D suggests that the planets have circular orbits around the sun. While it is a common misconception, in reality, most planets in the solar system have elliptical orbits rather than perfectly circular orbits.
Therefore, the correct answer is A.