Question

1. At what phase does the Earth appear to be in, as seen from Venus during each of its phases in heliocentric theory? Now in general, compare the phases exhibited by an inner planet to those exhibited by an outer planet in the heliocentric theory.
2. Venus takes 225 days to go around the Sun; yet Venus takes more than 225 days to go from one new phase to the next new phase as seen from the Earth. Why is this?

3. Why Venus changes in sizes from one phase to the next?

4. Does the Geocentric theory can explain this size change? Explain your answer.

5. Using this exercise and the previous one, which theory, the Heliocentricor the Geocentricone is favored with these observations. Why?

I need help with these questions. Thanks in advance.

Answer 1

1.As the planet Venus moves around its orbit, it displays phases like those of the Moon: it is new when it passes between the Earth and the Sun, small and full when it is on the opposite side of the Sun, and a half-phase when it is at its maximum elongations from the Sun. Venus brightest when it is a large but thin crescent and much closer to the Earth.

2.Venus has an atmosphere that can be seen at new in a telescope by the halo of light refracted around the planet. The full cycle from new to full to new again takes 584 days.because it is very closer to the sun than earth.

3.When venus is on the opposite side of the sun from the Earth, it appears full (or nearly so) and rather small because it is far away. But because venus moves with a greater velocity around the sun than the Earth, it gradually gets closer and looms progressively larger in apparent size.

4.The geocentric model of Ptolemy predicted that only crescent and new phases would be seen, since Venus was thought to remain between the Sun and Earth during its orbit around the Earth.

5.The heliocentric theory of the solar system developed by Copernicus predicted that all phases would be visible since the orbit of Venus around the Sun would cause its illuminated hemisphere to face the Earth when it was on the opposite side of the Sun and to face away from the Earth when it was on the Earth-side of the Sun. Galileo's observations of the phases of Venus proved that it orbited the Sun and lent support to the heliocentric theory.