Hi everyone. One of the many joys in astronomy is watching the bright planet Venus grace either the evening or morning skies. All last summer, I watched her brilliance beam above the treetops towards the west.
On October 26th of 2018, Venus reached inferior conjunction; meaning, it got very close to the Sun (as seen from Earth), and thus, impossible to see (as shown in this graphic).
This photograph was taken on October 26th showing Venus as a very thin crescent. Being that we are the third planet from the Sun, we are basically seeing the backside of our sister planet at this particular time.
As we moved into the month of November with us now greeting Venus in the morning sky towards the east. Venus is now climbing higher and higher, rapidly, into the skies during the months of November and December with Venus reaching its highest on December 23rd at some 30 degrees above the horizon!
As the New Year begins, we see Venus beginning to head back towards the horizon which it will do throughout the first half of 2019. Venus will reach superior conjunction, or on the far side of the Sun, on August 14th.
So let’s animate the days from October to July. As you can see, the stars arc towards the upper right of the screen, with Venus and Mercury having their own separate motions. This is over a time-period of 274 days.
Now let us look under the hood (so to speak). Let’s strip away the trees and lake and ground so we can see what is going on.
We can see Venus moving rapidly up into the sky along with two outer planets – Jupiter and Saturn. In two instances, we see Mercury making brief appearances in the morning sky near the horizon. We see the crescent Moon moving across quite rapidly at thirty day intervals.
Now let me add the dotted paths and labels to Mercury and Venus so you can get a better appreciation of what is going on during the morning twilight.
The Sun, over this time span, will move from right, then left, and then slightly right again horizontally below the horizon. Each frame of animation of the Sun is set at exactly 30 minutes before sunrise.
So why are the inner planets moving across the morning sky the way they are?
Because they orbit the Sun! The red ring is the orbital path of Mercury, and the orbital path for Venus is the white outer ring. Both planets are moving away from us while Earth is following along at a slower speed.
My viewing location is 37 degrees north latitude, so I am looking at Venus and Mercury from at an angle here on Earth. Again, the two inner planets are pulling away from us, because they are moving faster than we are as we orbit the Sun in the same direction.
Nothing complicated about this! All planets in our solar system orbit the Sun. We, here on Earth, just follow along and enjoy the view!