Rare Simultaneous Mercury and Venus Transits Will Occur July 26, 69163

Summary: Computer programmer John Walker finds that rare simultaneous Mercury and Venus transits will occur July 26, 69163.

Mercury's May 9, 2016, transit (left); Venus's June 5-6, 2012, transit; images captured by NASA's Solar Dynamics Observatory (SDO); Mercury transit, public domain, via NASA Goddard Space Flight Center's SDO; Venus transit, CC BY 2.0, via NASA Goddard Space Flight Center/Flickr

On his website, Fourmilab Switzerland, computer programmer John Walker shares that rare simultaneous Mercury and Venus transits, in front of the sun and visible from Earth, will occur July 26, 69163.

The back-to-back transits of Mercury, Wednesday, May 7, 2003, and Venus, Tuesday, June 8, 2004, triggered a complicated question for John Walker.

The co-founder of Autodesk Inc., an American multinational software corporation, wondered: “Is there ever a simultaneous transit of Mercury and Venus visible from Earth?”

The passage in front of the solar disc, by a planet nearer to the sun, that is visible to a more distant planet occasions a planetary transit. Only planetary transits by Mercury and Venus are visible to Earth-based observers.

Walker's tantalizing question superficially may seem an impossibility. Presently, Mercury's transits happen in May and November. Venus's transits occur in June and December.

The bigger view, however, considers the evolution of planets' orbits over time. So Walker began his search for the proposed, exceptionally rare event of simultaneous Mercury and Venus transits within the framework of a quarter-million years beginning with the Common Era.

During his investigations, Walker discovered that astronomical algorithm expert Jean Meeus (born Dec. 12, 1928) and numerical integration expert Aldo Vitagliano had posed the same question and had already found the answer. By continuing his own research, with reference to high-precision numerical integration expert Stephen L. “Steve” Moshier's code for the solar system, Walker arrived at an independent confirmation of Meeus and Vitagliano's results.

Walker shares that astronomers know the date, according to barycentric dynamic time (TDB), as Julian day 26982533. The relativistic coordinate time scale takes into account time dilation in calculating ephemerides, or astronomical positions, and orbits for solar system objects.

Walker notes that the rare simultaneous Mercury and Venus transits are, indeed, highly unusual. The event's uniqueness is logged at once in a quarter-million years.

The rare simultaneity of the Mercury and Venus transits July 26, 69163, does not last long. Venus's transit begins before Mercury's transit. Venus's transit, which takes place across the solar disc's lower quarter, lasts 6 hours 43 minutes. Mercury's transit, which passes through the crescent of the solar disc's bottom limb, or edge, lasts 2 hours 24 minutes. Simultaneity endures for 43 minutes, from 19:12 to 19:55 Coordinated Universal Time (3:12 to 3:55 p.m. Eastern Daylight Time).

Four contact points mark the progress of planetary transits. The first two, Contacts I and II, pinpoint initial external and internal adjacencies. Contact I identifies initial external adjacency of the planet's leading edge to the solar disc's outside limb. Contact II marks initial internal adjacency of the planet's trailing edge to the solar disc's inside limb.

The second set of contact points pinpoints final internal and external adjacencies on the solar disc's opposite side. Contact III registers internal adjacency of the planet's leading edge to the solar disc's inside limb. Contact IV indicates external adjacency of the planet's trailing edge to the solar disc's outside limb.

Venus's transit begins with Contact I at 13:12 UTC (9:12 a.m. EDT). Contact II occurs at 13:27 UTC (9:27 a.m. EDT).

Mercury's transit begins with Contact I at 19:12 UTC (3:12 p.m. EDT). Contact II takes place at 19:27 UTC (3:27 p.m. EDT).

At 19:41 UTC (3:41 p.m. EDT), 14 minutes after Mercury's clocking of Contact II, Venus reaches Contact III.

At 19:55 UTC (3:55 p.m. EDT), Venus clocks Contact IV.

One hour 27 minutes later, at 21:22 UTC (5:22 p.m. EDT), Mercury registers Contact III.

Fourteen minutes later, at 21:36 UTC (5:36 p.m. EDT), Mercury reaches Contact IV.

The search for the rare simultaneous Mercury and Venus transits, conducted independently by the Meeus-Vitagliano and Walker-Moshier teams, yielded a positive result. The event's rarity, however, precludes the satisfaction of its occurrence within the researchers' lifetimes.

The takeaway for the rare simultaneous Mercury and Venus transits that will occur July 26, 69163, is the hope that, in the farthest reaches of future time, there will be Earthlings who will look upon the rare event, with proper solar filters, and be amazed by the once-in-a-quarter-million-years' phenomenon.

simultaneous Mercury and Venus transits, July 26, 69163: John Walker, Public Domain, via Fourmilab Switzerland

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Mercury's May 9, 2016, solar transit; NASA’s Solar Dynamics Observatory image taken in wavelength of extreme ultraviolet light: NASA Solar Dynamics Observatory, Public Domain, via NASA Goddard Space Flight Center’s Solar Dynamics Observatory @ http://sdo.gsfc.nasa.gov/gallery/potw/item/713

ultra high-definition image of Venus's June 5 to 6, 2012 transit; image captured June 6; NASA's Solar Dynamics Observatory (SDO)/NASA Goddard Space Flight Center, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/gsfc/7343985500/

simultaneous Mercury and Venus transits, July 26, 69163: John Walker, Public Domain, via Fourmilab Switzerland @ http://www.fourmilab.ch/documents/canon_transits/movies/a26982532.gif

For further information:

Marriner, Derdriu. "After May 9, 2016, Next Mercury Solar Transit Happens November 2019." Earth and Space News. Wednesday, May 18, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/05/after-may-9-2016-next-mercury-solar.html

Marriner, Derdriu. "May 9, 2016, Mercury Solar Transit Takes Seven and One-Half Hours." Earth and Space News. Wednesday, May 4, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/05/may-9-2016-mercury-solar-transit-takes.html

Meeus, Jean; Aldo Vitagliano. “Simultaneous Transits.” The Journal of the British Astronomical Association, vol. 114, no. 3 (June 2004).

Moshier, Steve. “Numerical Integration of Sun, Moon, and Planets.” Steve Moshier.net: Astronomy and Numerical Software Source Codes.
Available @ http://www.moshier.net/ssystem.html

Reim, Bernie. “What's Up in May?” Skylights: Newsletter of the Astronomical Society of Northern New England (ASNNE). May 2016.
Available @ http://www.asnne.org/skylights/MAY2016.pdf

Sinnott, Roger W. "Will Mercury and Venus Ever Transit the Sun Simultaneously?" Sky and Telescope > Astronomy Resources > Astronomy Q&A. July 19, 2006.
Available @ http://www.skyandtelescope.com/astronomy-resources/astronomy-questions-answers/will-mercury-and-venus-ever-transit-the-sun-simultaneously/

“Systems of Time.” United States Naval Observatory Time Service Department.
Available @ http://tycho.usno.navy.mil/systime.html

Walker, John. “Calendar Converter.” Fourmilab Switzerland. September MMXV (2015).
Available @ https://www.fourmilab.ch/documents/calendar/

Walker, John. “Quarter Million Year Canon of Solar System Transits.” Fourmilab Switzerland.
Available @ http://www.fourmilab.ch/documents/canon_transits/

Walker, John. “Sic Transit Glorious Venus: Transit of Venus June 8th, 2004.” Fourmilab Switzerland > Images. June 8, 2004. Revised June 23, 26, 2006.
Available @ http://www.fourmilab.ch/images/venus_transit_2004/

Walker, John. “Transit of Mercury May 7th, 2003.” Fourmilab Switzerland > Images. May 2003.
Available @ http://www.fourmilab.ch/images/mercury_transit_2003/

Webb, Brian. “Coordinated Universal Time.” Space Archive.
Available @ http://spacearchive.info/utc.htm