why does the size of venus appear to change
Two reasons. First, Venus and we are in our own orbits around the Sun. Now Venus and we are on the same side of the sun - we re close together. Then. Two reasons. First, Venus and we are in our own orbits around the Sun. Now Venus and we are on the same side of the sun - we re close together. Then Venus is on the other side of the Sun in her own orbit - we re much farther away and Venus looks smaller. Second, Venus goes through phases just like the Moon.
When she is showing a nearly full disc (a Full Venus? ) she will appear brighter. When she is showing a slender crescent she will reflect less light and look smaller. It is the balance between these two factors which make Venus appear to change in size.
The phases of Venus result from the planet's around the inside the 's orbit giving the observer a sequence of progressive lighting similar in appearance to the. It presents a full image when it is on the opposite side of the Sun.
It shows a quarter phase when it is at its maximum from the Sun. Venus presents a thin crescent in telescopic views as it comes around to the near side between the Earth and the Sun and presents its new phase when it is between the Earth and the Sun. Since the planet has an atmosphere it 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 (the time it takes Venus to overtake the Earth in its orbit).
The planet also changes in apparent size from 9. 9 at full ( ) up to a maximum of 68 arc seconds at new ( ). Venus reaches its greatest of 4. 5 when it is an intermediate crescent shape at the point in its orbit, when it is 68 million km away from the Earth (a combination of its closeness and the fact that it is 28% illuminated).
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