Conjunction Functions
Venus is ending its several month run as our morning star. Earth’s nearest planetary neighbor hangs very low in the southeast just before sunrise. It will be “too close to the Sun” to view safely in several weeks.
What do we mean when we say “too close to the Sun”? Astronomers throw this term around often, but it can be misleading to the public.
Nothing is actually moving closer to the Sun.
We call it a conjunction when the Sun, Moon, or planets appear visually close together in the sky. Remember that we are looking into three-dimensional space. We perceive only two dimensions: left-right and updown. The third dimension of depth is not evident.
Right now,Venus and Mars are just past a conjunction and appear very close together visually. However, we know that they are always at least 70 million miles apart. That distance between them is not evident to the observer.
All of the planets have a close conjunction with the Sun each year. Currently, Mercury and Saturn are in conjunction just visually at the bottom of the Sun. The important thing to remember is we cannot safely observe objects in conjunction with the Sun!
Venus reaches the point called superior conjunction on June 4 when it is directly behind the Sun when observed from Earth. After that, Venus returns to the western sky at sunset for the rest of 2024.
Mercury and Venus have superior conjunctions when they appear behind the Sun. These two planets also experience inferior conjunctions when they are directly between the Earth and the Sun. All the other planets can only experience superior conjunctions, as they never pass between the Earth and the Sun!
Venus and Mercury orbit between the Earth and the Sun. This means they rise and set in the east and the west over several months. All the other planets only rise in the east and set in the west.
When Venus and Mercury approach superior conjunction, they move toward the eastern horizon in the morning sky. Understanding their motion requires a lot of observation.
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