Why does Venus have its largest angular diameter when it is new and its smallest angular diameter when it is full?
2007-09-19 07:11:32 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Venus is in an orbit closer to the Sun than Earth's. That means that from our point of view it has to be on the opposite side of the Sun from us to appear fully illuminated, and between us and the Sun to appear new. Since it is closer by millions of miles when new, it appears substantially larger in angular diameter than when it is full.
2007-09-19 09:44:43 · answer #1 · answered by Jason T 7 · 1⤊ 0⤋
The terms "new" and "full" are used only for the Moon, and not for Venus. The proper term for when Venus is between the Sun and the Earth is "inferior conjunction." At that time (August 18, 2007 is the most recent), Venus is at its closest to Earth, and so is at its largest. It is lit from behind by the Sun, so is equivalent to the appearance of our Moon at New Moon. Venus then moves to greatest elongation west on October 28, when it appears 50% illuminated, similar to a Last Quarter Moon. Next it moves to the far side of the Sun relative to the Earth, called "superior conjunction," on June 8. At that time it is farthest from the Earth, and it appears "full." Then it moves to greatest elongation east in January 2009, when it will look like a First Quarter Moon, and finally back to inferior conjunction on March 27 2009.
Notice that Venus goes through its phases in reverse order compared to the phases of the Moon: "new, " "third quarter," "full," "first quarter." That's because it is in orbit around the Sun, not the Earth, and is closer to the Sun than the Earth. We're on the outside looking in.
2007-09-21 03:16:10 · answer #2 · answered by GeoffG 7 · 0⤊ 0⤋
Ceres is now no longer categorized as an asteroid, that could be a dwarf planet in accordance to the sturdy IAU designation, after all, the optimal angular diameter may be counted on the kit used to video exhibit it, the Keck telescopes besides by using fact the HST have detected floor helpful properties
2016-12-26 18:25:00 · answer #3 · answered by Anonymous · 0⤊ 0⤋
When Venus is full then it is on the opposite side of the Sun from the Earth. It is at its furthest point from the Earth and therefore looks smaller. When it is new, it is between the Earth and the Sun and is much much closer to the Earth.
2007-09-19 07:24:29 · answer #4 · answered by luvlaketahoe 4 · 0⤊ 0⤋
When it's new, that means it's between the sun and the earth, i.,e, closest to us. When it's full it's on the opposite side of the sun from earth, i.e., farthest away.
2007-09-19 07:23:13 · answer #5 · answered by alan_has_bean 4 · 1⤊ 0⤋
Addendum:
Venus is the ball, so it looks full for us when the sun shines on it in the direction of our look. This is when it is at the other side of the Sun.
2007-09-19 12:32:32 · answer #6 · answered by Dims 2 · 0⤊ 0⤋