05/19/2020 – Ephemeris – Venus will leave the evening sky in 15 days

This is Ephemeris for Tuesday, May 19th. Today the Sun will be up for 14 hours and 59 minutes, setting at 9:09, and it will rise tomorrow at 6:08. The Moon, 3 days before new, will rise at 5:25 tomorrow morning.

In 15 days Venus will leave the evening sky by passing between the Earth and the Sun in what astronomers call an inferior conjunction. Eight years ago, June 6th 2012, Venus went through another inferior conjunction. That time it passed directly between the Earth and the Sun so we could see the black spot that was Venus cross the face of the Sun as a rare Transit of Venus. Eight years before that, on June 8th 2004, we had another transit. However we will not see another in our lifetimes. The next one will occur in 2117. With the June 3rd conjunction Venus will pass north of the Sun from our vantage point, since Venus’ orbit is tilted a bit more than 3 degrees to the Earth’s orbit. So enjoy Venus while you can, unless you want to get up really early next month.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Transits of Venus-Two hits and a miss. Image created using Cartes du Ciel (Sky Charts).

Earth and Venus have a 13:8 orbital resonance.  That is Venus orbits the Sun 13 times in the same time that the Earth orbits the Sun  8 times. So Venus has the same position in our skies it had 8 years ago.  Actually the resonance is not perfect The resonance comes out 2.4 days short. So events like inferior conjunctions like the ones in the example above back track two and a fraction days from the 8 year interval.

Venus goes through a 584 day cycle from one inferior conjunction to the next.  Five of those cycles equals 7.994 years. The Maya were well aware of this and one of their calendars was based on the Venus-Earth relationship.